Keyword Alert: desulfuricans

“You may never know what results come of your action, but if you do nothing there will be no result” -- Mahatma Gandhi (Indian Philosopher, internationally esteemed for his doctrine of nonviolent protest, 1869-1948)

Google® desulfuricans and one of the results is …

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Desulfovibrio is a genus of Gram-negative sulfate-reducing bacteria. Desulfovibrio species are commonly found in aquatic environments with high levels of organic material, as well as in water-logged soils, and form major community members of extreme oligotrophic habitats such as deep granitic fractured rock aquifers.
Like other sulfate-reducing bacteria, Desulfovibrio was long considered to be obligately anaerobic. This is not strictly correct: while growth may be limited, these bacteria can survive in O2-rich environments. These types of bacteria are known as aerotolerant.
Some Desulfovibrio species have in recent years been shown to have bioremediation potential for toxic radionuclides such as uranium by a reductive bioaccumulation process.
source: https://en.wikipedia.org/wiki/Desulfovibrio
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How did I identify this key word? I searched USPTO Patent Applications for desulfurization and browsed the results.  One of the results was …

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Microorganisms For Producing 1,4-Butanediol And Methods Related Thereto
Abstract
The invention provides non-naturally occurring microbial organisms comprising a 1,4-butanediol (BDO), 4-hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine pathway comprising at least one exogenous nucleic acid encoding a BDO, 4-hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine pathway enzyme expressed in a sufficient amount to produce BDO, 4-hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine and further optimized for expression of BDO. The invention additionally provides methods of using such microbial organisms to produce BDO, 4-hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine.
United States Patent Application 20160264978
Applicant:  Genomatica, Inc.
source: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=3&f=G&l=50&co1=AND&d=PG01&s1=desulfurization&OS=desulfurization&RS=desulfurization
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Searching desulfurization within the text of this patent application I found references to the desulfuricans bacterium.

This looked interesting.  So I then Googled® desulfuricans.

TIP #1: Stumbling across a useful reference, mine it for keywords to use for future searches.
TIP #2: Finding a useful key word, store that key word in a file for future searchers.

Assorted Desulfurization Articles & Patents

A sampler of recent desulfurization articles and patents appears below.

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Adsorptive desulfurization by zinc-impregnated activated carbon: characterization, kinetics, isotherms, and thermodynamic modeling

Type	Journal Article
Author	Sandeep Kumar Thaligari
Author	Vimal Chandra Srivastava
URL	http://link.springer.com/article/10.1007/s10098-015-1090-y
Volume	18
Issue	4
Pages	1021-1030
Publication	Clean Technologies and Environmental Policy
Date	2016/01/13
Abstract	Refineries are required to meet increasingly stringent liquid fuel standards by using innovative desulfurization methods. Authors report the results of the studies on adsorptive removal of sulfur compounds from model fuel by zinc-impregnated granular activated carbon (GAC). Researchers characterized Zn-loaded adsorbent (Zn-GAC) prepared by wet impregnation for its textural, morphological, and structural characteristics. The adsorbent was further used for the removal of dibenzothiophene (DBT), a sulfur compound, from iso-octane.

A template-free solvent-mediated synthesis of high surface area boron nitride nanosheets for aerobic oxidative desulfurization

Type	Journal Article
Author	Peiwen Wu
Author	Wenshuai Zhu
URL	http://pubs.rsc.org/en/content/articlelanding/2016/cc/c5cc07830j
Volume	52
Issue	1
Pages	144-147
Publication	Chemical Communications
Date	2015/12/15
Abstract	Hexagonal boron nitride nanosheets (h-BNNs) with rather high specific surface area (SSA) are important two-dimensional layer-structured materials. A solvent-mediated synthesis of h-BNNs revealed a template-free lattice plane control strategy inducing high SSA nanoporous structured h-BNNs with outstanding aerobic oxidative desulfurization performance.

Cu–Cr–O Functionalized ETS-2 Nanoparticles for Hot Gas Desulfurization

Type	Journal Article
Author	Farzad Yazdanbakhsh
Author	Moien Alizadehgiashi
Volume	16
Issue	1
Pages	878-884
Publication	Journal of Nanoscience and Nanotechnology
Date	2016-01-01
URL	http://www.ingentaconnect.com/content/asp/jnn/2016/00000016/00000001/art00111
Abstract	Engelhard Titanium Silicate-2 (ETS-2), a sodium nanotitanate, was surface functionalized by ion exchanging the solid with copper and chromium ions. Researchers assessed the ability of this bi-metallic adsorbent to remove H2S at elevated temperatures using a dynamic breakthrough system, which they compared to an analogous mixed metal oxide, Cu–Cr–O. Unlike Cu–Cr–O, the H2S capacity for CuCr-ETS-2 remains unchanged from 350 °C up to 950 °C. Using ETS-2 as a support for the metals increased the adsorbents surface area and improved its sulfur capacity from 35 mg H2S/g for Cu–Cr–O to 61 mg H2S/g adsorbent for CuCr-ETS-2. The consistent presence of Cu9S5 on the sulfided adsorbents would indicate that chromium effectively stabilizes the copper against reduction to metallic copper up to temperatures as high as 950 °C.

Deep extractive desulfurization and denitrogenation of various model oils by H3+nPMo12−nVnO40 supported on silica-encapsulated γ-Fe2O3 nanoparticles for industrial effluents applications

Type	Journal Article
Author	Ezzat Rafiee
Author	Susan Rezaei
URL	http://www.sciencedirect.com/science/article/pii/S1876107015005398
Volume	61
Pages	174-180
Publication	Journal of the Taiwan Institute of Chemical Engineers
Date	April 2016
Abstract	Researchers fabricated a series of magnetic nanocatalysts by immobilization of H3+nPMo12−nVnO40 on the surface of silica-encapsulated γ-Fe2O3 nanoparticles (Fe@Si). They examined extractive oxidation of the sulfur-based compounds under optimized and mild conditions. Magnetic catalyst exhibited excellent yield and selectivity for liquid and solid sulfides in oxidation reaction. They studied catalytic activity of magnetic catalyst in the oxidative desulfurization (ODS) of different model oils, as well as denitrogenation and the effect of nitrogen containing, one ring and two ring aromatic compounds on sulfur removal of model oil. Effect of various extractants in performance of ODS process was examined. Resulting conversions show that the catalyst has strong activity, which is responsible for its catalytic performance. ODS system containing the catalyst could be recycled at least four times with only a slight decrease in the catalytic performance.

Density functional theory study of adsorption of benzothiophene and naphthalene on silica gel

Type	Journal Article
Author	Junpei Fujiki
Author	Eiji Furuya
URL	http://www.sciencedirect.com/science/article/pii/S0016236115010133
Volume	164
Pages	180-185
Publication	Fuel
Date	January 15, 2016
Abstract	Metal-ion-exchanged zeolites exhibit high desulfurization performance. Unfortunately, zeolites cause side reactions due to their strong acidity. Silica-based adsorbents showing lower acidity have potential for the desulfurization adsorbent. To facilitate the development of efficient desulfurization adsorbents, researchers studied the mechanisms of benzothiophene and naphthalene adsorption onto silica surface using density functional theory (DFT) in conjunction with experimental approaches. Both the computational and the experimental results indicated that the sites at which benzothiophene and naphthalene adsorb onto silica gel are different types of silanol groups. The adsorption sites of benzothiophene at the initial stage were vicinal-type and/or geminal-type silanols and the final adsorption sites were isolated-type silanols. In addition, the results of DFT calculations suggest that multilayer adsorption might occur. In contrast, the adsorption sites of naphthalene at the initial stage were vicinal-type silanols. Subsequently, multilayer adsorption through a T-shape interaction might occur successively on the silica surface.

Desulfurization of fuel oils: Mutual solubility of ionic liquids and fuel oil

Type	Journal Article
Author	Shurong Gao
Author	Guangren Yu
URL	http://www.sciencedirect.com/science/article/pii/S0016236116000697
Volume	173
Pages	164-171
Publication	Fuel
Date	June 1, 2016
Abstract	Extractive and oxidative desulfurization of fuel oil using ionic liquids (ILs) as solvents have been studied intensively. In such processes, the mutual solubility of ILs and fuel oil remains a major concern. Less mutual solubility is necessary to reduce the loss of ILs and the contamination of fuel oil. Researchers used Conductor-like Screening Model for Real Solvents (COSMO-RS) to calculate the mutual solubility of 1830 ILs and model fuel oil to screen the ideal ILs with less mutual solubility with fuel oil and to understand the effects of ILs structural characteristics on the mutual solubility. Cations with smaller non-polarity, shorter alkyl chain length and less symmetry tend to have weaker vdW energies and smaller mutual solubility, while anions with larger polarity tend to have stronger HB energies and smaller mutual solubility. The functional groups also show remarkable effects on mutual solubility; those functional groups that decrease the non-polarity and vdW energies or increase the polarity and HB energies favor the small mutual solubility. Moreover, experimental determinations of the mutual solubility indicate [C1pyr]H2PO4 is a good solvent for desulfurization. This work provides the theoretical basis to design and select the ILs, which have small mutual solubility with fuel oil.

Direct preparation of [(CH3)3NC16H33]4Mo8O26 and its catalytic performance in oxidative desulfurization

Type	Journal Article
Author	Xiangwen Zhang
Author	Yawei Shi
URL	http://pubs.rsc.org/en/content/articlelanding/2016/cy/c5cy01439e
Volume	6
Issue	4
Pages	1016-1024
Publication	Catalysis Science & Technology
Date	2016/02/15
Abstract	Researchers prepared the catalyst [(CH3)3NC16H33]4Mo8O26 using a direct precipitation method under room conditions from commercially available (NH4)6Mo7O24·4H2O and (CH3)3NC16H33Cl, avoiding the use of toxic organic solvents. They used the catalyst for oxidative desulfurization using H2O2 as an oxidant under mild conditions. High dibenzothiophene (DBT) removal was obtained after an adsorption process to remove the residual DBT sulfone (DBTO2). The catalyst could be used for at least nine cycles without a noticeable decrease in activity. Researchers observed leaching of Mo species to be negligible during the reaction. Moreover, they found that the sulfur removal remained unchanged, decreased slightly or dramatically in the presence of 10 wt% n-octene, para-xylene or naphthalene, respectively, which was attributed to the different solubilities of DBTO2 in these solvents. The reaction system was further applied for the desulfurization of a kerosene-range jet fuel and a diesel fuel. After oxidation and extraction, 86.4% and 93.2% sulfur removals were derived for the diesel fuel and jet fuel, respectively.

Engineering synthetic bacterial consortia for enhanced desulfurization and revalorization of oil sulfur compounds

Type	Journal Article
Author	Igor Martínez
Author	Magdy El-Said Mohamed
URL	http://www.sciencedirect.com/science/article/pii/S1096717616000069
Volume	35
Pages	46-54
Publication	Metabolic Engineering
Date	May 2016
Abstract	The 4S bioprocess pathway has been intensively studied for the removal of recalcitrant sulfur of aromatic heterocycles present in fuels. It is composed of three sequential functional units, encoded by the dszABCD genes, through which the model compound dibenzothiophene (DBT) is transformed into the sulfur-free 2-hydroxybiphenyl (2HBP) molecule. Authors report a study in which a set of synthetic dsz cassettes were implanted in Pseudomonas putida KT2440, a model bacterial “chassis” for metabolic engineering studies. The complete dszB1A1C1-D1 cassette behaved as an attractive alternative to the previously constructed recombinant dsz cassettes for the conversion of DBT into 2HBP.

Improving Ultra-Deep Desulfurization Efficiency by Catalyst Stacking Technology

Type	Journal Article
Author	Chong Peng
Author	Rong Guo
URL	http://link.springer.com/article/10.1007/s10562-015-1675-4
Volume	146
Issue	3
Pages	701-709
Publication	Catalysis Letters
Date	2015/12/31
Abstract	The catalyst for diesel ultra-deep desulfurization is selected on the basis of several factors, including feedstock composition, liquid hourly space velocity, and operation pressure. Owing to their specific processing purposes,a variety of catalyst systems, including straight distillation, coking distillation, blends of straight distillation, and secondary processing oil, are applied for various feeds due to their significant difference in terms of sulfur content, nitrogen content, aromatics constitute, and cetane number. Authors results of a study to determine the most appropriate catalyst and grading scheme by evaluating the deep desulfurization efficiency of different schemes when processing various feeds. Results revealed the W–Mo–Ni/Mo–Co catalyst stacking to be the most effective among various schemes because of the following reasons: (1) loading W–Mo–Ni catalyst on the upper bed of reactor not only benefits the saturation of polyaromatics even in the middle or at the end of the run but also provides low nitrogen feed for the bottom bed; (2) loading Mo–Co type catalyst with alkyl transfer performance in the bottom bed at high temperature reaction zone facilitates alkyl transfer reaction and mitigates the effect of thermodynamic equilibrium limitations in the middle and at the end of the run, consequently improving the HDS efficiency under high temperatures.

Ionic liquid@MIL-101 prepared via the ship-in-bottle technique: remarkable adsorbents for the removal of benzothiophene from liquid fuel

Type	Journal Article
Author	Nazmul Abedin Khan
Author	Zubair Hasan
URL	http://pubs.rsc.org/en/content/articlelanding/2016/cc/c5cc08896h
Volume	52
Issue	12
Pages	2561-2564
Publication	Chemical Communications
Date	2016/02/02
Abstract	Ionic liquids (ILs) were synthesized inside a porous metal–organic framework (MIL-101) via a ship-in-bottle (SIB) technique. Unlike previously reported IL-incorporated MIL-101s, IL@MIL-101 prepared by the SIB approach was very stable over several cycles for the liquid phase adsorption of benzothiophene from liquid fuel.

MIL-101 promotes the efficient aerobic oxidative desulfurization of dibenzothiophenes

Type	Journal Article
Author	Adrián Gómez-Paricio
Author	Andrea Santiago-Portillo
URL	http://pubs.rsc.org/en/content/articlelanding/2016/gc/c5gc00862j
Volume	18
Issue	2
Pages	508-515
Publication	Green Chemistry
Date	2016/01/18
Abstract	MIL-101 promotes aerobic oxidation in n-dodecane of dibenzothiophene (DBT) and its methyl-substituted derivatives to their corresponding sulfones with complete selectivity, without observation of the sulfoxide. DBT sulfones can be completely separated from n-dodecane by water extraction. Researchers observed MIL-101(Cr) without the need of pre-activation to be more convenient than the also-active MIL-101(Fe) analog. The reaction exhibits an induction period due to the diffusion inside the pore system of the solvent or oxygen and it is not observed if the MIL-101 sample is first in contact with the solvent at the reaction temperature for a sufficiently long time. MIL-101 is reusable for at least five times without any sign of deactivation according to the time-conversion plots.

Mixing-assisted oxidative desulfurization of model sulfur compounds using polyoxometalate/H2O2 catalytic system

Type	Journal Article
Author	Angelo Earvin Sy Choi
Author	Susan Roces
URL	Free Full Text Source:  http://www.sciencedirect.com/science/article/pii/S2468203916300231
Volume	26
Issue	4
Pages	184-190
Publication	Sustainable Environment Research
Date	July 2016
Abstract	Desulfurization of fossil fuel derived oil is needed in order to comply with environmental regulations. Dibenzothiophene and benzothiophene are major sulfur compounds in raw diesel oil. Researchers conducted mixing-assisted oxidative desulfurization of dibenzothiophene and benzothiophene using polyoxometalate/H2O2 systems and a phase transfer agent. They studied the effects of reaction time and temperature in the oxidation of model sulfur compounds mixed in toluene. They employed a pseudo first-order reaction kinetic model and the Arrhenius equation to evaluate the kinetic rate constant and activation energy of each catalyst tested in the desulfurization process. Results revealed the order of catalytic activity and activation energy of the different polyoxometalate catalysts to be H3PW12O40 > H3PM12O40 > H4SiW12O40 for both dibenzothiophene and benzothiophene.

One-Pot Cation–Anion Double Hydrolysis Derived Ni/ZnO–Al2O3 Absorbent for Reactive Adsorption Desulfurization

Type	Journal Article
Author	Rooh Ullah
Author	Zhanquan Zhang
URL	http://dx.doi.org/10.1021/acs.iecr.5b04421
Volume	55
Issue	13
Pages	3751-3758
Publication	Industrial & Engineering Chemistry Research
Date	April 6, 2016
Abstract	Researchers prepared a series of Ni/ZnO–Al2O3 adsorbents by a one-pot cation–anion double hydrolysis (CADH) method. The reactive adsorption desulfurization (RADS) performance of the adsorbents was evaluated in a fixed bed reactor using thiophene in n-octane as a model fuel. Results revealed that the adsorbents exhibited better RADS performance than those prepared using the conventional kneading method. The thiophene conversion and sulfur capacity of adsorbents decreased with increasing the crystallization temperature. Among all tested adsorbents, the Ni/ZnO–Al2O3 sample prepared at 28 °C presented the largest adsorption capacity and highest RADS reactivity. Textual characterization results indicated that the sample Ni/ZnO–Al2O3 possessed relatively bigger pore size and larger pore volume than other samples, which may alleviate the pore shrinkage/blockage during the RADS process. A combination of XRD, UV–vis, and H2-TPR characterization results demonstrate that a high crystallization temperature favors the growth of inactive ZnAl2O4 crystals and induce the formation of more less-reducible Ni2+ ion, causing the loss of active ZnO phase and Ni0 atoms. This may account for the lower RADS activity of the adsorbent synthesized at higher crystallization temperatures.

Synthesis and characterization of CeO2/TiO2 nanotube arrays and enhanced photocatalytic oxidative desulfurization performance

Type	Journal Article
Author	Xiaowang Lu
Author	Xiazhang Li
URL	http://www.sciencedirect.com/science/article/pii/S0925838815317047
Volume	661
Pages	363-371
Publication	Journal of Alloys and Compounds
Date	March 15, 2016
Abstract	Describes well-aligned CeO2/TiO2 nanotube arrays photocatalyst prepared by anodization and microwave homogeneous synthesis technique. Photocatalytic activities of the prepared samples were examined by the photocatalytic oxidation of benzothiphene (BT) under visible light irradiation. The CeO2/TiO2 nanotube arrays photocatalyst showed higher photocatalytic activity than that of TiO2 nanotube arrays. Researchers found that more than 90% of sulfur compounds in model oil were photocatalytic oxidized and removed by using CeO2/TiO2 nanotube arrays as photocatalyst.

Using response surface methodology to optimize ultrasound-assisted oxidative desulfurization

Type	Journal Article
Author	Javad Alaei Kadijani
Author	Elhameh Narimani
URL	http://link.springer.com/article/10.1007/s11814-015-0276-7
Volume	33
Issue	4
Pages	1286-1295
Publication	Korean Journal of Chemical Engineering
Date	2016/02/23
Abstract	Ultrasound-assisted oxidative desulfurization (UAOD) is an alternative for conventional desulfurization methods which can remove sulfur compounds from fuels under mild process conditions. Researchers optimized UAOD of gasoil using tungstophosphoric acid catalyst and tetraoctylammonium bromide as a phase transfer agent in the presence of hydrogen peroxide as an oxidant. They generated optimal design of experiments based on central composite face-centered design of Response surface methodology (RSM) to study effects of four process variables, including oxidant volume, mass of catalyst, mass of phase transfer agent and the ultrasonic wave amplitude on the sulfur conversion of gasoil. In addition, a predictive model of sulfur conversion was obtained based on RSM. The optimal values of process variables were evaluated to be 21.96 mL of oxidant, 1 gr of catalyst and 0.1 gr of phase transfer agent to achieve the maximum sulfur conversion of 95.92%.

Desulfurization Method For Gas Containing Sulfur Oxide And Desulfurization Apparatus (Chiyoda)
United States Patent Application 20160236142
YASUDA; Hirokazu ;   et al.   August 18, 2016
Assignee: Chiyoda Corporation
Abstract
Provided is a desulfurization method for sulfur oxide gas that includes: bringing a first sulfur oxide gas into contact with a humidifying liquid to obtain a second gas; separating at least part of the humidifying liquid from the second gas to obtain a third gas; contacting the third gas with an alkaline agent-containing liquid and oxygen to remove sulfur oxide from the third gas; using the alkaline agent-containing liquid as the humidifying liquid to be brought into contact with the first gas in the humidifying liquid contact step; acquiring at least part of the humidifying liquid separated from the second gas; removing gas from the humidifying liquid; and recovering a by-product, the alkaline agent-containing liquid, and oxygen from the humidifying liquid from which the gas has been removed in the gas removal step, the by-product recovery step being performed only downstream of the humidifying liquid acquisition step.
BACKGROUND ART
[0002] A combustion exhaust gas discharged from a coal-fired furnace or a coal-fired thermal power plant contains sulfur oxide (SOx), and a desulfurization apparatus is installed in order to treat sulfur oxide (SOx). As a method of removing sulfur oxide from a gas containing sulfur oxide in the desulfurization apparatus, there is given a method involving allowing the gas containing sulfur oxide to react with an alkaline agent and oxygen in an absorbing liquid. Waste water generated in such method of removing sulfur oxide contains a nitrogen compound and a chemical oxygen demand (COD) component, and hence waste water treatment is performed for their removal. However, there is a problem of degradation in performance of a waste water treatment apparatus for the waste water treatment.
[0003] As a technology for solving the above-mentioned problem, in Patent Literature 1, there is disclosed "a wet-type flue-gas desulfurization method, including: using a soot-mixing wet-type flue-gas desulfurization apparatus in order to remove sulfur oxide in an exhaust gas; and performing first gas-liquid contact and then second gas-liquid contact in a series in regions adjacent to each other, the first gas-liquid contact including spraying a first alkaline agent-containing liquid to an exhaust gas to allow gas-liquid contact therebetween, the second gas-liquid contact including allowing gas-liquid contact between the exhaust gas after the first gas-liquid contact and a second alkaline agent-containing liquid containing an absorber to remove mainly sulfur oxide in the exhaust gas in the presence of an oxygen-containing gas for oxidation of sulfur oxide, the wet-type flue-gas desulfurization method including: extracting a slurry containing solid matter generated through the second gas-liquid contact to use at least part thereof as the first alkaline agent-containing liquid; extracting the first alkaline agent-containing liquid spontaneously separated from the exhaust gas after the first gas-liquid contact through precipitation separation; and feeding the extracted first alkaline agent-containing liquid to a waste water treatment apparatus subsequent to the soot-mixing wet-type flue-gas desulfurization apparatus." According to the method disclosed in Patent Literature 1, the concentration of an oxidizing substance, such as a peroxide, in the waste water can be reduced. As a result, degradation in performance of the waste water treatment apparatus can be suppressed.
CITATION LIST
Patent Literature
[0004] PTL 1: Japanese Patent Application Laid-Open No. 8-299754
SUMMARY OF INVENTION
Technical Problem
[0005] However, the method and the apparatus disclosed in Patent Literature 1, in which a by-product, such as gypsum, generated through a sulfur oxide removal reaction involving allowing sulfur oxide to react with oxygen and the alkaline agent-containing liquid is removed through a plurality of paths, are complicated. Therefore, there is a demand for a simpler method and apparatus. In addition, there is also a demand for recovery of the by-product at a high recovery rate and a high purity because the by-product can be used separately.
[0006] It should be noted that a possible approach to improving removal performance of sulfur oxide in the gas is to promote an oxidation reaction or increase a pH in the sulfur oxide removal reaction. However, when the oxidation reaction is promoted or the pH is increased, the problem of degradation in performance of the waste water treatment apparatus and a problem of a reduction in purity of the by-product owing to an increase in concentration of an alkaline substance in the by-product become particularly remarkable.
[0007] In view of the above-mentioned problems, an object of the present invention is to provide a desulfurization method for a gas containing sulfur oxide and a desulfurization apparatus which have a simple configuration, are reduced in a load on waste water treatment device, and enable recovery of a by-product at a high recovery rate and a high purity.
Solution to Problem
[0008] As a result of extensive investigations, the inventors of the present invention have found that the above-mentioned object can be achieved by a configuration including: circulating an alkaline agent-containing liquid brought into contact with a gas containing sulfur oxide, which is a gas to be treated, and oxygen to use the alkaline agent-containing liquid as a humidifying liquid to be brought into contact with the gas to be treated in a stage prior to a reaction among the gas to be treated, oxygen, and the alkaline agent-containing liquid; separating the humidifying liquid from the gas to be treated brought into contact with the humidifying liquid; extracting the separated humidifying liquid; removing a gas inhibiting pump action or the like; and performing an operation of recovering a by-product generated through a reaction among sulfur oxide, oxygen, and the alkaline agent-containing liquid only on the humidifying liquid extracted after the separation. Thus, the present invention has been completed.
[0009] A desulfurization method for a gas containing sulfur oxide according to one embodiment of the present invention as described above includes: a humidifying liquid contact step of bringing a first gas containing sulfur oxide into contact with a humidifying liquid to obtain a second gas; a humidifying liquid separation step of separating at least part of the humidifying liquid from the second gas to obtain a third gas; a sulfur oxide removal step of bringing the third gas into contact with an alkaline agent-containing liquid and oxygen to remove the sulfur oxide from the third gas; a circulation step of circulating the alkaline agent-containing liquid brought into contact with the third gas and oxygen to use the alkaline agent-containing liquid as the humidifying liquid to be brought into contact with the first gas in the humidifying liquid contact step; a humidifying liquid acquisition step of acquiring at least part of the humidifying liquid separated from the second gas in the humidifying liquid separation step; a gas removal step of removing a gas from the humidifying liquid acquired in the humidifying liquid acquisition step; and a by-product recovery step of recovering a by-product generated through a reaction among the sulfur oxide, the alkaline agent-containing liquid, and oxygen from the humidifying liquid from which the gas has been removed in the gas removal step, the by-product recovery step being performed only downstream of the humidifying liquid acquisition step.
[0010] In addition, the humidifying liquid acquisition step may include adding oxygen to the humidifying liquid to allow the oxygen, the sulfur oxide in the humidifying liquid, and the alkaline agent-containing liquid to react with each other, to thereby generate a by-product and reduce an amount of the sulfur oxide in the humidifying liquid.
[0011] The sulfur oxide may include SO.sub.2, the alkaline agent may be calcium carbonate, and the by-product may be gypsum.
[0012] A desulfurization apparatus for a gas containing sulfur oxide according to one embodiment of the present invention includes: a reaction tank; gas introduction device for introducing a first gas containing sulfur oxide, which is a gas to be treated, to the reaction tank; humidifying liquid contact device for bringing the first gas into contact with a humidifying liquid; humidifying liquid separation device for separating at least part of the humidifying liquid from a second gas obtained by the bringing the first gas into contact with a humidifying liquid; sulfur oxide removal device for bringing a third gas obtained by the separating at least part of the humidifying liquid from a second gas into contact with an alkaline agent-containing liquid and oxygen to remove the sulfur oxide from the third gas; gas discharge device for discharging, from the reaction tank, the third gas from which the sulfur oxide has been removed by the sulfur oxide removal device; circulation device for circulating the alkaline agent-containing liquid brought into contact with the third gas and oxygen by the sulfur oxide removal device to use the alkaline agent-containing liquid as the humidifying liquid to be brought into contact with the first gas by the humidifying liquid contact device; humidifying liquid acquisition device for acquiring at least part of the humidifying liquid separated by the humidifying liquid separation device; gas removal device for removing a gas from the humidifying liquid acquired by the humidifying liquid acquisition device; and by-product recovery device for recovering a by-product generated through a reaction among the sulfur oxide, the alkaline agent-containing liquid, and oxygen from the humidifying liquid from which the gas has been removed by the gas removal device, in which the by-product recovery device is arranged only downstream of the humidifying liquid acquisition device.
[0013] The humidifying liquid separation device may include a liquid descending pipe for feeding the humidifying liquid separated from the second gas to the humidifying liquid acquisition device, and the humidifying liquid acquisition device may include a pot surrounding an end of the liquid descending pipe on an outlet side.
[0014] The humidifying liquid acquisition device may include oxygen supply device for supplying oxygen into the pot.
[0015] The pot may include in an inside thereof a tilted plate for allowing the humidifying liquid to descend thereon obliquely in a vertical direction, and the humidifying liquid acquisition device may include a pipe for acquiring the humidifying liquid from a central portion of the tilted plate in the vertical direction.
[0016] A desulfurization apparatus according to one embodiment of the present invention includes: a reaction tank including: a humidifying liquid contact chamber communicating with an introduction port for a gas to be treated for introducing a gas to be treated; and an alkaline agent-containing liquid chamber for accommodating an alkaline agent-containing liquid in a lower portion thereof, the alkaline agent-containing liquid chamber communicating with a discharge port for a gas to be treated for discharging the gas to be treated, and with the humidifying liquid contact chamber, and being arranged below the humidifying liquid contact chamber; a humidifying liquid supply pipe for spraying a humidifying liquid to the gas to be treated; a first oxygen supply pipe for supplying oxygen into the alkaline agent-containing liquid accommodated in the alkaline agent-containing liquid chamber; circulation device for extracting the alkaline agent-containing liquid accommodated in the alkaline agent-containing liquid chamber and supplying the alkaline agent-containing liquid to the humidifying liquid supply pipe; a liquid descending pipe for allowing the humidifying liquid spontaneously separated from the gas to be treated to which the humidifying liquid has been sprayed to descend therethrough, the liquid descending pipe being arranged so as to extend downward from a bottom surface of the humidifying liquid contact chamber and reach below a liquid level of the alkaline agent-containing liquid accommodated in the alkaline agent-containing liquid chamber; a gas descending pipe for allowing the gas to be treated, the gas being obtained by spontaneously separating the humidifying liquid from the gas to be treated to which the humidifying liquid has been sprayed, to descend therethrough to be dispersed in the alkaline agent-containing liquid accommodated in the alkaline agent-containing liquid chamber, the gas descending pipe being arranged so as to extend downward from the bottom surface of the humidifying liquid contact chamber and reach below the liquid level of the alkaline agent-containing liquid accommodated in the alkaline agent-containing liquid chamber; a pot including a side wall surrounding a lower end portion of the liquid descending pipe from a side; a second oxygen supply pipe for supplying oxygen into the pot; a pipe for extracting the humidifying liquid from an inside of the pot; an air separator arranged in the pipe for extracting the humidifying liquid from an inside of the pot; and solid-liquid separation device arranged downstream of the air separator.
[0017] A desulfurization apparatus according to one embodiment of the present invention includes: a reaction tank configured such that: a gas to be treated is introduced from an introduction port for a gas to be treated arranged at an upper surface thereof; the gas to be treated is discharged from a discharge port for a gas to be treated arranged at a side wall thereof; and an alkaline agent-containing liquid is accommodated in a lower portion thereof; a humidifying liquid supply pipe for spraying a humidifying liquid to the gas to be treated, the humidifying liquid supply pipe being arranged in an upper portion of the reaction tank; a first oxygen supply pipe for supplying oxygen into the alkaline agent-containing liquid accommodated in the reaction tank; circulation device for extracting the alkaline agent-containing liquid accommodated in the reaction tank and supplying the alkaline agent-containing liquid to the humidifying liquid supply pipe; a separation plate including: an inclined plate of a doughnut shape, the inclined plate being arranged below the humidifying liquid supply pipe in the reaction tank and inclined downward toward a central portion thereof; a funnel-shaped liquid collector of a doughnut shape having an outer diameter larger than an inner diameter of the inclined plate, the funnel-shaped liquid collector being inclined downward toward a central portion thereof; and a liquid descending pipe for allowing the humidifying liquid spontaneously separated from the gas to be treated to which the humidifying liquid has been sprayed to descend therethrough, the liquid descending pipe being arranged so as to be connected to a hole of the funnel-shaped liquid collector in the central portion and reach below a liquid level of the alkaline agent-containing liquid accommodated in the reaction tank; a pot including a side wall surrounding a lower end portion of the liquid descending pipe from a side; a second oxygen supply pipe for supplying oxygen into the pot; a pipe for extracting the humidifying liquid from an inside of the pot; an air separator arranged in the pipe for extracting the humidifying liquid from an inside of the pot; and solid-liquid separation device arranged downstream of the air separator.
Advantageous Effects of Invention
[0018] According to the embodiments of the present invention, a reduction in a load on waste water treatment device and recovery of a by-product generated through a reaction among sulfur oxide, oxygen, and an alkaline agent-containing liquid at a high recovery rate and a high purity can be achieved by a simple configuration in which the by-product is recovered through only one path in desulfurization of a gas containing sulfur oxide by performing the specific separation step, circulation step, extraction step, gas removal step, and the like.
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Method For Deep Desulfurization Of Gasoline (China University Of Petroleum-Beijing)
United States Patent Application 20160222304
Zhao; Liang ;   et al.   August 4, 2016
Applicant: China University Of Petroleum-Beijing
Abstract
The present invention provides a method for deep desulfurization of gasoline. The method includes steps of: cutting a gasoline feedstock into light, medium, and heavy gasoline fractions; the medium gasoline fraction being subjected to adsorption desulfurization to obtain a desulfurized medium gasoline fraction; the heavy gasoline fraction being subjected to selective hydrodesulfurization to obtain a desulfurized heavy gasoline fraction; mixing the light gasoline fraction with the desulfurized medium gasoline fraction and the desulfurized heavy gasoline fraction to obtain a desulfurized gasoline, where, a cutting temperature of the light and the medium gasoline fractions is 35-60.degree. C., a cutting temperature of the medium and the heavy gasoline fractions is 70-130.degree. C. The method according to the present invention not only can realize deep desulfurization of gasoline, but also has a less loss of octane number.
FIELD OF THE TECHNOLOGY
[0002] The present invention relates to a desulfurization method and, in particular, to a method for deep desulfurization of gasoline.
BACKGROUND
[0003] As worldwide environmental regulations are becoming more strict, people place a higher requirement upon quality of gasoline products. For instance, China has implemented State IV discharge criteria for oil products nationwide since Jan. 1, 2014, which requires sulfur content of gasoline to be reduced below 50 ppm; meanwhile, China has also put forward State V discharge criteria, which requires sulfur content to be reduced below 10 ppm and olefin content to be controlled below 24%.
[0004] Compared with developed countries, China's gasoline has a relatively high content of sulfur, which is mainly due to the fact that about 70-80% of China's gasoline comes out from a fluid catalytic cracking (FCC) process. In the gasoline products, about 90% of olefin content and sulfur content comes out from the fluid catalytic cracking gasoline, which causes that China's gasoline products are far from meeting a requirement for new criteria where sulfur content .ltoreq.10 ppm and olefin content .ltoreq.24%. Thus, reduction of sulfur content in the fluid catalytic cracking gasoline is a key to upgrading quality of China's motor gasoline.
[0005] Hydrodesulfurization is the most effective method to remove sulfide from gasoline. Sinopec Research Institute of Petroleum Processing developed an FCC gasoline selective hydrodesulfurization process (RSDS-I) in 2001, where FCC gasoline is firstly cut into a light fraction and a heavy fraction at a cutting temperature of 90.degree. C., and then the light fraction is subjected to alkali extraction mercaptan removal, and the heavy fraction is subjected to selective hydrodesulfurization using a main catalyst of RSDS-I and a protective agent of RGO-2; and in a second generation of FCC gasoline selective hydrodesulfurization technique (RSDS-II) for improvements on the process above, a cutting point of the light fraction and heavy fraction is decreased to 70.degree. C., and a second generation of hydrogenation catalysts RSDS-21 and RSDS-22 are used in a selective hydrodesulfurization portion of the heavy fraction.
[0006] Axens Corporate of French Institute of Petroleum (IFP) developed a Prime-G+ process, where a process flow of full range pre-hydrogenation, light and heavy gasoline cutting and heavy fractions selective hydrodesulfurization is used, and the cutting temperature is set between 93-149.degree. C. according to a target value of sulfur content, and during the full range pre-hydrogenation process, light sulfide reacts with diolefin in the presence of a catalyst of HR845 to form sulfide with a high boiling point, thus olefin is not saturated; furthermore, two catalysts of HR806 and HR841 are used in the selective hydrodesulfurization of the heavy fraction, thus the operation is more flexible.
[0007] Sinopec Fushun Research Institute of Petroleum and Petrochemicals developed an OCT-M process, where FCC gasoline is cut into light and heavy fractions at a cutting temperature of 90.degree. C., in which the light fraction is subjected to demercaptan and the heavy fraction is subjected to selective hydrodesulfurization using a combined catalyst of FGH-20/FGH-11.
[0008] Hai shunde Special Oil Co., Ltd developed an HDDO series diolefin removal catalyst, an HDOS series deep hydrodesulfurization catalyst, an HDMS series mercaptan removal catalyst and a corresponding FCC gasoline selective hydrodesulfurization process (CDOS), where FCC gasoline is subjected to diolefin removal reaction at a relatively low temperature in a hydrogen condition, then the FCC gasoline is cut into light and heavy components, the heavy fraction is subjected to deep hydrodesulfurization, and the hydrogenated heavy fraction is reconciled with the light fraction to obtain a clean gasoline with less sulfur.
[0009] The above techniques have a common problem that the light fraction formed by the cutting has a low yield, and there are fewer components having a content less than 10 ppm, and it is difficult to reduce sulfur content of the light fraction below 10 ppm by means of mercaptan removal only; when gasoline products having sulfur content less than 10 ppm are produced, a majority of light fraction still need to be hydrodesulfurized, thus loss of octane number of full range gasoline is higher (for instance, up to 3.0-4.0). Furthermore, even though the sulfur content is allowed to be less than 10 ppm by means of hydrodesulfurization, there are still defects that investment and operational costs are high, and a large number of olefin is saturated while sulfide is removed, which not only increases hydrogen consumption, but also reduces octane number of gasoline greatly.
[0010] The adsorption desulfurization may be carried out at a room temperature and atmospheric pressure with low energy consumption and almost no loss of octane number, which is a relatively potential method for deep desulfurization, and which is reported mostly at present. For instance, an IRVAD technique jointly developed by Black & Veatch Pritchard Inc. and Alcoa Industrial Chemicals employs multi-stage fluidized bed adsorption method, which uses an aluminum oxide substrate as a selective solid adsorbent to process liquid hydrocarbons, during the adsorption, the adsorbent is countercurrent in contact with the liquid hydrocarbons, the used adsorbent countercurrently reacts with a regenerated thermal current (such as hydrogen) for regeneration. A desulfurization rate of this technique can reach above 90%, however, this adsorbent is of less selectivity, sulfur adsorption capacity thereof is limited, and the regeneration process is relatively complex.
[0011] Philips Petroleum Company developed an S-Zorb process where a specific adsorbent is used for desulfurization in a hydrogen condition, the adsorbent takes zinc oxide, silicon dioxide and aluminium oxide as a carrier and loads metal components such as Co, Ni, Cu, etc., which can absorb a sulfur atom in sulfide to maintain it on the adsorbent, whereas the hydrocarbon structure part of the sulfide is released back to the process stream so as to implement a desulfurization process. This process does not generate H.sub.2S during the reaction, thereby preventing H.sub.2S from reacting with olefin again to generate mercaptan. However, the desulfurization technique places a relatively harsh requirement upon process operation conditions, the temperature of the desulfurization reaction is 343-413 and the pressure is 2.5-2.9 MPa.
[0012] The adsorbent of desulfurization described above cannot be better used in the selective hydrodesulfurization of the heavy fraction due to problems such as limited deep desulfurization and small sulfur adsorption capacity, low selectivity, short lifespan, relatively complex regeneration process and harsh desulfurization conditions. Thus, there is a pressing demand to develop a method for deep desulfurization of gasoline, of which loss of octane number is less, desulfurization degree is highly deep, and the operation is convenient and flexible.
SUMMARY
[0013] The present invention provides a method for deep desulfurization of gasoline, which is used to solve said problems in the prior art such as limited deep desulfurization of the method for desulfurization of gasoline and great loss of octane number.
[0014] The present invention provides a method for deep desulfurization of gasoline, including steps of:
[0015] cutting a gasoline feedstock into a light gasoline fraction, a medium gasoline fraction, and a heavy gasoline fraction;
[0016] the medium gasoline fraction being subjected to adsorption desulfurization to obtain a desulfurized medium gasoline fraction;
[0017] the heavy gasoline fraction being subjected to selective hydrodesulfurization to obtain a desulfurized heavy gasoline fraction; and
[0018] mixing the light gasoline fraction with the desulfurized medium gasoline fraction and the desulfurized heavy gasoline fraction to obtain a desulfurized gasoline;
[0019] wherein, a cutting temperature of the light and the medium gasoline fractions is 35-60.degree. C., and a cutting temperature of the medium and the heavy gasoline fractions is 70-130.degree. C.
[0020] In the present invention, the gasoline feedstock may be fluid catalytic cracking gasoline, coking gasoline, etc.; the cutting refers to cutting of the gasoline feedstock into light, medium and heavy gasoline fractions according to a distillation range from low to high, where a distillation range of the medium gasoline fraction is from a range of 35-60.degree. C. to a range of 70-130.degree. C.
[0021] In an embodiment, before cutting the gasoline feedstock into the light, the medium and the heavy gasoline fractions, the gasoline feedstock is firstly subjected to demercaptan treatment.
[0022] In another embodiment, before the mixing, the light gasoline fraction is firstly subjected to demercaptan treatment to obtain a demercaptan light gasoline fraction, and then the demercaptan light gasoline fraction is mixed with the desulfurized medium gasoline fraction and the desulfurized heavy gasoline fraction to obtain the desulfurized gasoline.
[0023] In the present invention, a conventional method may be used for the demercaptan treatment, such as an alkali extraction method or a mercaptan conversion method. The alkali extraction method uses an alkali solution to extract mercaptan therein for its removal, the amount of alkali contained in the alkali solution may be 5-50%, a volume ratio of oil to alkali may be (1-15):1, an operating temperature may be 10-60.degree. C.; the mercaptan conversion method is to convert a small molecule of mercaptan into other sulfides for its removal, which may be conducted by means of prehydrogenation in a conventional alkali-free deodorization process and Prime-G+ process, where a condition for the alkali-free deodorization process may be: an operating pressure of a reactor is 0.2-1.0 MPa, a reaction temperature is 20-60.degree. C., a feeding space velocity is 0.5-2.0 h.sup.-1, a volume ratio of an air flow to a feeding flow is 0.2-1.0, the catalyst and the cocatalyst used may be a common catalyst in the art.
[0024] In the present invention, the adsorption desulfurization is conducted using a desulfurization adsorbent, the desulfurization adsorbent is obtained by loading an active metal component onto a composite carrier made of zeolite and active carbon which are subjected to alkali treatment respectively, wherein, the active metal is selected from one or more elements of IA, VIII, IB, IIB and VIB groups in the periodic table.
[0025] In the composite carrier of the present invention, the zeolite and the active carbon have a mass ratio of (20-80):(80-20), preferably (20-60):(80-40).
[0026] Furthermore, the zeolite is an X type, a Y type or a ZSM-5 typezeolite. The present invention does not strictly limit the zeolite adopting the X type and the ZSM-5 type; a ratio of silicon atoms to aluminum atoms in skeleton of the Y type zeolite is no less than 3.0 (as measured by an XRD method). In addition, the present invention does not strictly limit the active carbon used, and a specific surface area thereof may be about 1000 m.sup.2/g generally.
[0027] In the present invention, the active metal selected from IA group in the periodic table is, for instance, potassium (K), sodium (Na), etc.; the active metal selected from VIII group in the periodic table is, for instance, iron (Fe), cobalt (Co), nickel (Ni), etc.; the active metal selected from IB group in the periodic table is, for instance, copper (Cu), silver (Ag), etc.; the active metal selected from IIB group in the periodic table is, for instance, zinc (Zn), etc.; the active metal selected from VIB group in the periodic table is, for instance, molybdenum (Mo), etc.
[0028] Furthermore, the active metal is selected from at least two of Ni, Fe, Ag, Co, Mo, Zn and K, in which, Ni may have a loading of 10-30% on the composite carrier; Fe may have a loading of 5-15% on the composite carrier; Ag may have a loading of 5-10% on the composite carrier; Co may have a loading of 5-10% on the composite carrier; Mo may have a loading of 5-10% on the composite carrier; Zn may have a loading of 5-15% on the composite carrier; K may have a loading of 5-15% on the composite carrier. The loading is a loading of each active metal on the composite carrier respectively.
[0029] Furthermore, the active metal has a loading of 2-30% on the composite carrier, preferably 5-25%, more preferably 5-20%. When more than two active metals are loaded on the composite carrier, the loading is an overall loading of the active metals.
[0030] In an embodiment, the active metal is K and Ni; furthermore, K has a loading of 5-15% on the composite carrier, Ni has a loading of 10-25% on the composite carrier; furthermore, K and Ni which are loaded on the composite carrier have a mass ratio of (0.2-0.5):1.
[0031] In another embodiment, the active metal is Zn and Fe; furthermore, Zn has a loading of 5-15% on the composite carrier, Fe has a loading of 8-15% on the composite carrier; furthermore, Zn and Fe which are loaded on the composite carrier have a mass ratio of (0.5-1):1.
[0032] In an embodiment, the light gasoline fraction may be mixed with the desulfurized medium gasoline fraction and the desulfurized heavy gasoline fraction after being subjected to adsorption desulfurization to obtain the desulfurized gasoline. Moreover, the light gasoline fraction may be subjected to the adsorption desulfurization using any one of the desulfurization adsorbent described above.
[0033] In another embodiment, the demercaptan light gasoline fraction may be mixed with the desulfurized medium gasoline fraction and the desulfurized heavy gasoline fraction after being subject to adsorption desulfurization to obtain the desulfurized gasoline. Moreover, the demercaptan light gasoline fraction may be subjected to the adsorption desulfurization using any one of the desulfurization adsorbent described above.
[0034] The method for preparing the above desulfurization adsorbent may include steps of:
[0035] preparing a composite carrier made of the zeolite and the active carbon in proportion which are respectively treated with alkali;
[0036] impregnating the composite carrier with a soluble salt solution of the active metal, and drying the impregnated material for calcination to obtain the desulfurization adsorbent.
[0037] In an embodiment, the alkali treatment includes mixing the zeolite and the active carbon respectively in a proportion where a mass ratio of the zeolite or the active carbon to alkali to water is (0.1-2):(0.05-2):(4-15), and stirring the mixture for 0.1-24 h in a condition where the temperature is maintained at 0-120.degree. C., then drying, and including at least one time of the alkali treatment process.
[0038] The present invention does not strictly limit the alkali used in the alkali treatment, for instance, a NaOH solution at 0.1-1.0 mol/L may be used. Furthermore, a temperature of the stirring treatment may be 30-100.degree. C., and the time may be 1-10 h; furthermore, a temperature of the stirring treatment may be 70-80.degree. C., and the time may be 2-4 h. A temperature of the drying after the stirring treatment may be, for instance, 100-120.degree. C., and the time may be, for instance, 5-8 h. The alkali treatment process may be one time or two times.
[0039] In the present invention, a soluble salt solution of the active metal may be, for instance, a sulfate solution, a nitrate solution, etc., preferably the sulfate solution. The impregnation may be an incipient wetness impregnation which is a conventional impregnation method in the art, a specific operation thereof may be, for instance: at an room temperature and in a stirring condition, instilling a soluble salt solution of the active metal into the composite carrier until the composite carrier is aggregated to a ball, and then standing for a period of time (for instance, 1-3 h). Especially, when two active metal components are loaded on the composite carrier, firstly a soluble salt solution of the first active metal is loaded by incipient wetness impregnation, upon washing, drying and calcinating, then a soluble salt solution of the second active metal is loaded by incipient wetness impregnation, upon washing, drying and calcinating, a composite carrier loading two active metal components may be prepared.
[0040] During the impregnation, the amount of soluble salt of the active metals needed for the impregnation may be calculated according to a requirement for the loading of the active metals on the composite carrier respectively and a requirement for the overall loading (loading more than two active metal components) of the active metals on the composite carrier.
[0041] Furthermore, the drying for the impregnated material is conducted for 12-24 h at a temperature of between 90-120.degree. C., preferably for 18-24 h at a temperature of between 110-120.degree. C. The impregnated material is subjected to calcinations for 4-6 h at a temperature of between 450-640.degree. C. after being dried.
[0042] Furthermore, the impregnated material being subjected to calcinations after being dried includes cooling the dried material down to a room temperature, elevating the temperature to 400.degree. C. at a speed of 6.degree. C./min firstly, and then elevating the temperature to 450-640.degree. C. at a speed of 3.degree. C./min.
[0043] In the present invention, the adsorption desulfurization is conducted using a fixed bed at an atmospheric pressure, and a temperature of the adsorption desulfurization is controlled between 20-100.degree. C., for instance, 30-80.degree. C., a flow rate of the medium gasoline fraction or the light gasoline fraction is 0.3-1 mL/min, for instance, 0.5 mL/min.
[0044] The method for deep desulfurization of gasoline according to the present invention may further include:
[0045] washing the desulfurization adsorbent which has been subject to the adsorption desulfurization with a steam to collect a sulfur-rich component;
[0046] the sulfur-rich component and the heavy gasoline fraction being subjected to the selective hydrodesulfurization after mixing them together.
[0047] Furthermore, the method for deep desulfurization of gasoline also includes:
[0048] after washing the desulfurization adsorbent which has been subjected to the adsorption desulfurization with the steam, drying the washed desulfurization adsorbent with nitrogen at a temperature of 200-400.degree. C., and cooling the dried desulfurization adsorbent with nitrogen to realize regeneration of the desulfurization adsorbent.
[0049] That is, the method for regeneration of the desulfurization adsorbent includes washing the desulfurization adsorbent to be regenerated with steam, drying the same with nitrogen at a temperature of 200-400.degree. C. and cooling the same with nitrogen in sequence.
[0050] Specifically, steam at a temperature of 130-180.degree. C. may be used to sweep the desulfurization adsorbent which is subjected to the adsorption desulfurization for 1-3 h for washing, then nitrogen at a temperature of 200-400.degree. C. is used to sweep a same for 10-60 min for drying, and finally nitrogen at a room temperature is used to sweep the same for 10-60 min for cooling.
[0051] In the method for deep desulfurization of gasoline of the present invention, the heavy gasoline fraction and hydrogen are subjected to the selective hydrodesulfurization in the presence of a selective hydrodesulfurization catalyst to obtain desulfurized heavy gasoline fraction, wherein, a temperature of the selective hydrodesulfurization is 200-300.degree. C., a pressure thereof is 1.5-2.5 MPa, a liquid hourly space velocity (the heavy gasoline fraction) is 1-5 h.sup.-1, a volume ratio of hydrogen to oil is 400-600.
[0052] The selective hydrodesulfurization catalyst described in the present invention may be a conventional catalyst subjecting gasoline to selective hydrodesulfurization in the prior art, such as a catalyst of RSDS-I, RSDS-21, RSDS-22 in the RSDS process, a catalyst of HR806 and HR841 in the Prime-G+ process, a combined catalyst of FGH-20/FGH-11 in the OCT-M process, an HDOS series deep hydrodesulfurization catalyst in the CDOS process, etc.
[0053] In an embodiment, the hydrodesulfurization catalyst is obtained by a carrier loading an active metal component, where, the carrier is a zeolite (such as the X type, the Y type or the ZSM-5 type) or a metal oxide (such as aluminium oxide), and the active metal includes Co and Mo. Furthermore, Co and Mo have an overall loading of 5-20% on the carrier. Furthermore, Co and Mo which are loaded on the carrier have a mass ratio of (0.2-0.6):1.
[0054] Implementations of the present invention have at least the following advantages:
[0055] 1. The method for deep desulfurization in the present invention, after a gasoline feedstock has been subjected to demercaptan treatment, the gasoline feedstock is cut into light, medium and heavy gasoline fractions, which are processed respectively according to features of the respective gasoline fractions. This method not only helps to reduce regeneration times of the desulfurization adsorbent, but also helps to reduce component content of hydrodesulfurization; this method can realize deep desulfurization of the gasoline feedstock, and meanwhile there is no loss of octane number.
[0056] 2. The method for deep desulfurization in the present invention may use a specific desulfurization adsorbent, which not only has a large sulfur capacity and good selectivity for sulfur, but also the desulfurization is highly deep, and sulfur may be desulfurized to 1 ppmw (part per million by weight); in addition, it has a long lifespan and relatively environment-friendly.
[0057] 3. The method for deep desulfurization in the present invention, after adsorption desulfurization, the desulfurization adsorbent may be washed, a sulfur-rich component formed by the washing may be mixed with heavy gasoline fraction for selective hydrodesulfurization, thereby avoiding a waste of feedstock and improving utilization of the feedstock; meanwhile, regeneration of the desulfurization adsorbent may be realized by conducting a drying and cooling process subsequent to the washing, this way is simple and easy to operate, and the regenerated desulfurization adsorbent does not need hydrogen reduction prior to use, which is environment-friendly and economical; moreover, the desulfurization adsorbent may be regenerated many times, which can still maintain a relatively high sulfur capacity and an excellent desulfurization effect after the regeneration.
[0058] 4. The method for deep desulfurization in the present invention, when gasoline is subjected to desulfurization, an operating condition is mild and operations are flexible for the process, which may conducted at an atmospheric pressure and a relatively low temperature, thus energy consumption is saved and operational costs are reduced.
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Method For Upgrading Fluid Catalytic Carcking Gasoline (China University Of Petroleum-Beijing)
United States Patent Application 20160222303
Gao; Jinsen ;   et al.   August 4, 2016
Applicant: China University Of Petroleum-Beijing
Abstract
A method for upgrading fluid catalytic cracking gasoline includes the following steps: cutting fluid catalytic cracking gasoline into light, medium, and heavy gasoline fractions; subjecting the medium gasoline fraction to an aromatization/hydroisomerization reaction in the presence of a catalyst to obtain a desulfurized medium gasoline fraction; and blending the light gasoline fraction, the desulfurized medium gasoline fraction and the heavy gasoline fraction to obtain upgraded gasoline; where, a cutting temperature of the light and the medium gasoline fractions is 35-60.degree. C., and a cutting temperature of the medium and the heavy gasoline fractions is 70-160.degree. C. The method according to the present invention not only can realize deep desulfurization of fluid catalytic cracking gasoline, but also can improve octane number significantly.
FIELD OF TECHNOLOGY
[0002] The present invention relates to the technical field of petrochemicals and, in particular, to a method for upgrading fluid catalytic cracking gasoline (FCC gasoline).
BACKGROUND
[0003] Petroleum resources have constantly deteriorated and crude oil becomes more and more heavy in compositions, requirements for environmental protection are getting more and more strict, and new environmental regulations around the world have imposed more stringent requirements on gasoline quality. For instance, the National V Standard for motor gasoline which will be implemented by Jan. 1, 2017 will require olefins content to be below 24%, sulfur content to be below 10 ppm, and octane number to be above 93. Upgrading gasoline quality standard are mainly embodied in: reducing the olefins content and the sulfur content while increasing the octane number.
[0004] Currently, developed countries mainly target at improving "formulations" of the gasoline to meet a corresponding quality standard. They use various processes to manufacture gasoline, and then blend various types of gasoline. Generally, in the gasoline, fluid catalytic cracking gasoline containing olefins accounts for about less than 1/3, reformulated gasoline which contains aromatics but frees of olefins accounts for about more than 1/3, and other clean gasoline components subjected to alkylation, isomerization and etherification which contains neither aromatics nor olefins account for about 1/3. The sulfur content and the olefins content are low, and the octane number is high.
[0005] The fluid catalytic cracking gasoline is a major part of China's motor gasoline, which accounts for about 75% in a gasoline pool. Approximately 90% of olefins content and sulfur content in finished gasoline comes from the fluid catalytic cracking gasoline, resulting in that China's gasoline products are far from meeting new index requirements of sulfur content.ltoreq.10 ppm and olefins content.ltoreq.24%. In another aspect, currently, mainly 93# gasoline is used China, however, as the manufacturing technology of domestic automotive industry continuously improves and domestic retention quantity of imported automobile unceasingly increases, there is an increasing demand for 95# gasoline or gasoline with higher octane number. Since the fluid catalytic cracking gasoline is limited by the process itself, octane number thereof is maintained primarily by large amounts of olefins, and RON is generally about 90, thus the octane number of the fluid catalytic cracking gasoline directly influences the octane level of the finished gasoline. Moreover, at present, a main process for removing sulfur and lowering olefins in fluid catalytic cracking gasoline is catalytic hydrogenation, which inevitably leading to large amounts of olefins being saturated, resulting in a greater loss of octane number, and seriously affecting economic returns of enterprises.
[0006] As crude oil becomes increasingly heavier in compositions, the catalytic cracking capacity of heavy oil is expanded constantly and environmental regulations become increasingly stringent, this problem mentioned above is more prominent, which is objectively forcing the petrochemical industry to research and develop new processes for upgrading the fluid catalytic cracking gasoline efficiently, especially an efficient upgrading process which can realize both deep desulfurization of the fluid catalytic cracking gasoline and improvement of the octane number.
[0007] Existing sulfur reduction techniques of the fluid catalytic cracking gasoline are mainly represented by S-zorb of Sinopec, RSDS of Sinopec Research Institute of Petroleum Processing and Prime-G+ of French. S-zorb is developed by U.S. Conocophillips Corporation, bought out and improved by Sinopec Group, and is used for desulfurization of full-range fluid catalytic cracking gasoline, the sulfur content of the full-range gasoline after desulfurization may be controlled to be below 10 ppm, and an octane number loss of the full-range gasoline is 1.0.about.2.0 units. RSDS is developed by Sinopec Research Institute of Petroleum Processing, this technique firstly cuts catalytic gasoline into light and heavy gasoline fractions, then the light gasoline fraction is subjected to sweetening by extraction, and the heavy gasoline fraction is subjected to selective hydrodesulfurization; when a product with sulfur content of less than 10 ppm is manufactured by this technique, the yield of light gasoline fraction is about 20%, most of the fractions requires hydrogenation, and an octane number loss of the full-range gasoline is between 3.0.about.40. Prime-G+ is developed by French Axens Corporation, which uses a technological process comprising full-range prehydrogenation, cutting of light and heavy gasoline and selective hydrodesulfurization of heavy gasoline fraction, and is characterized by reaction light sulfide with diolefins to form a sulfide with high boiling point during the full-range prehydrogenation process, where olefins is not saturated, and then light gasoline fraction with sulfur content less than 10 ppm and heavy gasoline fraction with high sulfur content are obtained by cutting of light and heavy gasoline, and the heavy gasoline fraction is subjected to hydrodesulfurization; this technique is the same as RSDS, although a part of light gasoline fraction with low sulfur content may not be subjected to hydrogenation, since light gasoline fraction with sulfur content less than 10 ppm have a low yield, most of the fractions requires hydrogenation, resulting in that the octane number loss of the full-range gasoline is also between 3.0.about.4.0.
[0008] CN1611572A discloses a catalytic conversion method for improving octane number of gasoline. This method enables heavy gasoline fraction having an initial boiling point greater than 100.degree. C. to be contacted with a catalyst having a temperature lower than 700.degree. C., and reacted in a condition where a temperature is 300.about.660.degree. C., a pressure is 130.about.450 KPa, a weight hourly space velocity is 1.about.120 h.sup.-1, a weight ratio of the catalyst to the gasoline fractions is 2.about.20, and a weight ratio of steam to the gasoline fractions is 0.about.0.1, and a reaction product is separated from a coked catalyst, where the coked catalyst is recycled by stripping and regeneration. Octane number of fluid catalytic cracking gasoline may be increased by 3.about.10 units by using the method provided in the present invention. This method follows a catalytic cracking mechanism of oil hydrocarbons, subjecting gasoline to a hydrogen transfer reaction and a cracking reaction, although octane number of the gasoline can be improved, the cutting of fractions need to be carried out firstly, and only the heavy gasoline fraction having the initial boiling point greater than 100.degree. C. are collected for the reaction, thus there is a great loss of gasoline.
[0009] CN1160746A discloses a catalytic conversion method for improving octane number of low-grade gasoline. This method enables gasoline having low octane number to be contacted with a high temperature catalyst coming from a regenerator by injecting the gasoline into a riser reactor from an upstream of an inlet of a conventional catalytic cracking feedstock, and reacted in a condition where a reaction temperature is 600.about.730.degree. C., a ratio of the catalyst to the gasoline is 6.about.180, and a weight hourly space velocity is 1.about.180 h.sup.-1. This method may increase octane number of the gasoline, but all the gasoline having low octane number in the method is required to participate in the reaction, thus there is a great loss of gasoline.
[0010] CN103805269A proposes a method for deep hydrodesulfurization of catalytic gasoline, a clean gasoline product is obtained by subjecting light gasoline and medium gasoline fractions to alkali-free sweetening, then separating the light and the medium gasoline through a hydrogenation pre-fractionating tower, where the hydrogenation pre-fractionating tower is imported with hot diesel simultaneously; subjecting the separated medium gasoline and heavy gasoline to selective hydrogenation after blending them, and blending the resulted distillate oil with the light gasoline being subjected to alkali-free sweetening. Although this method can realize effective desulfurization and a degree of decrease of octane number is also alleviated to some extent, the octane number cannot be increased effectively, and there are considerable differences between the technological process of this method and that of the present invention.
[0011] In conclusion, generally, there are problems such as a large proportion of hydrogenation and a great loss of octane number when a current technique dealing with the deep desulfurization requirement of fluid catalytic cracking gasoline. Effects of some supporting processes for restoring octane number during hydrodesulfurization are not obvious either. There is a pressing demand on the market to develop a technique for deep desulfurization of fluid catalytic cracking gasoline, which has less loss of octane number or significant rise of octane number.
SUMMARY
[0012] In order to solve the above technical problems, the present invention provides a method for upgrading fluid catalytic cracking gasoline, which not only can deeply remove sulfide contained in fluid catalytic cracking gasoline to below 10 ppm, but also can significantly improve octane number of the fluid catalytic cracking gasoline by 1-3 units.
[0013] The objective of the present invention is achieved through the following technical solutions:
[0014] A method for upgrading fluid catalytic cracking gasoline, including the following steps:
[0015] cutting fluid catalytic cracking gasoline into light, medium, and heavy gasoline fractions;
[0016] subjecting the medium gasoline fraction to an aromatization/hydroisomerization reaction in the presence of a catalyst to obtain a desulfurized medium gasoline fraction; and
[0017] blending the light gasoline fraction, the desulfurized medium gasoline fraction and the heavy gasoline fraction to obtain upgraded gasoline;
[0018] wherein, a cutting temperature of the light and the medium gasoline fractions is 35-60.degree. C., and a cutting temperature of the medium and the heavy gasoline fractions is 70-160.degree. C.
[0019] The term cutting in the present invention refers to segmenting the fluid catalytic cracking gasoline into light, medium and heavy gasoline fractions according to a boiling range from low to high, and controlling the boiling range of the medium gasoline fraction from 35-50.degree. C. to 130-160.degree. C.
[0020] According to the upgrading method of the present invention, the fluid catalytic cracking gasoline (FCC gasoline) is subjected to fraction cutting firstly, by controlling the cutting temperature, the collected light gasoline fraction is fluid catalytic cracking gasoline rich in olefins and with high octane number, the medium gasoline fraction is fluid catalytic cracking gasoline with moderate content of olefins and aromatics and with lowest octane number, and the heavy gasoline fraction is fluid catalytic cracking gasoline with relatively low content of olefins but with relatively high content of aromatics and high octane number. Furthermore, in the present invention, the medium gasoline fraction with lowest octane number is subjected to an aromatization/hydroisomerization reaction, the resultant is then blended with other gasoline fractions, through this blending, FCC gasoline with significant increase of octane number is obtained.
[0021] In the implementations of the present invention, according to a situation of the FCC gasoline, a boiling range of the medium gasoline fraction may be determined with overall consideration of handling capacities and effects for gasoline feedstock. The inventors found that, the medium gasoline fraction having a boiling range of 40-160.degree. C. accounts for about 40 m % of the fluid catalytic cracking gasoline, which is basically the part with the lowest octane number, and has an RON below 80, a minority part of the medium gasoline fraction even has an RON below 70, thus the medium gasoline fraction may be controlled as a gasoline fraction having the boiling range of 40-160.degree. C., preferably a gasoline fraction having a boiling range of 40-150.degree. C. Obviously, the longer the boiling range, the more the amount of the fraction can be collected, and the greater the amount of oil that needs to undergo the aromatization/hydroisomerization reaction is, thus, the cutting temperature of the medium and the heavy gasoline fractions may be further set to 70-130.degree. C.
[0022] In a specific implementation of the present invention, the catalyst used for the aromatization/hydroisomerization reaction of the medium gasoline fraction may be a catalyst commonly used for the aromatization/hydroisomerization reaction for processing the FCC gasoline. In an implementation, the catalyst used for the aromatization/hydroisomerization reaction is obtained by using a zeolite and a metallic oxide as a composite carrier to load an active metal component, where the active metal is zinc and/or gallium.
[0023] More specifically, the zeolite may be one or more of an MFI type zeolite, an MCM type zeolite and an LTL type zeolite, and the metallic oxide is aluminum oxide, where the MFI type zeolite may be a zeolite such as a ZSM-5, an HZSM-5 and the like, the MCM type zeolite may be a zeolite such as an MCM-41, and the LTL type zeolite may be an L type zeolite.
[0024] Furthermore, in the catalyst used for the aromatization/hydroisomerization reaction, a weight ratio of the zeolite to the metallic oxide is 1:(0.2-0.5), and the active metal has a loading capacity of 0.5-3% on the composite carrier. The catalyst may be obtained by immersing the composite carrier with a soluble salt solution of the active metal, and calcinating the impregnated material subsequent to drying; the immersion may be incipient wetness impregnation.
[0025] Furthermore, a reaction temperature of the aromatization/hydroisomerization reaction is 260-400.degree. C., a reaction pressure is 0.8-2.0 MPa, a volume ratio of hydrogen to oil is 200-800:1 and a weight hourly space velocity is 1.0-6.0 h.sup.-1. Moreover, the aromatization/hydroisomerization reaction according to the present invention may be carried out by using a fixed bed reactor, thereby facilitating the control of the reaction process and improving the efficiency and lifespan of the catalyst.
[0026] The method for upgrading fluid catalytic cracking gasoline according to the present invention, before the medium gasoline fraction is subjected to the aromatization/hydroisomerization reaction, the medium gasoline fraction may also be subjected to desulfurization firstly to obtain a first desulfurized medium gasoline fraction, and then the first desulfurized medium gasoline fraction is subjected to the aromatization/hydroisomerization reaction in the presence of the catalyst to obtain a second desulfurized medium gasoline fraction, and then the light gasoline fraction is blended with the second desulfurized medium gasoline fraction and the heavy gasoline fraction to obtain upgraded gasoline.
[0027] In an implementation, the desulfurization of the medium gasoline fraction is solvent extraction desulfurization, and the solvent extraction desulfurization may be performed by using a technique known in the art, and there is no strict limitation. For instance, a method for solvent extraction desulfurization of gasoline fractions disclosed in a patent with a publication number of CN103555359A may be used for processing the medium gasoline fraction, which specifically includes steps: introducing the medium gasoline fraction from a middle lower part of an extraction tower and a solvent from a top of the extraction tower, injecting C5 paraffin from a backflow device at the bottom of the extraction tower, controlling a temperature at the top of the extraction tower between 55-100.degree. C., a temperature at the bottom of the extraction tower between 40-80.degree. C., and a pressure at the top of the extraction tower between 0.2-0.7 MPa, controlling a feed ratio of the solvent to the medium gasoline fraction between 1.0-5.0, and controlling a feed ratio of the C5 paraffin to the medium gasoline fraction at 0.1-0.5. A reason for adding the C5 paraffin to the solvent extraction desulfurization process is to increase separation efficiency. In an implementation of the present invention, the C5 paraffin may be selected from one or both of n-pentane and isopentane.
[0028] According to the described manner, the medium gasoline fraction is subjected to solvent extraction desulfurization firstly so as to separate desulfurized medium gasoline fraction and residual oil, and the desulfurized medium gasoline fraction is subjected to the aromatization/hydroisomerization reaction subsequently, which not only reduces the amount of the fraction that needs to be processed in the aromatization/hydroisomerization reaction, but also helps to improve the efficiency of the aromatization/hydroisomerization reaction. Furthermore, the residual oil may be blended with resultants of the aromatization/hydroisomerization reaction, the light gasoline fraction and the heavy gasoline fraction to obtain the upgraded gasoline.
[0029] For the desulfurization performed by using solvent extraction, the selection of solvent and separation operations and steps all may be determined by persons skilled in the art based on their basic knowledge and skills. For instance, the extraction may be completed in an extraction tower, and the solvent may be selected from one or more of diethylene glycol, triethylene glycol, tetraethylene glycol, dimethyl sulfoxide, sulfolane, N-formyl-morpholine, N-methyl pyrrolidone, polyethylene glycol and propylene carbonate; tetraethylene glycol and/or sulfolane are preferred.
[0030] In another implementation, the desulfurization of the medium gasoline fraction is adsorption desulfurization, and the adsorption desulfurization is carried out by using a desulfurization adsorbent, the desulfurization adsorbent is obtained by using a zeolite and an active carbon that have been respectively subjected to alkali treatment as a composite carrier to load an active metal component, where the active metal is selected from one or more elements of groups IA, VIII, IB, IIB and VIB of the period table.
[0031] In the composite carrier of the desulfurization adsorbent according to the present invention, a weight ratio of the zeolite to the active carbon is (20-80):(80-20), preferably (20-60):(80-40); the zeolite in the composite carrier of the desulfurization adsorbent is an X type, a Y type or a ZSM-5 type zeolite. The present invention does not have strict limit on employing X type or ZSM-5 type zeolite; a ratio of silicon atoms to aluminum atoms in a framework of the Y type zeolite is no less than 3.0 (as measured by an XRD method). In addition, the present invention does not have strict limit on the active carbon used, and a specific surface area thereof generally may be about 1000 m.sup.2/g.
[0032] In the present invention, the active metal selected from group IA of the period table is, for instance, potassium (K), sodium (Na), etc.; the active metal selected from group VIII of the period table is, for instance, iron (Fe), cobalt (Co), nickel (Ni), etc.; the active metal selected from group IB of the period table is, for instance, copper (Cu), silver (Ag), etc.; the active metal selected from group IIB of the period table is, for instance, zinc (Zn), etc.; the active metal selected from group VIB of the period table is, for instance, molybdenum (Mo), etc.
[0033] Furthermore, the active metal in the desulfurization adsorbent is selected from at least two of Ni, Fe, Ag, Co, Mo, Zn and K. Ni may have a loading capacity of 10-30% on the composite carrier; Fe may have a loading capacity of 5-15% on the composite carrier; Ag may have a loading capacity of 5-10% on the composite carrier; Co may have a loading capacity of 5-10% on the composite carrier; Mo may have a loading capacity of 5-10% on the composite carrier; Zn may have a loading capacity of 5-15% on the composite carrier; K may have a loading capacity of 5-15% on the composite carrier. The loading capacity is a loading capacity of each active metal on the composite carrier respectively.
[0034] Furthermore, the active metal in the desulfurization adsorbent has a loading capacity of 2-30% on the composite carrier, preferably 5-25%, further preferably 5-20%. When more than two active metals are loaded on the composite carrier, the loading capacity is an overall loading capacity of the active metals.
[0035] In an implementation, the active metal is K and Ni; furthermore, K has a loading capacity of 5-15% on the composite carrier, Ni has a loading capacity of 10-25% on the composite carrier; furthermore, K and Ni which are loaded on the composite carrier have a weight ratio of (0.2-0.5):1.
[0036] In another implementation, the active metal is Zn and Fe; furthermore, Zn has a loading capacity of 5-15% on the composite carrier, Fe has a loading capacity of 8-15% on the composite carrier; furthermore, Zn and Fe which are loaded on the composite carrier have a weight ratio of (0.5-1):1.
[0037] A method for preparing the desulfurization adsorbent described above may include steps of:
[0038] preparing a composite carrier with a zeolite and an active carbon that have been respectively subjected to alkali treatment in proportion; immersing the composite carrier with a soluble salt solution of an active metal, subjecting the impregnated material to calcination after being dried so as to obtain the desulfurization adsorbent.
[0039] In an implementation, the alkali treatment includes blending the zeolite with alkali and water at a weight ratio of (0.1-2):(0.05-2):(4-15), and blending the active carbon with alkali and water at a weight ratio of (0.1-2):(0.05-2):(4-15), respectively, and stirring the blending for 0.1-24 h in a condition where a temperature is maintained between 0-120, then drying, and the alkali treatment process is proceeded at least once.
[0040] The present invention does not have strict limit on the alkali used in the alkali treatment, for instance, a solution of NaOH at 0.1-1.0 mol/L may be used. Furthermore, a temperature of the stirring treatment may be 30-100.degree. C., and the time may be 1-10 h; furthermore, a temperature of the stirring treatment may be 70-80.degree. C., and the time may be 2-4 h. A temperature of the drying after the stirring treatment may be, for instance, 100-120.degree. C., and the time for drying may be, for instance, 5-8 h. The alkali treatment process may be proceeded once or twice.
[0041] In the present invention, a soluble salt solution of the active metal may be, for instance, a sulfate solution, a nitrate solution, etc., preferably the sulfate solution. The immersion may be incipient wetness impregnation, which is a conventional immersion way in the art, a specific operation thereof may be, for instance: at a room temperature and stirring, dropping the soluble salt solution of the active metal into the composite carrier until the composite carrier is aggregated into a ball, and then standing the solution for a period of time (for instance, 1-3 h). Especially, when two active metal components are loaded on the composite carrier, the composite carrier was firstly impregnated with a soluble salt solution of a first active metal, after being washed, dried and calcinated, then impregnated with a soluble salt solution of a second active metal, after being washed, dried and calcinated, a composite carrier loading two active metals components may be prepared then.
[0042] During the impregnation, the amount of soluble salt of each active metals needed for the immersion may be calculated according to a requirement for the loading capacity of each active metals on the composite carrier and a requirement for the overall loading capacity (loading more than two active metals components) of the active metals on the composite carrier.
[0043] Furthermore, the drying for the impregnated material is conducted for 12-24 h at a temperature of between 90-120.degree. C., preferably for 18-24 h at a temperature of between 110-120.degree. C. The impregnated material is subject to calcination for 4-6 h at a temperature of between 450-640.degree. C. after being dried.
[0044] Furthermore, subjecting the impregnated material to calcination after being dried includes cooling the dried material down to room temperature, elevating the temperature to 400.degree. C. at a speed of 6.degree. C./min firstly, and then elevating the temperature to 450-640.degree. C. at a speed of 3.degree. C./min.
[0045] In the present invention, the adsorption desulfurization is conducted at a normal atmospheric pressure using a fixed bed, and a temperature of the adsorption desulfurization is controlled between 20-100.degree. C., for instance, 30-80.degree. C., a flow rate of the medium gasoline fraction is 0.3-1 mL/min, for instance, 0.5 mL/min.
[0046] The method for upgrading fluid catalytic cracking gasoline according to the present invention may further include:
[0047] washing the desulfurization adsorbent which has been subjected to the adsorption desulfurization with steam to collect a sulfur-rich component;
[0048] blending the sulfur-rich component with the heavy gasoline fraction to conduct the selective hydrodesulfurization.
[0049] Furthermore, the method for upgrading fluid catalytic cracking gasoline also includes:
[0050] after washing the desulfurization adsorbent which has been subjected to the adsorption desulfurization with the steam, drying the desulfurization adsorbent with nitrogen at a temperature of 200-400.degree. C., and cooling the dried desulfurization adsorbent with nitrogen so as to realize regeneration of the desulfurization adsorbent.
[0051] That is, the method for regeneration of the desulfurization adsorbent includes: washing the desulfurization adsorbent to be regenerated with steam, drying the same with nitrogen at a temperature of 200-400.degree. C. and cooling the same with nitrogen in sequence.
[0052] Specifically, steam at a temperature of 130-180.degree. C. may be used to sweep the desulfurization adsorbent which has been subjected to the adsorption desulfurization for 1-3 h for washing, then nitrogen at a temperature of 200-400.degree. C. is used to sweep a same for 10-60 min for drying, and finally nitrogen at a room temperature is used to sweep the same for 10-60 min for cooling.
[0053] Furthermore, according to the method for upgrading fluid catalytic cracking gasoline in the present invention, before cutting the fluid catalytic cracking gasoline into the light, the medium and the heavy gasoline fractions, the fluid catalytic cracking gasoline may be subjected to sweetening treatment firstly; or, before the light gasoline fraction is blended with the desulfurized medium gasoline fraction and the heavy gasoline fraction, the light gasoline fraction is subjected to sweetening treatment firstly to obtain a sweetened light gasoline fraction, and then the sweetened light gasoline fraction is blended with the desulfurized medium gasoline fraction and the heavy gasoline fraction to obtain upgraded gasoline.
[0054] In the present invention, a conventional method may be used for the sweetening treatment, such as an alkali extraction method or a mercaptan conversion method. The alkali extraction method uses an alkali liquor to extract mercaptan therein for its removal, the amount of alkali contained in the alkali liquor may be 5-50%, a volume ratio of oil to alkali may be (1-15):1, an operating temperature may be 10-60.degree. C.; the mercaptan conversion method is to convert a small molecule of mercaptan into other sulfides for its removal, which may be conducted by means of a conventional alkali-free sweetening process and prehydrogenation in Prime-G+ process, where a condition for the alkali-free sweetening process may be: an operating pressure of a reactor is 0.2-1.0 MPa, a reaction temperature is 20-60.degree. C., a feeding space velocity is 0.5-2.0 h.sup.-1, a volume ratio of an air flow amount to a feeding quantity is 0.2-1.0, the catalyst and the cocatalyst used may be a common catalyst in the art.
[0055] Furthermore, according to the method for upgrading fluid catalytic cracking gasoline in the present invention, before the light gasoline fraction is blended with the desulfurized medium gasoline fraction and the heavy gasoline fraction, the heavy gasoline fraction may be subjected to selective hydrodesulfurization firstly to obtain a desulfurized heavy gasoline fraction, and then the desulfurized heavy gasoline fraction is blended with the light gasoline fraction and the desulfurized medium gasoline fraction to obtain upgraded gasoline.
[0056] Specifically, the heavy gasoline fraction and hydrogen may be subjected to selective hydrodesulfurization in the presence of a selective hydrodesulfurization catalyst to obtain the desulfurized heavy gasoline fraction, where a temperature of the selective hydrodesulfurization is 200-300.degree. C., a pressure thereof is 1.5-2.5 MPa, a liquid hourly space velocity is 1-5 h.sup.-1, a volume ratio of hydrogen to oil is 400-600.
[0057] The selective hydrodesulfurization catalyst described in the present invention may be a conventional catalyst for the selective hydrodesulfurization of gasoline in the prior art, such as catalysts RSDS-I, RSDS-21, RSDS-22 in an RSDS process, catalysts HR806 and HR841 in a Prime-G+ process, a combined catalyst of FGH-20/FGH-11 in an OCT-M process, an HDOS series deep hydrodesulfurization catalyst in a CDOS process, etc.
[0058] In an implementation, the hydrodesulfurization catalyst is obtained by a carrier which loads a third active metal component, where the carrier is a zeolite (such as the X type, the Y type or the ZSM-5 type) or a metallic oxide (such as aluminium oxide), and the third active metal includes Co and Mo. Furthermore, Co and Mo have an overall loading capacity of 5-20% on the carrier. Furthermore, Co and Mo which are loaded on the carrier have a weight ratio of (0.2-0.6):1.
[0059] Implementations of the present invention have at least the following advantages:
[0060] 1. In the method for upgrading fluid catalytic cracking gasoline in the present invention, gasoline feedstock is cut into light, medium and heavy gasoline fractions, which are processed separately according to features thereof. The method is not only flexible in operation, but also helps to reduce the amount of components that need to be processed in the hydrodesulfurization; moreover, this method can realize deep desulfurization of the gasoline feedstock, and meanwhile octane number of full-range gasoline is increased by 1-3 units, thereby having a great practical value.
[0061] 2. The method for upgrading fluid catalytic cracking gasoline in the present invention may use specific desulfurization adsorbents, which not only have a large sulfur capacity, good selectivity for sulfur, but also can achieve highly efficient deep desulfurization, and sulfur may be desulfurized to 1 ppmw (part per million by weight);
[0062] besides, the desulfurization adsorbents also have long lifespan and are environment-friendly.
[0063] 3. According to the method for upgrading fluid catalytic cracking gasoline in the present invention, the desulfurization adsorbent may be washed subsequent to adsorption desulfurization, a sulfur-rich component formed by the washing may be blended with heavy gasoline fraction for selective hydrodesulfurization, thereby avoiding a waste of feedstocks and improving utilization of the feedstocks; meanwhile, regeneration of the desulfurization adsorbent may be realized by conducting a drying and cooling process subsequent to the washing, these processes are simple and easy to operate, and the regenerated desulfurization adsorbent does not need to be reduced by hydrogen prior to use, which is environment-friendly and economical; moreover, the desulfurization adsorbent may be regenerated many times, a relatively high sulfur capacity and an outstanding desulfurization effect can still be maintained after the regeneration.
[0064] 4. According to the method for upgrading fluid catalytic cracking gasoline in the present invention, the aromatization/hydroisomerization reaction of the first desulfurized medium gasoline fraction may be carried out in a fixed bed, since gas residence time in the fixed bed reactor may be strictly controlled, and temperature distribution may be regulated, thus it helps to improve conversion and selectivity of chemical reactions; moreover, catalysts in the fixed bed reactor has good abrasion-resistance, and may be continuously used for a long time; the fixed bed reactor has a simple structure and stable operation, which is easy to control and to achieve large-scaled and continuous production.
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Adsorbent For Desulfurization Of Gasoline And Method For Desulfurization Of Gasoline (China University Of Petroelum-Beijing)
United States Patent Application 20160222302
Zhao; Liang ;   et al.   August 4, 2016
Applicant: China University Of Petroelum-Beijing
Abstract
The present invention provides an adsorbent and a method for desulfurization of gasoline. The adsorbent is obtained by loading active metal component on a composite carrier comprising zeolite and active carbon subjected to alkali treatment respectively, the active metal is selected from one or more elements of IA, IIA, VIII, IB, IIB and VIB groups in the periodic table. This method uses the adsorbent to conduct gasoline adsorption desulfurization, which especially cuts the gasoline into a light and a heavy gasoline fraction firstly, then the light fraction is subjected to adsorption desulfurization using the adsorbent, and the heavy fraction is subjected to selective hydrodesulfurization, a cutting temperature of the light and the heavy gasoline fraction is 70-110.degree. C. The adsorbent has a large sulfur adsorption, a long service life, and simply to be regenerated; the method can realize deep desulfurization of gasoline, and has a less octane number loss.
FIELD OF THE TECHNOLOGY
[0002] The present invention relates to a desulfurization adsorbent and a desulfurization method and, in particular, to an adsorbent for desulfurization of gasoline and a method for desulfurization of gasoline.
BACKGROUND
[0003] About 70% of the commercial gasoline in China comes out from a heavy oil fluid catalytic cracking (FCC) processes, since feedstock of heavy oil contains a great number of sulfur, nitrogen and oxygen heteroatom compounds as well as colloidal asphaltenes, fluid catalytic cracking gasoline not only has a high content of sulfur, but also has a high content of olefin components, in the commercial gasoline, more than 90% of sulfur comes from the fluid catalytic cracking gasoline, which makes sulfur content of China's gasoline much higher than that of foreign gasoline. Thus, how to reduce sulfur content in the fluid catalytic cracking gasoline is a key for reducing sulfur content in the commercial gasoline. Especially, State V gasoline quality criteria which will be implemented nationwide on Jan. 1, 2018 requires that sulfur content in gasoline should be no more than 10 ppm and olefin content should be no more than 24%, exploration and promotion of techniques for deep desulfurization of gasoline has become a pressing demand for the petroleum refining industry.
[0004] Desulfurization techniques used by the petroleum refining industry are divided into hydrodesulfurization technique and non-hydrodesulfurization technique, currently hydrodesulfurization is the main approach for desulfurization. For instance, Sinopec Research Institute of Petroleum Processing developed an FCC gasoline selective hydrodesulfurization process (RSDS-I) in 2001, where FCC gasoline is firstly cut into a light fraction and a heavy fraction at a cutting temperature of 90.degree. C., and then the light fraction is subjected to alkali extraction mercaptan removal, and the heavy fraction is subjected to selective hydrodesulfurization using a main catalyst of RSDS-I and a protective agent of RGO-2; and in a second generation of FCC gasoline selective hydrodesulfurization technique (RSDS-II) for improvements on the process above, a cutting point of the light fraction and heavy fraction is decreased to 70.degree. C., and a second generation of hydrogenation catalysts RSDS-21 and RSDS-22 are used in a selective hydrodesulfurization portion of the heavy fraction.
[0005] Axens Corporate of French Institute of Petroleum (IFP) developed a Prime-G+process, where a process flow of full range pre-hydrogenation, the light and heavy gasoline cutting and heavy fraction selective hydrodesulfurization is used, and the cutting temperature is set between 93-149.degree. C. according to a target value of sulfur content, and during the full range pre-hydrogenation process, light sulfide reacts with diolefin in the presence of a catalyst of HR845 to form sulfide with a high boiling point, thus olefin is not saturated; furthermore, two catalysts of HR806 and HR841 are used in the selective hydrodesulfurization of the heavy fraction, thus the operation is more flexible.
[0006] Sinopec Fushun Research Institute of Petroleum and Petrochemicals developed an OCT-M process, where FCC gasoline is cut into a light fraction and a heavy fraction at a cutting temperature of 90.degree. C., in which the light fraction is subjected to mercaptan removal and the heavy fraction is subjected to selective hydrodesulfurization using a combined catalyst of FGH-20/FGH-11.
[0007] Hai shun de Special Oil Co., Ltd developed an HDDO series diolefin removal catalyst, an HDOS series deep hydrodesulfurization catalyst, an HDMS series mercaptan removal catalyst and a corresponding FCC gasoline selective hydrodesulfurization process (CDOS), where FCC gasoline is firstly subjected to a diolefin removal reaction at a relatively low temperature in a hydrogen condition, then the FCC gasoline is cut into light and heavy components, the heavy fraction is subjected to deep hydrodesulfurization, and the hydrogenated heavy fraction is reconciled with the light fraction to obtain a clean gasoline with less sulfur.
[0008] The above techniques have a common problem that the light fraction formed by the cutting has a low yield, and there are fewer components having a content less than 10 ppm, and it is difficult to reduce sulfur content of the light fraction below 10 ppm by means of mercaptan removal only; when gasoline products having sulfur content less than 10 ppm are produced, a majority of light fraction still need to be hydrodesulfurized, thus loss of octane number of full range gasoline is higher (for instance, up to 3.0-4.0). Furthermore, even though the sulfur content can be made less than 10 ppm by means of hydrodesulfurization, there are still the drawbacks that investment and operational costs are high, and a large number of olefin is saturated while sulfide is removed, which not only increases hydrogen consumption, but also reduces octane number of gasoline greatly.
[0009] The non-hydrodesulfurization technique is further classified as adsorption desulfurization, oxidation desulfurization, extraction desulfurization, and biological desulfurization techniques, etc., the adsorption desulfurization technique which has been studied widely so far is one of potential methods for deep desulfurization with low energy consumption and almost no loss of octane number since it is carried out at room temperature and atmospheric pressure.
[0010] An IRVAD technique jointly developed by Black & Veatch Pritchard Inc. and Alcoa Industrial Chemicals employs multi-stage fluidized bed adsorption, which uses an alumina substrate selective solid adsorbent to process liquid hydrocarbons, during the adsorption, the adsorbent is in countercurrent contact with the liquid hydrocarbons, the used adsorbent countercurrently reacts with a recycled hot gaseous flow (such as hydrogen) to be regenerated. The desulfurization rate of this technique can reach above 90%, however, this adsorbent is of less selectivity, sulfur adsorption capacity thereof is small, and the regeneration process is relatively complicated.
[0011] Philips Petroleum Company developed an S-Zorb process where a specific adsorbent is used for desulfurization in a hydrogen condition, the adsorbent takes zinc oxide, silicon dioxide and aluminium oxide as a carrier and loads metal components such as Co, Ni and Cu, etc., which can absorb a sulfur atom in sulfide to maintain it on the adsorbent, whereas the hydrocarbon structure part of the sulfide is released back to the process stream so as to realize a desulfurization process. This process does not generate H.sub.2S during the reaction, thereby preventing H.sub.2S from reacting with olefin again to generate mercaptan. However, the desulfurization technique places a relatively harsh requirement upon process operation conditions, the temperature of the desulfurization reaction is 343-413.degree. C. and the pressure is 2.5-2.9 MPa.
[0012] The adsorption desulfurizer described above cannot be satisfactorily used in the selective hydrodesulfurization of the heavy fraction due to problems such as limited deep desulfurization and small sulfur adsorption capacity, low selectivity, short lifespan, relatively complicated regeneration process and harsh desulfurization conditions. Thus, there is a pressing demand to develop a method for desulfurization of gasoline, of which loss of octane number is less, desulfurization degree is highly deep, and the operation is convenient and flexible.
SUMMARY
[0013] The present invention provides an adsorbent for desulfurization of gasoline, which is used to solve said drawbacks in the prior art such as limited deep desulfurization and small sulfur adsorption capacity of the desulfurization adsorbent, low selectivity, short service life, relatively complicated regeneration process, and harsh desulfurization conditions.
[0014] The present invention further provides a method for desulfurization of gasoline, which is used to solve said drawbacks in the prior art such as limited desulfurization of the desulfurization method and great loss of octane number.
[0015] The present invention provides an adsorbent for desulfurization of gasoline, which is obtained by loading an active metal component on a composite carrier, the composite carrier comprises a zeolite and an active carbon which are subjected to alkali treatment respectively, where, the active metal is selected from one or more elements of IA, VIII, IB, IIB and VIB groups in the periodic table.
[0016] In the composite carrier of the present invention, a mass ratio of the zeolite to the active carbon is (20-80):(80-20), preferably (20-60):(80-40).
[0017] Furthermore, the zeolite is an X type, a Y type or a ZSM-5 type zeolite. The present invention does not strictly limit the adopted X type and the ZSM-5 type zeolite; a ratio of silicon atoms to aluminum atoms in skeleton of the Y type zeolite is no less than 3.0 (as measured by an XRD method). In addition, the present invention does not strictly limit the active carbon used, and a specific surface area thereof may be about 1000 m.sup.2/g generally.
[0018] In the present invention, the active metal selected from IA group in the periodic table is, for instance, potassium (K), sodium (Na), etc.; the active metal selected from VIII group in the periodic table is, for instance, iron (Fe), cobalt (Co), nickel (Ni), etc.; the active metal selected from IB group in the periodic table is, for instance, copper (Cu), silver (Ag), etc.; the active metal selected from IIB group in the periodic table is, for instance, zinc (Zn), etc.; the active metal selected from VIB group in the periodic table is, for instance, molybdenum (Mo), etc.
[0019] Furthermore, the active metal is selected from at least two of Ni, Fe, Ag, Co, Mo, Zn and K, in which Ni may have a loading of 10-30% on the composite carrier; Fe may have a loading of 5-15% on the composite carrier; Ag may have a loading of 5-10% on the composite carrier; Co may have a loading of 5-10% on the composite carrier; Mo may have a loading of 5-10% on the composite carrier; Zn may have a loading of 5-15% on the composite carrier; K may have a loading of 5-15% on the composite carrier. The loading is a loading of each active metal on the composite carrier respectively.
[0020] Furthermore, the active metal has a loading of 2-30% on the composite carrier, preferably 5-25%, more preferably 5-20%. When more than two active metals are loaded on the composite carrier, the loading is an overall loading of the active metals.
[0021] In an embodiment, the active metal is K and Ni; furthermore, K has a loading of 5-15% on the composite carrier, Ni has a loading of 10-25% on the composite carrier; furthermore, K and Ni which are loaded on the composite carrier have a mass ratio of (0.2-0.5):1.
[0022] In another embodiment, the active metal is Zn and Fe; furthermore, Zn has a loading of 5-15% on the composite carrier, Fe has a loading of 8-15% on the composite carrier; furthermore, Zn and Fe which are loaded on the composite carrier have a mass ratio of (0.5-1):1.
[0023] The present invention further provides a method for preparing the desulfurization adsorbent described above, including steps of:
[0024] blending the zeolite and the active carbon subjected to alkali treatment, respectively, in proportion to prepare the composite carrier;
[0025] impregnating the composite carrier with a soluble salt solution of the active metal, and drying the composite carrier impregnated with soluble salt solution and, then, calcinating to obtain the desulfurization adsorbent.
[0026] In an embodiment, the alkali treatment includes treating the zeolite and the active carbon, respectively, as follows: blending at a mass ratio of the zeolite or the active carbon to alkali to water: (0.1-2):(0.05-2):(4-15), and stirring the mixture for 0.1-24 h at the temperature of 0-120.degree. C., and then drying, the above alkali treatment is conducted at least one time.
[0027] The present invention does not strictly limit the alkali used in the alkali treatment, for instance, a NaOH solution at 0.10-1.0 mol/L may be used. Furthermore, a temperature of the stirring treatment may be 30-100.degree. C., and the time may be 1-10 h; furthermore, a temperature of the stiffing treatment may be 70-80.degree. C., and the time may be 2-4 h. A temperature of the drying after the stirring treatment may be, for instance, 100-120.degree. C., and the time may be, for instance, 5-8 h. The alkali treatment process may be one time or two times.
[0028] In the present invention, a soluble salt solution of the active metal may be, for instance, a sulfate solution, a nitrate solution, etc., preferably the sulfate solution. The impregnation may be incipient wetness impregnation which is a conventional impregnation method in the art, a specific operation thereof may be, for instance: at an room temperature and in a stiffing condition, instilling a soluble salt solution of the active metal into the composite carrier until the composite carrier is aggregated to a ball, and then standing for a period of time (for instance, 1-3 h). Especially, when two active metal components are loaded on the composite carrier, firstly a soluble salt solution of the first active metal is loaded by incipient wetness impregnation, upon washing, drying and calcinating, then a soluble salt solution of the second active metal is loaded by incipient wetness impregnation, upon washing, drying and calcinating, a composite carrier loading two active metal components may be prepared.
[0029] During the impregnation, the amount of soluble salt of the active metals needed for the impregnation may be calculated according to a requirement for the loading of the active metals on the composite carrier respectively and a requirement for the overall loading (loading more than two active metal components) of the active metals on the composite carrier.
[0030] Furthermore, the drying for the impregnated material is conducted for 12-24 h at a temperature of between 90-120.degree. C., preferably for 18-24 h at a temperature of between 110-120.degree. C. The impregnated material is subjected to calcinations for 4-6 h at a temperature of between 450-640.degree. C. after being dried.
[0031] Furthermore, the impregnated material being subjected to calcinations after being dried includes cooling the dried material down to a room temperature, elevating the temperature to 400.degree. C. at a speed of 6.degree. C./min firstly, and then elevating the temperature to 450-640.degree. C. at a speed of 3.degree. C./min.
[0032] The present invention further provides a method for regenerating any one of the desulfurization adsorbents described above, including: sequentially conducting steam washing, nitrogen drying at a temperature of between 200-400.degree. C. and nitrogen cooling to the desulfurization adsorbent to be regenerated.
[0033] Furthermore, the regenerating method includes firstly sweeping the desulfurization adsorbent to be regenerated with steam at a temperature of 130-180.degree. C. for 1-3 h for washing, then sweeping for 10-60 min with nitrogen at a temperature of 200-400.degree. C. for drying, and finally sweeping for 10-60 min with nitrogen at a room temperature for cooling.
[0034] The present invention further provides a method for desulfurization of gasoline, including: conducting adsorption desulfurization to gasoline using any one of the desulfurization adsorbents described above.
[0035] In an embodiment, the gasoline is firstly cut into a light gasoline fraction and a heavy gasoline fraction, and then the light gasoline fraction is subjected to adsorption desulfurization using the desulfurization adsorbent to obtain a desulfurized light gasoline fraction, and the heavy gasoline fraction is subject to selective hydrodesulfurization to obtain a desulfurized heavy gasoline fraction, wherein, a cutting temperature of the light gasoline fraction and the heavy gasoline fraction is 70-110.degree. C., for instance, 80-100.degree. C.
[0036] In the present invention, the gasoline may be fluid catalytic cracking gasoline, coking gasoline, etc.; the cutting refers to cutting of the gasoline into a light gasoline fraction and a heavy gasoline fraction according to a distillation range from low to high. Moreover, a desulfurized gasoline may be prepared by mixing the desulfurized light gasoline fraction with the desulfurized heavy gasoline fraction.
[0037] Furthermore, the adsorption desulfurization is conducted using a fixed-bed at atmospheric pressure, a temperature of the adsorption desulfurization is controlled between 20-100.degree. C., for instance, 30-80.degree. C., and a flow rate of the gasoline is 0.3-1 mL/min, for instance, 0.5 mL/min.
[0038] The method for desulfurization of gasoline of the present invention may further include:
[0039] washing the desulfurization adsorbent which is subjected to the adsorption desulfurization with steam to collect a sulfur-rich component;
[0040] mixing the sulfur-rich component with the heavy gasoline fraction to conduct the selective hydrodesulfurization.
[0041] Furthermore, the method for desulfurization of gasoline also includes:
[0042] after washing the desulfurization adsorbent which is subjected to the adsorption desulfurization with the steam, drying the washed desulfurization absorbent with nitrogen at a temperature of 200-400.degree. C., and cooling the dried desulfurization adsorbent with nitrogen to realize regeneration of the desulfurization adsorbent.
[0043] Specifically, steam at a temperature of 130-180.degree. C. may be used to sweep the desulfurization adsorbent which is subjected to the adsorption desulfurization for 1-3 h for washing, then nitrogen at a temperature of 200-400.degree. C. is used to sweep a same for 10-60 min for drying, and finally nitrogen at a room temperature is used to sweep the same for 10-60 min for cooling.
[0044] In the method for desulfurization of gasoline according to the present invention, the heavy gasoline fraction and hydrogen are subjected to the selective hydrodesulfurization in the presence of a selective hydrodesulfurization catalyst to obtain the desulfurized heavy gasoline fraction, wherein, a temperature of the selective hydrodesulfurization is 200-300.degree. C., a pressure thereof is 1.5-2.5 MPa, a liquid hourly space velocity (the heavy gasoline fraction) is 1-5 h.sup.-1, a volume ratio of hydrogen to oil is 400-600.
[0045] The selective hydrodesulfurization catalyst described in the present invention may be a conventional catalyst subjecting gasoline to selective hydrodesulfurization in the prior art, such as a catalyst of RSDS-I, RSDS-21, RSDS-22 in the RSDS process, a catalyst of HR806 and HR841 in the Prime-G+process, a combined catalyst of FGH-20/FGH-11 in the OCT-M process, an HDOS series deep hydrodesulfurization catalyst in the CDOS process, etc.
[0046] In an embodiment, the hydrodesulfurization catalyst is obtained by loading a carrier with an active metal component, wherein, the carrier is a zeolite (such as the X type, the Y type or the ZSM-5 type zeolite) or a metal oxide (such as aluminium oxide), and the active metal includes Co and Mo. Furthermore, Co and Mo have an overall loading of 5-20% on the carrier. Furthermore, Co and Mo which are loaded on the carrier have a mass ratio of (0.2-0.6):1.
[0047] In an embodiment, the light gasoline fraction may be subjected to the adsorption desulfurization after being subjected to demercaptan treatment.
[0048] In another embodiment, the gasoline may also be cut into the light gasoline fraction and the heavy gasoline fraction after being subjected to demercaptan treatment.
[0049] Furthermore, a conventional method may be used for the demercaptan treatment, such as an alkali extraction method or a mercaptan conversion method. The alkali extraction method uses an alkali solution to extract mercaptan therein for its removal, the amount of alkali contained in the alkali solution may be 5-50%, a volume ratio of oil to alkali may be (1-15):1, an operating temperature may be 10-60.degree. C.; the mercaptan conversion method is to convert a small molecule of mercaptan into other sulfides for its removal, which may be conducted by means of prehydrogenation in a conventional alkali-free deodorization process and Prime-G+process, where a condition for the alkali-free deodorization process may be: an operating pressure of a reactor is 0.2-1.0 MPa, a reaction temperature is 20-60.degree. C., a feeding space velocity is 0.5-2.0 h.sup.-1, a volume ratio of an air flow to a feeding flow is 0.2-1.0, the catalyst and the cocatalyst used may be a common catalyst in the art.
[0050] Implementations of the present invention have at least the following advantages:
[0051] 1. The desulfurization adsorbent in the present invention uses a composite carrier comprising a zeolite and an active carbon which are subjected to alkali treatment respectively, and a specific active metal component is loaded on the composite carrier, the adsorbent not only has a large sulfur capacity and a good selectivity for sulfur, but also has highly deep desulfurization, and sulfur may be desulfurized to 1 ppmw (part per million by weight); in addition, the adsorbent has a long service life and relatively environment-friendly.
[0052] 2. When using the desulfurization adsorbent of the present invention to conduct gasoline desulfurization, the operational condition of the process is mild, which can be conducted at an atmospheric pressure and a relatively low temperature, thus energy consumption is saved and operational costs are reduced.
[0053] 3. The method for regenerating the desulfurization adsorbent of the present invention is simple and easy to operate, the regenerated desulfurization adsorbent does not need to be reduced with hydrogen prior to use, which is environment-friendly and economical; moreover, the desulfurization adsorbent can be regenerated many times, and still maintain a good desulfurization effect after being regenerated.
[0054] 4. The desulfurization method in the present invention, after gasoline is cut into a light gasoline fraction and a heavy gasoline fraction, the light gasoline fraction is subjected to adsorption desulfurization, and the heavy gasoline fraction is subjected to selective hydrodesulfurization, this method not only can reduce the content of the hydrodesulfurized components, but also can realize deep desulfurization of gasoline feedstock, and there is almost no loss of octane number
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Adsorptive Desulfurization (University Of Connecticut)
United States Patent Application 20160175806
SUIB; Steven L. ;   et al.   June 23, 2016
Applicant: University Of Connecticut
Abstract
The disclosure relates to a method for removing sulfur-containing compounds from a fluid. The method involves adding manganese oxide to the fluid; doping the manganese oxide in situ with iron, cobalt, or combinations thereof to give a doped manganese oxide adsorbent; and contacting the fluid with a selected amount of the doped manganese oxide adsorbent and at a selected temperature and pressure sufficient for the doped manganese oxide adsorbent to preferentially adsorb the sulfur-containing compounds in the fluid. The disclosure also relates to a process for preparing a doped manganese oxide adsorbent, and a doped manganese oxide adsorbent prepared by the process. The disclosure further relates to a method for tuning structural properties (e.g., surface area, pore size and pore volume) of a doped manganese oxide adsorbent.
BACKGROUND
[0002] 1. Field of the Disclosure
[0003] This disclosure relates to doped manganese oxide adsorbent materials useful in adsorptive desulfurization. In particular, this disclosure relates to doped manganese oxide adsorbent materials and processes for preparing the doped manganese oxide materials having tunable properties, for example, tunable surface area, pore size and pore volume.
[0004] 2. Discussion of the Background Art
[0005] Metal oxides and mixtures are generally chosen as desulfurization sorbents for hot gas desulfurization processes. However, the problem with these largely existing materials is that they suffer from low performance and thermally instability. For example, zinc oxide materials are widely used, and they have been investigated for practical applications. The main drawback of using zinc oxide is the fact that reduction of zinc oxide to metallic zinc occurs around 700.degree. C., largely decreasing the sulfur adsorption capacity. Although other materials, such as carbon or metal doped carbon, are much lower in price, they have a much lower capacity than metal oxide based material. Therefore, there is a need for new sulfur adsorbents with both high performance and low cost.
[0006] High sulfur sorption capacity materials are high in demand, having already been investigated due to their potential applications in conventional power generation, polymer electrolyte fuel cells and other processes requiring desulfurization. Manganese oxide octahedral molecular sieves (OMS) materials are promising, having shown to be among the best in terms of performance for desulfurization processes. It would be desirable to increase the sulfur capacity and lower the cost of material.
[0007] The present disclosure provides many advantages over the prior art, which shall become apparent as described below.
SUMMARY OF THE DISCLOSURE
[0008] This disclosure relates to doped manganese oxide adsorbent materials useful in adsorptive desulfurization. In particular, this disclosure relates to doped manganese oxide adsorbent materials and processes for preparing the doped manganese oxide materials having tunable properties, for example, tunable surface area, pore size and pore volume.
[0009] This disclosure also relates in part to a method for removing sulfur-containing compounds from a fluid. The method involves adding manganese oxide to the fluid; doping the manganese oxide in situ with iron, cobalt, or combinations thereof to give a doped manganese oxide adsorbent; and contacting the fluid with a selected amount of the doped manganese oxide adsorbent and at a selected temperature and pressure sufficient for the doped manganese oxide adsorbent to preferentially adsorb the sulfur-containing compounds in the fluid.
[0010] This disclosure further relates in part to a process for preparing an adsorbent material. The process involves adding manganese oxide to the fluid; doping the manganese oxide in situ with iron, cobalt, or combinations thereof to give a doped manganese oxide adsorbent; and contacting the fluid with a selected amount of the doped manganese oxide adsorbent and at a selected temperature and pressure and for a period of time sufficient to prepare a doped manganese oxide adsorbent material.
[0011] This disclosure yet further relates in part adsorbent material prepared by a process. The process involves adding manganese oxide to the fluid; doping the manganese oxide in situ with iron, cobalt, or combinations thereof to give a doped manganese oxide adsorbent; and contacting the fluid with a selected amount of the doped manganese oxide adsorbent and at a selected temperature and pressure and for a period of time sufficient to prepare a doped manganese oxide adsorbent material.
[0012] This disclosure also relates in part to a method for tuning structural properties of an adsorbent material. The method involves adding manganese oxide to a fluid; doping the manganese oxide in situ with iron, cobalt, or combinations thereof to give a doped manganese oxide adsorbent; and contacting the fluid with a selected amount of the doped manganese oxide adsorbent and at a selected temperature and pressure and for a selected period of time sufficient to tune the structural properties (e.g., surface area, pore size and pore volume) of the doped manganese oxide adsorbent.
[0013] This disclosure also relates in part to a composition comprising at least one derivative, doped or reduced compound of the formula
MMn.sub.8O.sub.16
wherein M is an alkali metal or an alkaline earth metal. In an embodiment, the composition comprises at least one derivative, doped or reduced compound of the formula
KMn.sub.8O.sub.16
or at least one derivative, doped or reduced compound of the formula
M.sub.vCo.sub.xFe.sub.yMn.sub.zO.sub.16
wherein M is an alkali metal or an alkaline earth metal, and v, x, y, and z independently have a value from 0 to 8. In an embodiment, the composition has a Birnessite type structure or a Cryptomelane type structure.
[0014] Further objects, features and advantages of the present disclosure will be understood by reference to the following drawings and detailed description.
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