Monday, April 24, 2017

CATALYSIS: Warming the Bench (Part 10 of the Catalysis Series)



Today, let’s take a closer look at the results of the desulfurization bench scale results featured in yesterday’s post.

As you will recall, the Google® search string desulfurization AND bench resulted in 467,000 results

We will browse the results to see what we can find that fits into anything from 2 to 7 on the Technology Readiness scale.

2
validated concept
experimental proof of concept using physical model tests
3
prototype, prototype tested
system function, performance and reliability tested
4
environment tested
preproduction system environment tested
5
system tested
production system interface tested
6
Reid qualified, system installed
production system installed and tested
7
field proven
production system field proven

Google® search string:
desulfurization AND bench

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RESULTS (browsing and selecting 5 pages deep)
Hielscher Ultrasonics: Oxidative Desulfurization of Fuel Oils by Ultrasonication
All over the world, the emission standard regarding desulfurization of fuels are tightened and this process will continue. Governmental regulations that concern e.g. USA, Europe and Japan issue ultra-low sulfur diesel specifications whereby a very deep desulfurization is necessary to comply with this environmental requirement. Environmental objective is the emission reduction of sulfur dioxide (SO2). The US government pledges all refineries since 1st of June 2006 to produce at least 80% of ultra-low sulfur diesel (ULSD). Since October 2006, only this ultra-low sulfur diesel is allowed for use on road. Before the governmental regulations in 2006, the permitted sulfur value was at 500pmm, but today´s ultra-low sulfur diesel specification means a maximum quota of 15pmm sulfur resulting in the complete depletion of sulfur in fuels. Since 2010 also non-road engines are affected by the ULSD specification. This means that the standard of 15pmm sulfur is applied to the non-road diesel fuel production. The table below shows the non-road diesel fuel standard, constituted by US Environmental Protection Agency (EPA). Crude oil, also known as petroleum, is consisting of hydrocarbons of various molecular weights and other organic compounds. The sulfur containing compounds are sulfides, thiols, thiophenes, substituted benzothiophenes (BT) and dibenzothiophenes (DBT), benzonaphthothiophenes (BNT), and further complex molecules. To remove the sulfur compounds from processed crude oil products, such as naphta, kerosene, diesel oil and heavier oils, the commonly used industrial desulfurization process is the hydrodesulfurization (HDS). This is a highly cost-intensive process, that is furthermore not capable of removing recalcitrant aromatic sulfur compounds, such as 4,6- dimethyldibenzothiophene, as a result of their low reactivity. Next to the conventional HDS are existing some alternative desulfurization methods, such as biodesulfurization, ionic liquid-catalysis, microwave catalytic desulfurization, oxidative desulfurization and the ultrasound-assisted oxidative desulfurization (UAOD). Ultrasound offers a potential alternative for removing sulfur from crude oil and petroleum products. This process is known as Ultrasound-Assisted Oxidative Desulfurization – as the name indicates, it is an oxidative process. This means that the sulfur of thiophenes is oxidized to sulfoxides and sulfones. For the UAOD processing, a multiphase reaction medium of fuel, an aqueous fluid, oxidants, catalysts, phase transfer agent has to be sonicated. The most common oxidizing agent is hydrogen peroxide (H2O2) used. Ultrasound shock waves at high intensities, applied to the multiphase reaction medium, generate alternating highpressure and low-pressure cycles. During the low-pressure cycle, highly intensive ultrasound waves create small vacuum bubbles in the liquid. When the vacuum bubbles attain a volume at which they cannot longer absorb energy, they collapse impetuously during a high pressure cycle. This high-energy action is called cavitation. The cavitational forces create in liquids locally extreme conditions, such as very high temperatures (approx. 4500°C or 5000K) and pressures (approx. 2000atm). The implosion of the cavitation bubbles also results in liquid jets with velocities up to 280m/sec. These conditions enhance the micro-mixing and bear thereby a better surface chemistry of catalysts. As the ultrasound-assisted oxidation generates heat, additional heating of the processed fuel mix is not required. The heat caused by ultrasonic processing promotes the chemical reaction that is faster at high temperatures, e.g. in the range between 60°C and 70°C. By ultrasonic desulfurization and the emerging oxidation, an aqueous and an organic phase are produced. The organic phase contains the sulfones and sulfoxides, which are generated by oxidative reaction. Due to their polarity, the sulfoxides and sulfones can be easily separated by decantation or extraction. Besides the treatment of automotive fuels, such as gasoline, diesel, kerosene and jet fuels, UAOD is also an interesting application for residuum-based fuel oils like bunker fuels and residual fuels. Hielscher Ultrasonics as top supplier of high power ultrasonic processor in every scale offers with its UIP10000 (10kW) and UIP16000 (16kW) ultrasonic systems for high volume desulfurization processes. Both, UIP10000 and UIP16000, can be installed as clusters so there are virtually no limitations for continuous processing of larger volume flows. Industrial fuel processing does not need much ultrasonic energy. The actual energy requirement can be determined using a 1kW ultrasonic processor in bench-top scale. All results from such bench-top trials can be scaled up easily and linear. If required, FM and ATEX certified ultrasonic devices (e.g. UIP1000-Exd) are available for the sonication in hazardous environments.
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U.S. Army RDECOM (ARL)
Creating desulfurized fuel for fuel cells
This invention represents a substantial advance toward the goal of providing clean, sulfur-free fuel to solid oxide fuel cells (SOFCs). Researchers at the Sensors and Electron Devices Directorate of the U.S. Army Research Laboratory (ARL), successfully tested a new method and apparatus that removes performance-killing sulfur compounds from petroleum-based fuels converted for use in SOFCs. Desulfurization is a critical step in SOFC operation, and ARL's invention offers a significant advantage over current methods and can undoubtedly enable wider application of this new green energy technology.
INVENTION OVERVIEW
Novel design simplifies process for removing sulfur impurities from fuel cell gas feedstock
Does not require special equipment or processing techniques to create sorbent apparatus
Industrial, home, and military fuel cell applications
TRL 3 - Fully functioning bench-scale apparatus and test data available
URL

Bench-scale demonstration of hot-gas desulfurization technology
Submitted to:
U.S. Department of Energy, Federal Energy Technology Center
Prepared by:
S.K. Gangwal & J.W. Portzer, RTI, Research Triangle Park, NC
April 2002
The U.S. Department of Energy (DOE), Federal Energy Technology Center (FETC), is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal-derived fuel-gas) streams of integrated gasification combined-cycle (IGCC) power systems. The hot gas cleanup work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs. Hot-gas desulfurization research has focused on regenerable mixed-metal oxide sorbents that can reduce the sulfur in coal-derived fuel-gas to less than 20 ppmv and can be regenerated in a cyclic manner with air for multicycle operation. Zinc titanate (Zn(sub 2) TiO(sub 4) or ZnTiO(sub 3)), formed by a solid-state reaction of zinc oxide (ZnO) and titanium dioxide (TiO(sub 2)), is currently one of the leading sorbents. Overall chemical reactions with Zn(sub 2) TiO(sub 4) during the desulfurization (sulfidation)-regeneration cycle are shown below: Sulfidation: Zn(sub 2) TiO(sub 4)+ 2H(sub 2)S(yields) 2ZnS+ TiO(sub 2)+ 2H(sub 2)O; Regeneration: 2ZnS+ TiO(sub 2)+ 3O(sub 2)(yields) Zn(sub 2) TiO(sub 4)+ 2SO(sub 2) The sulfidation/regeneration cycle can be carried out in a fixed-bed, moving-bed, or fluidized-bed reactor configuration. The fluidized-bed reactor configuration is most attractive because of several potential advantages including faster kinetics and the ability to handle the highly exothermic regeneration to produce a regeneration offgas containing a constant concentration of SO(sub 2)
Type
Web Page
URL

Bench Scale Development Of Meyers Process For Coal Desulfurization (2002)
Type
Web Page
Author
Office of Research & Development
URL
Abstract
The report gives results of coal desulfurization experiments to determine the feasibility and advantages of combining gravity separation of coal with chemical desulfurization. The investigations led to the definition of the Gravichem Process, a combination physical/chemical coal desulfurization scheme involving Meyers Process reagent and chemistry. Two coals were investigated: a run-of-the-mine coal sample and a mine-cleaned (MC) coal sample, both from the Martinka Mine, Lower Kittanning seam, and furnished by the American Electric and Power System (AEP Utility). Coal selection was influenced by the 60 million tons of recoverable Martinka Mine coal reserves, by the availability of coal output from a modern, commercial size, physical coal cleaning plant at the same mine, and by AEP's expressed interest in physical and chemical coal desulfurization as a means of solving sulfur pollution problems. MC Martinka coal will be the first coal to be tested at the 8 tons per day Meyers Process Reactor Test Unit.

Bench Scale Evaluation of the Intramicron Desulfurization Technology Suite | AIChE Academy
The IntraMicron Desulfurization Technology Suite (IM-DTS) is an innovative sulfur removal and recovery system that was developed to address the current need for scalable desulfurization technology for a variety of feedstocks including but not limited to natural gas, biogas, landfill gas, frac gas, petroleum gas, refinery off gas, flare gas, syngas, as well as gasified biomass, coal, and municipal solid waste (MSW).  IM-DTS is the synergistic combination of a selective catalytic oxidative sulfur removal (OSR) stage that transforms up to 99% of sulfur contaminants (H2S, COS, mercaptans, etc.) into elemental sulfur using a proprietary, patent-pending catalyst and a polishing adsorbent bed equipped with an in-situ bed-life capacity sensor (BLS) that enables optimal adsorbent bed operation and cycling.  IntraMicron’s OSR catalyst does not produce significant amounts of SO2, even in the presence of a high concentrations of oxidizers and is tolerant to numerous contaminants (halogens, NH3, etc.).   IntraMicron’s BLS optimizes the polishing adsorbent step of the process by providing an indication of the remaining capacity in the adsorbent bed.  IM-DTS was evaluated at the bench scale to determine its performance at a wide range of experimental conditions with the goal of assisting in determining process economics and appropriate scaling parameters.  The results of the bench-scale evaluations were used in conjunction with process simulations to show that IM-DTS can provide up to a 75% reduction in total life cycle desulfurization cost compared to current state of the art desulfurization technologies at several scales.
Type
Web Page
URL
Date
2015

Coal Desulfurization via Different Methods
Type
Journal Article
Author
AYHAN DEMIRBAS
Author
MUSTAFA BALAT
URL
Volume
26
Issue
6
Pages
541-550
Publication
Energy Sources
Date
May 1, 2004
Library Catalog
Taylor and Francis+NEJM
Abstract
Inorganic materials of coal contain a number of inorganic constituents, especially sulfur, which plays an important role in almost all coal utilization systems. Some methods have been applied to coal to remove its inorganic materials from the organic part. Coal before utilization is subjected to some physical, chemical and biological desulfurization methods. However, physical and biological methods are ineffective and time consuming and they can be applied only on the bench scale. Most of the effective coal desulfurization techniques are based on chemical methods. Main desulfurization methods are chemical desulfurization, leaching, extraction, flotation, oxydesulfurization and biodesulfurization. The alkaline desulfurization is more effective in removing the pyritic sulfur from the coal, which is the less abundant form than the organic sulfur.

Enhanced Selenium Removal from Flue Gas Desulfurization Wastewater
Dr. Higgins will present the paper, “Demonstration Test of Iron Addition to a Flue Gas Desulfurization (FGD) Absorber to Enhance Flue Gas Selenium Removal,” at the International Water Conference on Tuesday, November 15, in Orlando, Florida. Dr. Higgins is also the discusser for the presentation, “Selenium Control in Wet FGD Systems,” by Katherine Searcy, Trimeric Corporation, Buda, TX; Mandi K. Richardson, Gary M. Blythe, URS Corporation, Austin, TX; Paul Chu, Charles Dene, EPRI, Palo Alto, CA; and Dirk Wallschläger, Trent University, Peterborough, ON, Canada, Tuesday afternoon.
Tightening regulations on sulfur dioxide flue gas emissions are leading more electric utilities to install flue gas desulfurization (FGD) systems on coal-fired units, often in the form of limestone forced-oxidation wet scrubbers. These FGD systems also remove a portion of the selenium and other volatile metals from the flue gas stream. Some of the selenium is incorporated in the byproduct gypsum; additional selenium ends up in the chloride purge stream; and the remainder is discharged in the scrubbed flue gas. The purge water includes both particulate and dissolved selenium, and discharge standards often require that this purge stream be treated to a selenium concentration of less than 10 parts per billion (ppb).
Chemistry simulatorWhile selenium is principally absorbed from the flue gas as selenite, the selenite can be oxidized to selenate by the forced oxidation process.  While there are commercial physical chemical processes for selenite removal from FGD wastewater, FGD wastewater treatment for selenate removal has been limited to biological processes, which adds to the complexity and cost of FGD wastewater treatment. It has been estimated that biological systems, such as an attached growth bioreactor, cost over $30 million in capital and $3 million per year in operating costs for 1 million gallons per day (mgd) of FGD wastewater treatment.
Selenite can be removed from water by adsorption on precipitated iron hydroxide particles at an acidic pH. This process is easily added to a chloride purge wastewater system that uses iron addition for coagulation and clarifiers for solids removal. Such clarifier-based systems are already being used on dozens of FGDs, and the iron co-precipitation process has been tested and employed at full-scale in various industries.
For this reason, we have been studying whether the addition of an iron salt to a limestone forced-oxidation scrubber could result in absorption of selenite on the ferrihydrite solid before it can be oxidized to selenate, and thus remove these particles in a subsequent process for solids removal. We began by evaluating whether selenium was adsorbing to naturally occurring precipitate iron hydroxide in FGD absorber slurries, and found a strong correlation between particulate selenium and particulate iron. Based on these observations, bench-scale testing of iron salt addition to FGD absorbers was performed in 2008. Results showed a reduction in selenate formation compared to operation without iron addition, so we followed up with full-scale tests in 2009 and 2011.
Iron addition equipmentI will share details of the full-scale tests in my International Water Conference presentation this week, but am pleased to share here that results indicate that the iron addition does appear to result in conversion of selenite to a particulate form and significantly reduces selenate formation, resulting in a steady decline of selenium in the absorber slurry. These full-scale pilot tests were not only able to demonstrate the effectiveness of the technology, but also determined that there were no problems associated with the technology that would affect FGD operation and gypsum dewatering. This is good news for owners and operators of coal-fired electric utilities, as this technology is also a much less costly solution for selenium removal than implementing biological systems, averaging in the low hundreds of thousands of dollars for equipment and operating costs compared to millions.
FGD wastewater treatment is a hot topic, with numerous presentations on the subject being given at the International Water Conference.  In addition to presenting my own paper on the topic, I have also been invited to be the discusser on the paper presentation, “Selenium Control in Wet FGD Systems,” by Katherine Searcy, Trimeric Corporation; Mandi K. Richardson, Gary M. Blythe, URS Corporation; Paul Chu, Charles Dene, EPRI; and Dirk Wallschläger, Trent University. The paper discusses results from bench- and pilot-scale scrubber test campaigns to reduce selenium in FGD wastewater as well as ongoing efforts to develop improved sample handling methods for measuring selenium species.  As a discusser, I will share my thoughts and critiques on the tests and analysis discussed in the paper after it is presented. The presentation followed by discussion is a unique format which demonstrates how our industry is working together across organizational lines to ensure that the best technologies and treatment solutions are available for our communities around the world.
Dr. Higgins is an internationally-recognized early leader in the treatment of water contaminated with mercury and other metals. A recognized and respected expert in his field, Dr. Higgins is the lead author of 3 books and has contributed his work to over 90 publications. In addition, Dr. Higgins led efforts to develop treatment technologies for the removal of mercury and other metals from industrial wastewaters and remediation groundwater. His efforts have led to 4 patents for his innovative treatment processes, with an additional mercury related technology patent in process. He has demonstrated another innovative process for mercury removal in a highly chemical scaling wastewater utilizing iron and organosulfide precipitation of mercury and vacuum microfiltration.
Type
Web Page
Author
Access Water
URL
Date
2015

FBC desulfurization process using coal with low sulfur content, high oxidizing conditions and metamorphic limestones
A metamorphic limestone and a dolomite were employed as SO2 sorbents in the desulfurization of gas from coal combustion. The tests were performed in a fluidized bed reactor on a bench and pilot scale. Several parameters such as bed temperature, sorbent type, and sorbent particle size at different Ca/S molar ratios were analyzed. These parameters were evaluated for the combustion of coal with low-sulfur/high-ash content, experimental conditions of high air excess and high O2 level in fluidization air. Under these conditions, typical of furnaces, few published data can be found. In this work, a medium level of desulfurization efficiency (~60%) for Ca/S = 2 was obtained.
Type
Journal Article
Author
S. R. Bragança
Author
J. L. Castellan
URL
Volume
26
Issue
2
Pages
375-383
Publication
Brazilian Journal of Chemical Engineering
ISSN
0104-6632
Date
06/2009

Gasification-2015-Workshop-Gupta-Presentation-FINAL.pdf
RTI Warm Gas Cleanup Technology
An advanced enabling technology for other downstream technologies, such as novel hydrogen enrichment, syngas conversion, WGS, warm CO2 capture.
RTI has developed a platform of warm syngas cleanup technologies:
Increase efficiency and lower costs
Operate at 250-600ºC
Pressure independent
Effective for all forms of sulfur
Fully compatible with all CO2 capture
Flexible modular approach enables specific syngas purity needs to be met
Systems tested on actual coal-based syngas
Warm desulfurization process (WDP) now tested through pre-commercial demo scale Installed Pilot Plant Systems (2006-2008) Eastman’s Kingsport, TN, Coal Gasification Facility
Type
Attachment
URL

Pilot-Scale Demonstration Of Hzvi Process For Treating
The hybrid Zero Valent Iron (hZVI) process is a novel chemical treatment platform that has shown great potential in our previous bench-scale tests for removing selenium, mercury and other pollutants from Flue Gas Desulfurization (FGD) wastewater. This integrated treatment system employs new iron chemistry to create highly reactive mixture of Fe^0, iron oxides (FeOx) and various forms of Fe (II) for the chemical transformation and mineralization of various heavy metals in water. To further evaluate and develop the hZVI technology, a pilot-scale demonstration had been conducted to continuously treat 1-2 gpm of the FGD wastewater for five months at Plant Wansley, a coal-fired power plant of Georgia Power. This demonstrated that the scaled-up system was capable of reducing the total selenium (of which most was selenate) in the FGD wastewater from over 2500 ppb to below 10 ppb and total mercury from over 100 ppb to below 0.01 ppb. This hZVI system reduced other toxic metals like Arsenic (III and V), Chromium (VI), Cadmium (II), Lead (II) and Copper (II) from ppm level to ppb level in a very short reaction time. The chemical consumption was estimated to be approximately 0.2-0.4 kg of ZVI per 1 m^3 of FGD water treated, which suggested the process economics could be very competitive. The success of the pilot test shows that the system is scalable for commercial application. The operational experience and knowledge gained from this field test could provide guidance to further improvement of technology for full scale applications. The hZVI technology can be commercialized to provide a cost-effective and reliable solution to the FGD wastewater and other metal-contaminated waste streams in various industries. This technology has the potential to help industries meet the most stringent environmental regulations for heavy metals and nutrients in wastewater treatment.
Type
Thesis
Author
PHANI KUMAR PEDDI
URL
Date
2011
University
Texas A&M University

Stabilized Nano-ZnO for Diesel Desulfurization for Fuel Cell Applications | SBIR.gov (2002)
The hybrid Zero Valent Iron (hZVI) process is a novel chemical treatment platform that has shown great potential in our previous bench-scale tests for removing selenium, mercury and other pollutants from Flue Gas Desulfurization (FGD) wastewater. This integrated treatment system employs new iron chemistry to create highly reactive mixture of Fe^0, iron oxides (FeOx) and various forms of Fe (II) for the chemical transformation and mineralization of various heavy metals in water. To further evaluate and develop the hZVI technology, a pilot-scale demonstration had been conducted to continuously treat 1-2 gpm of the FGD wastewater for five months at Plant Wansley, a coal-fired power plant of Georgia Power. This demonstrated that the scaled-up system was capable of reducing the total selenium (of which most was selenate) in the FGD wastewater from over 2500 ppb to below 10 ppb and total mercury from over 100 ppb to below 0.01 ppb. This hZVI system reduced other toxic metals like Arsenic (III and V), Chromium (VI), Cadmium (II), Lead (II) and Copper (II) from ppm level to ppb level in a very short reaction time. The chemical consumption was estimated to be approximately 0.2-0.4 kg of ZVI per 1 m^3 of FGD water treated, which suggested the process economics could be very competitive. The success of the pilot test shows that the system is scalable for commercial application. The operational experience and knowledge gained from this field test could provide guidance to further improvement of technology for full scale applications. The hZVI technology can be commercialized to provide a cost-effective and reliable solution to the FGD wastewater and other metal-contaminated waste streams in various industries. This technology has the potential to help industries meet the most stringent environmental regulations for heavy metals and nutrients in wastewater treatment.
Type
Web Page
URL

Ultrasonic Alternative to Hydrodesulfurization
Oil refineries are facing increasingly sulfurous (sour) crude supplies and environmental regulatory pressure on sulfur content of gasoline. At the same time, the costs of conventional hydrodesulfurization (HDS) are rising because of the hydrogen needed. Ultrasonic cavitation treatment is an effective alternative method. Fossil fuels contain sulfur compounds. These result from the degradation of biological matter containing sulfur during the natural formation of fossil fuels.
Vehicles, such as cars, aircrafts and marine vessels or power plants cause sulfur dioxide (SO2) emissions as a result of the petroleum fuel combustion. The same sulfur – even in very low concentrations – causes damages to noble metal catalysts in the downstream catalytic reforming in petroleum refineries. Latest environmental regulations require a very deep desulfurization to meet the ultra-low sulfur diesel (ULSD) specifications.
Background – Hydrodesulfurization (HDS) Hydrodesulfurization (HDS) is the standard catalytic process for the removal of sulfur from petroleum products. In this process, the sulfurous fractions of the crude oil are mixed with hydrogen and a catalyst to react to hydrogen sulfide. Typically, the catalyst consists of an alumina base impregnated with cobalt and molybdenum. As the oil supplies get more sour, higher pressures and alternative catalysts are required for the desulfurization. Recalcitrant aromatic sulfur compounds (e.g. 4,6-dimethyldibenzothiophene) cannot be removed using hydrodesulfurization, due to their low reactivity (see Deshpande 2004). Ultrasonically Assisted Desulfurization An alternative to hydrodesulfurization is the ultrasonically assisted desulfurization. The exposure of liquids to ultrasonic waves of high intensity causes acoustic cavitation. This is the formation and subsequent violent collapse of small vacuum (cavitation) bubbles. Locally, extreme conditions arise from the violent collapse of each bubble: Temperature: up to 5000 Kelvin Pressure: up to 2000 Atmospheres Liquid Jets: up to 1000km/hr. Such conditions promote a better surface chemistry of catalysts by enhanced micro-mixing. In particular the high local temperatures change the chemical reaction kinetics of the desulfurization process. (see sonochemistry). This effect allows for alternative – less expensive – catalysts or alternative desulfurization chemistry to be used. Deshpande et al. (2004) investigates an oxidative system composed of sodium carbonate and hydrogen peroxide in a biphasic system of diesel and acetonitrile. Ultrasonication was applied to the biphasic system. The study achieved a reduction of the DMDBT content by more than 90% in the diesel samples. Ultrasonic Process Equipment Hielscher is the leading supplier of high capacity ultrasonic devices, worldwide. As Hielscher makes ultrasonic processors of up to 16kW power per single device, there is no limit in plant size or processing capacity. Clusters of several 16kW systems are being used the processing of larger volume flows. Industrial fuel processing does not need much ultrasonic energy. The actual energy requirement can be determined using a 1kW ultrasonic processor in bench-top scale. All results from such bench-top trials can be scaled up easily. If required, FM and ATEX certified ultrasonic devices (e.g. UIP1000-Exd) are available for the sonication in hazardous environments. Costs of Ultrasonication Ultrasonication is an effective processing technology. Ultrasonic processing costs result mainly from the investment for ultrasonic devices, utility costs and maintenance. The outstanding energy efficiency (see chart) of Hielscher ultrasonic devices helps to reduce the utility costs.
Type
Web Page
URL

High intensity ultrasound for industrial applications
Ultrasound-Assisted Oxidative Desulfurization of Crude Oil
Industrial Sonomechanics, LLC (ISM), offers high-amplitude ultrasonic processors for the oxidative desulfurization of crude oil. The processors are based on ISM’s patented Barbell Horn Ultrasonic Technology (BHUT), which makes it possible to tremendously intensify ultrasound-assisted oxidative desulfurization and guarantees reproducible and predictable results at any scale of operation.
BACKGROUND
Crude oil contains sulfur in the form of sulfides, thiols, thiophenes, substituted benzo- and dibenzothiophenes, benzonaphthothiophene, etc. Extensive desulfurization is required in order to comply with current environmental regulations, such as the ultra-low sulfur diesel (ULSD, 15 ppm sulfur) specification.  Ultrasound-assisted oxidative desulfurization (UAOD) has been developed as an alternative technology to the traditional hydrotreating, which suffers from significant costs associated with high-pressure, high-temperature hydrodesulfurization equipment, boilers, hydrogen plants, and sulfur recovery units. Ultrasound-assisted oxidative desulfurization permits carrying out the process under much milder conditions, faster, safer and much more economically.
The oxidative desulfurization of crude oil is commonly done by mixing it with an oxidant, a catalyst and a phase-transfer agent (e.g. hydrogen peroxide solution in water, formic and/or acetic acid, quaternary ammonium). During the process, sulfur-containing compounds in crude oil are converted to polar sulfur oxides and sulfones, which are subsequently removed via selective adsorption or extraction. However, since all added reagents are water-based, they do not readily mix with the crude oil and must be emulsified. The reaction is mass transfer-limited and its rate strongly depends on the mixing efficiency and the resulting size of the contact surface area between the water and the oil phases.
ULTRASOUND-ASSISTED OXIDATIVE DESULFURIZATION
Ultrasound-assisted oxidative desulfurization is a very attractive alternative to the traditional hydrodesulfurization technology. Exposing liquids to high-intensity ultrasound greatly promotes mass transfer-limited reactions and surface chemistry of catalysts. Ultrasound creates acoustic cavitation, which produces violently imploding vacuum bubbles, causing shock waves, micro-jets and strong shear forces as well as extreme local temperatures (~5,000 K) and pressures (~1,000 atm). These extreme conditions result in exceptionally efficient mixing, yielding nanoemulsions with very small droplet sizes and enormous contact areas between all components. The oxidative desulfurization of crude oil is, therefore, considerably accelerated by exposure to high-intensity ultrasound.
THE IMPORTANCE OF HIGH ULTRASONIC AMPLITUDES
Ultrasonic intensification of commercial-scale oxidative desulfurization of crude oil requires the use of an industrial-size flow-through ultrasonic processor able to maintain high vibration amplitudes of about 80 - 100 microns. The amplitudes directly relate to the intensity of ultrasonic cavitation-generated shear forces and must be maintained at a sufficiently high level for the mixing to be efficient. Similar amplitudes are required for the production of high-quality nanoemulsions – a process which is a prerequisite for mass transfer-limited reactions.
Ultrasound-assisted oxidative desulfurizationWhy ISM's Ultrasonic Technology?
ISM has significant experience in the development of continuous-flow ultrasonic liquid processors for the oxidative desulfurization of crude oil. In the past, ISM served as a consultant and equipment provider to Sulphco, Inc. – a former Houston-based company, which employed the ultrasound technology to desulfurize and hydrogenate crude oil and other oil related products, upgrading sour heavy crude oils into sweeter, lighter crudes and producing more gallons of usable oil per barrel. During this project, commercial ultrasonic processors have been designed and implemented for the treatment of large volumes of petroleum products using relatively low temperatures and pressures, and without phase-transfer catalyst.
ISM is the only company that currently offers high-amplitude industrial-scale ultrasonic processors. The processors are based our proprietary Barbell Horn Ultrasonic Technology (BHUT), which permits increasing the sizes of ultrasonic horns without sacrificing the amplitudes they provide. Bench-scale (BSP-1200) and Industrial-scale (ISP-3000) processors are available, both of which are designed to maintain high ultrasonic vibration amplitudes and can be configured for continuous (24/7) operation under production floor conditions.
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2 comments:

  1. Thanks for your comment. Are you a researcher?

    ReplyDelete
  2. Thanks for your comment, Rajesh. I would love to know which posts in particular you found most helpful.

    ReplyDelete