Free Newsletter: Refinery Operations

“How often we recall, with regret, that Napoleon once shot at a magazine editor and missed him and killed a publisher. But we remember with charity that his intentions were good.” -- Mark Twain (American Humorist, Writer and Lecturer. 1835-1910)

According to its Web, Refinery Operations (http://refineryoperations.com/) is a biweekly newsletter focusing on refinery operations, maintenance, automation, safety and reliability. Its editorial content is of relevance to process, operations, automation and maintenance engineers with technical and managerial responsibilities in the refinery. Editor Rene G. Gonzalez is a chemical engineer by academic training, having previously worked as a process engineer in the refining industry. Throughout the year, Refinery Operations provides its refinery readers with a range of articles, updates and direct links to technical literature and white papers that include catalytic and thermal based processes, product recovery, rotating equipment, metallurgical, refractory, instrumentation and control, regulatory and compliance, and safety-related procedures.

The editor welcomes article submissions. Refinery Case studies and technical updates are the primary focus of Refinery Operations biweekly on-line newsletter as well as the Refinery Operations quarterly publication. Technical briefs and updates should be between 300-1000 words. These non-commercial write-ups should be written in succinct “technical” English that is of maximum benefit to the practicing refinery engineer, supported by graphics, photos and references.

Access to past issues of the newsletter is free.  Here are a few paragraphs from lead articles appearing in three issues from 2013.

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Refinery Operations, V. 4, Issue 1, January 2, 2013
Maintaining FCC Catalyst Activity and Bottoms Cracking
How does iron (Fe) affect FCC catalysts? What is tramp iron and how much is normally found on
equilibrium catalyst (E-cat)?
Kenneth Bryden, Manager, Evaluations Research at Grace Catalysts Technologies in Columbia, Maryland, USA
(kenneth.bryden@grace.com)
A distinction must be made between tramp Fe and Fe deposited on the cracking catalyst. Tramp Fe is composed of Fe particles in the catalyst stream that originate from erosion of pipes, vessels and other hardware. To the extent that these particles do not break up in very fine particles that can attach themselves to the cracking catalyst, they have little effect on catalyst activity and selectivity. However, they could affect CO oxidation and SOx emissions.
Fe deposited on the catalyst is in most cases the result of organic, colloidal or other finely dispersed Fe in the feed. It has been recently recognized that this latter form of Fe is an important factor causing FCC catalyst deactivation and observed loss of bottoms cracking. Decreases in average bed density (ABD) have also been reported. In general, the more finely dispersed the depositing Fe is, the more effective it is in causing catalyst deactivation.
Al-sol based catalyst resistance to Fe deactivation
At Grace Catalyst Technologies, we have studied extensively the effects of Fe on cracking catalysts. Using a combination of different techniques and lab deactivation experiments (Figure 1), we have been able to determine that Fe deposits only on the exterior surface of catalyst particles forming Fe-rich rings. In these areas, Fe, Ca and Na oxides mix with silica from the underlying catalyst giving the catalyst a characteristic texture with surface nodules and a “glassy” appearance. The deposition of Fe on the FCC catalyst does not depend on the catalyst used, its properties or composition. However, the deactivation process is greatly affected by the chemical composition of the underlying catalyst.
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Refinery Operations, March 27, 2013 VOL: 4 ISS: 2
Co-Processing Coker Naphtha in ULSD Service
High Olefins in Coker Stocks Requires Planning for Excessive Hydrogen Consumption, Heat Generation, Pressure Drop, Polymerization, Si & Ar Poisoning and Other Concerns that can Quickly Downgrade Hydrotreater Operations
Meredith Lansdown, Brian Watkins and Brian Slemp, Advanced Refining Technologies
Co-processing coker naphtha in ULSD service can have several undesirable effects on performance of the hydrotreater and the catalyst, if the system was not properly designed to handle coker naphtha. In general, coker stocks have a higher level of olefins present from the coking process. Once in the hydrotreater, these olefins will quickly become saturated, thereby consuming additional hydrogen and generating extra heat.
As a general rule of thumb, 1.0 moles of hydrogen is required per mole of carbon-carbon double bond, or between 5-10 times the bromine number reduction in standard cubic feet of hydrogen per barrel (scfhb). This additional heat (130-160 Btu/scf hydrogen consumed), if not spread out through a decent portion of the catalyst bed, will initiate the subsequent reactions creating a much higher temperature rise than expected. This excess temperature can also speed up the coking or polymerization mechanism, which will leads to an increase in pressure drop. This can set an upper limit as to how much coker naphtha can be processed either by a need to limit the heat rise, or from too much hydrogen consumption that could starve the downstream catalysts.
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Refinery Operations, November 18, 2013 VOL: 4 ISS: 3
Custom Catalyst Systems for Higher Diesel Yields: Part I
A critical element with all approaches to increasing diesel yield is the proper design and selection of a catalyst system for the hydrotreater. Part I discusses strategies for taking advantage of the properties of a premium diesel catalyst formulation with appropriate operating conditions.
Brian Watkins and Charles Olsen, Advanced Refining Technologies
Brian Watkins is Manager, Pilot Plants and Technical Service Engineer with Advanced Refining Technologies (ART) in Chicago, Illinois. He has 19 years of experience in hydroprocessing and has held a variety of technical research and research management positions at ART, including managing pilot plant operations. He holds a B.S. degree in Chemistry from Illinois Western Illinois University in Macomb Illinois. Watkins has written and presented numerous technical papers at the NPRA, AFPM and CLG symposiums (brian.watkins@grace.com).
Charles “Chuck” Olsen is Director, Distillate R&D and Technical Services with Advanced Refining Technologies (ART) in Chicago, Illinois. Olsen earned a degree in chemical engineering from the University of Illinois at Urbana- Champaign (chuck.olsen@grace.com).
High middle distillate demand provides opportunities for considering custom catalysts for higher diesel yields. Even more so, relatively low cost hydrogen production in certain markets provides further incentive to invest in premium catalyst. Options under consideration have included operating FCC pretreaters in mild hydrocracking mode, switching to maximum LCO mode or extending feed endpoint to a ULSD unit and converting the heavy fraction into diesel range material.1 The use of opportunity feedstocks and synthetic type feedstocks can also be considered.2
These approaches require specialized catalyst systems capable of providing some cracking conversion or changes to traditional unit operation, and careful attention must be given to minimizing production of excess gas and naphtha while maximizing diesel. Another seemingly simple option is to maximize product volume swell from a current ULSD unit through a change in catalyst and understanding demand on operating conditions. This approach to increasing diesel yields requires a detailed understanding of feed and operating conditions such that the hydrotreater can be operated at the maximum product volume swell for the majority of the unit cycle. In this case, increased diesel yield benefits need to be balanced against the potential costs of higher hydrogen consumption and decreased cycle length.
Maximizing Product Volume Swell
It is useful to understand hydrotreating chemistry, particularly with regard to maximizing product volume swell. Table 1 lists several different classes of hydrocarbon compounds found in diesel range feeds, showing that compound density decreases as hydrogen is added to the molecule. This indicates that even some simple reactions involved in hydrotreating result in product density reduction and a resulting product volume increase. This is especially apparent with aromatic species.
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