FCC Catalyst Age Distribution Impacts Unit Performance

July 06, 2011 VOL: 2 ISS: 12 FCC Catalyst Age Distribution Impacts Unit Performance Grace Davison has Developed Sink/Float Method to Track Ecat Performance and Optimize Addition/Withrawal of Purchased Ecat and Fresh Catalyst

The FCC unit is one of the most dynamic and performance of the various age- and complex processes in a refinery. distributed fractions of Ecat using the In This Issue... The reactor-regeneration configuration Sink/Float method, the health of an FCC and the tons of catalyst flowing per min- unit’s catalyst inventory (e.g., remaining FEATURE ute means the unit can quickly become activity, metals poisoning, etc.) can be FCC Catalyst Age Distribution Impacts unstable, requiring immediate operator determined and steps can be taken to Unit Performance interaction. To better manage FCC cata- improve operations. lyst inventory and mitigate the cost of Grace Davison has Developed Sink/ adding fresh catalyst, it would benefit Float Method to Track Ecat Perfor- Why Separate Ecat? mance and Optimize Addition/With- the refinery operator to know the age FCC Ecat generally displays a skeletal rawal of Purchased Ecat and Fresh distribution of the catalyst in circulation. density between 2.4-2.8 g/ml. Ecat is Catalyst For this reason, FCC experts at Grace mixed with varying concentrations of Davison have developed the “Sink/ tetrabromoethane (TBE density = 2.96 PROCESS OPERATIONS Float” method for distinguishing the g/ml) and tetrachloroethane (TCE = 1.58 Improving Hydrocracker Quench Design separation and percentage of FCC Ecat g/ml). TBE:TCE ratios are adjusted until into fractions based on their respective the desired split is achieved. Providing Real-Time Compositional densities. “Older” fractions tend to have Due to continuous catalyst additions, Data in FCC Operations higher density than “younger” Ecat frac- the catalyst inventory has a broad age Avoiding Catalyst Reversal in FCC tions. By evaluating the characteristics distribution. Recently operations Cont. page 2 Crude and Product Blending Optimization Refinery Emissions Monitoring Intensifies INDUSTRY NEWS Heavy Maintenance in June Curtailed Chinese Refinery Processing Plans for New Ugandan Refinery Follows Recent Crude Discoveries Pakistani Refinery Increasing Capacity Azerbaijan Refineries Reduce Throughput Indian Refiners Looking to Process more Saudi Arabian Crude New Report on Iran Refining Industry EDITORIALLY SPEAKING Small Refineries at Higher Risk of Closure

Figure 1. Determining length of time that catalyst is in the unit CALENDAR

Copyright 2011. Refinery Operations RefineryOperations.com | 2011.07.06 1 July 06, 2011 added catalyst will display relatively Cyclone Problems An economical solution is this case may high activity and low metals. Older Another case demonstrates how the be to continue withdrawing catalyst and re- fractions may be in the unit for weeks Sink/Float method helped predict an place with purchased Ecat. This will lower or months and have high levels of met- impending cyclone problem. In this ex- overall Ecat activity but allow for the purge als and low activity. Understanding how ample, a “standard” gas oil feed with of older fractions. The use of purchased equilibrium catalyst age distribution an initial catalyst addition rate of about Ecat and fresh catalyst may also provide impacts catalyst performance can lead 0.28 lbs/bbl and 137 days that Ecat was an economical way of maintaining catalyst to unit improvement opportunities as in the unit before being withdrawn (τ = withdrawals, keep unit inventory healthy shown in Figure 1 (on page 1). 137 days). However, a developing cy- and keep activity constant. n To demonstrate the importance of clone problem resulted in a τ value of knowing the amount of time that a only 79 days and a higher catalyst addi- Editor’s Note: More details on determining catalyst is circulating in a unit, several tion rate of about 0.48 lbs/bbl needed to FCC catalyst age distribution with the Sink/Float “real world” examples (e.g., heavily hy- match the losses. method and employing this information to trouble- drotreated feeds) developed by Grace At this point, the refinery opera- shoot unit operations will be discussed in the Fall Davison experts show the frequency tor could decide to stop withdrawing 2011 issue of the Grace Davison Refining Tech- of Ecat turnover and catalyst addition catalyst until the cyclone problem is nologies Catalagram #110 (www.grace.com). rates. For example, due to the low delta resolved. The “challenged” cyclone is coke displayed by the heavier fractions retaining the older, heavier and less ac- (higher density), high additions of an ac- tive catalyst particles. So, the activity is tive catalyst are required for units with lower than expected despite the elevated severely hydrotreated feeds. catalyst addition rate of 0.48 lbs/bbl.

PROCESS OPERATIONS Improving Hydrocracker Quench Design

The hydrocracker reactor’s (Figure 1) below the quench box after the intro- quench zone is an integral part of the duction of the quench stream. reactor internals dictating stability of Hydrocracker quench boxes that are the hydrocracking catalytic reactions. in poor condition could result in higher The hydrocracking reactions occur- than desirable radial temperature ring on the zeolitic catalyst has a high spread in the bed below the quench apparent activation energy, due to the box. Hydrocracking technology sup- interaction of nitrogen adsorption and pliers such as Axens have developed cracking reactions. quench boxes for optimal remixing In design, the maximum tempera- of the effluents between beds. For ex- ture rise per bed is usually limited at ample, Axen’s emphasizes that its pro- 20 to 25 °F for hydrocracking catalyst prietary EquiFlow quench boxes are according to guidelines developed by particularly useful when hot product control experts at H2Advance (www. from the previous bed is mixed with h2advance.com). A good quench box fresh, cooler hydrogen, providing the design should limit the radial tem- mixture with a uniform temperature Figure 1. Modern hydrocracker operations perature spread for the bed inlet to benefit from improved internals and reactor before it makes contact with the sub- control schemes. less than 5 °F. sequent bed. The function of a well designed The combination of the reactor in- quench box is to reduce the tempera- ternals revamp and an improved reac- ture spread for the stream coming from tor control scheme enables a reliable the bed above the quench box to attain operation for hydrocracker reactors. n minimal temperature spread to the bed

Providing Real-Time Compositional Data in FCC Operations Editor, Rene Gonzalez, Refinery Operations Process gas chromatographs are in- a role in FCC unit optimization and PO Box 11283 creasingly being used to provide performance, including: real-time compositional data in up- Spring, TX. 77391 USA • Monitoring the CO-to-CO2 ratio Mobile: +1 713-449-5817 graded refinery process units, such in the flue gas leaving the top Office: +1 281-257-0582 as with FCC process control systems. of the regenerator: This ratio is Fax: +1 281-686-5846 The typical vacuum gas oil (VGO) critical to regulating regenerator [email protected] feed to the FCC unit can also be temperature since high tempera- supplemented by coker gas oil and tures damage the catalyst Published biweekly by nEMESIS Media Group, LLC other heavy petroleum streams such • Monitoring main fractionators PO BOX 5416 as from the deasphalter. In general, overhead vapors: This gas chro- Kingwood TX 77325. USA FCC optimization objectives include matograph application is typi- Phone: (713) 344-1379 the ability to process a wider variety cally used for two purposes. The [email protected] of feedstocks from thermal conver- first is to minimize the loss of sion units (e.g., coker gas oil) and Support naphtha/gasoline components in catalytic conversion units (e.g., hy- the overhead stream by keeping Client Support drotreated feeds). the C concentration low. The [email protected] 5 Based on information avail- second purpose is to monitor the Advertising able from Emerson Process Man- C and C olefins generated in agement Gas Chromatographs 4 5 Advertising & Marketing Dept. the reactor. These olefins are im- [email protected] Division (www.emersonprocess. portant feed components to other com), they have reported on op- processes in the refinery such as Group Subscriptions portunities that exist where pro- the alkylation unit. n Client Services cess gas chromatographs can play [email protected] Copies & Reprints Circulation Dept. Avoiding Catalyst Reversal in [email protected] Subscription / Renewal FCC Operations I want to subscribe to Refinery Operations for $739/yr or $1,378/2 yr, and receive biweekly issues plus unlimited access to the The FCC unit’s reactor-regenerator reactor-regenerator section. Ensuring online premium content and archives. configuration and the tons of cata- the differential pressure measurement lyst flowing per minute can quickly is working properly is crucial, as the Name:______lead to unstable operating conditions. impulse lines for this application tend Title:______With elevated temperatures and se- to plug. In addition, the main frac- Organization:______vere operating conditions, field in- tionator bottoms is severe requiring Address:______strument measurements are essential correct selection and installation of City:______State:____ZIP:______to understanding how the process is field instruments to ensure true mea- Phone: ______Fax:______Email:______performing at any given moment. As surements. In these circumstances the traditional heavy oil conversion the Rosemount’s 3051S differential I want to renew my $739 or $1,378 unit in many refineries, the overall pressure transmitter with statistical subscription to Refinery Operations. refinery suffers significant financial process management has been put impact if the FCC unit experiences an into service to detect line plugging My account number is:______unscheduled shutdown. and give adequate time to act before Charge my Card No.______One main challenge for an FCC unit a reversal of catalyst incident occurs Exp.______Signature:______is to avoid a catalyst reversal in the (www.rosemount-transmitter.com). n Check enclosed (Payable to Refinery Operations, LLC) Postage and processing add/yr: $25 within U.S., $100 outside U.S.

Crude and Product Blending Optimization

Princeps has launched two new applica- target recipes. The system can handle operational constraints such as feed tions for optimized refinery operations, hot rundown components as well as and rundown capacity limitations, both based on Paragon’s optimization tank components, including tanks in tankage capacity limitations, rundown software AIMMS. OPTIMIX for multi- running-gauge operations. It also takes quality requirements and all kinds of period blending enables the refinery into account tank rotation and logisti- logistical constraints. operations manager to optimize prod- cal constraints, which are unique fea- Both tools are typically used as com- uct blending, enabling them to realize tures according to refinery specialists. panions to a simulation-based refinery higher value out of the available com- In addition, COMPASS for crude oil scheduling system and are designed to ponents. OPTIMIX can perform multi- blending and scheduling enables the be easily interfaced with such systems period blends over a planning horizon refinery operations manager to formu- like Aspentech. of several weeks. late crude oil blends, determine optimal Princeps brings together engineers It is a generic tool that can be eas- cut-points and schedule crude transfers and experts specialized in industrial ily configured to any refinery and bring and crude runs in order to maximize processes and applied mathematics for instant value for money. Optimiza- the crude distillation units’ throughput. the development. n tion can be done on component costs, COMPASS can handle several distil- quality specifications give-away or lation units and takes into account all Refinery Emissions Monitoring Intensifies

In a recent posting on AnalyticExpert. Historically, refineries were re- streams and sulfur recovery unit com by by Michael Gaura, product man- quired to measure the hydrogen sulfide (SRU) emissions. In Guara’s blog ager at Emerson’s Analytical Solutions, (H2S) concentration in refinery fuel post, he reviews some of the emis- he noted that in late 2010, the U.S. En- and flare gases. The new requirements sions monitoring changes and chal- vironmental Protection Agency (EPA) mandate the measurement of H2S and lenges that refineries are facing with published new standards of performance total reduced sulfur (TRS) – defined these new requirements and how in 40CFR60 subpart Ja that impact as H2S, carbonyl sulfide (COS) and to meet them. n refinery emissions monitoring. carbon disulfide (CS2) – in flare gas Industry News Heavy Maintenance in June Curtailed Chinese Refinery Processing China’s apparent oil demand in June May 2011, and June’s oil demand at 9.01 age of 8.69 million bpd, the lowest daily was 36.92 million metric tons (mt), million bpd was just marginally higher processing volume in nine months. In or an average of 9.01 million bpd, as than the previous low of 8.95 million bpd in September 2010, the country had pro- a heavy maintenance program during October 2010. cessed 34.91 million mt of crude oil, or the month curtailed consumption, ac- June’s oil demand growth was the low- an average of 8.53 million bpd. Analysts cording to Platts’ analysis that is based est in over two years as a number of Chi- are expecting Chinese oil demand to re- on recent statistics released by the nese refineries decided to shut their plants bound for the rest of 2011, especially in Chinese government. for repairs and maintenance last month be- the fourth quarter. June’s demand of 36.92 million mt cause of lofty global crude oil prices, and “With the peak summer refinery turn- marked a slim rise of 0.5% from the same output declined after an easing in a recent around period ending in August, crude month a year ago. This year-on-year in- domestic diesel supply crunch,” said Cal- runs will likely soon recover. Also, if his- crease of 0.5% was drastically slower than vin Lee, senior writer, China, for Platts. tory of the past two years is any indica- year-on-year growth rates of between 8% In June, Chinese refineries processed tion, China’s oil consumption could ramp and 15.8% recorded between January and 35.56 million mt of crude oil, or an aver- up in the fourth quarter,” said Lee. n Copyright 2011. Refinery Operations RefineryOperations.com | 2011.07.06 4 July 06, 2011

Plans for New Ugandan Refinery Follows Recent Crude Discoveries

According to a July 21 report in the rising to 200,000 over 30 years. At pres- in East Africa will continue to rise and Financial Times of London, Uganda is ent, a refinery in the Kenyan port city the Mombasa refinery is well placed to planning to build only the second oil re- of Mombasa is the only facility of its meet this demand,” said Bimal Mukher- finery in East Africa by 2015. Follow- kind in East Africa, exporting fuel to jee, chief executive of Kenya Petroleum. ing the recent discovery of 2.5 billion Uganda, Rwanda and Burundi. But it Following the discovery of reserves barrels of oil, Uganda aims to develop only produces 32,000 bpd. Essar Group, at Albertine Graben in 2006, govern- a refinery in Hoima, according to Fred the Indian company that owns 50% of ment analysts estimate that Uganda will Kabagame Kaliisa, permanent secretary the plant, has suggested plans to upgrade be able to support the production of over at the energy ministry. the 40 year-old facility to improve its ef- 100,000 bpd for the next 20 years, mak- The $2 billion plant should be ficiency and raise production. ing the country the primary oil producer able to produce an initial 20,000 bpd, It is clear that demand for oil products in East Africa. n Pakistani Refinery Increasing Capacity

Pakistan based Business Recorder pub- diversification of its existing system due which would reach 53,000 bpd after the lication recently reported that the At- to ever-increasing demand of refining pre-flash unit installation. tock Oil Refinery (ARL) has planned products in the country. The planned ARL is seriously considering instal- to expand its existing crude oil refining pre-flash unit would utilize additional lation of an isomerization complex to capacity through a pre-flash unit and 20,000-25,000 bpd of crude from TAL upgrade its light strain run naphtha. A isomerization unit, which would cost Block near (Kohat) projected within diesel hydrotreater unit has also been $100 millions. three-four years. The company is in- planned. Pakistan’s current crude pro- According to documents available stalling the pre-flash with distillation duction is 65,000 to 67,000 bpd and total with Business Recorder, the oldest oil unit on a least-cost option, which would capacity of the refineries is 287,000 bpd refinery in the region is in the bidding increase its capacity by 10,400 bpd. The or 12 million tons. n process for expansion, up-gradation and existing capacity of ARL is 42,000 bpd, Azerbaijan Refineries Reduce Throughput

The Azerbaijan based publication yev Refinery and Azerneftyag, both in May and 464,920 tonnes in June. known as News.Az recently reported of which are owned by the State Oil In 2010 as a whole, SOCAR supplied that Azerbaijan's oil refineries refined Company, SOCAR. 6,220,000 tonnes of oil to both oil refin- 3.018m tonnes of oil in January-June, The two refineries refined 512,460 eries. In 2009, the oil refineries received a fall of 115,000 tonnes compared to tonnes of oil in January, 418,540 tonnes 6,035,000 tonnes of oil, 1,312 tonnes the same period in 2010. Azerbaijan in February, 575,930 tonnes in March, fewer than in 2008. n has two oil refineries, the Heydar Ali- 532,830 tonnes in April, 513,760 tonnes Indian Refiners Looking to Process more Saudi Arabian Crude A Reuters sourced report from July 21 Iran will halt supply of 400,000 bpd as Hindustan Petroleum and Essar Oil have noted that Indian refiners have asked Tehran escalates a seven-month long each asked for one million barrels extra top exporter Saudi Arabia for more oil payment suspension triggered by US for August, from Saudi Arabia, a source in August, sources said, as they fear pressure. India’s Bharat Petroleum, with knowledge of the matter said. n

New Report on Iran Refining Industry

Research and Markets (www.research- Iran refining industry for all industry operations of each of the major refin- andmarkets.com) has announced release professionals and strategists interested ing companies in the country are ana- of their study “The Future of Iran Oil in the industry. It provides insights lyzed in detail. According to Research Refining Market to 2015--- Forecasts and forecasts of refinery capacities (at- and Markets, the study identifies key and Insights into Iran Refining Markets, mospheric, coking, FCC, HCC), oil investment areas in Iran refining mar- Companies and Refineries.” This is a products production and consumption ket and also analyzes all the upcoming source of information and analysis on to 2015. Key refining strategies and refineries in detail. n

Editorially Speaking Small Refineries at Higher Closure Risk An article that appeared in the Bris- Middle Eastern refineries. “ s e c u r e ” bane Times on July 28, “The Future Of an additional concern to Austra- supplies are none- of Oil Refining in Australia Appears lia’s refining sector, Caltex has refused theless leveraged Clouded,” bears a strong resemblance to to commit publicly to the future of its by the technical similar refinery closures in Europe and Kurnell refinery in Sydney. Caltex has challenges that the North America. The article, published in industry is facing Rene Gonzalez, Editor publicly stated that it was undertaking Refinery Operations the wake of Shell's decision to cease re- improvements to ''maintain the viabil- in bringing these finery operations at the Clyde refinery in ity'' of the Kurnell facility. Mobil has hydrocarbons to Sydney, exemplifies how other resource- also publicly stated that it has no plans upgrading facilities, such as the recently rich regions have also seen refinery clo- to close its Altona facility. discovered Tepi oil field in Brazil’s sures over the past three years, including It was also noted in the Brisbane deep offshore. some US and Canadian refineries on the Times article that the security of Aus- However, it’s no secret that new eastern seaboard, where terminal opera- tralia's fuel supply was not at risk. oil fields such as the Eagle Ford tions have nonetheless continued. Just like in North America, the secu- Shale formation is breathing new In the case of the Clyde refinery, the rity of fuel supply in certain regions of life into land-locked inland refin- closure will cost 310 jobs at the refin- North America (e.g., US East Coast) is eries in certain areas. For example, ery, although Shell said between 30 not at risk as some oil companies close as discussed in a previous issue of and 50 people would be required to or sell off their refining assets, such Refinery Operations, the Valero re- continue working at the site once it had as ConocoPhillps. finery in Three Rivers, Texas is re- been transformed into a fuel-importing It is still too early to project how portedly receiving 100% of its crude terminal. The growth of larger, cheaper recent upstream developments and feedstock from the Eagle Ford Shale refineries in developing Asian countries, discovery of hydrocarbon rich zones play. Nonetheless, even though this such as India has factored into making of oil and gas in US, Canada, Poland, feedstock may have a 63 API gravity, the Clyde facility unviable but Shell ex- offshore Brazil and elsewhere will af- it has been reported that higher-than- ecutives stressed that Clyde's relatively fect refiners in those respective regions. expected naphthenic acid gener- small 75,000 bpd size was also a sig- For now, economies of scale and pro- ated from processing these feeds nificant factor. Shell’s larger Australian cess complexity compete as the most requires well planned corrosion refinery at Geelong would be better able important factors relative to security of control programs. n to withstand pressures from Asian and supply. To be sure, many of these

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