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RENEWABLE & RECYCLABLE FEEDSTOCKS ADVANCEMENTS IN CATALYST MATERIALS
TRANSITION TO NET ZERO
CATALYST TESTING SYSTEMS
MAKE EVERY MOLECULE MATTER
At Shell Catalysts & Technologies, we understand how small, unseen chemical reactions can affect the health of our loved ones, neighbors, and the planet at large. That’s what motivates us in our mission to Make Every Molecule Matter. Every member of our team is focused on the same goal — developing cleaner energy solutions that enable industry to tackle global climate challenges starting at the molecular level. Together, our experienced scientists and expert engineers put our diverse, unique owner-operator expertise to work — collaborating with you to create solutions that can solve your specific emissions and energy efficiency challenges. Learn more at catalysts.shell.com/MEMM
Every little helps Security of feedstock supply
2022 www.digitalrefining.com Vol 26 No 2 2021 Vol 13 No 2 2008
Catalyst for energy efficiency
Transition to net zero: steps to decarbonise the oil refining industry Marie Goret-Rana and Carl Keeley Johnson Matthey espite sig s in 2007 of a slowd wn in various sect rs of the economy, r fi ers remain a big play for prospective investors. It used to be conventional wisdom that higher fuel prices and a slowing economy would curb demand and increase supply, but for the past seven years
Editor Chris Cunningham firstname.lastname@example.org Production Editor Rachel Storry email@example.com Production Editor Rachel Zamorski production petroleu technology.com Graphics Peter Harper firstname.lastname@example.org Graphics Editor Mohamm d Samiuddin email@example.com Editor René G Gonzalez firstname.lastname@example.org Editorial tel +44 844 5888 773 fax +44 844 5888 667 Business Development Director Paul Mason email@example.com Editorial PO Box 11283 Spring TX 77391, USA tel +1 281 374 8240 fax +1 281 257 0582 Advertising Sales Office tel +44 844 5888 771 fax +44 844 5888 662 Managing Director RichardWatts firstname.lastname@example.org Advertising Sales Bob Aldridge email@example.com Circulation Fran Havard firstname.lastname@example.org EMAP, 10th Floor, Southern House, Wellesley Grove, Croydon CR0 1XG tel +44 208 253 8695 Publisher Nic Allen email@example.com Register to receive your regular copy of PTQ at www.eptq.com/register Circulation Ja ki Watts circul ion@p troleu technology.com Crambeth Allen Publishing Ltd Hopesay, Craven Arms SY7 8HD, UK PTQ (PetroleumTechnology Quarterly ) (ISSN No: 1632-363X, USPS No: 014-781) is published quarterly plus annual Catalysis edition by Crambeth Allen Publishing Ltd and is distributed in the US by SP/Asendia, 17B South Middlesex Avenue, Monroe NJ 08831. Periodicals postage paid at New Brunswick, NJ. Postmaster: send address changes to PTQ (PetroleumTechnology Quarterly) , 17B South Middlesex Avenue, Monroe NJ 08831. Back numbers available from the Publisher at $30 per copy inc postage. tel +44 870 90 600 20 fax +44 870 90 600 40 ISSN 1362-363X Petroleum Technology Quarterly (USPS 0014-781) is published quarterly plus annual Catalysis edition by Crambeth Allen Publishing Ltd and is distributed in the USA by SPP, 75 Aberdeen Rd, Emigsville, PA 17318. Periodicals postage paid at Emigsville PA. Postmaster: send address changes to Petroleum Technology Quarterly c/o PO Box 437, Emigsville, PA 17318-0437 Back numbers available from the Publisher ISSN 1362-363X Advertising Sales Manager Paul Mason firstname.lastname@example.org Ad e tising Sales Office tel +44 870 90 303 90 fax +44 870 90 246 90
©2022. The entire content of this publication is protected by copyright full details of which are available from the publishers. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means – electronic, mechanical, photocopying, recording or otherwise – without the prior permission of the copyright owner. The opinions and views expressed by the authors in this publication are not necessarily those of the editor or publisher and while every care has been taken in the preparation of all material included in Petroleum Technology Quarterly and its supplements the publisher cannot be held responsible for any statements, opinions or views or for any inaccuracies. Returning to the value of recovered metals, this page in past years addressed the issue of rare earth metals, their sources (just one, really), and their prices inflating by multiple factors of ten when supplies became restricted. Catalyst suppliers responded in the best ways they could, including development of non-rare earth material. Is this a local crisis due for a repeat perf rmanc ? If so, the calculati n in favour of me als recovery is ertainly more straightforward. However, any expansion of the value chain (eg, ethylene-to-propylene via dehydrogenation) requires investment in catalytic-based process s, as discussed in the following articles authored by experts in the field of downstream process technology. PTQ wishes to extend its gratitude to the authors who provided editorial and responded to the Q&A published in this issue of PTQ Catalysis, as well as to those respondents who addressed the online questions (www.eptq.com) that addressed the specifics of certain reactor and catalytic issues of importance to the industry. Data quality obtained in refinery catalyst testing Tiago Vilela Avantium Catalysis Forming a sustainable catalyst partnership Michael Ross Evonik Non-catalytic processes are also playi g a significant role in the refiner’s ability to process whatever unconventional crude sources become available. For example, some refiners processing hi her volumes of resid and atmospheric tower bottoms have consid ed adding certain typ s of solvent-ext action processes i addition to overall improvements to crude unit ( g, vacuum tower revamp ) a d delayed coker op rations. Improvemen s in furnace technology, such as with olefin steam cracker operations, ave resulted n significant incr as s in worldwide ethyl ne capacity. 41 What is the value to a refiner of recover d met ls? A always in an assess- ment of the industry’s economics, answers are far from straightforward. Storing spent catalyst is an expense, landfilling even more so. Furthermore, simply burying the evidence could well have a detrimental impact on a refin- er’s reputation for environmental care. Who can calculate the potential for lost value in that case? The vagaries of metals trading might favour recovery this week, b t next week maybe ot. Kevin Siters surface ar k Al ea ancd egen atalyst contact 45 Low-cost mesoporous zeolites deliver catalytic benefits Kurt Du Mong and Danny Verboekend Zeopore Technologies So what, in process terms, is the route to recovery? The pages of PTQ have from time to time highlighted a well established business based on pyromet- allurgy, the process of roasting spent catalyst to recover precious metals such as platinum. One of our Q&A correspondents, on the other hand, draws atten- tion to the growing role of hydrometallurgy in metals recovery. In this case, lower-valued metals are leached from spent material. This is also an industrial process with a lengthy history. For example, a fair amount of the cobalt in cat- alysts emplo ed in desulphurisation originates in central Africa where linear heaps of mined ore are sprayed with concentrated sulphuric acid (which in turn is more likely than not produced from the output of a refinery’s or gas plant’s sulphur recovery unit). The resulting liquor is processed before pass- ing to the electrowinning plant where cobalt metal is recovered. 29 Study of CCRU first reformer reactor ΔP behaviour using multiple linear regression Ali Al Shehhi ADNOC T his 2021 issue of Catalysis features a Q&Asection that breaks all records for content. Warm thanks to our respondents for their insights, expertise, and news of developments. Indeed, special thanks to contributors affected by the recent ‘polar storm’ that in particular hit Texas, who found the time and opportunit to provide esponses. The l test extreme weather event to affect the states sharing th Gulf coastline will require some time for recovery, both personal and industrial. 35 Performance of titania based tail gas catalyst at start-up Bart Hereijgers Euro Support Environmental issues come to the fore in the replies to a question on the feasibility of recovering non-precious metals from spent catalyst (begin- ning on page 23). Is it economically worthwhile to glean the likes of nickel and cobalt, for instance, from refinery waste? Or is it best to take the simple landfill approach? Fiber based specialty catalyst material maximises No massive new s urces of e ergy are expected t com on s ream for the foreseeable futur . The world will remain dependent on oil d gas for decades to come even though the upstream i dustry faces increasing challenges in th discovery and production of new sources. In fact, some well-placed industry analysts think 2008 may be the y ar where there is no increase in crude supply at all from regions outside of OPEC. For this reason, we will continue to see significant investment in refinery upgrades despite surging costs — security of feedstock supply, albeit unconventional low-quality feedstock, takes precedence over the quality of feedstock supply. 50 Feedstock options such as biomass (for biofuels production), Canadian tar sands (for distillate production) and other types of unconventional crude sources require reactor technology that allows for the integration of these operations into existing process configurations. The quality of these types of feedstock are one important reason why a wider array of catalysts has been introduced into the market. For example, as refiner cut deeper into the vacuum tower, the concentration of metals in the VGO requires a properly designed guard bed system to protect active catalysts in the hydrocracker. The characteristics of feedstock with low API gravity (eg, <10), high metals, nitrogen and other undesirable components is one of the main reasons why hydrotreaters and hydrocrackers are becoming larger — to accommodate not only higher volumes of catalyst, but also a wider variety of catalyst with specific formulations. Co-processing renewable and recyclable feedstocks in the FCC unit Lucas Dorazio, Jian Shi and James Fu BASF Corporation Snehesh S Ail, Marco J Castaldi and Golam S Chowdhury The City College of New York 62 Recovering metals from refinery waste is more likely than open-plan ore leaching to require the approval of health and safety inspectors. In a process devised by the Indian Institute of Technology, spent catalyst is first roasted to around 700°C, then leached with acid before a sequence of chemical conver- sions produces a suitable electrolyte for metal recovery. If there is demand, the technology will emerge. 54 Cover Oil refinery that has not proved to be the case. While the rate of increase in world oil demand has declined since the surprising 4% surge in 2004, it nevertheless appears that demand beyond 2008 will grow, along with prices. It is a safe b t that rapidly increasing o l consumption by China, India and even the Middle East producers themselves will co tinue. It is also safe to assume that refinery and petrochemical conversion u it capacity will ne d to expand.
René G Gonzalez
Catalyst for energy efficiency W h ilst events such as the global COVID pandemic, the Russian invasion of Ukraine, along with ongoing conflicts in the Middle East demand our immediate attention, the energy transition will remain a strategic focus for all energy intensive industries over the next decades, up to and beyond 2050. Energy prices are on anupward trendand likely to reachnewrecords over the next fewmonths. These short-term trends currently make the energy transition more compelling. The downstreamoil and gas industrymust be unstinting in its drive for energy and process efficiency, even as we incorporate renewable and recyclable feedstocks. C atalysts and catalytic systems represent one of the major operating cost components in refineries and petrochemical plants. Yet advancements in catalyst systems are fundamental in giving refiners the flexibility needed to process a wide range of alternative feedstocks and adjust to changing market demands. T his 2021 issue of Catalysis features a Q&Asection that breaks all records fo co tent. Warm thanks to our respondents for their insights, expertise, and news of developments. I deed, special thanks to contributors affected by the recen ‘polar storm’ that in particular hit T xas, who found the time and opportu ity to provide r sponses. The latest extreme wea her event to affec th states sharing the G lf coastline will require some time for recovery, both personal and industrial. F ollowing on from last year’s edition of Catalysis , the 2022 edition starts with a Q&A section that reflects how our readers value sharing learnings and experience, as operators, process licensors, and catalyst developers. I n the first article, Johnson & Matthey emphasises how refiners should first focus on available expertise, catalysts, technologies to drive down direct emissions from existing processes and hydrogen production. It then discusses the emergence of industrial hubs for blue hydrogen production and carbon dioxide capture and other opportunities to reduce indirect emissions from energy. Finally, it describes technologies used to process renewable feeds, including bio-and waste components, to produce decarbonised fuels and petrochemical products as a means of reducing Scope 3 emissions. T he articlebyBASFdescribes adaptationsmade to its catalyst testing laboratories and experimental work to explore the behaviour of renewable and recyclable feedstocks in FCC units, needed to inform the design of new catalysts. For complex upgrading units such as fluid catalytic crackers, hydrocrackers, and residue upgraders, knowledge of the unit and overall refinery objectives are fundamental to the design of higher performing catalysts and catalytic systems. Environmental issues come to the fore in the replies to a question on the feasibility of recovering non-precious metals from spent catalyst (begin ning on page 23). Is it economically worthwhile to glean the likes of nicke and cobalt, for instance, from refinery waste? Or is it best to take the simple landfill approach? What is the value to a refiner of recovered metals? As always in an assess ment of the industry’s economics, answers are far from straightforward Storing spent catalyst is an expense, landfilling eve more so. Furthermore s ply bu ying the vidence c ld well h v a etrimental impact on a refin er’s reputation for environmental care. Who can calculate the pote tial for los value in th t case? The vagaries of metals trading might favour recovery thi week, but next week maybe not. So what, in process terms, is the route to recovery? The pages of PTQ have from time to time highlighted a well established business based on pyromet allurgy, the process of roasting spent catalyst to recover precious metals such as platinum. One of our Q&A correspondents, on the other hand, draws atten tion to the growing role of hydrometallurgy in metals recovery. In this case lower-valued metals are leached from spent material. This is also an industria process with a lengthy history. For example, a fair amount of the cobalt in cat alysts employed in desulphurisation originates in entr l Africa where linea he ps of mi ed ore are sprayed with concentrated sulphuric cid (which in turn is more lik ly than not produced fr m the output of a refinery’s or ga plant’s sulphur recovery unit). The resulting liquor is processe before pass ing to the electrowinning plant where cobalt metal is recovered. T he article by ADNOC considers the use of linear regression analysis to better determine the principle causes of catalyst attrition and pressure drop due to increasing severity in an operational continuous catalytic reformer (CCR) unit. This illustrates the importance of understanding the impacts of changing conditions over the operating cycles. Whilst the main purpose of this study is to optimise the CCR unit, such analyses are also useful inputs for the design of higher performing catalysts. T he next three articles describe advancements in catalyst materials and shapes of support. E uroSupport shares results from laboratory testing comparing its titania based tail gas treating catalyst against the industry standard, alumina based catalyst. The company concludes that the use of titania allows more uniform sulphiding, resulting in better catalyst stability and performance when compared with industry standard alumina based catalysts. A lkegen’s article introduces the use of ‘fiber’ catalyst supports with applications such as hydrogen production and treatment of industrial emissions. In one application, propane dehydrogenation, Alkegen reports increased selectivity and yields of propene, with significant improvements in operational stability. Z eopore describes developments in zeolite mesopore chemistry and manufacturing to produce stable highly mesoporous zeolites which can give improved selectivity and product yields across a range of applications for zeolitic catalysts. A vantium describes advances in multi-reactor catalyst testing systems for mass balance closure, higher precision and accuracy to give better reactor-to-reactor repeatability and ultimately higher data quality with better translation to full-scale unit behaviour. This edition of Catalysis finishes with a short discussion by Evonik of the desired characteristics for a successful long-term relationship between a catalyst manufacturer and their clients. Recovering metals from refinery waste is more likely than open-plan ore leaching to require the approval of health and safety inspectors. In a proces devised by the Indian Institute of Technology, spent catalyst is first roasted to around 700°C, then leached with acid before a sequence of chemical conver sions produces a suitable electrolyte for metal recovery. If there is demand, the technology will emerge. Non-catalytic processes are also playing a significant role in the refiner’s abilit to process whatever unconventional crude sources become available. For example some refiners processing hi her volumes of resid and atmospheric tower bottom have consid ed adding certain typ s of solvent-ext action processes i additio to overall improvements to crude unit (eg, vacuum tower revamps) a d delaye coker op rations. Improvemen s in furnace technology, such as with olefin steam cracker operations, have resulted n significant incr ases in worldwide ethyl n capacity. Returning to the value of recovered metals, this page in past year addressed the issue of rare e rth metals, their sources (just one, really) nd heir prices inflating by multiple factors of ten when s pplies became r stricted. Catalyst suppliers responded in the best ways they could, including development of non-rar earth material. I this a local crisis due for a repea performance? If so, the calculation in favour of metals recovery is certainly more straightforward. However, any expansion of the value chain (eg, ethylene-to-propylene vi dehydrogenation) requires investment in catalytic-based processes, as discussed i the following articles authored by experts in the field of downstream proces technology. PTQ wishes to extend its gratitude to the authors who provide editorial and responded to the Q&A published in this issue of PTQ Catalysis, a well as to those respondents who addressed the o line questions (www.eptq.com that addressed the specifics of certain reactor and cat lytic issues of importance t the industry. Ev y little helps Security of feedstock supply espite signs in 2007 of a slowdow in various s ctors of th economy refiners remain a big play for prospective investors. It used to b conven ional wisdom that higher fuel prices and a slowing econom would curb demand and incre se supply, but for he p st seven year that has not prov d to be the case. While the rate of increase in world oil deman has declined since the surprising 4% surge in 2004, it nevertheless appears tha demand beyond 2008 will grow, along with prices. It is a safe bet that rapidl increasing oil consumption by China, India and even the Middle East producer themselves will co tinue. It is also safe to assume that refinery and petrochemica conversion unit capacity will need to expand. No massive new s urces of e ergy are expected to com on s ream for th foreseeable futur . The world will remain dependent on oil and gas for decades t come even though the upstream i dustry faces increasing challenges in th discovery and production of new sources. In fact, some well-placed industr analysts think 2008 may be the y ar where there is no increase in crude supply a all from regions outside of OPEC. For this reason, we will continue to see significan investment in refinery upgrades despite surging costs — security of feedstoc supply, albeit unconventional low-quality feedstock, takes precedence over th quality of feedstock supply. Feedstock options such as biomass (for biofuels production), Canadian tar sand (for distill te production) and other types of unconventional crude sources requir reactor technology that llow for the integration of these operations into existin proc ss configurations. The quality of these types of feedstock are one importan r ason w y a w der rray of c talysts has been intro uce into the market. Fo example, as refiners ut deeper into the vacuum tower, the concentration o etals in the VGO requires a properly desi ned guard bed sys em to protect activ atalysts n hydrocracker. The characteristic of feedstock with low API gravit (eg, <10), high metals, nitrogen and other undesirable components is one of th main reasons why hydrotr aters and hydrocr ckers are becoming larger — t accommodate not only higher volumes of catalyst, but also a wider variety o catalyst with specific formulations. D
Vol 13 No 2 2008
Vol 27 No 2 2022 Vol 26 No 2 1
Editor email@example.com Editor Chris Cunningham firstname.lastname@example.org Production Editor Rachel Storry email@example.com Production Editor Rachel Zamorski production petroleu technology.com Production Editor Rachel Storry firstname.lastname@example.org Graphics Peter Harper email@example.com Gr ics Peter Harper firstname.lastname@example.org Graphics Editor Mohamm d Samiuddin email@example.com Editorial tel +44 844 5888 773 fax +44 844 5888 667 Editorial tel +44 844 5888 773 fax +44 844 5888 667 Business Development Director Paul Mason firstname.lastname@example.org Business Development Director Paul Ma on email@example.com el +1 281 374 8240 fax +1 281 257 0582 Advertising Sales Office tel +44 844 5888 771 fax +44 844 5888 662 Managing Director RichardWatts firstname.lastname@example.org Advertising Sales Office tel +44 844 5888 771 fax +44 844 5888 662 Advertising Sales Manager Paul Mason email@example.com Circulation Fran Havard firstname.lastname@example.org EMAP, 10th Floor, Southern House, Wellesley Grove, Croydon CR0 1XG tel +44 208 253 8695 Circulation Fran Havard email@example.com Advertising Sales Office tel +44 870 90 303 90 fax +44 870 90 246 90 ISSN 1362-363X EMAP, 10th Floor, Southern House, Wellesley Grove, Croydon CR0 1XG tel +44 208 253 8695 Publisher Nic Allen firstname.lastname@example.org Register to receive your regular copy of PTQ at www.eptq.com/register PTQ (Petroleum Technology Quarterly ) (ISSN No: 1632-363X, USPS No: 014-781) is published quarterly plus annual Catalysis edition by Crambeth Allen Publishing Ltd and is distributed in the US by SP/ Asendia, 17B South Middlesex Avenue, Monroe NJ 08831. Periodicals postage paid at New Brunswick, NJ. Postmaster: send address changes to PTQ (Petroleum Technology Quarterly) , 17B South Middlesex Avenue, Monroe NJ 08831. Back numbers available from the Publisher at $30 per copy inc postage. PTQ (PetroleumTechnology Quarterly ) (ISSN No: 1632-363X, USPS No: 014-781) is published quarterly plus annual Catalysis edition by Crambeth Allen Publishing Ltd and is distributed in the US by SP/Asendia, 17B South Middlesex Avenue, Crambeth Allen Publishing Ltd Hopesay, Craven A ms SY7 8HD, UK tel +44 870 90 600 20 fax +44 870 90 600 40 Register to receive your regular copy of PTQ at www.eptq.com/register Circulation Jacki Watts circula ion@p troleumtechnology.com Managing Director RichardWatts email@example.com Advertising Sales Bob Aldridge firstname.lastname@example.org ISSN 1362-363X Monroe NJ 08831. Periodicals postage paid at New Brunswick, NJ. Postmaster: send address changes to PTQ (PetroleumTechnology Quarterly) , 17B South Middlesex Avenue, Monroe NJ 08831. Back numbers available from the Publisher at $30 per copy inc postage. ISSN 1362-363X Petroleum Technology Quarterly (USPS 0014-781) is published quarterly plus annual Catalysis edition by Crambeth Allen Publishing Ltd and is distributed in the USA by SPP, 75 Aberdeen Rd, Emigsville, PA 17318. Periodicals postage paid at Emigsville PA. Postmaster: send address changes to Petroleum Technology Quarterly c/o PO Box 437, Emigsville, PA 17318-0437 Back numbers available from the Publisher at $30 per copy inc postage. Editor René G Gonzalez email@example.com Editorial PO Box 11283 Spring TX 77391, USA
Catalysis 2022 5
René G Gonzalez
Vacuum tower cutpoint delivers profits
poorly designed heaters may experience coking with COT below 700°F (370°C).
Crude unit vacuum tower performance is often critical to a refiner’s bottom line. e vacuum tower bottoms stream is valued far below the gas oil cuts, so most refineries look to minimize it. Many vacuum columns are also designed or revamped to produce a diesel cut, recovering diesel slipped from the atmospheric column that would otherwise be downgraded to VGO product. Good vacuum column performance can maximize the profitability of downstream units by removing distillate hydrotreater feed (diesel) from FCCU or hydrocracker feed (VGO) and removing VGO from coker feed (resid). One important measure of vacuum column performance is VGO/resid cutpoint. e cutpoint is the temperature on the crude TBP curve that corresponds to the vacuum tower resid yield. Vacuum column cutpoint depends on three variables: 1. Flash zone temperature 2. Flash zone pressure 3. Stripping section performance (if present) Flash zone temperature is driven by vacuumheater coil outlet temperature (COT). Increasing COT increases cutpoint. Vacuum heater outlet temperature is typically maximized against firing or coking limits. When processing relatively stable crudes, vacuum heaters with better designs and optimized coil steam can avoid coking even at very high COT (800°F+, 425°C), but
Flash zone pressure is set by vacuum system performance and column pressure drop. Lower flash zone pressure increases cutpoint until the tower shell C-factor limit is reached, at which point the packed beds begin to flood. Vacuum producing systems are mysterious to many in the industry, so a large number of refiners unnecessarily accept poor vacuum system performance. With technical understanding and a good field survey, the root causes of high tower operating pressure can be identified and remedied. In columns with stripping trays, stripping steam rate and tray performance are important. Stripping steam rate is limited by vacuum column diameter (C-factor) and vacuum system capacity. Any steam injected into the bottom of the tower will act as load to the vacuum system, so vacuum system size, tower operating pressure, and stripping steam rate must be optimized together. Depending on the design, a stripping section with 6 stripping trays can provide between zero and two theoretical stages of fractionation, which can drive a big improvement in VGO yield. Although the variables for maximizing vacuum tower cutpoint are simple, manipulating them to maximize cutpoint without sacrificing unit reliability is not. Contact Process Consulting Services, Inc. to learn how to maximize the performance of your vacuum unit.
3400 Bissonnet St. Suite 130 Houston, TX 77005, USA
+1 (713) 665-7046 firstname.lastname@example.org www.revamps.com
Q What could be causing rapid catalyst deactivation in the hydrogenation of heavier fractions downstreamof our steam cracker furnace? A Yoeugourthen Hamlaoui, Global Market Manager, Yoeugourthen.HAMLAOUI@axens.net and Edouard Barange, Olefins Product Line Manager, Edouard.BARANGE@axens. net, Axens Several cuts are valorised downstream of the steam cracker furnace. The heavier fraction corresponds to the pyrolysis gasoline, also known as pygas. Raw pygas contains highly valuable components such as BTX (ben- zene, toluene, xylenes), unsaturated compounds like diolefins, styrenics and olefins, and sulphur-containing compounds. Depending on the feed quality, the catalyst used in the pygas first stage could either be palladium based or nickel based. For a feed highly contaminated with metal such as arsine, mercury, silicon or lead, nickel based catalyst is recommended as the metal contaminant resistance is higher than the resistance allowed by palladium based catalyst. However, in operation, some rapid catalyst deactiva- tion episodes can be observed in pygas hydrogenation units. Let us define first the different types of contaminant that could be present: • Inhibitors or activity moderators that compete with reactants for catalyst active surface. As the adsorption is reversible, the catalyst activity is recovered once the contaminant is no more present in the feed without any specific treatment • Temporary poisons with strong adsorption on the active surface of the catalyst. The catalyst activity is recovered with specific treatment (hot H 2 stripping/ regeneration), which requires a shutdown of the unit • Permanent poisons with very strong adsorption on the active surface of the catalyst. The catalyst activity cannot be recovered. Among these contaminants, arsine, silicon, sulphur species, oxygenates compounds, free water, gums may often be found in the pygas feed. These contaminants may be carried out by the crack- ing furnace feed or/and the process itself. For example: • Free water could come from an issue relative to the operation around the raw pygas storage tank or the operation of the caustic tower • Silicon can be brought by injection of anti-fouling chemical agent upstream • Metal contaminants come mainly with the steam crackers feed.
Contaminants that could have a drastic impact on catalyst activity, causing a rapid deactivation, are free water (free water combined with caustic soda is a tem- porary poison) and sulphur species. Indeed, pygas feed may contain up to several hundred parts per million of sulphur. Speciation of sulphur, including CS 2 , has high- lighted the presence of thiophenes (80 wt% of the total sulphur species), mercaptans/sulphides/disulphides (15 wt%), CS 2 (5 wt%), and H 2 S/COS (below 0.5 wt%). These sulphur species have different poisoning effects on the catalyst. Among the sulphur species described here, thiophenes present the lowest poisoning effect, followed by mercaptans, sulphides, and disulphides in ascending order. H 2 S/COS has the strongest poisoning effect, and CS 2 has the second strongest. Another source of contamination is the H 2 make-up used in the pygas first stage, where CO is the most com - mon one acting as a strong inhibitor. High CO could occur with methanator upsets. At a glance, rapid catalyst deactivation in pygas units is often explained by contamination issues that can be mitigated by a better understanding of the operational constraints and closed monitoring of the feed quality and upstream operation. These could be combined with a well-adapted loading diagram including adsorbent, grading, and catalyst to ensure the longest cycle length possible. Q What is the latest progress in FCC catalysis to boost bottoms upgrading? A Heather Blair, Senior FCC Technical Service Engineer, email@example.com, Rick Fisher, Senior FCC Technical Service Engineer, firstname.lastname@example.org , Todd Hochheiser, Global Technical Service Manager, todd. email@example.com Johnson Matthey There are multiple catalytic options available for improving FCC bottoms upgrading, but one of the most effective methods of improving bottoms upgrading is using a separate particle additive. This gives the refiner ultimate flexibility to quickly change bottoms upgrad - ing based on changing economics, feed, and/or unit constraints. Johnson Matthey’s BCA-105 is a very effective bot - toms cracking additive. The additive is made from highly selective matrix that provides the first cracking sites for larger FCC feed molecules. By doing this, the larger hydrocarbons (C 20 -C 40 ) are cracked into smaller, more easily crackable hydrocarbons that can be fur- ther cracked on the Y-Zeolite of the FCC catalyst. This function allows lower Z/M base catalysts to continue
Additional Q&A can be found at www.digitalrefining.com/qanda
Catalysis 2022 7
cracking towards LCO, and higher Z/M base catalysts to convert towards gasoline and LPG. The additive can also be combined with ZSM-5 additives to increase LPG yield. Bottoms reduction of up to 25-30% is achievable using the additive. The separate particle approach is more effective than simply adding extra matrix to the base catalyst. In FCC catalyst, zeolite coking is initially much faster than matrix. The coke precursors formed in Y-Zeolite migrate onto the matrix, therefore prematurely deac - tivating matrix cracking activity. In BCA-105 particles, the rate of matrix coking is much slower, resulting in higher matrix activity and more bottoms cracking. Also, metal dehydrogenation reactions occur rela - tively quickly, but the metals must first be reduced in the riser. BCA-105 enables cracking reactions to occur before metals being reduced, having a neutral and, in some cases, decrease in dry gas yield. Generally, when adding matrix to the base catalyst, it tends to make more hydrogen and coke due to the nickel and vana - dium laydown on the base catalyst caused by the quick cracking reactions of the base catalyst Y-Zeolite. These metals then migrate to the base catalyst matrix. BCA- 105 does not have the same effect as it does not contain any Y-Zeolite. BCA-105 is an effective bottoms cracking additive that allows refiners flexibility without increasing coke or dry gas and impacting fluidisation. It is com - patible with all FCC unit designs and base catalyst technologies. A Rainer Rakoczy, TechnologyAdvisor Fuel, andMaximilian Dochnahl, Head of Modelling & On-site Technology, Clariant Catalysts Today’s cocktail of catalysts is composed to react to the requirements driven by the feed to the FCC unit. The product mix leaving the unit has reached capabilities to provide outstanding flexibility. Until today, the produced middle distillate fraction, namely light cycle oil (LCO), can reach density levels that are sometimes hard to process in distillate hydrotreater towards ULSD specifications, especially if FCC operation and catalyst selection is selected to produce predominantly olefins-rich off-gas, with naphtha fractions providing high knock resistance. With the current need for co- processing of biogenic triglycerides from used cooking oil, fats from sewage, or vegetable oils, there is an option to expand the capability of handling high-density LCO. In addition, with more and more focus on fuel to chemicals FCC unit and the right catalyst selection helps to optimise light olefins yield in combination with naphtha, which can be utilised in a steam cracker after appropriate hydroprocessing. Clariant and its partners offer tailored catalytic solutions for optimised product recovery and hydrogen management to follow these new challenges. A Corbett Senter, Regional Marketing Manager – Refining Catalysts, Europe, Middle East, & Africa, BASF, james. firstname.lastname@example.org Refiners are constantly challenged to maximise refin -
ing margin by converting heavier feed to lighter val - ue-added molecules. FCC catalysts need to enable the FCC to have additional flexibility to further upgrade bottoms and overcome process constraints. This means a coke selective bottoms upgrading catalyst that max - imises transportation fuels, especially for the resid market. BASF is very active in developing new products that maximise bottoms upgrading in FCC units. We have seen multiple FCC trials of newer catalyst products, such as Boroflex, Fourte, and Luminate, which have improved bottoms upgrading compared to incum - bent catalysts. BASF’s latest FCC catalyst product for maximum bottoms upgrading, Altrium, is designed to maximise the destruction of bottoms to more valuable FCC products. The product incorporates our Advanced Innovative Matrix (AIM) and the proven Improved Zeolite-Y (IZY) technology. The key features include higher meso-macro porosity for larger molecule diffu - sivity, deeper conversion, and improved metal passiv - ation while having good attrition resistance to increase retention and reduce stack opacity and slurry fines. Commercial trials of Altrium have confirmed its ability to deliver better economic performance through coke selectivity and deeper resid bottoms conversion. By improving the gasoline and distillate yields, we help refiners increase profitability. With FCC catalyst, there is no ‘one size fits all’ approach to improving bottoms upgrading. Refiners need to talk with their catalyst pro - vider to determine which product best fits their objec - tives and constraints. A Steven van Vegten, Global Market Application Advisor , Albemarle, Steven.vanVegten@Albemarle.com Bottoms upgrading capabilities are mainly determined by the catalyst’s accessibility, matrix activity level, and low coke selectivity. Two technological advances by Albemarle, Denali and RiFT, help refiners either minimise fuel oil production or seek additional bottoms upgrading capabilities, as we recognise feedstocks are becoming more difficult and grow in diversity. Accessibility measures the ease of diffusion of high molecular weight feedstock to diffuse into the catalyst particle, reach active sites, and subsequently be cracked to more valuable products. Albemarle’s high accessi - bility catalyst technology delivers unhindered access to active sites, of which the active matrix plays a cru - cial role in bottoms upgrading. Albemarle’s latest RiFT matrix delivers enriched PoSD and supplementary acid sites, increasing total catalyst acidity by up to 20%, pre - senting favourable implications for bottoms cracking and hydrogen transfer. Our next-generation USY zeolite technology, ZT-600, is a cutting-edge zeolite technology that provides multiple benefits and is employed in our Denali cat - alysts. One benefit is higher intrinsic zeolitic stability and retention, which provides a tool for extricating and controlling activity versus hydrogen transfer. In addition, acid sites have been optimised with less non-framework alumina for fewer undesired reactions, particularly lower coke and gas. Lastly, more mesopo -
8 Catalysis 2022
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rosity has been incorporated to increase zeolitic contact with reactants and result in fewer secondary reactions owing to faster disengagement. Overall, Denali cata- lysts deliver improved yields, especially improved coke selectivity and more selective cracking of larger mole- cules to assist in bottoms cracking. Q What steps can we take in our mild hydrocracking operations to improve FCC conversion performance? A Per Zeuthen, Senior Director, Haldor Topsoe, pz@topsoe. com Aromatic compounds are not converted in FCC units, so steps to improve FCC conversion will be minimising feed monoaromatic and polyaromatic compounds the most. A mild hydrocracker is typically a single-stage reac- tor unit loaded with various hydroprocessing catalysts, including hydrotreating and hydrocracking catalysts. To improve FCC conversion, the following should be considered: • Increase hydrogen partial pressure the most; this will increase aromatic saturation, lower aromatic com- pounds in the FCC feed, and increase conversion by increasing the total pressure or the hydrogen purity in the make-up hydrogen supply. • Increase aromatic saturation activity of the loaded catalysts and ensure that the most HDA active catalysts are used. This is important also for the conversion cata- lyst if this is included in the catalyst load. Topsoe has a number of catalysts (hydrotreating and hydrocracking) with improved aromatic saturation activity. • Use the latest generation of reactor internals; this will ensure that all loaded catalyst is utilised and exposed to hydrogen – a very important step that is often overseen. Again, Topsoe holds an extensive reference list and industrial feedback for such improvements. Finally, mild hydrocrackers are typically being oper- ated at relatively high temperatures, particularly during the second half of the cycle. This ensures the right product sulphur and nitrogen level in the FCC feed and sulphur specks in the FCC products. However, high temperatures, higher than 390°C, at the outlet of the mild hydrocracker are unfavourable for the saturation of the polyaromatic compounds. Thus, for thermody- namic reasons, there are no catalytic ways to lower the product aromatics in the FCC feed at such conditions. A minor revamp of the unit, for example, with Topsoe’s Aroshift layout, by installing a small high LHSV with- out fractionation, being operated at a lower tempera- ture with a proprietary catalyst, will lower the FCC feed polyaromatics by typically 25% and thus show a great positive impact to the FCC conversion and yield structure. A Rainer Rakoczy, Technology Advisor Fuel, andMaximilian Dochnahl, Head of Modelling & On-site Technology, Clariant Catalysts Besides asphaltic species, the level viscosity of the desired FCC feed can be key to improving and optimis-
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ing FCC unit operations. Clariant has various options to improve FCC feed viscosity in FCC pretreaters with Clariant’s HYDEX Series catalysts, including mild hydrocracking and beyond. A NievesÁlvarez, email@example.com,Meritxell Vila, firstname.lastname@example.org, MERYT Catalysts & Innovation To improve the conversion performance of our FCC, we can consider three different actions: 1. Revise the quality of the HCK bottom residue: It is important to have a detailed analysis of the HCK bot- tom residue: the content of aromatic carbon, naphthenic carbon, and its distribution. If we want to increase yields in the FCC, this residue should have a high naph- thenic carbon content and a low triaromatic+ in the aromatic carbon distribution. Of course, these contents depend on the aromatic feed content, on the tempera- ture of the hydrocracker unit, and on the catalyst capac- ity to convert aromatics into naphthenes. We recommend performing some changing reaction temperature testing of the hydrocracker to obtain the best conditions to produce maximum HCK residue with maximum carbon naphthene. This should be tested for each VGO quality to the HCK and the catalyst in use. Pay attention to these tests results regarding the residue and the other products and the qualities you need to obtain in the hydrocracker, such as sulphur and metals. 2. Adjust the cutpoint of the HCK bottom residue: to obtain more yield (m 3 /h or kg/h) in FCC is to increase the feed quantity. This yield increasing, of course, depends on the products you need to obtain in your FCC. If you want to produce more LCO or naphtha, you could reduce the HCK residue you send to the FCC, making this FCC feed lighter and decreasing the cat/oil ratio. Conversion will be adjusted with riser tempera- ture and maximum regeneration limits. But if you want to produce more olefins, you could increase the FCC feed until maximum riser cat/oil with riser tempera- ture, considering maximum regenerator temperature GasCon limits. 3. Make an integrated evaluation of both units: HCK and FCC. We recommend making an integrated evalua- tion of both units regarding the performance of all the catalysts involved and the processes and, therefore, doing an integrated economic balance. It may be that the best catalyst for the FCC is not the best when we evaluate the yields and economy integrating both units. Alternatively, the upgraded catalyst for HCK may not be the optimum when we do the global evaluation of the performance of both units. The best way is to evaluate the impact on both units when you evaluate the catalysts with the help of pro- cess simulation models A Eelko Brevoord, Consultant, Catalyst Intelligence Sarl, Brevoord@catalyst-intelligence.com To boost FCC performance, the mild hydrocracker product should have the following features:
1. Minimum nitrogen content 2. Maximum hydrogen content
In mild hydrocracking (MHC), the reactor tempera- ture is usually maximised immediately from start of run (SOR) to obtain maximum conversion of feed to diesel. At SOR, this leads to product quality give-away, as the catalyst activity is still very high, and the reactor temperature does not need to be maximised to meet, for instance, product sulphur requirements. The conditions for the best FCC operation should be optimised over the full cycle, which does not necessarily mean that you maximise reactor temperature at SOR. This is especially valid as MHC units operate at relatively mild pressures, and at high temperatures, aromatics saturation is not favoured. Consequently, hydrogen addition is not opti- mal if you focus only on the conversion in the MHC unit itself. Overall, we can conclude that an operation at the highest aromatics saturation point and the lowest nitrogen content over the cycle is optimal. It is recom- mended to do a sophisticated modelling study to obtain the best operating strategy. Catalyst Intelligence has developed the HydroScope model, which can optimise the MHC unit with the FCC operation in mind. Q What level of SOx emissions from the FCC should we expect from current catalyst additives? A Corbett Senter, Regional Marketing Manager – Refining Catalysts. Europe, Middle East, & Africa, BASF, james. email@example.com SOx emissions from FCC depend on several factors (not just additive usage and performance), as SOx emission and the mechanism of SOx additives are both multi- step processes. SOx is formed when sulphur in feed enters the regenerator either as coke or due to poor stripping of FCC product from the circulating catalyst after the reactor. The sulphur in the regenerator is then combusted to SO 2 and SO 3 which can leave the FCC as emissions. SOx additives function by capturing SO 3 in the regenerator, reducing the captured S-oxide on the additive in the riser and enabling conversion of S-oxide to H 2 S in the stripper, which causes the sulphur to exit with effluent from the reactor. Thus, the amount of sulphur in feed, feed type (type of sulphur compounds and metals in feed), stripper performance, catalyst cir- culation rate, regen operation, and the amount of SOx additive used will all play a role in SOx emissions. The key to understanding the expected emissions levels is to consider all these factors to develop a plan for reducing SOx emissions. A Victor Batarseh, FCC Technical Service Manager, W. R. Grace & Co., firstname.lastname@example.org Units using SOx additives can achieve anywhere from 30 to >95% SOx emission reduction depending on unit configuration, operating conditions, additive usage rates, and feed quality. Low feed sulphur, full burn units can achieve the lowest SOx emissions at levels below 25 ppm utilising SOx additive alone, while par- tial burn units may only be able to achieve a 30-70%
Catalysis 2022 11
50 Flue gas SOx reduction (%)
75 50 Flue gas S Ox reduction (%)
Figure 1 (a) Pickup factor vs %SOx reduction (b) Additive rate vs %SOx reduction
• Feed sulphur, type, and degree of hydrotreating • Product recycle streams • Reactor stripper conditions • Coke yield Any factor that can influence the SOx capture by the additive or the additive regeneration mechanisms in the reactor can impact SOx additive performance. These factors include: • Oxygen availability in the regenerator (excess O 2 , full or partial burn operation) • Regenerator air distribution • Regenerator temperature • Reactor temperature • Reactor stripper conditions • Additive usage rates The two most powerful drivers of the achievable SOx emissions levels are the feed sulphur levels and the oxygen availability in the regenerator. Feed sulphur levels directly impact the uncontrolled SOx levels in the regenerator. Feeds that produce higher levels of uncon - trolled SOx require a greater percentage of SOx reduc - tion to achieve the same emissions targets. For a given set of conditions, SOx additive perfor - mance can be characterised by a pickup factor, which is defined by lbs of SOx removed per lb of additive uti - lised. A typical performance curve of pickup factor vs % flue gas SOx reduction is shown in Figure 1 . It can be observed in Figure 1 that the pickup factor is not constant across the range of SOx reduction; this results in a nonlinear increase in the additive required as the targeted SOx reduction percentage is increased. This operational curve for a given set of conditions and additive type set the feasibility of achieving different SOx emissions levels with additive. As the additive required increases, it may not be desirable to further reduce SOx emissions with additive due to performance concerns or logistical constraints. SOx additive does not have the same cracking functionality as FCC catalyst and, when utilised in excess amounts, can negatively impact the unit operation. While uncontrolled SOx and emissions targets dictate where an operation lies on the pickup factor curve, oxy - gen availability can dramatically shift the curve up or down, as shown in Figure 2 . As a result of this phenomenon, full-burn FCCs
reduction in SOx emissions with additives and may require the operation of a wet gas scrubber to attain emissions compliance. While this question mentions expected SOx emissions with additives, it is important to recognise that factors such as feed sulphur and oper- ating conditions play a major role in SOx emissions, and these factors are discussed in detail below. There are a variety of avenues for controlling SOx emissions from the FCC, and a refiner may select any one or a combination of control options, depending on the crude slate, refinery configuration, and economics. Sulphur in FCC feedstock distributes amongst all FCC products, including coke, which is combusted in the regenerator and ultimately produces SOx emissions. As a result, the expected emissions from an FCC are pri - marily dependent on the sulphur levels in the feedstock and how this sulphur partitions to coke. SOx additives often represent a flexible and more cost-effective tech - nology to alternative solutions for SOx compliance, including switching to sweeter crudes, FCC feed hydro - treatment, and wet gas scrubbing. The SOx emission levels obtained when using SOx additives depend on factors that can be split into two broad categories: those that influence sulphur to the regenerator and those that impact additive perfor- mance. Factors that influence sulphur to the regenerator are important as they determine the level of SOx emis - sions for an FCC without SOx additive, or ‘uncontrolled SOx’. The higher the uncontrolled SOx, the more chal - lenging it is to achieve environmentally compliant SOx emissions. These factors include:
Partial burn low CO Partial burn high CO Full burn low excess O Full burn high excess O
50 Flue gas SOx reduction (%)
Figure 2 Pickup factor vs %SOx reduction
12 Catalysis 2022
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