PTQ Q1 2026 Issue

REFINING GAS PROCESSING PETROCHEMICALS ptq Q1 2026

RESID HYDROCRACKING

CHEMICAL RECYCLING FCC CORROSION

BURNER TECHNOLOGY

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3 Challenges facing European refineries Rene Gonzalez 5 ptq&a 11 Catalytic pathways to circularity Marc Nicolas and Jaap Bergwerff Ketjen Corporation 16 Unlocking ANCAP RFCC performance with key hardware modifications Francy Barrios Axens Marcel Sabag ANCAP 23 From residue to revenue with ebullated bed residue hydrocracking Colin Baillie, Darryl Klein, and Sidhartha Mohanty W. R. Grace & Co. 29 Trust through testing: How to select the right hydroprocessing catalyst Rahul Singh and Xavier E Ruiz Maldonado Topsoe 37 The future of petroleum refining: transform now or later? Part 2 Eric Pratchard and Todd Grubb Zeeco Hector Ayala, Aloke Sarkar, and HS Lee ExxonMobil Technology and Engineering Company 57 Identify corrosive regimes in hydrofluoric alkylation units: Part 2 Ezequiel Vicent OLI 63 Wireless vibration monitoring on tank mixers Murat Barış Türkoğlu and Mert Uztemur Tüpraş 69 Hybrid trays: strategic configuration for optimal column performance Rasna Rajendran, Anupriya Shahi, and Navneet Agarwal Engineers India Limited 75 From landfill to polymers: pyrolysis as a path to plastic circularity Stephany Romanow Global Energy Writers 81 The rising threats to FCC units Keisuke Karaki Kurita Water industries Ltd. Arthur Lamm Kurita America, Inc. 86 Technology In Action Balancing sulphur removal with octane retention Evonik Diana Brown and Thomas Yeung Hydrocarbon Publishing Company 45 Advanced simulation of polyolefin production Ghoncheh Rasouli and Alan Chew KBC (A Yokogawa Company) 51 Advancements in ultra-low NOx burner technology

Cover Whether for desulphurisation, hydroprocessing, etc., an older unit’s bankability and potential to support the energy transition should not be underestimated . Photo courtesy of Dheeraj Singh at Pexels.

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Vol 31 No 1 Q1 (Jan, Feb, Mar) 2026 ptq PETROLEUM TECHNOLOGY QUARTERLY

Challenges facing European refineries

T he European refining industry has faced significant challenges over the past decade, primarily due to geopolitical factors. While many members of the public may not realise that deep decarbonisation is capital-intensive, 46% of Europe’s population sees climate change as a pressing concern. Europe’s older refinery facilities cannot compete with new, world-scale export refineries, such as the 600,000 bpd Dangote facility in Nigeria. In addition, European refiners are facing higher refinery operating costs, including increased utility costs, at a time when they are expected to deliver higher shareholder value. Prescriptive regulations, such as Annex IX of the Renewable Energy Directive (RED), continue to transform and accelerate the production of biofuels. In contrast, some US refiners see value in going back to ‘traditional’ oil refining. RED’s Annex IX could facilitate the expansion of feedstocks that help the EU meet its climate targets. However, not all transition pathways are driven by policy, as seen in Central and Eastern Europe. Increasing refinery naphtha production for ethylene steam cracker feedstock or the naphtha-to-plastics route provides an opportunity to optimise a facility’s core business away from conventional fuels. Given that the industry’s investment and production timelines are measured in decades, Annex IX gives long-term clarity on renewable feedstock classification and eligibility. This broadens the range of eligible raw materials for producing sustainable aviation fuels (SAF), as defined in ReFuelEU Aviation (Regulation (EU) 2023/2405), and provides positive market prospects for a significant ramp-up of biofuels. Aside from distillate (diesel) and SAF production, European refinery margins opportunities have moved further down the value chain into petrochemicals like polymers. By the end of 2026, the industry may reach a consensus on the viability of pyrolysis oil upgrading to transform end-of-life plastics into circular feedstocks. Discussions at this year’s European Refining Technology Conference (ERTC 2025) focused on achieving commercial-scale production of waste plastics to polymers by the early 2030s, including integrating new units with older facilities. It was noted that although Europe accounts for ‘only’ 6.5% of the world’s total CO 2 emissions, there is an upside when increasing fuels production from biomass- derived feedstocks. However, increasing biomass co-processing above 5% in petro- leum refineries presents complex technical, operational, and economic challenges, as biogenic feeds require metallurgical upgrades and resistance to severe corrosion. Biomass-derived oils have inconsistent composition, oxygen content, and stability compared to fossil feedstocks. Increased co-processing magnifies these variations, causing unstable product quality and unit upsets. Bio-oils can contain 10-40% oxy- gen vs less than 1% in fossil feeds. In addition, alkali metals such as sodium and potassium, as well as nitrogen and phosphorus, are all catalyst poisons. However, if achievable, increasing biomass co-processing from 5-20% funda- mentally shifts refinery operation from ‘tolerant’ to bio-integrated mode, following investment in pre-upgrading units (like hydrotreaters for pyrolysis oil or glyceride pretreatment). Robust catalyst systems can achieve stable 20% co-processing while gaining renewable credit benefits, according to some proponents at the conference. AI-based tools are expected to help European refiners stay competitive, even though some experts have noted productivity losses from their use. Heather Gilligan, Senior Advisor at Pyxis Group, stated at ERTC 2025: “The value of AI will be unlocked by people generating creative ideas and augmenting their work with the help of AI embedded in day-to-day tasks.” Given the unique circumstances of European refin - ers, while immediate profitability is not expected, significant gain is achievable. Rene Gonzalez

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Q What chemical treatment programmes can help limit FCC unit bottoms circuit coking and fouling? A Rainer Rakoczy, Technology Advisor Fuels, Clariant International Ltd, rainer.rakoczy@clariant.com While fluid catalytic cracking (FCC) technology offers valu - able flexibility in processing different feedstocks, this flex - ibility comes with inherent efficiency trade-offs. As refiners optimise their processes, they must balance the desire for maximum feedstock utilisation against the production of higher-value products, which often requires compromises in overall process efficiency. Many FCC unit operations can utilise the bottom residue product thanks to its comparable high carbon-to-hydrogen atomic ratio as a heat producer in the regenerator. Unfortunately, this residue remains highly active and can accumulate throughout the entire downstream process - ing, resulting in severe fouling, especially in cases where piping is not optimised from a hydraulic flow perspective. The application of small quantities of supporting chemicals may help keep overall residue homogenised and movable to reduce any laydown of debris in the machinery. A Ghoncheh Rasouli, Technical Presales Consultant, Technology/SIM Product Management, KBC (A Yokogawa Company), ghoncheh.rasouli@kbc.global FCC unit bottoms circuit coking and fouling occur through a combination of high coke precursors and thermal instabil - ity within the main fractionator bottoms, slurry exchangers, and pumparound loops. The primary drivers are heavy feed components with high aromatic content, asphaltenes, res - ins, and elevated Conradson carbon (CCR), such as vacuum gas oil (VGO) and slurry oil. Poor feed hydrotreatment allows sulphur, nitrogen, and metals (including nickel and vanadium) to enter the unit. These metals, either present in the slurry or deposited on the catalyst, promote dehydrogenation reactions that gen - erate hydrogen and unsaturated hydrocarbons, accelerat - ing polymerisation and coke growth. Catalyst fines carried into the bottoms stream provide nucleation sites for deposit formation, while localised hot spots, high temperatures, and long residence times encourage thermal cracking of heavy hydrocarbons into lighter gases and solid carbon. Stagnant or low-flow areas further increase contact time with hot surfaces, compounding the tendency for fouling. Prevention requires a combined approach of feed quality improvement, operating control, and chemical treatment. Upgrading hydrotreating to lower CCR, sulphur, nitrogen, and metal contaminants is fundamental, and blending or hydrocracking heavy aromatic streams helps limit high-CCR feed components. Controlling slurry recycle rates is essen - tial to prevent excessive accumulation of heavy aromatics, while effective catalyst stripping reduces entrained hydro - carbons and minimises heavy-end carryover. Maintaining

stable temperature profiles and eliminating hot spots limits thermal cracking and the formation of coke precursors. Chemical treatment complements these practices by neu - tralising or passivating metals that catalyse coke formation. Antimony (Sb) compounds are commonly used to passiv - ate nickel, suppressing its dehydrogenation activity, while magnesium or rare-earth compounds neutralise vanadium and prevent catalyst degradation. Through cleaner feed, controlled recycle, optimised oper - ation, and targeted chemical passivation, FCC unit bottoms coking and fouling can be significantly mitigated, ensuring more reliable and efficient unit performance. A Berthold Otzisk, Senior Product Manager, Process Chemicals, Kurita Europe GmbH, berthold.otzisk@kurita- water.com A chemical treatment programme can be a great help in keep - ing fouling in the slurry oil system to a minimum. To select a suitable additive, it is very important to carry out a stream analysis, stream characterisation, and deposit analysis. Stream analysis determines the proportion of polynuclear aromat - ics (PNAs), catalyst fines, solids, carbon content, metals, and catalyst fines content. Stream characterisation assesses the aliphatic and aromatic content to determine the fouling poten - tial. Deposit analysis provides very important information and quantifies the amount of organic vs inorganic foulants present. Several antifoulants can be used. They should remain thermally stable even at high temperatures >350°C to be effective. Coke suppressants inhibit the high-temperature reaction of condensed aromatic compounds, which may lead to unwanted agglomeration and coke formation. This kind of additive will stop or reduce the formation of coke, but cannot remove existing coke deposits from the system. Catalyst fines dispersants prevent agglomeration and react with the surface of catalyst fines. Depending on the product, they either keep the catalyst fines in suspension or prevent them from sticking together. Asphaltene stabilisers avoid agglomeration and pre - cipitation of large molecules by forming an artificial layer between the asphaltene molecules. Organic dispersants avoid agglomeration and deposition of condensed poly - nuclear aromatic compounds on heat exchanger surfaces. This type of chemistry often exhibits relatively poor thermal stability at the temperatures present in the fractionator bot - toms and should not be injected into the slurry return line. It is possible to combine different additives with various func - tions in one antifoulant product to achieve the best results. Q What cost-effective strategies are available to increase naphtha production? A Rainer Rakoczy, Technology Advisor Fuels, Clariant International Ltd, rainer.rakoczy@clariant.com Naphtha is an important intermediate for the chemical,

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Rethinking Old Problems

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Revamp projects are difficult. Limitations imposed by plot space, congested pipe racks, and outdated equipment, to name a few, present unique challenges. Solutions that rely on excessive margins or comfortable designs lead to overspend. Now more than ever, process designers must find solutions that do more with less. P roven M ethods There is growing awareness that better scope definition earlier in the engineering phase saves time, reduces overall engineering cost, and leads to more successful projects. There is no argument that work completed during Conceptual and Feasibility phases is critical to getting a project on the right path. Engineers at Process Consulting Services, Inc. have developed a proven approach that makes the most of this precious time. At site, PCS engineers coordinate rigorous test runs, much of it through direct field measurements. Data collected is invaluable and often leads to low hanging fruit or hidden gems. Some refinery equipment performs better than design, and for various reasons others perform worse. Good test run data allows seasoned engineers to quickly identify what equipment needs investment and what equipment can be exploited. This way, solutions are developed that direct capital expense in the right areas and overspending is avoided. In one example, pressure drop measurements of a long crude oil transfer pipe showed the line could be reused, saving millions of dollars. Contact us today to learn how PCS’ proven methods can help you do more with less in your next revamp.

Projections for global supply and demand of refined products vary greatly depending on the pace of technological progress and degree of government policy enforcement associated with reducing greenhouse gas emissions. Without major advances in technology, it is hard to imagine a future without conventional fossil fuels over the next decade or two. Based on history, continued rationalization of refining assets is likely. Small, low-complexity refineries will struggle, while large, complex ones will thrive. Capacity creep through gradual improvement of refining units will continue to be a differentiating characteristic for remaining players. Focused revamps will play a critical role. Post-pandemic, inflation and a shortage of skilled construction labor have dramatically increased costs for refinery revamps. It is becoming increasingly difficult for many projects to meet corporate return on investment thresholds.

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petrochemical, and solvent industries, and it will continue to be so. Measures to enhance light production in non-hydro- processing applications, such as FCC units, visbreaker units (VBU), and delayed coking units (DCU), include both short- term and operational adjustments. However, these utili- ties may deliver more branched paraffins and naphthenic compounds, as the refinery operation is optimised for these types of naphtha molecules to keep high resistance to knocking, with the focus on road gasoline production. Nevertheless, there are options for modifying kerosene hydrotreaters, aromatics saturation, gasoil hydrotreat- ers and beyond by using a layered approach. This can be achieved by applying Clariant’s proprietary Hysopar and Hydex technologies in combination with HDMax slim cata- lyst layers, to enhance the desired naphtha portion in the product slate without a major revamp and (most appropri- ately) hydrogen management. A Edward Tay, Head Refinery Technology, Technologies & Solutions Management, Sulzer Chemtech, edward. tay@sulzer.com The most cost-effective strategy to increase naphtha pro- duction lies in revamping existing capacity-constrained fractionation towers using enhanced mass-transfer com- ponents. This approach leverages existing infrastructure, minimises capital expenditure, and accelerates implemen- tation timelines. For example, to boost straight-run naphtha production, targeted upgrades can be made to the fractionation or pumparound sections of the crude distillation tower, naph- tha splitter, and naphtha stabiliser. These upgrades may include high-performance structured packing, advanced tray technologies, or ultra-capacity trays. Similarly, to increase FCC naphtha production, refiners can enhance FCC unit throughput by consistently recov- ering more atmospheric gas oil (AGO) and vacuum gas oil (VGO). This can be achieved by upgrading the fractionation and wash sections in the crude and vacuum towers, respec- tively. Depending on the severity of the service, a tailored selection of structured packing, high-performance trays, or grid packing can be deployed. Q Can you discuss how HEFA co-processing can safely be increased from 5% to 10% or higher? A Rainer Rakoczy, Technology Advisor Fuels, Clariant International Ltd, rainer.rakoczy@clariant.com Co-processing of fats and oils (biogenic triglycerides [BTG]) has been a high-interest topic since the early 2000s. Besides encountering substantial hydrogen demand and the release of heat and unwanted small molecules, there are options to increase the co-processing level below 15-20 wt% under certain circumstances. In particular, for more complex fossil gas oil hydrotreaters that handle large quantities of cracked feed components, which negatively affect density, blending with BTG can be beneficial. This blending can help in hydrogen and heat management, as deep (mono-) aromatics saturation is not required, with the contribution of low-density normal paraffins sourced from

BTG hydrodeoxygenation (HDO). For shaping the distilla- tion curve and adjusting cold flow properties, there is an appropriate catalyst layer solution from Clariant’s propri- etary Hydex or Hysopar families. A Joris Mertens, Principal Consultant, KBC (A Yokogawa Company), joris.mertens@kbc.global The risks associated with processing vegetable oils and/or animal fats relate to the following: • Catalyst deactivation, primarily caused by phosphor pres- ent in biofeed (irreversible) and the formation of CO during the decarboxylation reaction (reversible). • Corrosion, resulting from acids in the feed and water formed during decarbonylation, reverse water-gas shift, and methanation reaction. • Hydrogen consumption and reaction exotherm. The specific hydrogen consumption when hydrotreating bio-oils tends to be higher than full conversion VGO hydrocracking. • Product cold flow property (freeze-, cloud point, cold filter plugging point [CFPP]) deterioration due to the paraffining nature of hydrotreated triglyceride biofeeds. Industry experience shows that up to 5% of bio-oils and fats can be processed relatively easily without modifica - tions to the unit, except for catalyst changes and possi- bly minor modifications to quench systems, provided the unit is equipped with an effective feed filter system. Co-processing up to 5% may be feasible without a full- blown feed pretreatment unit (PTU) that removes phos- phorus (P), metals, and other contaminants. However, this requires a strict selection of the biofeeds purchased and monitoring of P, metals, solids, chloride, and acidity. Therefore, even 5% co-processing is often done using pretreated feeds, which adds cost but ensures better and more stable feed quality. Co-processing of more than 20% biofeed has been dem- onstrated. However, it requires significant investments in new reactors, recycle gas compressor debottlenecking, metallurgy changes, liquid recycling requirements, and other significant changes to the design of the preheat and separation/fractionation sections. A move from 5% to 10% co-processing should aim at avoiding these high capital investments. The first step in this process is to assess the performance at 5% compared to operation without co-processing. Extrapolation of the move to 5% will give an indication of constraints and risks, such as mechanical bottlenecks, reaction exotherms, and cold flow property deterioration. If 5% co-processing has been sustained for a sufficiently long period, the extrapola - tion will clarify impacts on catalyst performance and pos- sibly corrosion. This analysis helps establish the co-processing limit and define actions to overcome these, such as: • Feed adjustment : Keep the acidity (TAN) of the feed mix below approximately 1 mg KOH/g. Processing of feeds with high levels of free fatty acids, such as palm oil mill effluent (POME) and palm fatty acid distillate (PFAD), will therefore need to be limited, even if pretreated, which may increase the cost of the feed blend.

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• Catalyst : A shift from NiMo to CoMo catalysts will be required to limit CO inhibition, and the isomerisation potential should be considered to limit cold flow property degradation. • Hardware adjustments : More limited adjustments to hardware can be considered, such as quench changes, col- umn improvements, enhanced water separation, and better drainage systems. Increasing co-processing will inevitably come at a cost in terms of catalyst, cycle length, feed, and capital expen- diture. The key is to balance these costs against the ben- efits using the following techno-economic approach that includes: • Risk identification, as mentioned earlier. • Process simulation, design verification, and collaboration with the catalyst supplier to identify and quantify mitigation measures. • Economic evaluation that balances the increased product value against operational and capital costs. A Milica Folić, Product Line Director, Topsoe, MFOL@ topsoe.com Raising the renewable feed co-processing ratio for sus- tainable aviation fuel (SAF) from the ASTM D1655 limit of 5% to 10% or higher demands a holistic strategy, balanc- ing catalyst performance and process safety to maintain Optimising unit performance at elevated co-processing levels means fine-tuning temperature, hydrogen-to-oil ratio, and space velocity for controlled reactions and desired yields reliability and product quality in existing refinery units. Co-processing renewable feedstocks introduces opera- tional changes, including high hydrogen demand for oxy- gen removal and olefin saturation, increased exotherms, increased water formation, and corrosion risk. These feedstocks also contain high levels of contami- nants, such as metals and phosphorus, which can accelerate catalyst deactivation. Therefore, specialised hydrodeoxy- genation catalysts with optimal activity become essential to efficiently remove oxygen and contaminants. Additionally, a deep dewaxing is required to convert n-paraffins into i-paraffins, ensuring the final product meets jet fuel speci - fications (for example, freezing point) while keeping the renewable molecules in the jet product. Topsoe’s selective dewaxing catalyst TK-930 D-wax has demonstrated opti- mal results for this purpose. Increasing the co-processing share to 10 vol% or more would require improved feedstock quality, consistent con- taminant monitoring, and a tailored catalyst management strategy. In some cases, additional reactor volume or cata- lyst beds may be necessary to maintain throughput and

product quality over a reasonable cycle length. On the pro- cess side, limitations intensify at higher blends: more water and heat increase the risks of exotherms, corrosion, and process instability. Robust water management, including improved separa- tion, treatment, and possible wash water injection, is critical. Existing metallurgy may need upgrades to resist corrosion from increased water and organic acids. Hydrogen supply, distribution, gas-liquid separation, and compressor capac- ity must be reviewed and potentially upgraded to handle higher demands and flows. Optimising unit performance at elevated co-processing levels means fine-tuning tempera - ture, hydrogen-to-oil ratio, and space velocity for controlled reactions and desired yields. With ASTM D1655 currently capping co-processing at 5%, any increase requires regulatory compliance and con- tinuous, accurate tracking of sustainability attributes and biogenic content for credits. Each refinery faces unique challenges, so partnering with a trusted catalyst and technology provider through feasibility studies, process design, and catalyst selection ensures a safe, efficient transition to higher SAF co-processing when regulations permit. This integrated approach positions refiners to meet future mandates and capitalise on the growing SAF market. Q Under what circumstances do you see transmix pro - cessing facilities delivering value? A Rainer Rakoczy, Technology Advisor Fuels, Clariant International Ltd , rainer.rakoczy@clariant.com There is always interest in upgrading transmix fractions to generate value beyond skimming through distillation by midstream companies operating pipelines or termi- nals. There are various options for generating high-value hydrocarbons through flexible hydroprocessing solutions that deliver value within or beyond the fuel market. With skid-mounted modular concepts improving constantly, even very small streams can be handled with attractive economics. The biggest obstacle for many interested com- panies is the transformation from a skimming or distilla- tion operation to a conversion operation, particularly from the perspective of the local authorities’ permit process. Clariant receives numerous inquiries in this field and offers case studies. Q How can higher volumes of straight-run VGO be con- verted to Euro VI quality distillates? A Rainer Rakoczy, Technology Advisor Fuels, Clariant International Ltd, rainer.rakoczy@clariant.com With the reduction in demand for gasoline and other light products, VGO conversion to optimise distillates yields that fulfil Euro VI requirements can be quite challeng - ing, focusing solely on FCC unit operation. Having VGO pretreating available, there are options to apply Hydex catalysts to optimise the VGO pretreater’s product slate to gain value from kerosene fractions and ultra-low sul- phur diesel.

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Catalytic pathways to circularity

Chemical recycling of waste plastics requires advanced catalysis to reduce energy intensity and technical complexity

Marc Nicolas and Jaap Bergwerff Ketjen Corporation

T he global plastics industry has reached a critical juncture. Since the 1950s, synthetic polymers have become indispensable across packaging, consumer goods, construction, and transportation. Yet, their durability and low cost have contributed to the environmental crisis. Estimates for global production of plastics in 2022 range from 400 to 460 million tons (Mt) per annum, with an expectation of growth to 884 Mt in 2050. 1 , ² Recent pub- lications 3 found that in the same year just under 38 Mt (9.5%) were produced from recycled plastic. Ninety-eight per cent of the remaining 362 Mt were produced from fossil fuels, predominantly coal and oil. Around 268 Mt of plastic are disposed of annually, of which 40% goes to landfill and 34% is incinerated. Despite the implementation of recycling targets and pol- icies in some jurisdictions, such as the EU, the recycling rate is globally stuck near 9-10%. This is due to several factors: too little of the right material is being captured and sorted cleanly; economics often favour virgin over recy- cled post-consumer resin; policy is incomplete or unevenly enforced; and the intrinsic design/chemistry of many plas- tic products defies high‑value mechanical reprocessing. Complementing concerns about the environmental impact of plastics include dependency on fossil feedstocks and their contribution to greenhouse gas (GHG) emissions. As early as the 1930s, biogenic alternatives, such as cello- phane and soy-based plastics, were developed. Around the 2010s, bio-PE and bio-PET became available on an industrial scale and currently account for around 1-2% of global plas- tics production. However, growth has been limited by cost, feedstock concerns, performance gaps, recycling infrastruc- ture, and the massive scale and low price of petroplastics. Chemical recycling, which breaks down plastics into their molecular building blocks, offers a pathway to true circularity. Unlike mechanical methods, chemical recycling

can handle mixed and contaminated streams, producing feedstocks suitable for new polymers, fuels, and chemicals. The polymers produced are safe to use in pharmaceutical and food-grade applications. Moreover, chemical recycling reduces the dependency on fossil feedstocks and can be implemented quickly by utilising assets at existing refin - ing and petrochemical installations. To be economically and environmentally viable, chemical recycling pathways require advanced catalysis to reduce energy intensity and technical complexity. Regulatory frameworks and market trends Chemical recycling is gaining attention as a way to process plastics that are unsuitable for mechanical recycling, but its market growth faces significant regulatory and operational hurdles: • The EU’s Packaging and Packaging Waste Regulation (PPWR) and Single-Use Plastics Directive set ambitious recycled content targets (for example, 10% for food con- tact packaging by 2030, 30% for bottles). However, the regulatory environment remains complex. The EU is final - ising mass balance accounting standards, which are critical for recognising chemically recycled content and enabling producers to leverage existing assets. Without clear, har- monised rules, investment risks remain high, and imple- mentation costs may rise. • The US approach is fragmented, with 24 states reclassi- fying advanced recycling as manufacturing to lower bar- riers, but no federal mandate exists. State-level recycled content laws (for example, California’s AB 793) drive some demand, but the lack of national standards and ongoing environmental debates create uncertainty for long-term investment. • South Korea’s new mandates require 10% recycled PET in large-scale production from 2026, with plans to expand.

Hydrothermal liquefaction

Waste plastics oil hydroprocessing

Fluid catalytic cracking

Fuels

Waste plastics

Pyrolysis

Catalytic upgrading

Steam cracking

Monomers

Gasication

Catalytic aromatisation

Chemicals

Feedstock

Primary conversion

Upgrading

Valorisation

Products

Figure 1 Pathways for chemical recycling of waste plastics, illustrating the primary conversion, upgrading, and valorisation steps for a variety of pathways

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Increasing waste plastic oil quality

350 Decreasing the boiling point distribution of waste plastics oil

100%

90%

300

Pyrolysis

C+

80%

250

70%

200

Naphthenes

60%

Catalytic Pyrolysis

150

Iso-parans

50%

100

Aromatics

40%

Olens

30%

20%

100

Parans

Mass (wt%)

10%

Figure 2 Effect of catalytic pyrolysis on boiling range of WPO

Thermal pyrolysis

Catalytic pyrolysis

Catalytic upgrading

The government supports advanced recycling projects, but enforcement details and broader adoption remain unclear. • Major plastics producers have announced ambitious chemical recycling targets for 2030, but actual capacity remains low (under 1 million tons in 2022). Even optimistic projections (10-25 million tons by 2030) represent only a fraction of global plastic waste, and operational, economic, and regulatory challenges persist. For the time being, the conclusion is that while chemi- cal recycling is positioned as a solution for hard-to-recycle plastics, its future depends on regulatory clarity, especially While chemical recycling is positioned as a solution for hard- to-recycle plastics, its future depends on regulatory clarity, mass balance accounting, and the ability to retrofit existing infrastructure to control costs. Without this, market expan - sion may be slower and more costly than industry forecasts suggest. Recycling: stages and catalytic challenges Chemical recycling pathways Chemical recycling encompasses a variety of pathways and technologies (see Figure 1 ), including pyrolysis, hydrother- mal liquefaction, gasification, depolymerisation, and others, that convert waste plastics into monomers, fuels, or chem- ical intermediates. The landscape of technology developers and licensors is currently still fairly scattered along the value chain, with technologies at different stages of development between bench-top and commercial scale. However, com- mon to most pathways is that the process unfolds in three main stages: especially mass balance accounting, and the ability to retrofit existing infrastructure to control costs

Figure 3 Stepwise improvement of WPO quality

u Primary conversion: Plastics are decomposed into smaller molecules (oils, gases) via thermal or catalytic processes. v Upgrading: The resulting products are refined to remove impurities and tailor their chemical properties. w Valorisation: Upgraded intermediates are integrated into existing petrochemical units (for example, steam crack - ers and fluid catalytic cracking [FCC] units) to produce new monomers, fuels, or specialty chemicals. Each stage presents unique catalytic challenges, from enhancing selectivity and yield to managing contami- nants that can poison catalysts or degrade product quality required for the intended downstream use. Primary conversion: catalytic pyrolysis and beyond Pyrolysis, the thermal decomposition of plastics in the absence of oxygen, is the most widely adopted chemical recycling technology for polyolefins (PE, PP). However, conventional pyrolysis produces oils with a broad boiling range and high levels of impurities, limiting their direct use in downstream processes. Introducing proprietary catalysts either (i) directly into the pyrolysis reactor or (ii) in a subsequent catalytic step can be a means of lowering the boiling point distribution of pyroly- sis oils. In this way, the fraction suitable for steam cracking could be increased and the need for extensive downstream upgrading reduced. Recent academic reviews highlight the importance of catalyst design in pyrolysis: zeolites, sili- ca-alumina, and metal-doped materials can enhance selec- tivity toward desired products and reduce coke formation. The choice of catalyst affects not only product distribution but also process economics and environmental impact. FCCSA, Ketjen’s joint venture in Brazil, exemplifies the integration of advanced catalysis with commercial-scale chemical recycling. Two different types of catalyst technol- ogy were deployed to produce high-quality oils suitable for steam cracking and aromatics production. A first catalyst is introduced in powder form into the pyrolysis reactor, while

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Strong metal poisons As (3 ppb), Sn (?), Pb (50 ppb), Hg (3 ppb) Mass transfer inhibitors Si (1 ppm), P (0.5 ppm), Fe (20 ppb), Ni (0.1 ppm), V (50 ppb) Halogens - corrosion risk Converted to acids under hydrogenating conditions Alkali metals and alkaline earth metals Na (125 ppb), Ca (500 ppb), K (500 ppb) Other elements of possible concern (darker colour=found in WPO samples in literature)

K V CrMnFe CoNi CuZnGaGeAsSe Br Kr Al Si P S Cl Ar B C N O F Ne He Rb Sr Y Zr NbMoTc Ru RhPd AgCd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt AuHg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Bh Hs H Li Be Na Mg Ca Sc Ti

Figure 4 (left) Periodic table of inorganic impurities Table 1 (right) Published limits for steam cracker feedstock⁶

the second catalyst is applied in a separate fixed bed reac - tor for catalytic upgrading of the oil vapours. From the boil - ing point distribution curves in Figure 2 , it can be observed that application of the catalyst in the pyrolysis reactor sig- nificantly decreases the boiling point of the produced oil, making that a larger fraction of the oil is in the naphtha fraction and hence, suitable as a feed for steam crackers. As we look at the molecular distribution of the oil, as pre - sented in Figure 3 , we can see what has happened and the role of the catalysts. By comparing the product com- position of non-catalytic pyrolysis (left) to the pyrolysis product with the presence of a catalyst in the pyrolysis reactor (middle), it can be seen that the catalytic pyrolysis has resulted in the cracking of larger C15 + molecules into olefins. Subsequently, the product slate after the upgrading step demonstrates that, in the fixed bed reactor, these ole - fins are isomerised, creating an oil that is highly paraffinic and has very good properties to be used as a steam cracker feed (right). Hydrothermal liquefaction and gasification are alter - native primary conversion routes, particularly for mixed or contaminated plastic streams. These processes oper- ate under higher pressure and temperature. Currently, most are non-catalytical, while some catalytic processes under development require robust catalysts to withstand harsh conditions and manage a wide range of feedstock impurities. Upgrading: hydroprocessing and catalytic aromatisation Plastics that are mechanically recycled need to meet defined standards for composition, type, and level of contamination, thus limiting their provenance. The chemical recycling path- ways are complementary to mechanical pathways and can cast a much wider net of feedstock materials. It results in a wider range of compositions and contaminants that vary with source, method of collection, and intended use, which change over time. The oils produced from primary conversion are typically unstable and contain a variety of contaminants, includ - ing chlorine, nitrogen, metals, and oxygenates that must be removed before integration into petrochemical assets. Hydroprocessing (hydrotreating and hydrocracking) meth- ods, similar to those applied for upgrading fossil-derived

feeds, are very suitable for upgrading oils from primary conversion and are now being adapted for waste plastic oils (WPOs). Catalysts that stabilise reactive molecules (di-olefins), trap inorganic impurities (phosphorus, silicon) and ena- ble precise control over boiling point distributions. Guard bed catalysts are essential for protecting downstream units from catalyst poisons, while hydrocracking catalysts facilitate the production of feedstocks suitable for steam crackers. Catalytic aromatisation technologies are being developed to convert pyrolysis products into aromatic compounds (benzene, toluene, xylene), which are critical building blocks for the chemical industry. Different processes are being explored where the catalyst is employed during pyrolysis or in a separate fixed bed or fluidised bed reactor. Valorisation: integration with petrochemical assets The final stage, valorisation, involves feeding upgraded products into conventional petrochemical units. FCC units, for example, can co-process WPOs with traditional feeds to produce monomers (especially propylene), fuels, and spe- cialty chemicals. However, the presence of contaminants such as iron and sodium in WPOs can deactivate conven- tional FCC catalysts. Catalysts are designed with tailored porosity and composition to maintain activity and selectiv- ity even in the presence of high impurity loads. This inno- vation enables refiners to incorporate recycled feedstocks without compromising performance or product quality. Valorisation of WPO via steam cracking is expected to be one of the leading chemical recycling pathways in the coming decade. 4 However, there are substantial safety and operational risks when using WPO instead of con- ventional fossil-based feedstocks. This is due to the vast number of contaminants. WPO can only meet the specifi - cations set for industrial steam cracker feedstocks if they are upgraded, with hydrogen-based technologies being the most effective, in combination with an effective pre - treatment. Moreover, steam crackers are reliant on stable and predictable feedstock quality and quantity, which rep - resents a challenge as plastic waste is largely influenced by consumer behaviour, seasonal changes, and local sort - ing efficiencies.

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Boiling point reduction Hydrocarbon type improvement

Di-olen saturation

ReNewFine

Olen saturation

HDS/HDO/HDN

ReNewFine

Guard bed

ReNewFine

HYC Polishing

Silicon trap

Boiling point

Figure 5 The upgrading of WPO via subsequent hydroprocessing steps as followed by 2D chromatography

WPOs: feedstock characterisation and processing The composition of WPOs varies widely depending on the source plastic, conversion technology, and operating con- ditions. Accurate characterisation is essential for catalyst design and process optimisation for each use case. Figure 4 illustrates the proverbial ‘periodic table’ of inorganic impu- rities that have been found in WPO. The FCC process has a reputation for tolerance to impurities, largely based on many years of experience across a range of crude qualities. Steam crackers tend to operate with lower risk tolerance. Few publications define clear limits on impurities for steam There is a need for standardised characterisation protocols and benchmarking of catalyst performance across studies cracker operations. Table 1 gives a summary of values from a paper that is widely referenced in the industry, combined with Ketjen’s own intelligence. 5 For molecular impurities, Ketjen employs multi-dimen- sional chromatography and elemental analysis to profile WPOs, identifying key contaminants and their structures. This data informs the selection and design of catalysts for hydroprocessing, ensuring robust performance across a range of feedstocks. The use of 2D chromatography to follow the composition of the hydrocarbon stream during the different steps in the upgrading of WPOs via hydroprocessing is illustrated in Figure 5 . In the 2D chromatograms, each dot represents the concentration of a molecular compound with a certain

boiling point (horizontal position) and polarity (vertical posi- tion). When analysing the WPO before and after the olefin saturation step (left side of the figure), it can be observed that reactive dienes are selectively removed, which allows for deep hydroprocessing over more active catalysts with- out the risk of an extreme exotherm in downstream catalyst beds. During the hydrocracking step that concludes the upgrading of the WPO, the boiling point of the then-pure hydrocarbons is effectively reduced to yield a product that is suitable as steam cracker feed. There is a need for standardised characterisation pro- tocols and benchmarking of catalyst performance across studies. The complexity of WPOs, which contain additives, stabilisers, and degradation products, poses ongoing chal- lenges for both research and industrial implementation. Challenges and opportunities Despite significant progress, several challenges remain: • Feedstock variability: The wide range of waste plastics feedstocks and their contaminant profile complicate pro - cess design and catalyst selection. In theory, feedstock variability could be addressed by standardisation and clas- sification, similar to what is the current practice for varia - bility in crude oil qualities. Unlike crude that comes from reservoirs, waste plastics come from a range of disparate resources (such as municipal waste), and the current collec- tion and sorting techniques do not yield constant qualities. • There is a need for standardised characterisation pro- tocols and benchmarking of catalyst performance across studies. The complexity of WPOs containing additives, stabilisers, and degradation products poses ongoing chal- lenges for both research and industrial implementation. • Detailed analyses of the mechanisms underlying catalytic plastic recycling are key for future progress. For instance, it is clear that zeolites and silica-alumina catalysts promote

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influencing product selectivity. However, further elucidation of the structure-function relationship of catalysts – active site accessibility, metal dispersion, support interactions – is critical for optimising performance and durability. • Contaminant management : Additives, stabilisers, and degradation products can poison catalysts and degrade product quality. • Process integration : Aligning chemical recycling outputs with existing petrochemical infrastructure requires careful tuning of product properties and impurity profiles. • Economic viability : High capital and operating costs, cou- pled with volatile feedstock prices, challenge the business case for chemical recycling. Opportunities abound in the development of advanced catalysts, process intensification, and digitalisation (for example, real-time analytics for feedstock characterisation and process control). Conclusion Chemical recycling represents an essential pathway toward a more sustainable and circular economy. Advanced cata- lyst technologies that are used in several process pathways enable the transformation of waste plastics into high-value products, helping industries reduce their environmental footprint while maintaining economic viability. Much is to be said for utilising existing assets where pos- sible, as this is cost-effective (Opex), reduces investment (Capex), accelerates incrementation (speed), and lowers the need for all-or-nothing alternatives (risk).

By integrating recycled feedstock into existing assets, Ketjen’s solutions offer a pragmatic and impactful approach to sustainability. As the demand for circular products contin- ues to grow, catalysis will remain at the core of innovation. ReNewFine is a mark of Ketjen. References 1 OECD, 2022. Global Plastics Outlook. https://www.oecd-ilibrary.org/ environment/data/global-plastic-outlook_c0821f81-en. 2 Plastics Europe, Plastics – the fast Facts 2024. https://plasticseurope. org/knowledge-hub/plastics-the-fast-facts-2024/ 3 Houssini, K., Li, J., and Tan, Q., Complexities of the global plas- tics supply chain revealed in a trade-linked material flow analysis. Commun Earth Environ 6 , 257, 2025. https://www.nature.com/articles/ s43247-025-02169-5 4 Kusenberg, M., Eschenbacher, A., Djokic, M. R., Zayoud, A., Ragaert, K., De Meester, S., & Van Geem, K. M. Opportunities and challenges for the application of post-consumer plastic waste pyrolysis oils as steam cracker feedstocks: To decontaminate or not to decontami- nate?. Waste Management 138, 83 (2022). https://doi.org/10.1016/j. wasman.2021.11.009 5 Baumgartner, A. J., Blaschke, M. W., Coleman, S. T., Kohler, R., and Paxson, T. E. (2004, April 25-29). Feedstock contaminants in ethyl- ene plants – an update. Paper presented at the AIChE Spring National Meeting, New Orleans, LA. Marc Nicolas is Global Business Director at Ketjen Corporation in Amsterdam, The Netherlands. Jaap Bergwerff is Business Development Director Renewables in Amsterdam, The Netherlands.

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