Catalysis 2026 Issue

transporting higher-value but unstable PPO to upgrading facilities. Optimising this logistics network is essential for both economic and environmental performance, and it is not yet fully solved at scale. To integrate high levels of PPO into conventional steam crackers, upgrading of the PPO quality is essential. There are many technologies available for upgrading, each with its own limitations and opportunities. Against this back- drop, PureStep upgrades PPO through hydroprocessing. The technology has already been proven with two operat- ing commercial units at SABIC and OMV in Europe, both producing fully on-spec, contaminant-free PPO feedstock used in existing crackers. From a technology readiness per- spective, upgrading is no longer the bottleneck (PureStep has reached TRL 9). The hydroprocessing-based upgrad- ing route has key benefits: • It scales (i.e., the larger the unit, the lower the processing cost per ton). • It produces a PPO on-spec that does not require blending with fossil feedstock. • It can transform PPO to naphtha-range material, avoiding major revamps on steam cracker furnaces, so that once PPO is available at sufficient scale and quality, existing cracker assets can absorb 10-30% circular feedstocks with ease. However, even with mature technologies, project econom- ics and policy remain major barriers. Today, ethane crackers can produce ethylene at roughly half the cost of many naph- tha crackers, making large investments in naphtha-based circular pathways difficult under current market margins. At the same time, the industry is facing tariffs, regional overcapacity, and generally low margins in base chemicals, which makes it harder to secure attractive returns on large Capex projects. In this context, reaching the 10-30% range is not only about the technology, but also creating conditions under which long-term investments in pyrolysis, logistics, and upgrading can deliver acceptable risk-adjusted returns. A Mel Larson, Advisor, Becht, mlarson@becht.com Scaling up chemical recycling via plastic pyrolysis requires the recovery of plastics, separation, and production to a vol- ume that is sustainable for the system. This issue is inher- ently complex because it must be evaluated across the entire energy and process lifecycle. Pyrolysis oils typically contain contaminants, such as metals, chlorides, and elements, that poison conventional refinery catalyst systems. In addition, pyrolysis is an oxygen/hydrogen-deficient pro - cess. As a result, the pyrolysis gas is not immediately suitable as a refinery feedstock and requires further processing to make an acceptable feedstock. When the full energy balance and carbon footprint are considered, economics become a critical constraint. Economics in some credit form is neces- sary to allow a return on the required investment. A Danny Verboekend, Chief Scientific Officer, Zeopore Technologies, danny.verboekend@zeopore.com The chemical conversion of waste plastics typically involves three steps in which the plastic polymer structures are reduced in size, with the target to return to viable chemi- cal building blocks: ideally, the same monomers from which

they were first composed. Hence, making ethylene from polyethylene and propylene from polypropylene. These three steps are: • Pyrolysis (yielding light gases, oils, vapours, and char). • Upgrading of the pyrolysis oils. • Upgrading of the pyrolysis vapours. Thermal pyrolysis is generally the most used process to start the chemical breakdown of waste polymers into desired species. Although many developments have been achieved, pyrolysis needs to be done at very high temperatures, and the amount of undesired products (char and light gases) is still significant, negatively affecting the productivity of any potential follow-up conversion of the oils or vapours. Using zeolite-based catalysts, the pyrolysis of waste plas- tics can be executed at lower temperatures and, importantly, boost the yields of desired products. Also, in the upgrading of pyrolysis vapours and oils, zeolite-based catalyst have shown, typically on pure virgin plastic feedstocks, outstand- ing potential. However, to scale up such technology, several challenges exist. First, the complexity and variety of plastic polymers imply a plethora of contaminants, which complicates the cost-effective use of the catalyst, especially for catalytic pyrolysis. Results based on pure virgin waste plastics have proven simply not relevant to the dirty, complex nature of real-world waste streams. Secondly, the large nature of plastic polymer and the reac- tivity of the derived vapours or oils make traditional zeolites yield suboptimal performance. Here, the challenge is first designing a superior, premium-performance zeolite and sec- ond ensuring that the premium zeolite is scalable. As com- municated in PTQ , mesoporous zeolites offer great potential to boost the performance of catalytic conversion of waste plastics or derived intermediates.¹ 1 Du Mong, K, Verboekend, D., Low-cost mesoporous zeolites deliver catalytic benefits, PTQ Catalysis 2022, pp.45-49 , Q How can refiners cost-effectively play a role in the structural shift from fuels to polyolefins production? A Hernando Salgado, Technical Service Manager, BASF, hernando.salgado@basf.com The refining process technology with the highest degree of flexibility is perhaps fluid catalytic cracking (FCC). Refineries with an FCC unit can take advantage of its intrinsic flexibility to shift from fuels maximisation (mainly gasoline compo- nents) to maximising the production of petrochemical build- ing blocks, such as propylene and ethylene, which are the main raw materials to produce polyolefins. It must be noted that a downstream polymerisation process would be needed to convert these light olefins into polyolefins. Typically, the most common way to shift fuels (gasoline) to light olefins in an FCC unit is by using an olefin additive based on ZSM-5 zeolite, which acts as a secondary cata- lyst that, when properly combined with the primary zeolite Y-based catalyst, can easily boost light olefins production. The impact of this catalytic system can be explained by using a two-step approach (see Figure 1 ) as follows:

Catalysis 2026