To support the transition toward a more circular economy, various technologies have been explored to convert plastic waste into valuable materials. Among these is pyrolysis, a thermochemical process that produces gas, solid, and liquid products, where the latter is known as plastic pyrolysis oil (PPO). These oils typically contain hydrocarbons and impurities such as oxygenates, nitrogenates, and organochlorides, depending on the composition of the plastic feedstock and process conditions. Since these contaminants must be removed before PPOs can be used in industrial steam crackers, their speciation is essential to define appropriate upgrading strategies. In this context, this study evaluates a gas chromatograph coupled with a halogen selective detector (GC-XSD) system, in combination with a comprehensive gas chromatograph system coupled with high resolution time-of-flight mass spectrometry (GC × GC-HR-TOFMS), for the identification of organochlorides in hydrocarbon matrices. Initially, the selectivity of the XSD, reactor temperature, and response to Cl standards were assessed. The method was then applied to the distilled fractions of a PPO. Using GC × GC-HR-TOFMS, several organochlorides were identified, including 1-chlorobutane, which was found at the highest concentration in the first distilled fraction (50-100 °C), and 3-(chloromethyl)heptane and 1,3-dichlorobezene, which were eluted primarily in the third fraction (150-200 °C). Other compounds, such as 1,2-dichloroethane, chlorobenzene, and 2-chloroethyl benzoate, were also detected at lower concentrations. The GC-XSD was proved to exhibit robust and selective capability for organochloride speciation in PPOs and could be potentially implemented in quality control and routine laboratories. When combined with hyphenated techniques such as GC × GC-HR-TOFMS, GC-XSD also facilitates the identification of unknown organochlorides.

Ethane is a key raw material to produce ethylene that has a foundation role in the modern petrochemical industry. Nevertheless, the industrial production of ethylene through ethane steam cracking is a process with high energy consumption and high carbon emissions. Given these issues, this presentation introduces a novel electrochemical method for the efficient decomposition of ethane in molten alkali metal halide salt systems at a temperature range of 400–600°C. The electrolysis of molten alkali metal chlorides causes the chlorination of ethane near the anode, and, as the bubbles rise, the chloroethanes and hydrogen chloride are reduced by the liquid alkali metal produced at the cathode or the solvated electrons generated. This process not only produces valuable chemicals such as hydrogen, ethylene, and carbon but also regenerates the alkali metal chloride. This study also reveals the effects of parameters such as temperature, molten salt composition, and electrolysis current on the performance of ethane decomposition. In a small laboratory-scale molten LiCl–NaCl–KCl electrolytic cell, at a current of 1.5 amperes and a temperature of 550°C, the ethane conversion rate reached 71%, with a hydrogen selectivity of 48% and an ethylene selectivity of 34%. This molten salt electrochemical method provides promising technology for converting ethane into high-value products.

Efficient separation of light hydrocarbons-including the removal of CH4 from N2 and the purification of olefins such as C2H4 and C3H6 from their corresponding alkanes (C2H6 and C3H8)-is critical in natural gas upgrading, steam cracking, and downstream petrochemical production. Traditional adsorbents are tailored to specific mixtures, limiting their broader applicability. The development of multifunctional adsorbents that can efficiently operate across multiple gas separation systems represents a promising strategy to simplify material design and broaden industrial relevance. Herein, methyl-functional groups are innovatively introduced into porous coordination polymers (PCPs), synthesizing PCP-BDC-M and PCP-BDC-DM with precisely tailored microporous structures. Notably, the dimethyl-functionalized PCP-BDC-DM demonstrates superior multifunctional selectivity toward CH4/N2, C2H6/C2H4, and C3H8/C3H6 gas mixtures. Adsorption isotherms and Ideal Adsorbed Solution Theory (IAST) calculations reveal significantly higher alkane selectivity in PCP-BDC-DM compared to PCP-BDC-M and existing alkane-selective adsorbents. Grand Canonical Monte Carlo (GCMC) simulations provide molecular-level insight, confirming that methyl groups effectively enhance interactions between alkane molecules and the framework. Dynamic breakthrough experiments further validate PCP-BDC-DM's excellent practical separation capability and structural stability. This study offers valuable insights into designing advanced adsorbents for alkane-selective gas separation.

Towards sustainable textile waste management: Exploring valuable chemicals production through steam cracking in a dual fluidized bed

Plastic pyrolysis oils (PPOs) as potential steam cracker feedstocks contain several undesired molecules, such as oxygenates, nitrogenates, halogenated species, and metals. In this context, the speciation of these components is crucial to define an effective upgrading process before feeding PPO into steam crackers. In this work, a methodology is presented to identify and quantify nitrogen-containing molecules in PPOs using a comprehensive two-dimensional gas chromatography system coupled to a high-resolution time-of-flight mass spectrometer (GC×GC-HR-TOFMS) and a (comprehensive two-dimensional) gas chromatography system coupled to a nitrogen chemiluminescence detector (GC(×GC)-NCD). In addition, spectra analysis tool, a toolkit paired with the Leco ChromaTOF software, was used to filter HR-TOFMS data and allowed identifying fragments which contained nitrogen. A crude PPO and its distilled fractions were analyzed. The analysis of different boiling point ranges of PPO allowed the identification of several compounds which would be challenging in the full-range oil and provided additional insights into the sample composition, especially regarding the heavier fractions containing several branched paraffinic nitriles. Nitrogen species such as benzonitrile, caprolactam, benzenedicarbonitrile, hexadecanenitrile, and others were identified and quantified. The nitrogen content of all distilled fractions of PPOs obtained with GC-NCD was similar to the values from elemental analysis, with a recovery of approximately 100%. Therefore, the GC-NCD method proved to be robust for quantifying nitrogen species in PPOs and can potentially be implemented in quality control labs, while GC×GC-HR-TOFMS and GC(×GC)-NCD are powerful tools for speciation of unknown N-compounds.

In this study, non-isothermal pyrolysis of a mixture of disposable surgical face masks (FMs) and nitrile gloves (NGs) was conducted, using a heating rate of 100 °C/min, N2 flowrate of 100 mL/min, and temperatures between 500 and 800 °C. Condensable product yield peaked at 600 °C (76.9 wt.%), with gas yields rising to 31.0 wt.%, at 800 °C. GC-MS of the condensable product confirmed the presence of aliphatic compounds (>90%), while hydrogen, methane, and ethylene dominated the gas composition. At 600 °C, gasoline (C4 to C12)-, diesel (C13 to C20)-, motor oil (C21 to C35)-, and heavy hydrocarbon (C35+)-range compounds accounted for 23.7, 46.7, 12.5, and 17.1%, of the condensable product, respectively. Using model-free methods, the average activation energy and pre-exponential factor were found to be 309.7 ± 2.4 kJ/mol and 2.5 ± 3.4 × 1025 s-1, respectively, while a 2-dimensional diffusion mechanism was determined. Scale-up runs confirmed high yields of condensable product (60-70%), with comparable composition to that obtained from lab-scale tests. The pyrolysis oil exceeds acceptable oxygen, nitrogen, chlorine, and fluorine levels for industrial steam crackers-needing pre-treatment-while other contaminants like sulphur and metals could be managed through mild blending. In summary, this work offers a sustainable approach to address the environmental concerns surrounding disposable FMs and NGs.

Catalytic hydrogenation of trace alkynes in excess alkenes is essential for producing polymer-grade olefins from steam cracking and alkane dehydrogenation, but achieving high selectivity without sacrificing activity remains a significant challenge. Herein, we report a catalyst design that synergistically integrates computationally proposed surface Pd1Sb2 trimer sites with near-surface Pd sites (Pdns) on the P63/mmc PdSb intermetallic catalyst to achieve the semihydrogenation of alkynes with both high activity and selectivity. Alkynes can be readily activated through strong σ-bonding on the Pd1Sb2 trimer sites, whereas alkenes are only weakly adsorbed via π-interactions due to their matched electronic structures and spatial configurations. Moreover, the neighboring Pdns cooperates with the Pd1Sb2 sites to achieve spontaneous dissociation of H2 for subsequent hydrogenation. Consequently, the fabricated PdSb intermetallic catalyst exhibits ethylene and propylene selectivities of 96.50% and 98.65%, respectively, at nearly complete conversions of acetylene and propyne, under industrially relevant conditions, outperforming state-of-the-art catalysts. This study demonstrates a promising strategy that synergizes near-surface and surface ensemble sites to spatially and energetically match with the target reaction pathway, enabling the overcoming of the trade-off between activity and selectivity in hydrogenation.

Cradle-to-Gate greenhouse gas emissions of the production of ethylene from U.S. Corn ethanol and comparison to fossil-derived ethylene production.

Effects of initiator on steam cracking of naphtha model compound by high-throughput simulation

Steam cracking of polypropylene for the production of light olefins in a fountain confined conical spouted bed reactor

Describing heterogeneous catalysis is complicated bythe intricateinterplay of processes that govern catalyst performance. The evolvingchemical environment and the kinetics of catalyst’s structuralchanges during reactions often lead to unknown local geometries andchemistry, which can shift reactivity over time. Here, we performsystematic experiments and apply a focused artificial-intelligence(AI) approach to model the measured time-on-stream-dependent reactivityof palladium-based bimetallic catalysts. These materials are synthesizedvia mechanochemistry and applied in the selective hydrogenation ofconcentrated acetylene streams(>14.0 vol %)under industriallyrelevant pressures (10 bar), resulting from ahypothetical electric plasma-assisted methane-to-ethylene process.Unlike the well-established hydrogenation of diluted acetylene (0.1to 2.0 vol %) streams of naphtha steam cracking, the hydrogenationof concentrated acetylene streams remains largely underexplored dueto the harsh reaction conditions and the explosive nature of acetylene.This precludes operando characterization or atomisticsimulations to investigate catalyst time-on-stream behavior underrealistic conditions. Our AI approach first uses subgroup discoveryto identify descriptions of materials and reaction conditions resultingin noticeable acetylene conversion. Then, it models time-dependentselectivity focused on high acetylene conversion via the sure-independence-screening-and-sparsifyingoperator symbolic-regression approach. AI identifies key experimentaland theoretical physicochemical descriptive parameters correlatedwith the reactivity, which highlight the critical interplay betweenthe material structure and the chemical potential of the reactionmixture. The AI models enable the design of bimetallic and trimetalliccatalysts, which are experimentally validated.

Thermochemical recycling of mixed plastic wastes through pyrolysis and steam cracking – Assessment of centralized vs. Decentralized approaches

Abstract The catalytic hydrogenolysis of waste polyolefins into naphtha‐range hydrocarbons offers a promising strategy for advancing the circularity of plastics by enabling their transformation into feedstocks for steam crackers. Despite this potential, the suitability of existing commercial hydrotreatment catalysts for this application remains underexplored. In this study, a systematic evaluation of various commercially available catalysts—including monometallic (Pt/Al2O3), multimetallic Ni‐based and Au─Pd systems, and metal‐free materials (γ‐Al2O3 and mordenite)—was conducted to assess their activity in polyethylene (PE) hydrogenolysis. Pt/Al2O3 was used to establish model reaction conditions, which were then applied uniformly across all catalysts. The results revealed that catalytic operations are essential for liquid product formation; however, Pt/Al2O3 displayed only limited activity, yielding 3% liquid under optimized conditions. While Ni‐based and Au─Pd catalysts produced higher yields, the resulting product streams failed to meet naphtha specifications due to elevated olefin content. Metal‐free catalysts showed negligible performance. The study demonstrates that commercially available hydrotreatment catalysts are insufficient for the efficient catalytic transformation of PE to naphtha. The findings highlight the need for the development of catalysts specifically engineered for polymer depolymerization and selective C─C bond cleavage, as well as a deeper mechanistic understanding of catalyst structure–function relationships in this emerging field.

Electrification is a highly effective decarbonization and environmental incentive strategy for the chemical industry. Nevertheless, it may lead to downstream challenges in the process. This study analyzes the consequences of electrifying compressors within the steam cracker (SC) condensate system, focusing on the reduction in greenhouse gas (GHG) emissions and energy consumption without compromising the process’s energy efficiency. The aim is to study the impact that the reduction in steam expanded by turbines has on boiler feedwater (BFW) temperature and, subsequently, the behavior it triggers in fuel gas (FG) consumption and carbon dioxide (CO2) emissions in furnaces. It was concluded that condensate imports from the Energies and Utilities Plant (E&U) would increase by a factor of four, with approximately 60% of the imported condensate being cold condensate. The study revealed a mitigation of CO2 emissions, resulting in a 1.3% reduction and a reduction in FG consumption of 1.8% preventing an increase in site energy consumption by 795.4 kW in furnaces. Condenser optimization reduces CO2 emissions by 60%. Energy integration with quench water resulted in heat saving of 1824 kW in hot utility consumption and generating annual savings of EUR 2.3 M. The global carbon dioxide balance can achieve up to a 25% reduction.

Effect of Si/Al2 Ratio Over Zeolite Beta in Steam and Direct Catalytic Cracking of n-dodecane

Inductively Heated Electro-Balance Unit for Studying Coke Formation and Carburization for High-Temperature Alloys during Steam Cracking

This study presents a comprehensive examination of the chemistry and technology involved in monomer production, focusing on both petrochemical and bio-based routes. By investigating steam cracking of naphtha, propane dehydrogenation, ethylbenzene dehydrogenation, and lactic acid fermentation for lactide synthesis, the research compares yields, selectivity, and purity levels across different feedstocks and processes. Experimental setups ranged from high-temperature steam cracking (800–850°C) to tin-catalyzed ring-closing of lactic acid, with downstream purification by fractional distillation, caustic washing, and continuous vacuum distillation. Results showed that steam cracking remains a robust, mature technology for high-volume ethylene production, while dedicated propane dehydrogenation can achieve targeted propylene yields. Styrene production via ethylbenzene dehydrogenation emphasized careful temperature and catalyst management to reach high selectivity and maintain catalyst longevity. Meanwhile, bio-based lactide synthesis demonstrated potential for reduced carbon emissions, although it remains constrained by energy-intensive purification and feedstock costs. Life cycle assessment revealed a trade-off between established petrochemical infrastructure and the ecological advantages of renewable feedstocks. Future directions include refining catalyst materials, adopting efficient separation technologies, and integrating chemical recycling to foster a circular economy. Overall, the findings highlight how process optimization, catalysis innovation, and sustainability principles collectively shape the current and future landscape of monomer production for polymer industries.

Abstract Electric plasma activation of methane opens up the possibility to produce ethene, an important platform chemical in industry, by using sustainable resources like biogas or hydrogenated carbon dioxide and electricity from renewable energies. The ethene stream of such pyrolysis plants contains much higher concentrations of acetylene (≥15 vol.%) compared to ethene from conventional steam cracking of naphtha (<2 vol.%). In this study, silver‐palladium catalysts in various compositions supported on alumina were synthesized via a sol‐immobilization technique and investigated in the selective gas‐phase hydrogenation of equally concentrated acetylene‐ethene mixtures under industrially relevant pressures. A molar Pd concentration of around 10 % in the PdAg alloyed nanoparticles was identified as the optimum composition for simultaneous high activity and ethene selectivity under catalysis conditions. Higher temperatures seem to be crucial for the stability of the catalysts on‐stream most likely via increased desorption of active site blocking and high‐boiling oligomers from acetylene. The best performing Pd10Ag90 displayed an ethene, ethane and C4+ selectivity of 65%, 4%, and 14%, respectively, at 175 °C while being active for more than 200 min. The performance of the catalyst was compared with catalysts synthesized via a mechanochemical and a conventional wet‐impregnation procedure.

"With the growing global demand for polymers, especially polypropylene, propylene production technology is becoming of key importance for the petrochemical industry. Propylene is the second most important monomer after ethylene and is used in the production of a wide range of products, from packaging materials to automotive components and textile fibres. Given the trends of decarbonisation, circular economy development and tightening of environmental standards (in particular, within the framework of EU initiatives – CBAM, ESG, etc.), the choice of technology with an optimal combination of economic efficiency and environmental safety becomes critical. In this paper, a comprehensive comparative analysis of four industrial processes for propylene production: steam cracking, catalytic cracking (FCC), propane dehydrogenation (PDH) and methanol-to-propylene (MTP) technology is carried out. Such parameters as feedstock type, product yield, capital and operating costs, carbon footprint, technological maturity and prospects for implementation in Kazakhstan are considered. Special attention is paid to resource availability (naphtha, propane, coal) and current industrial projects in the country. Based on the analysis, conclusions are drawn on the short-term and long-term feasibility of introducing certain technologies. Keywords: Propylene, Polypropylene, Carbon footprint, Petrochemistry, Circular economy, Sustainable development, Process efficiency "

Site-specific factors are expected to influence the indication of cost-optimal decarbonization technology for the carbon-intensive process industry. This work presents a framework methodology to enhance the comparative analysis of decarbonization alternatives with a site-specific TEA method incorporating pertinent site-specific factors to obtain an enhanced indication of the optimal decarbonization solution. Site-specific cost factors such as energy supply options, space availability, site-layout constraints, local CO2 interconnections, forced downtime, and premature decommissioning are considered. Qualitative site-specific factors and technology-specific attributes are assessed via expert elicitation with a retrofitability assessment matrix, generalizable to other process industries considering their site-level conditions. The framework methodology is demonstrated with a steam cracker plant case study, considering post-combustion CO2 capture and pre-combustion CO2 capture with hydrogen-firing in the cracker furnaces as decarbonization options. Results complemented with factor-specific sensitivity analysis highlight the extent of cost-escalation due to site-specific factors. The primary cost-contributing factor to retrofitability was the impact on production in existing sites, followed by the opportunity cost of utilizing valuable space on-site. Finally, pre-combustion CO2 capture was found to be the optimal solution, offering significant site-specific advantages, with the lowest CO2 avoidance cost and reduced overall risk over the residual lifetime of the host plant.