Contaminant removal from plastic waste pyrolysis oil via depth filtration and the impact on chemical recycling: A simple solution with significant impact

Towards an Understanding of Poisoning of Steam Cracking Steels by Alkali Metals.

Abstract Zr based metallosilicalites, especially Zr‐ß, is promising catalyst for the conversion of ethanol to 1,3‐butadiene, which is considered to be a sustainable alternative to petroleum steam cracking. However it is suffering from deactivation derived from coking and unsatisfied catalytic activity derived from deficient Lewis acidity. For these issues, a dissolution‐recrystallization process through tetraethyl ammonium hydroxide treatment (TEAOH) for enhancing porosity and Lewis acidity of Zr‐ß zeolite was developed in this study. A balance of dissolution and recrystallization existed in this process, which was produced by OH− etching and templating of TEA+ ions, creating additional mesoporosity. Zirconium active sites maintained tetrahedral coordination, while the Lewis acidity was enhanced by creating higher proportion open sites in framework. The recrystallized Zr‐ß exhibited higher catalytic activity and stability in the conversion of ethanol‐acetaldehyde to butadiene due to the compromise of microporosity and mesoporosity, as well as the appropriate enhancement of Lewis acidity.

Background: Production of shale gas in the United States (US) increased more than 10-fold from 2008 to 2021, yielding greater quantities of hydrocarbon feedstocks and incentivizing expansion of petrochemical facilities. Steam crackers (SCs) convert hydrocarbon feedstocks into ethylene and propylene (the building blocks of plastics), while releasing toxic chemicals and greenhouse gases (GHGs). Analyses of environmental health and justice impacts of SCs are limited. Methods: We described SC operations, locations, and emissions, and evaluated sociodemographic characteristics of populations residing near SCs to better understand potential public health hazards and inform future studies. We summarized and described industry-reported emissions from the US Environmental Protection Agency’s Toxic Release Inventory and GHG Reporting Program. We compared population characteristics of US Census block groups ⩽5 km and >5 km from a steam cracker-containing facility (SCF) within the same county. Results: We identified 32 SCFs across five US states, with most in Texas and Louisiana. Toxic chemicals with the greatest reported cumulative air emissions in 1987–2019 were: ethylene, propylene, hydrochloric acid, benzene, n-hexane, 1,3-butadiene, ammonia, toluene, vinyl acetate, and methanol. Reported total annual GHG emissions were 4% higher in 2019 versus 2010, with total GHG emissions of >650 million metric tons (carbon dioxide equivalents) in 2010–2019. We found that 752 465 people live in census block groups ⩽5 km from an SCF, regardless of county. Compared to block groups >5 km away within the same county, block groups closer to SCFs had statistically significantly lower median incomes ($54 843 vs $67 866) and more vacant housing (15% vs 11%), and higher proportions of residents who were non-Hispanic Black (31% vs 19%) and unemployed (8% vs 6%). Conclusion: SCs emit substantial amounts of GHGs and toxic chemicals in locations with historically disadvantaged populations. Future research could further evaluate the accuracy of reported emissions, conduct monitoring in proximate communities, and assess population-level health impacts.

Light olefins (LOs) such as ethylene and propylene are critical feedstocks for many vital chemicals that support our economy and daily life. LOs are currently mass produced via steam cracking of hydrocarbons, which is highly energy intensive and carbon polluting. Efficient, low-emission, and LO-selective conversion technologies are highly desirable. Electrochemical oxidative dehydrogenation of alkanes in oxide-ion-conducting solid oxide fuel cell (SOFC) reactors has been reported in recent years as a promising approach to produce LOs with high efficiency and yield while generating electricity. We report here an electrocatalyst that excels in the co-production. The efficient catalyst is NiFe alloy nanoparticles (NPs) exsolved from a Pr- and Ni-doped double perovskite Sr2Fe1.5Mo0.5O6 (Pr0.8Sr1.2Ni0.2Fe1.3Mo0.5O6-δ, PSNFM) matrix during SOFC operation. We show evidence that Ni is first exsolved, which triggers the following Fe-exsolution, forming the NiFe NP alloy. At the same time as the NiFe exsolution, abundant oxygen vacancies are created at the NiFe/PSNFM interface, which promotes the oxygen mobility for oxidative dehydrogenation of propane (ODHP), coking resistance, and power generation. At 750 °C, the SOFC reactor with the PSNFM catalyst reaches a propane conversion of 71.40% and LO yield of 70.91% under a current density of 0.3 A cm-2 without coking. This level of performance is unmatchable by the current thermal catalytic reactors, demonstrating the great potential of electrochemical reactors for direct hydrocarbon conversion into value-added products.

Purification and characterisation of post-consumer plastic pyrolysis oil fractionated by vacuum distillation

C–H activation of hydrocarbons is extremely challenging, especially in short-chain hydrocarbons like propane. In industry, propane is first converted to propylene mostly by steam cracking, which is only oxidized to acetone in the cumene process, yielding acetone and phenol. In this work, we show that the simple FeCl3 salt in acetonitrile photocatalyzes the oxidation of propane to acetone at room temperature under aerobic conditions and visible-light irradiation. We achieved 100% conversion of propane with 67% selectivity in acetone after 4 h of irradiation and TON up to 600. Mechanistic studies, including electrospray ionization mass spectrometry, Mössbauer, and electroparamagnetic resonance spectroscopy, concluded that the reaction is driven by chlorine radicals generated by Fe–Cl bond photolysis. These results not only hold promise for the development of solar-based oxidation of hydrocarbons but more importantly also disclose deeper insights into the largely overlooked photochemistry of FeCl3.

The article presents the detailed study and analysis of structural transformations and measures carried out at “Azerikimya” Production Union, as well as their impact on energy and feedstock resources of the steam cracking (pyrolysis) unit. As provided in the paper, the full information on the relation between technical and economic parameters of petrochemical products produced in the Republic of Azerbaijan and the performance of the steam cracker and the latter’s contribution to the yield of quality products builds upon in-depth studies and analyses. Besides, consideration is given to the necessity of structural transformations as a consequence of issues that occurred after the national petrochemical facilities had been incorporated into SOCAR. The article also highlights the importance of economic recovery in the industry that once secured an important place in the national economy, improving operational efficiencies of refining and petrochemical industries that run as a single process chain, building the state-of-the-art enterprise in line with the advanced global practice, as well as upgrading the management mechanism and structure in the petrochemical industry. It underscores the positive outcomes of the long-term national policy of sustainable development in the petrochemical industry, as well as a decisive role of an increasingly efficient future performance aimed at improving profitability and synergy across the company.

Steam cracking in fluidized beds is an alternative method for producing valuable petrochemicals from plastic waste. Previous studies on the conversion of plastics in fluidized beds have revolved around non-catalytic cracking using silica sand as the bed material. On the other hand, studies on catalytic cracking have focused on the use of active materials such as olivine, bauxite, feldspar, and zeolites. The potential influence of the above-mentioned materials, in their natural or inactive state, on fluidized bed hydrocarbon cracking, is not well-documented in the literature. In this paper, steam cracking of polyethylene in a bubbling fluidized bed at 750 °C is investigated in the presence of four different natural ores: olivine, bauxite, silica sand, and feldspar. The paper compares the performance of the steam cracking process in terms of cracking severity, conversion, and product distribution among different hydrocarbon groups. The results show that there is only a marginal difference in cracking severity among the different bed materials, while the conversion remain relatively consistent, ranging from 93% to 95% (carbon.%). The yields of paraffins and carbon oxides are narrow, ranging from 15% to 16% and 3–4%, respectively, while the yields of light olefins and aromatics show a slightly wider range. The yield of olefins is in the range of 52–57%, and for aromatics, it ranges from 16% to 21%. The paper also discusses the potential impact of these bed materials on the cracking reactions, including their thermal and reactive interactions.

Molybdenum-based oxygen carrier for chemical looping oxidative dehydrogenation of isobutane

Development and lifecycle assessment of various low- and high-density polyethylene production processes based on CO2 capture and utilization

Numerical modeling of chemical looping oxidative dehydrogenation of ethane in parallel packed beds

Ethylene is a large-scale commodity which is produced from fossil ethane via steam cracking. As more renewable electricity becomes available, electro-chemical production processes for ethylene are gaining attractiveness due to the generally high efficiency of electro-chemical processes and the potential to reduce CO2 emissions. In this study we explore the economics of oxidative coupling of methane (OCM)-based ethylene production and compare it to the conventional ethane steam cracking route. While current OCM cells are not economically competitive due to high capital investment costs (+105%) and high operating costs (+145%), OCM has the potential to become economically viable once overpotentials are lowered and single pass conversion rates reach +60%.

Separation of ethylene and ethane using Co-Gallate pellets in a vacuum swing adsorption process

Anti-coking performance of Al/Si/Cr/Ce ceramic coating during naphtha steam cracking applied on Cr25Ni35Nb alloy

Steam cracking of methyl ester: A modeling study on the influence of the hydrocarbon backbone

Data-driven intelligent modeling framework for the steam cracking process

The steam cracker unit at ORLEN Unipetrol is a significant European producer of monomers. Due to heavy feedstocks, the steam cracker can produce (besides ethylene, propylene and benzene) very valuable hydrocarbons such as dicyclopentadiene. The staff of ORLEN Unipetrol (formerly Chemopetrol) has been investigating the possibility of producing dicyclopentadiene for almost 40 years. As a result of many years of research activities of several generations of researchers, the technology for production of dicyclopentadiene of various quality grades has been developed and realized in the plant in Litvínov. The paper summarizes the history of research on the production of dicyclopentadiene from the moment of the construction of the steam cracker unit in Litvínov in 1980 to the moment when the unit was put into operation in 2022. The paper is primarily an appreciation to all the researchers who have been involved in the research and development of this product over the years and it can be an inspiration for the further development of C5 chemistry.

The chemical industry needs new methods for sourcing carbon-containing feedstocks from renewable sources to decrease CO2emissions and reduce reliance on fossil fuels. Ethylene, a crucial base chemical used for making polymers and ethylene oxide, is primarily produced through steam cracking of fossil feedstocks. However, an evolving technology is the electrochemical reduction of CO2or CO to produce ethylene. The study assesses the environmental, economic and energetic performance of a new biomass-based process that produces ethylene based on the electrochemical reduction of CO. The results are based on mass and energy balances from process simulation. The CO is produced by either gasification of biomass or combustion of biomass with CO2capture and CO2electrolysis. Besides ethylene, the process produces acetic acid, ethanol, oxygen and hydrogen as by-products which are purified and sold. The annual output varies between 36 and 68 kt ethylene with a biomass input of 157 kt. The levelized cost of ethylene ranges from 3,920 to 7,163 €/t with the gasification routes being the most cost-effective. The ethylene price is heavily dependent on electricity price, current density, operating voltage, and by-product prices. The carbon efficiency of the gasification-based routes is lower (64%) than the combustion-based routes (85%–86%). However, the energy efficiency is higher for the gasification-based routes (42%) compared to the combustion-based routes (28%). Conversion of ethanol to ethylene increases the ethylene yield with minimal impacts on the ethylene price. In terms of CO2emissions, the gasification-based routes show lower emissions. Scenarios using wind power show a significant emission reduction potential compared to fossil products.

Highly (2 2 2)-oriented flexible hollow fiber-supported metal-organic framework membranes for ultra-permeable and selective H2/CO2 separation