Comparison of light olefins production routes in China: Combining techno-economics and security analysis

Process Safety and Environmental Protection, Journal Year: 2023, Volume and Issue: 194, P. 225 - 241

Published: April 19, 2023

Language: Английский

---

Outlooks for zeolite catalysts in a low-carbon scenario

Catalysis Today, Journal Year: 2023, Volume and Issue: 426, P. 114365 - 114365

Published: Sept. 9, 2023

Zeolites today are a unique and highly successful class of catalytic materials, but their role in future low-carbon scenarios comes into question. This perspective article summarises the authors' joint view on zeolite chemistry's direction for applications to stimulate discussion identifying pillars which scientific community should focus. Particular challenges discussed here include i) our synthesis focused new structures with optimised textural properties design catalysts precise control location active sites; ii) current, mostly industrial, requests zeolitic catalysts; iii) emerging zeolites play key role; last not least iv) opportunities types microporous solids. Although some these rather challenging, many barriers overcome, we suggest fostering research directions as maintaining crucial catalysts. Discussion science technology is organised consideration three possible scenarios: (i) BAU (business-as-usual) scenario (ii) two advanced scenarios, differ terms degree circularity (low high, LC HC respectively), (iii) level substitution fossil fuels alternative energy carbon sources. Trends characterising impact provide readers elements, tools clues identify priorities application

Language: Английский

---

Tuning the Acid Nature of the ZSM-5 Surface for Selective Production of Ethylene from Ethanol at Low Temperatures

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(5), P. 4492 - 4503

Published: Feb. 23, 2024

Solid-acid ZSM-5 catalysts stand out as highly reactive for ethanol dehydration, but the selective production of ethylene at low temperatures, however, is still a challenge. Herein, two zeolites with distinct Si/Al ratio have been modified Ce, La, or P species treated H2O NH3 to get better understanding on contribution acid sites ethanol-to-ethylene catalysis. The doping affects both number and strength sites, which Ce content inversely increases population weak (WAS). Atomically dispersed oxygen vacancy-rich CeOx synergistically contribute dissociation during synthesis Al-rich modify local Al environment by forming new Al–OH bonds, acting WAS. This significantly enhances conversion into intermediates ultimately (selectivity up 92%). Further poisoning strong (SAS) in situ NH3-titration confirms that catalysis temperatures occurs mostly over WAS, while SAS minor. underpinning insights can serve basis further developments combination other multivalence ex water treatments cofeeding design robust are able efficiently dehydrate bioethanol temperatures.

Language: Английский

---

Ce-Driven Ce-MnO_x/Na₂WO₄/SiO₂ Composite Catalysts for Low-Temperature Oxidative Coupling of Methane

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(7), P. 5116 - 5131

Published: March 21, 2024

Mn/Na2WO4/SiO2 catalyst is widely used in the oxidative coupling of methane (OCM) reactions because its high catalytic performance and stability. Nevertheless, complex elemental composition makes role each active component these catalysts still controversial. Herein, we conducted separate studies on by separating it into MnOx Na2WO4/SiO2 (NaWSi). This provided a persuasive strategy to turn manganese oxide from combustion selective for OCM at low temperatures through synergistic effect between Ce-MnOx catalyst. The introduction Ce key factor improving low-temperature activity temperature-programmed desorption oxygen (O2-TPD) 18O isotope labeling experiments confirm that surface lattice main species reaction Ce-driven presence strengthens cycle process catalyst, resulting higher exchange ability improved migration oxygen. Furthermore, situ Raman spectroscopy shows both 3Ce-MnOx NaWSi can enhance resistance carbon deposition catalysts. Hence, 3Ce-MnOx/NaWSi composite achieved 38.4% conversion CH4 15.6% yield C2 700 °C remained stable least 25 h.

Language: Английский

---

Tailoring the Olefin Selectivity in Catalytic Oxidative Dehydrogenation of Light Alkane by the Isolation Strategy

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(4), P. 2502 - 2521

Published: Feb. 2, 2024

Olefins are important building blocks that have been extensively used to produce diverse consumer products in petrochemical industry. Owing the requirement of low-carbon-footprint processes and increasing use light alkanes sourced from shale gas, an environmentally friendly economic route alternative state-of-the-art steam cracking crude oil has investigated for olefin production. The oxidative dehydrogenation (ODH) olefins attracted wide attention due absence thermodynamic limitations coke formation. However, excessive oxidation is prone occur this process. Developing a suitable ODH catalyst with high performance, particularly enhanced selectivity, more urgent but still remains challenge. In Review, we talk about representative currently developed isolation strategies optimize selectivity via process, conversion ethane ethylene, which include dispersion regulation metal oxide, nonmetal sites, construction dual functional sites isolate steps, adoption selective oxygen species promotion soft oxidants as reactants. Furthermore, mechanistic aspects activation participation tailoring then classified discussed detail. Finally, perspectives emerging technologies process listed evaluated.

Language: Английский

---