Enhancing ethylene selectivity in MTO reaction by incorporating metal species in the cavity of SAPO-34 catalysts

Small pore SAPO-14-based zeolites with improved propylene selectivity in methanol to olefins

Methanol to olefins (MTO) is an important non petroleum route to prepare light olefins, however, it still remains a challenge to improve the one-pass propylene selectivity towards the industrial SAPO-34...

Zr-doped SAPO-34 with enhanced Lewis acidity

Zr-doped SAPO-34 has enhanced Lewis acidity, leading to high catalytic activity for LDPE cracking.

Regulating the size and acidity of SAPO-34 zeolites using dual templates to enhance the selectivity of light olefins in MTO

To understand the relationship between the catalytic performance, crystallite size, and acidity of SAPO-34 zeolites, a series of SAPO-34 zeolites were prepared by hydrothermal crystallization using palygorskite and dual templates.

K+ located in 6-membered rings of low-silica CHA enhancing the lifetime and propene selectivity in MTO

Methanol-to-olefins (MTO) technology presently serves as a key to convert coal or natural gas to valuable hydrocarbons, in particular lower olefins.

Capture and identification of coke precursors to elucidate the deactivation route of the methanol-to-olefin process over H-SAPO-34

The evolution of retained species during the whole methanol-to-olefins process was revealed with the aid of GC-MS, thermogravimetric analysis (TG) and density functional theory (DFT) calculations. Precise routes for the transformation of retained methylbenzenes to methylnaphthalenes were proposed, based on the direct capture of three possible organic intermediates, to explain the catalyst deactivation procedure.

Synthesis of Highly Selective and Stable Co-Cr/SAPO-34 Catalyst for the Catalytic Dehydration of Ethanol to Ethylene

In this study, silicoaluminophosphate (SAPO)-34 and Me (Me = Cr, Co)-modified SAPO-34 were synthesized and used as catalysts to investigate the catalytic performance by means of a probe reaction from ethanol to ethylene. The metal oxides were loaded on the SAPO-34 support via an impregnation method. The synthesized catalysts were characterized using XRD, SEM, EDX, FT-IR, NH3-TPD, BET, and TGA techniques. Compared to SAPO-34, SAPO-34 doped with metal oxides showed the same chabazite (CHA) topology. The structure and properties of the catalyst were further optimized by varying the amount of Me. The experimental results showed that Co-Cr/SAPO-34 exhibited the best catalytic performance when the reaction temperature reached 400 °C at a weight hourly space velocity (WHSV) of 3.5 h−1, for which the single-pass conversion of ethanol was determined as 99.15%, and the selectivity of ethylene was 99.4% at an optimum catalytic performance in the reaction of up to 600 min. In addition, Co-Cr/SAPO-34 exhibited better catalytic activity and anti-coking ability than pure SAPO-34, which was attributed to its enhanced pore structure and moderate acidity. It can also be concluded from the results of this experiment that the performance of the Co-Cr bimetal-supported catalyst is better than that of the Cr mono-metal catalyst.

Enhanced ethene to propene ratio over Zn-modified SAPO-34 zeolites in methanol-to-olefin reaction

The enrichment of incorporated Zn-related species and the accommodation of facilitated aromatics impose increased diffusion restriction for bulky hydrocarbons, thus contributing to significant improvements in ethene selectivity and ethene to propene ratio over Zn modified SAPO-34 zeolites.