Authors: K.Y. Ushakov, I.Y. Petrov, A.S. Zyabrev, B.G. Tryasunov, A.R. Bogomolov

Title of the article: Liquefaction of Barzas coals in the presence of transition metal-based catalytic additives in carbon dioxide and hydrogen environments

Year: 2020, Issue: 6, Pages: 74-81

Branch of knowledge: 05.17.07 Chemical technology of fuel and high-energy substances

Index UDK: (66.092-977+66.092.097+66.094.25):662.65

DOI: 10.26730/1999-4125-2020-6-74-81

Abstract: Influence of the nature and concentration effects of transition metal-based catalytic additives on the liquefaction processes of two Barzas sapromixite forms [namely, a tile-like modification ("tile") and a product of its weathering ("gunny-like coal")] have been studied in carbon dioxide and hydrogen media. Experiments on liquefying Barzas coals were carried out in a micro-autoclave (with a working volume of ~ 20 cm³) at T = 475°C and P ~ 7-9 MPa in the presence of iron and molybdenum compounds (0.3-7.0 wt. % Fe₂O₃ and 0.5-7.0 wt% MoO₃, respectively), which were preliminarily supported on the coal samples by impregnation from aqueous solutions of corresponding metal salts; the duration of thermal treatment was ~ 20 min. For comparison, similar experiments were also performed with mechanical mixtures of Barzas coal and the additions of commercial cobalt-molybdenum-alumina hydrotreating catalyst (2.4-20.0 wt. % AlCoMo catalyst). It has been shown that in the presence of various catalytic additives (Fe₂O₃, MoO₃, AlCoMo catalyst), a decrease in the yield of gaseous products was observed for both media investigated. At the same time, the gas yields during liquefaction of samples based on the "gunny-like coal" were noticeably higher, and the yields of liquid products were significantly lower than those of the samples based on the "tile-like" coal (especially, in a hydrogen atmosphere).The concentration dependences for the total yields of liquefaction products (maltenes and asphaltenes) in a hydrogen atmosphere on the content of the catalytic additives studied had an extreme character with maximum values in the range of ~0.5 wt.% MoO₃, ~2-3 wt.% Fe₂O₃, and ~11 wt.% AlCoMo catalyst. The highest yield of maltenes and asphaltenes (up to 36-37 wt.% vs. ~29 wt.% for additive-free coal) was obtained during the liquefaction of Barzas tile-like coal samples in the presence of iron compounds (~2-3 wt.% Fe₂O₃) in a hydrogen environment.

Key words: Barzas coals thermal treatment liquefaction catalyst maltenes asphaltenes elemental analysis CO₂ H₂

Receiving date: 10.12.2020

Publication date: 29.12.2020

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