Methane decomposition with some CO_2 as co-feed: Co-production of syngas and carbon fibers/microspheres by using a hybrid of K_2CO_3 and coal char

摘要

Co-production of hydrogen and valuable carbonaceous materials by catalytic methane decomposition (CMD) is a promising process. However, nowadays it is still difficult for various carbon catalysts to make it. Here CMD with addition of some CO2 as co-feed was proposed and evaluated by using a hybrid of K2CO3 and coal char (CC). Effect of the additional CO2 as co-feed was investigated on methane conversion, the outlet gas composition, and the deposited carbon morphology. The results show that co-production of syngas (H-2 and CO) and carbon fibers/microspheres could be obtained along with high and stable methane (around 80%) and CO2 conversion (up to about 100%) in the process. Stable molar ratios of H-2/CO (ranging from 0.6:1 to 5:1) as well as different carbon morphologies (amorphous, fibrous or microspherical) can be regulated and controlled by the molar ratio of CH4/CO2 (from 75:10 to 75:75) in the feedstock. Quantitative and qualitative analysis of the products show that there is probably a synergy between K2CO3 and CC during the reaction process. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.