A novel hybrid iron-calcium catalyst/absorbent for enhanced hydrogen production via catalytic tar reforming with in-situ CO_2 capture

摘要

An iron-calcium hybrid catalyst/absorbent (Ca-Al-Fe) is developed by a two-step sol-gel method to enhance tar conversion, cyclic CO2 capture and mechanical strength of absorbent for hydrogen production in calcium looping gasification. The developed catalyst/absorbent consists of CaO and brownmillerite (Ca2Fe2O5) with mayenite (Ca12Al14O33) as inert support. Comparing with three candidate absorbents without Ca2Fe2O5 or Ca12Al14O33, cyclic carbonation reactivity and mechanical strength of Ca-Al-Fe are largely promoted. Meanwhile, Ca-Al-Fe approaches the maximum conversion rate of 1-methyl naphthalene (1-MN) with enhanced hydrogen yield around 0.15 mol/(h.g) under reforming conditions of present study. Ca-Al-Fe also shows the largest CO2 absorption and lowest coke deposition. Influences of operation variables on 1-MN reforming are evaluated and recommended conditions can be iron to CaO mass ratio of 10%, reaction temperature of 800 degrees C and steam carbon in 1-MN mole ratio of 2.0. Ca-Al-Fe hybrid catalyst/absorbent presents good potential to be applied in future. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.