Tailored hydrotalcite-based hybrid materials for hydrogen production via sorption-enhanced steam reforming of ethanol

摘要

Hydrotalcite-based (HT1c) materials in combination with reforming catalyst as hybrid system are a potential candidate for enhanced hydrogen (H-2) production. In the present investigation, four different cationic modified pet Ca2+, Cu2+ and Zn2+) HT1c based hybrid materials were tailor made for sorption-enhanced reforming process (or SERP) of ethanol. Their performances were weighed against one another in terms of their adsorption capacities and cyclic stabilities. Further, the influence of reaction variables like temperature, S/C ratio and sorbent mass fraction on the performance of the hybrid materials was evaluated. It was found that all the hybrid materials showed encouraging results for improved hydrogen production. Particularly, copper- and magnesium- based hybrid materials exhibited superior adsorption characteristics and longer breakthrough times than zinc- and calcium-based materials. Copper-based hybrid material reported highest adsorption capacity of 1.2 mol CO2/kg sorbent at 573 K producing almost 99 mole % of H-2. The stability of hybrid materials were assessed over 25 cyclic tests. Both copper- and magneSium-based materials remained stable for up to 21 and 18 cycles respectively. In contrast, zinc- and calcium-based hybrid materials were stable for 11 and 6 cycles respectively. A plausible reaction mechanism for SER of ethanol is also proposed. (C) Copyright 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.