Integration of sorption-enhanced steam glycerol reforming with methanation of in-situ removed carbon dioxide - An alternative for glycerol valorization

Coupling CO2 desorption and methanation in the presence of hybrid materials offers a promising alternative to convert the CO2 in-situ removed during sorption-enhanced steam glycerol reforming (SESGR) avoiding the high energy-intensive CO2 sorbent regeneration. The all-inclusive integrated process exemplifies an option for glycerol valorization via consecutive SESGR and CO2 conversion by catalytic hydrogenation. The dual-function catalyst performing successively, in the same reactor, SESGR and CO2 desorption/conversion encompasses reforming/methanation catalyst (10%Ni-5%Co) and dispersed nanosized CaO on gamma-Al2O2. Simultaneous CO2 desorption/conversion integrated process is explored in a fixed-bed reactor via an unsteady-state, two-scale, non-isothermal model, highlighting the impact of key parameters on the process performance. At large adsorbent/ catalyst mass ratio (2.0) and high CaO conversion (0.5) in preceding SESGR, CO2 is released and hydrogenated for an extended period with extra hydrogen consumption, without a balance between CO2 desorption and CO2 hydrogenation rates. Increasing pressure (3.0 MPa) and gas velocity offers a match between these competitive reaction rates, resulting low CO2 concentration in the exit stream. Desorption/methanation thermal behavior controls the magnitude of CO2 low concentration period and the methanation efficiency. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.