Evaluation of process variables on the performance of Sorption Enhanced Methane Reforming

Abstract

The joint performance of a synthetic Ca-based sorbent and a 10%wt.NiO/NiAl2O4 catalyst is tested under Sorption Enhanced Reforming (SER) of CH4 in a fixed bed reactor. The effects of the mass hourly space velocity (MHSV, mol CH4 h−1 (gcatalyst + gsorbent−1)), the sorbent-to-catalyst proportion (Z) for diverse steam-to-methane ratios (S/C) and the behavior of cycled solids under different regeneration conditions (by calcination under inert, oxidant, with steam and CO2 atmospheres) are studied.An H2 concentration close to equilibrium (≈95 vol.% for S/C = 3.2) is achieved working at both lower (0.01 mol CH4 h−1 (gcatalyst + gsorbent)−1 or 769 h−1) and higher MHSV (0.04 mol CH4 h−1 (gcatalyst + gsorbent)−1 or 3000 h−1). The practical operation window for the combination of the sorbent and catalyst used should be below 0.044 mol CH4 h−1 gsorbent−1, and around 0.44 mol CH4 h−1 gcatalyst−1. The stabilities of both solids (sorbent and catalyst) working cyclically are demonstrated, despite the demanding and realistic regeneration environments used. Thus, H2 purity close to equilibrium (≈88 vol.% for S/C = 2) is attained under SER conditions and no carbon deposition is found. In summary, the results obtained confirm the good joint performance of the synthesized solids in the SER process even when working under demanding conditions.