International Journal of Hydrogen Energy, Vol.42, No.22, 15010-15023, 2017
Novel quasi-autothermal hydrogen production process in a fixed-bed using a chemical looping approach: A numerical study
This paper presents a novel quasi-autothermal hydrogen production process. The proposed layout couples a Chemical Looping Combustion (CLC) section and a Steam Methane Reforming (SMR) one. In CLC section, four packed-beds are operated using Ni as oxygen carrier and CH4 as fuel to continuously produce a hot gaseous mixture of H2O and CO2. In SMR section, two fixed-beds filled with Ni-based catalyst convert CH4 and H2O into a H-2 rich syngas. Four heat exchangers were employed to recover residual heat content of all the exhaust gas currents. By means of a previously developed 1D numerical model, a dynamic simulation study was carried out to evaluate feasibility of the proposed system in terms of methane conversion (100% circa), hydrogen yield (about 0.65 mol(H2)/mol(CH4)) and selectivity (about 70%), and syngas ratio (about 2.3 mol(H2)/mol(CO)). Energetic and environmental analyses of the system performed with respect to conventional steam methane reforming, highlights an energy saving of about 98% and avoided CO2 emission of about 99%. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Keywords:Steam methane reforming;Chemical looping;Hydrogen;Near zero-CO2 emissions;Fixed-bed reactors network