New process for hydrogen production from raw coke oven gas via sorption-enhanced steam reforming: Thermodynamic analysis

A novel process for producing hydrogen from raw coke oven gas (RCOG), via CO2 sorption-enhanced steam reforming (SESR) was proposed in this paper, and was compared with a conventional steam reforming (CSR) process via thermodynamic analysis, in terms of equilibrium compositions, energy consumption and CO2 emissions. The SESR process with CaO as CO2 sorbent, can obtain over 4.0-fold H2 amount amplification and over 95 vol% H2 in the gaseous products after reforming, which were obviously higher than those in the CSR process, and meanwhile the corresponding optimal reforming temperature declined compared with that in CSR process. Although the SESR process has a unique desorbing reactor needing extra heat, its reforming reactor needs much less heat, resulting in the total demand energy was little different with and even lower than that of the CSR process. The SESR process also can convert the vast majority of carbon in RCOG into high-purity CO2 gas as co-product, thus reducing CO2 emissions obviously, compared to the CSR process and the conventional cleaning processes (CCPs).