Kinetic study of reactive sorption-enhanced reforming of coke oven gas for hydrogen production

The kinetic behavior of reactive sorption-enhanced reforming (ReSER) process of coke oven gas (COG) for hydrogen production was investigated. Experimental studies were performed on a laboratory-scale fixed-bed reactor with a Ni-nano-CaO/Al2O3 sorption complex catalyst. Based on hypothesis that the surface reaction of steam methane reforming in the ReSER-COG process is the rate-determining step, a reaction kinetic model of the reforming reaction of the ReSER-COG process was established. The kinetic data of the methane conversion were obtained under a reaction temperature from 560 °C to 680 °C, a residue time of 0.0417-0.0105 g min·mL−1, a steam-to-methane molar ratio of 4, and a reaction pressure of 0.1 MPa. The mean relative deviation of the methane conversion between the data from the simulated model and those from the experiments was determined to be 4.58%, which illustrates a good fit of the established model with the experimental data and confirmed the rationality of the hypothesis that the surface reaction of methane reforming in ReSER-COG process is rate-determining step. The calculation results show that the reforming reaction activation energy in ReSER-COG process is 95 kJ mol−1, nearly 145 kJ mol−1 decreased compared with the steam methane reforming without sorption-enhancement. This explains the reason that higher methane conversion rate at a lower reaction temperature observed in the ReSER-COG process.