Energy, Vol.82, 206-217, 2015
Reaction phenomena of catalytic partial oxidation of methane under the impact of carbon dioxide addition and heat recirculation
The reaction phenomena of CPOM (catalytic partial oxidation of methane) in a Swiss-roll reactor are studied numerically where a rhodium-based catalyst bed is embedded at the center of the reactor. CO2 is added into the feed gas and excess enthalpy recovery is performed to evaluate their influences on CPOM performance. In the study, the mole ratio of O-2 to CH4 (O-2/CH4 ratio) is fixed at 0.5 and the mole ratio of CO2 to O-2 (CO2/O-2 ratio) is in the range of 0-2. The results reveal that CO2 addition into the influent has a slight effect on methane combustion, but significantly enhances dry reforming and suppresses steam reforming. The reaction extents of steam reforming and dry reforming in CPOM without heat recovery and CO2 addition are in a comparable state. Once CO2 is added into the feed gas, the dry reforming is enhanced, thereby dominating CH4 consumption. Compared to the reactor without excess enthalpy recovery, heat recirculation drastically increases the maximum reaction temperature and CH4 conversion in the catalyst bed; it also intensifies the H-2 selectivity, H-2 yield, CO2 conversion, and syngas production rate. The predictions indicate that the heat recirculation is able to improve the syngas formation up to 45%. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords:Catalytic partial oxidation of methane (CPOM);Dry reforming and steam reforming;Syngas production;CO2 utilization;Numerical simulation;Swiss-roll reactor