The conventional methods for methane gas recovery from hydrate sediments require high investment but with low gas production efficiency and may cause potential environment and security problems. But the novel natural gas hydrate exploitation method by CO2/H2 replacement coupling methane reforming can improve the replacement effect and reduce the cost of gas separation. However, energy consumption and energy performance have not been investigated thoroughly. This work develops a detailed process simulation model and conducts an exergy analysis for producing hydrogen from the integrated natural hydrate gas exploitation with methane reforming via two different boundaries. Results show that the exergy ratio of the integrated process is 2.06, exergy efficiency of the hydrogen production process is 72.40 %, but exergy efficiency of the integrated process is much lower, which is 26.59 %.
Keywords natural hydrate gas production, hydrogen production, methane reforming, exergy analysis, carbon dioxide sequestration