Proposal for a low CO₂ emission power generation system utilizing oceanic methane hydrate

A power generation system with low carbon dioxide (CO₂) emission is proposed. This system simultaneously performs power generation, methane hydrate utilization, and carbon dioxide capture and storage (CCS). In this system, CO₂ resulting from the combustion is recovered by compressed seawater. A thermal stimulation method was selected to dissociate the oceanic methane hydrate. CO₂-dissolved seawater is heated by the exhausted gas and injected into the hydrate layer to dissociate the methane hydrate. By means of process simulation, a feasibility study of the proposed system was conducted, during which a power generation system with approximately 30% thermal efficiency and above 90% CO₂ recovery rate was achieved. Moreover, to quantify the heat loss during the injection of hot seawater into the hydrate layer, we conducted a numerical simulation of the internal pipe flow and determined that the appropriate pipe diameter can be selected in terms of heat and pressure loss through the pipe. In addition, the outlet temperature can be predicted by the thermal conductivity and the thickness of the insulation material. An appropriate insulation material can be selected to obtain the desired outlet temperature.