Study on the Numerical Simulation of Heat-Flow Coupling in the Heating Stage of Hydrogen Production by In-Situ Injection of Supercritical Water into Coal Seam
Hydrogen production by in-situ injection of supercritical water into underground coal seam is a new type of coal conversion technology.Based on the multi-field coupling principle of porous media,a mathematical model of heat flow coupling in the heating stage of in-situ injection of supercritical water into coal seam is proposed,The evolution law of temperature distribution as well as pore pressure of coal seam,roof and floor strata were studied by numerical simulation.The results show that after the injection of supercritical water,the temperature and seepage velocity near the injection well increase rapidly and gradually expand outward,and then the temperature continues to increase to about 1050 ℃ and no longer increases.The maximum flow rate can reach 5.89 cm/s,and the flow rate near the injection well decreases slightly with time.The flow velocity near the production well shows a negative exponential growth before 6 months,and the temperature and flow velocity near the production well remain basically constant after 6 months.The overall pressure increases slowly within 1 a,and the temperature outside 700 m from the injection well changes little within 1 a.
In-situ gasification of coalHydrogen production by supercritical waterHeating stageHeat-flow coupling modelNumerical simulation