| 主权项 |
1. A control method of a differential pressure water electrolysis system including
a differential pressure water electrolysis device configured to perform electrolysis of water and generate oxygen at the anode side, while generating hydrogen at the cathode side at a higher pressure than the oxygen, a gas-liquid separator configured to perform gas-liquid separation of hydrogen derived from the differential pressure water electrolysis device, a pressure loss part, which is disposed on a discharge tube to discharge liquid water stored in the gas-liquid separator, which causes a set amount of the liquid water to flow by providing pressure loss, an open/close valve to open and close the discharge tube, and a depressurization valve provided on a depressurizing tube to reduce pressure at the cathode side of the differential pressure water electrolysis device, which is opened when depressurizing, the method comprising: a water level setting process, where a reference water level of the gas-liquid separator is set for normal operations to discharge the liquid water stored in the gas-liquid separator to the discharge tube, and a depressurization reference water level which is a lower water level than the reference water level is set when depressurizing, to discharge the liquid water stored in the gas-liquid separator to the discharge tube; a depressurizing process, to open the depressurization valve and reduce pressure at the cathode side after operation of the differential pressure water electrolysis device has been stopped, in a state with voltage applied; a switching process to switch a permissible water level upper limit value, at which the open/close valve is opened, from the reference water level to the depressurization reference water level when the depressurizing process is started. |
