Water electrolysis system and method of operating water electrolysis system

Abstract

A water electrolysis system includes a water electrolysis apparatus, a gas-liquid separating apparatus, a hydrogen supply line, a water level detector, and a current regulator. The water electrolysis apparatus is to electrolyze water to generate oxygen and high-pressure hydrogen having a higher pressure than a pressure of the oxygen. The gas-liquid separating apparatus is disposed upstream of the water electrolysis apparatus in a gravitational direction to separate moisture contained in the high-pressure hydrogen. The hydrogen supply line is to supply the high-pressure hydrogen discharged from the water electrolysis apparatus to the gas-liquid separating apparatus. The water level detector is configured to detect a water level in the gas-liquid separating apparatus. The current regulator is configured to regulate a current to be applied to the water electrolysis apparatus based on the water level detected by the water level detector in the gas-liquid separating apparatus.

1 . A water electrolysis system comprising:
 a water electrolysis apparatus to electrolyze water to generate oxygen and high-pressure hydrogen having a higher pressure than a pressure of the oxygen;   a gas-liquid separating apparatus disposed upstream of the water electrolysis apparatus in a gravitational direction to separate moisture contained in the high-pressure hydrogen;   a hydrogen supply line to supply the high-pressure hydrogen discharged from the water electrolysis apparatus to the gas-liquid separating apparatus;   a water level detector configured to detect a water level in the gas-liquid separating apparatus; and   a current regulator configured to regulate a current to be applied to the water electrolysis apparatus based on the water level detected by the water level detector in the gas- liquid separating apparatus.   
     
     
         2 . The water electrolysis system according to  claim 1 , wherein
 the current regulator regulates the current to be applied to the water electrolysis apparatus to a current value lower than a predetermined current value when the water level detected by the water level detector exceeds an upper water level.   
     
     
         3 . The water electrolysis system according to  claim 2 , wherein
 the current regulator increases the current to be applied to the water electrolysis apparatus to the predetermined current value when the water level detected by the water level detector reaches a lower water level lower than the upper water level.   
     
     
         4 . The water electrolysis system according to  claim 3 , further comprising:
 a temperature detector configured to detect a temperature of the water electrolysis apparatus, wherein   the current regulator is configured to set the predetermined current value based on the temperature detected by the temperature detector.   
     
     
         5 . The water electrolysis system according to  claim 2 , further comprising:
 a temperature detector configured to detect a temperature of the water electrolysis apparatus, wherein   the current regulator is configured to set the predetermined current value based on the temperature detected by the temperature detector.   
     
     
         6 . A method of operating a water electrolysis system including a water electrolysis apparatus to electrolyze water to generate oxygen and high-pressure hydrogen having a higher pressure than a pressure of the oxygen, a gas-liquid separating apparatus disposed upstream of the water electrolysis apparatus in a gravitational direction to separate moisture contained in the high-pressure hydrogen, a hydrogen supply line to supply the high-pressure hydrogen discharged from the water electrolysis apparatus to the gas-liquid separating apparatus, a water level detector configured to detect a water level in the gas-liquid separating apparatus, and a current regulator configured to regulate a current to be applied to the water electrolysis apparatus, the method comprising:
 detecting the water level in the gas-liquid separating apparatus using the water level detector; and   limiting the current to be applied to the water electrolysis apparatus to or lower than a specified current value when it is determined that the water level detected by the water level detector in the gas-liquid separating apparatus is equal to or higher than a specified water level.   
     
     
         7 . The method according to  claim 6 , further comprising:
 detecting a temperature of the water electrolysis apparatus using a temperature detector; and   setting the specified current value based on the temperature detected by the temperature detector.