Insulating piping, water electrolysis system, and piping damage detection method

A water electrolysis system comprising:

• a water tank storing water;
• a plurality of water electrolysis stacks that perform water electrolysis;
• a hydrogen gas tank that stores hydrogen gas generated as a result of the electrolysis;
• an oxygen gas tank that stores oxygen gas generated as a result of the electrolysis;
• a DC power supply that applies DC voltage to each of the water electrolysis stacks;
• a determination device;
• a water supply piping that connects the water tank and the water electrolysis stack and through which the water flows;
• a hydrogen gas piping that connects the water electrolysis stack and the hydrogen gas tank and through which the hydrogen gas flows;
• and
• an oxygen gas piping connects the water electrolysis stack and the oxygen gas tank and through which the oxygen gas flows,
• at least the hydrogen gas piping and the oxygen gas piping being provided with an insulating piping,
• wherein the insulating piping is configured by a double tube including:
• an inner tube that is the hydrogen gas piping or the oxygen gas piping;
• and
• an outer tube provided on an outer side of the inner tube with a space interposed between the outer tube and the inner tube,
• the outer tube has an insulating property, and the inner tube is divided into two parts,
• an insulating tube that is a joint connecting the inner tube divided into two parts, and has an insulating property is provided,
• dry gas having a humidity of less than or equal to a predetermined value is enclosed in an outer tube inner space that is the space, at a pressure of gas flowing inside the inner tube and a pressure higher than an atmospheric pressure,
• a state detection unit that detects a state of the dry gas is provided to the outer tube, and a gas concentration measurement unit that measures a concentration of the gas flowing inside the inner tube is provided to the inner tube downstream of an installation place of the insulating tube, and
• the determination device detects that the insulating piping is damaged and specifies a place of damage, based on a state of the dry gas detected by the state detection unit and the concentration of the gas measured by the gas concentration measurement unit.

A piping damage detection method executed by a determination device of a water electrolysis system including:

• a water tank storing water;
• a plurality of water electrolysis stacks that perform water electrolysis;
• a hydrogen gas tank that stores hydrogen gas generated as a result of the water electrolysis;
• an oxygen gas tank that stores oxygen gas generated as a result of the water electrolysis;
• a DC power supply that applies DC voltage to each of the water electrolysis stacks;
• a determination device;
• a water supply piping that connects the water tank and the water electrolysis stack and through which the water flows;
• a hydrogen gas piping that connects the water electrolysis stack and the hydrogen gas tank and through which the hydrogen gas flows;
• and
• an oxygen gas piping that connects the water electrolysis stack and the oxygen gas tank and through which the oxygen gas flows,
• at least the hydrogen gas piping and the oxygen gas piping being provided with an insulating piping,
• the insulating piping being configured by a double tube including:
• an inner tube that is the hydrogen gas piping or the oxygen gas piping;
• and
• an outer tube provided on an outer side of the inner tube with a space interposed between the outer tube and the inner tube,
• the outer tube having an insulating property, and the inner tube being divided into two parts,
• an insulating tube that is a joint connecting the inner tube divided into two parts, and has an insulating property being provided,
• dry gas having a humidity of less than or equal to a predetermined value being enclosed in an outer tube inner space that is the space at a pressure of gas flowing inside the inner tube and a pressure higher than an atmospheric pressure, and
• a state detection unit that detects a state of the dry gas being provided to the outer tube, and a gas concentration measurement unit that measures a concentration of the gas being provided to the inner tube e downstream of an installation place of the insulating tube,
• the method comprising the steps, executed by the determination device, of:
• an in-outer tube state information acquisition step of acquiring information regarding a state inside the outer tube from the state detection unit;
• a gas concentration acquisition step of acquiring a concentration of the gas inside the inner tube from the gas concentration measurement unit;
• and
• a damage detection step of detecting that damage has occurred in the insulating piping and specifying a place of the damage based on the state of the dry gas detected by the state detection unit and the concentration of the gas measured by the gas concentration measurement unit.