Carbon dioxide removal apparatus, carbon dioxide desorption determination method, and carbon dioxide separation method

A carbon dioxide desorption determination method performable by a carbon dioxide removal apparatus including:

• a carbon dioxide adsorption module provided with a pressure meter and an adsorbent;
• a first valve provided in an intake part of the carbon dioxide adsorption module;
• a second valve provided in a discharge part of the carbon dioxide adsorption module;
• a third valve connected to the discharge part;
• and a vacuum pump connected to the carbon dioxide adsorption module via the third valve,
• the carbon dioxide desorption determination method comprising:
• bringing a pressure in the carbon dioxide adsorption module into a predetermined reduced pressure state by operating the vacuum pump in a state in which the first valve and the second valve are closed and the third valve is open,
• closing the first valve, the second valve, and the third valve;
• measuring a pressure in the carbon dioxide adsorption module by the pressure meter;
• and
• performing determination and/or detection based on a degree of increase in the pressure in the carbon dioxide adsorption module measured by the pressure meter, the performing determination and/or detection including:
• determining that carbon dioxide has desorbed from the adsorbent in the carbon dioxide adsorption module, in a case where the degree of increase in the pressure is greater than 0;
• detecting an abnormality indicating that the carbon dioxide adsorption module is experiencing pressure leakage, in a case where the degree of increase in the pressure is higher than a predetermined first value, and
• detecting an abnormality indicating that the adsorbent has deteriorated, in a case where the degree of increase in the pressure is lower than a predetermined second value, wherein
• in the detecting the abnormalities, the degree of increase in the pressure includes at least one of a pressure value at a point in time when a predetermined time has elapsed from a start of measurement of the pressure, or a rate of increase in the pressure within a predetermined period after the start of the measurement of the pressure.

A carbon dioxide separation method for separating carbon dioxide from air by a carbon dioxide removal apparatus including:

• a carbon dioxide adsorption module provided with a pressure meter and an adsorbent, a first valve provided in an intake part of the carbon dioxide adsorption module;
• a second valve provided in a discharge part of the carbon dioxide adsorption module;
• a third valve connected to the discharge part;
• a vacuum pump connected to the carbon dioxide adsorption module via the third valve;
• and a heater,
• the carbon dioxide separation method comprising:
• allowing the adsorbent to adsorb carbon dioxide from air;
• reducing a pressure in the carbon dioxide adsorption module using the vacuum pump in a state in which the first and second valves are closed and the third valve is open;
• continuously measuring the pressure in the carbon dioxide adsorption module by the pressure meter in a state in which the first, second, and third valves are closed and the heater is increasing a temperature of the adsorbent;
• and
• opening the third valve after the pressure measured by the pressure meter has stopped increasing, and causing the vacuum pump to start reducing the pressure in the carbon dioxide adsorption module, thereby desorbing the carbon dioxide adsorbed on the adsorbent.