Acid gas removal apparatus and acid gas removal method

An acid gas removal method comprising:

• an absorption step of bringing a gas to be treated containing acid gas into contact with an acid gas absorption liquid containing an amine compound to absorb the acid gas in the gas to be treated into the acid gas absorption liquid;
• and
• a regeneration step of desorbing the acid gas from the acid gas absorption liquid after acid gas absorption to regenerate the acid gas absorption liquid, wherein
• the acid gas absorption liquid regenerated in the regeneration step is reused in the absorption step,
• the acid gas removal method further comprises a separation step of separating a nonionic organic compound contained in the acid gas absorption liquid treated in the acid gas absorption step from the acid gas absorption liquid, and
• the separation step brings the acid gas absorption liquid treated in the absorption step into contact with a hydrophobic membrane, and separates the nonionic organic compound by allowing the nonionic organic compound to permeate the hydrophobic membrane, and
• the acid gas absorption liquid after the nonionic organic compound is separated by the separation step is subjected to the liquid regeneration step.