Absorbent liquid for CO2 and/or H2S, and apparatus and method using same

An absorbent liquid which absorbs at least one of CO2 and H2S from a gas, consisting of:

• water;
• a secondary linear monoamine;
• a tertiary linear monoamine;
• and
• a secondary cyclic diamine,
• wherein a concentration of each of the secondary linear monoamine, the tertiary linear monoamine and the secondary cyclic diamine is less than 30% by weight, the concentration of each of the secondary linear monoamine and the tertiary linear monoamine is 10% by weight or more, and the concentration of the secondary cyclic diamine is more than 1% by weight, and
• wherein the secondary linear monoamine is at least one selected from the group consisting of:
• N-(methylamino)ethanol, N-(ethylamino)ethanol, N-(propylamino)ethanol, and N-(butylamino)ethanol, and
• wherein the tertiary linear monoamine is at least one selected from the group consisting of:
• N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, 4-dimethylamino-1-butanol, 2-(dimethylamino)ethanol, 2-(diethylamino)ethanol, 2-di-n-butylaminoethanol, N-ethyl-N-methylethanolamine, 3-dimethylamino-1-propanol, and 2-dimethylamino-2-methyl-1-propanol,
• wherein a total concentration of the secondary linear monoamine, the tertiary linear monoamine, and the secondary cyclic diamine is 70% by weight or less,
• wherein the concentration of the secondary cyclic diamine is less than the concentration of the secondary linear monoamine and is less than the concentration of the tertiary linear monoamine in weight percent relative to the absorbent liquid,
• wherein the concentration of the secondary linear monoamine is from 10% by weight to 28% by weight, and
• wherein the concentration of the tertiary linear monoamine is 20% by weight or more.