Low energy consumption anhydrous co2 phase change absorption agent, and regeneration method and application thereof

A low-energy anhydrous CO2 phase change absorbent, wherein the absorbent uses a single diamine compound having both primary amine (NH2—) and tertiary amine (—N—) at a concentration of 100%, free of any other organic solvents, water and ionic liquids, wherein the tertiary amine nitrogen atom has two alkyl branches linked to it, which constitutes a certain degree of hydrophobicity, and its molecular structure formula is shown in Formula I:

• among them, R1, R2 and R3 are alkyl chains, and their typical representatives are:
• N,N′-dimethylenediamine (DMEDA), R1 and R2 are CH3—, and R3 is —CH2-CH2—,
• N,N′-diethylenediamine (DEEDA), R1 and R2 are CH3-CH2—, and R3 is —CH2-CH2—,
• N,N′-diisopropylenediamine (DIPEDA), R1 and R2 are CH3-CH (CH3)—, and R3 is —CH2-CH2—,
• N,N′-n-butyl ethylenediamine (DBEDA), R1 and R2 are CH3-CH2-CH2-CH2—, and R3 is —CH2-CH2—.