Chemical absorption (e.g., amine absorption): Utilizes a reversible reaction between an alkaline solution (e.g., MEA) and CO₂, followed by heating in a desorption tower to release high-purity CO₂. The absorbent is recycled. Typical capture efficiency reaches 85%-95%.
Physical adsorption: Employs adsorption materials such as activated carbon and molecular sieves to adsorb CO₂ under low temperature and high pressure, followed by desorption by depressurization or heating. Suitable for low-concentration CO₂ (e.g., <15%) scenarios, with relatively low energy consumption.
Membrane separation: Separates CO₂ through selective permeation membranes. The equipment is compact but requires gas pretreatment, suitable for small to medium-scale applications.
Cryogenic distillation: Cools the gas to below -78℃ to directly liquefy CO₂, achieving a purity of up to 99.9%, but with extremely high energy consumption.