What factors should be considered when selecting an absorbent?

1. The absorbent must have good absorption properties; this is the most important factor of all. 2. The absorbent must have good selectivity, capable of selectively absorbing the desired substances. 3. The absorbent has low volatility, which helps to reduce losses of the absorbent, lower operating costs, and protect the environment. 4. The absorbent should preferably be non-toxic and harmless; with the current strong emphasis on environmental protection, this approach not only helps protect the environment but also reduces processing costs. 5. The absorbent should preferably be inexpensive and readily available; since a large amount of the absorbent is used in the absorption process, it’s better if it is cheap. 6. The selected absorbent must be able to be easily separated from the solute during the subsequent separation process; otherwise, it is better not to use it for absorption.

1. Solubility: The absorbent should have a high solubility for the solute component, which helps to increase the absorption rate and reduce the amount of absorbent required. When a chemical reaction occurs between the absorbent and the solute component, the solubility can **increase**, but for the absorbent to be reusable, the chemical reaction must be reversible ； For physical absorption as well, an absorbent whose solubility changes significantly with operating conditions should be chosen in order to facilitate recovery. 2. Selectivity: The absorbent must have a strong ability to absorb the solute components, while showing little or no absorption of the other components in the mixed gas; otherwise, effective separation cannot be achieved. 3. Volatility: The vapor pressure of the absorbent at the operating temperature must be low, as the gas leaving the absorption unit is often saturated with absorbent vapor. The higher the volatility of the absorbent, the greater its loss. 4. Viscosity: The viscosity of the absorbent at the operating temperature should be low; this improves the flow conditions in the absorption tower, thereby enhancing absorption efficiency. It also helps to reduce pump power consumption and lowers heat transfer resistance.

If recycling is necessary, be sure to pay attention to the fact that the energy required for regeneration should be low… It’s really tragic when things go wrong in this regard……