Liquid desulfurizer
Due to proton transfer, the reaction between H2S and MDEA (N-methyldiethanolamine) is almost instantaneous chemical reaction controlled by gas membrane:
H2S+R2NCH3=[R2NHCH3] +[HS]–
Since MDEA is a tertiary amine, CO2 undergoes an acid-base neutralization reaction with the amine only after forming bicarbonate with water:
CO2+H2O+R2NCH3 R2NHCH3+HCO3
Because CO2 and water require a slow intermediate process, this large difference in reaction rate forms the basis for selective absorption, that is, MDEA in the presence of CO2 for H2S absorption has higher selectivity.
The acidic tail gas is washed with water to remove CH3OH and HCN, and then enters the bottom of the absorption tower to contact with the lean amine solution added from the top in countercurrent, and the purified gas after desulfurization escapes from the top of the absorption tower. The rich amine solution leaving the absorption tower is heated by heat exchange with the lean amine through a heat exchanger, and then regenerated in the regeneration tower, and the removed H2S and CO2 The regenerated acid gas is used as the feed to the Claus unit, and the lean amine is sent to the absorption tower through the cooling pump. [1]
| name | N-Methyldiethanolamine |
| Category | Focus products/Methyl alcohol amine series |
| Abbreviation | MDEA |
| Appearance (25°C) | It is colorless to light yellow transparent liquid at room temperature. |
| Content (%) | (GC)≥98.0% |
| Total amine value | 450-480mgKOH/g |
| Color (G) | (Hazen)≤120 |
| Moisture (%) | ≤1.0% |
| Melting process | Miscible with water and alcohol, slightly soluble in ether. |
| Application field | Widely used in oil field gas and coal gas desulfurization purification emulsifier and acid gas absorbent, acid-base control agent, polyurethane foam catalyst. Carbon dioxide in synthetic ammonia can be removed with the participation of activators. In addition, MDEA can also be used as insecticide, emulsifier, semi-finished product of fabric auxiliaries, intermediate of antineoplastic drug nitrogen mustard hydrochloride, catalyst of urethane coating, fiber auxiliaries, etc., and also a kind of paint Drying agent. |
| CAS NO. | 105-59-9 |
