A research institute has conducted research on diethanolamine, ethylene glycol dimethyl ether amine,
From the data below, we can see the desulfurization efficiency of the five desulfurizers in the comparative test desulfurizer H2S% H2S% in the regeneration gas
1. Diethanolamine 2.5 mol/L 40~50 8
2. Diisopropanolamine 2.5 mol/L 85~90 10~14
3. Polyethylene glycol dimethyl ether 95 25 65%
4. Polyethylene glycol dimethyl ether + 30% diisopropanolamine + 5% water 80 5~8
5. N-Methyldiethanolamine MDEA 94 33
It can be seen from the above that the performance of polyethylene glycol dimethyl ether is comparable to that of MDEA. But it must be known that using it as a solvent is a physical absorption process. To achieve the same processing capacity, its consumption is more than that of MDEA, which increases the cost of desulfurization.
N-Methyldiethanolamine is also unique in the process of ammonia decarburization. MDEA’s CO2 absorption and regeneration energy consumption is lower than that of monoethanolamine (MEA), and its solubility to non-polar gases such as hydrogen, nitrogen, methanol, methane and other higher hydrocarbons is extremely low, and its own loss is very small. MDEA reacts with CO2 to only generate bicarbonate but not carbamate, and the absorption process will not degrade, and the daily supplement amount is greatly reduced. MDEA has no corrosion on carbon steel, its alkalinity is very weak, and it does not produce thermal and chemical degradation products. The wet CO2 produced in the regeneration desorption section is slightly corrosive to carbon steel because of its low temperature (about 70°C). of. At present, there are five sets of synthetic ammonia decarburized by MDEA in China, all of which are made of carbon steel. Due to some chemical characteristics of MDEA itself, its use in the process of syngas deCO2 greatly saves energy consumption; for new plants, since the decarburization system can use carbon steel equipment, the investment can be reduced. In addition, the purity of the released CO2 can reach as high as 99.9%, which is beneficial to the subsequent urea plant and further utilization of CO2.
Diisopropanolamine, N-methyldiethanolamine, and polyethylene glycol dimethyl ether have been tested for comparison. The test results show why MDEA is the main ingredient of high-efficiency desulfurizer.
