Study On Mixed Amine Absorbents CO₂ Absorption In Flue Gas Of Coal-fired Power Plant

The greenhouse effect is mainly caused by greenhouse gases, the carbon dioxide contribution is the largest in greenhouse gases, it is mainly from the use of fossil fuels. Chemical absorption is the most widely studied and applied method, while the chemical properties and composition of the absorbents is the key to reducing operating energy consumption. Cyclic load and low temperature desorption are the key to the study of low energy consumption absorbent in this work, the main conclusions are as follows:(1)In this work, the absorption rate, cyclic loading, desorption energy,and energy dissipation of six kinds of mixed absorbent were studied with N-methyldiethanolamine (MDEA), The results showed that the cyclic loading of MDEA-diethylenetriamine (DETA)> MDEA-proline potassium>MDEA-alanine potassium>MDEA-arginine potassium>MDEA-MEA>MDEA-PZ, Which is superior to MDEA aqueous solution. Desorption energy consumption MDEA-proline potassium mixed solution, compared with MDEA-DETA reduced by 21.2%, MDEA-Proline potassium mixed solution has a good overall performance. The absorption capacity of the absorbent was substantially constant after 10 times of absorption /desorption cycle experiments, showing good stability. The optimum content was 5% wt and the temperature was 30 ? to 50 ? by studying the effect of potassium and proline potassium concentration and absorption temperature on the absorption properties in the mixed solution.(2) By adding ethanol to the DETA solution, the desorption temperature was reduced to 85 ? and the cyclic loading increased by 38.2%.The desorption temperature of MDEA-proline potassium solution was reduced to 88.6 ?and the cyclic loading remained essentially unchanged.Studies have shown that it is possible to reduce desorption temperature by adding a low boiling solvent to reduce the solution water content.(3) Build laboratory-scale absorption and desorption pilot test platform, the comprehensive performance of the absorbent is determined.Unit energy consumption of MDEA-potassium proline was 18.7% lower than that of aqueous MDEA-PZ solution. The aqueous DETA solution was added to 30% ethanol, unit energy consumption decreased from 4.85 GJ/t to 4.3 GJ/t, which was 11.3% lower than that of aqueous DETA solution.The aqueous DETA-ethanol solution after nine cycles of experiments, can still maintain a good absorption and desorption performance, indicating that the solution stability and reliable.