A Study On Regeneration Performance Of Potassium Glycinate Absorbent

Potassium glycinate absorbent has the same absorption capacity,absorption rate and higher surface tension as alkanolamine absorbent,which makes it more difficult for membrane to be wetted in membrane absorption technology.Therefore,it has great potential in the future industrial application of carbon dioxide capture.However,the high energy consumption in the process of solvent regeneration limits its widespread application,so efforts are being made to improve the energy efficiency of the regeneration process.This work intends to find an environmental and friendly regeneration method with high regeneration rate and low energy consumption.The content is divided into the following three parts:(1)A method was proposed based on the traditional thermal regeneration process and the regenerated performance of potassium glycinate was improved by adding a certain amount of glycine.We determined the optimal experimental conditions by adjusting the important parameters in the experimental process:the concentration of potassium glycinate is 1 mol/L,desorption temperature is 100?,acid amount is 175 g/L.Under the optimal experimental conditions,the regeneration time of potassium glycinate solution was 2.5?3 h,which was 1?1.5 h less than before,the regeneration rate was 91.6%,the energy consumption of desorption process was 0.99 MJ/mol CO2,the regeneration rate was 26.64%higher than the traditional thermal regeneration method,and the energy consumption was 32.67%lower than the traditional thermal regeneration method.The recovery rate of glycine was up to 97.24%with the method of alcohol precipitation.The performances on CO2 absorption-desorption cycles in potassium glycinate solutions were basically the same as in the fresh potassium glycinate solutions.(2)The regeneration performance and mass transfer performance of CO2 were studied with the method of membrane desorption.We determined the optimal experimental conditions by adjusting the important parameters in the experimental process:the concentration of potassium glycinate is 1 mol/L,desorption temperature is 85?,load factor in membrane contactor is 0.32,liquid flow rate is 4.75×10-6 m3/s,the gas phase flow rate is 10×10-6 m3/s,the regeneration time of potassium glycinate solution was 2-2.5 h,which was 1?1.5 h less than before,the regeneration rate was 72.92%,the energy consumption of desorption process was 0.83 MJ/mol CO2.(3)We coupled the acid addition method and the membrane desorption method,it was found that this method could combine the advantages of the two methods.The regeneration rate was between the two methods,which was 87.34%,the energy consumption of desorption was further reduced,which was 0.65 MJ/mol CO2.The regeneration time of potassium glycinate solution was 2 h,which was 0.5 h less than membrane desorption,the regeneration rate increased by 19.78%and the energy consumption decreased by 21.69%.