| In this paper, screening absorbents, optimization of process parameters and process improvement were discussed detailedly, which bases on research status at home and abroad of membrane-based absorption method.A direct absorption experiment station was set up which was used for screening efficient mother solutions and additives. MEA, DEA and MDEA as mother solutions, AAAP, SG, PT and AMP as additives were selected, and36types of composite solutions were made up according to three additive levels. Then CO2moore load, absorption rate, desorption rate and regeneration degrees of36composite solutions were examined. As a result,18%MEA+2%PT,18%DEA+2%AAAP,16%MDEA+4%AMP were screened as "good absorption and low energy consumption of desorption" composite solutions.The influence of the placement of membrane modules, the liquid flow rate, the concentration of CO2, and the type of absorbents four on absorption effects was studied using single-factor method. And then the optimum process parameters were determined in order to get better decarburization results. This step was done on membrane contact experiment station. The experiment showed that18%DEA+2%AAAP, as the composite solution, with a flow rate of Qaq=40mL/min absorbed the mixture gas with the CO2content of ACO=13.8%in the horizontal membrane module, as a result, rate of decarburization can reach50%to60%.Improving the original membrane contactor with hydrophilic PVDF membrane instead of hydrophobic PP membrane, the results showed that2.0mol/L DEA, as the absorbent, with a flow rate of Qaq=15mL/min absorbed the mixture gas with the CO2content of ACO=14.3%and Qg=275mL/min at the temperature of35℃in lengthways PVDF module, and the rate of decarburization can reach80%, which is much higher than the rate in PP module. |
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