The Behavioral Study Of Carbon Dioxide Absorption-Desorption Process In Hollow Fiber Membrane Contactors

The C02absorption-desorption process in hollow fiber membrane contactors overcome the traditional tower absorption-desorption of flooding, entrainment and operational constraints, provides mass larger specific surface area and low energy consumption, so it has a very good application prospect. In the real industrial process, CO2capture separation is always on the absorption-desorption cycle coupling form, but the lab research are still concentrated in a single absorption or single desorption process,so the factors affecting the membrane absorption-desorption coupled operating conditions in hollow fiber membrane contactors are less concerned.Therefore, the operating conditions which can influence the CO2absorption-desorption process in hollow fiber membrane contactors are researched in this paper, such as absorption/desorption temperature, liquid velocity, absorbent concentration and hollow fiber membrane structure parameters, analyze the impact of various factors on the process of mass transfer efficiency and the mechanism of thermal energy consumption.The experimental result show that:improve desorption temperature, reduce absorption temperature, reduced liquid velocity, increasing the concentration of absorbent, proper filling factor can enhance mass transfer efficiency; higher absorption temperature, lower desorption temperature, low liquid flow rate, the higher the concentration of absorbent and moderate filling factor are conducive to energy consumption reduce. Through a series of hollow fiber membrane contactor can effectively improve mass transfer effect of CO2, parallel through hollow fiber membrane contactor can increase the processing capacity of absorbent, and the mass transfer effect will not be reduced.This paper choose the following parameters as the optimal operating conditions:the loading factor of polypropylene hollow fiber membrane contactor:0.18; use multilevel series; absorbents:5.0mol/L MDEA; pressure in tube said:80kPa; liquid flow rate of shell side:0.035cm/s; temperature of absorption:40℃; temperature of desorption:90℃. Get: the payload ratio of CO2is66.31%, and mass transfer flux is19.98X10-4mol·m-2·s-1, the total mass transfer coefficient is10.97×10-4m·s-1, sensible heat of heat up is49.92kJ/molCO2, latent heat of evaporation is3.32kJ/molCO2. Experimental results show that under the high mass transfer efficiency, membrane absorption-desorption membrane coupling thermal energy consumption is far lower than conventional desorption process operation process.