Carbon Dioxide Absorption From Mixed Gases In A Rotating Packed Bed With Static Annular Baffle

Recently, as the development of economy, the demand of energy supply expanded. A large amount of carbon dioxide emitted to atmosphere from combustion of fossil fuels causes severe environment damage and greenhouse effect. On February 16,2005, the Kyoto Protocol that aims at reducing the emission of CO2 became effective, which made the reducing of the main greenhouse gas-CO2 a serious problem in several countries. On the other hand, CO2 is a potential resource which is widely used in food industry, chemical industry, agriculture, medical, business, transportation and some other fields. How to recover the CO2 effectively and economically from flue gas has long-term meaning.As an entirely new type and efficient multiphase flow contact device, Rotating Packed Bed can greatly enhance the process of mass transfer and has been widely used in chemical separation and the preparation of nano-materials. In this paper, innovative improvements of the structure of the traditional rotating packed bed were carried out, and a static annular baffle with a thickness of about 1.5cm was installed in the space between the rotor and shell. The absorption of CO2 from a mixing gas by chemical absorption with alkanolamine solutions in this new type rotating packed bed was investigated. The absorption efficiency was related to the static annular baffle, high gravity factor, absorbent temperature, pressure and gas-liquid ratio,etc. The results of pilot plant studies indicated that CO2 absorption efficiency increased significantly owing to the static annular baffle in RPB, bringing an increase about 10% in absorption efficiency. CO2 absorption efficiency first increases with the rising high gravity factor and then stabilizes when the high gravity factor is higher than 125. CO2 absorption efficiency increased first and decreased subsequently with the absorbent temperature, and an absorbent temperature of about 40℃was suggested in this research. It is found that the CO2 absorption efficiency increased with pressure and the absorbent concentration, but reduced with gas liquid ratio. The effect of inlet gas concentration on the CO2 absorption efficiency was relevant to the high gravity factor. With the addition of piperazine, a rate activator, CO2 absorption efficiency was significantly improved. Based on a lot of experimental data, the empirical correlations of CO2 absorption efficiency was given:η=0.088β0.058(G/L)-0.219T0.65P0.123x0.323y-0.027,and the fitting error was less than 5%. Moreover, the volumetric mass transfer coefficient of the main area and the static annular baffle was calculated respectively, and the results showed that the KGa of the main area increased with gas liquid ratio and high gravity factor, however, the KGa of static annular baffle had not changed much with gas liquid ratio and high gravity factor.