Experimental Study On CO₂Absorption By Chemical Method

The global warming caused by greenhouse effect has become an important global environmental problem. It is mainly due to the enhanced greenhouse effect produced by greenhouse gas emission into the atmosphere as a result of fossil fuels combustion and the forests cutting down in the land. With the rapid development of economy in our country, mainly for coal consuming has been increasing day by day. Therefore, the development of an effective carbon dioxide capture technology and good CO2absorbent are imperative. Coal-fired power plant contributes more to the CO2emission and is a concentrative CO2emission source. Improving power generating efficiency, accelerating the fuel substitution and capturing CO2directly from the flue gas of the power plant can be taken into account to control and reduce CO2emission to the atmosphere, with the last being the most important method to control CO2emission nowadays.In this paper, flow chart, characteristic, and the state of the research of chemical absorption, physical adsorption, cryogenic distillation and membrane absorption technologies et al. are analyzed and compared with each other. It indicates that chemical absorption is the most effective CO2capture technology. The researches of chemical solvent absorption method are mainly focus on the selection of absorbent, the research of the reaction mechanism, the selection of reactor, the ascertainment of the operating conditions and so on.In this paper, coal-flue gas as the object was simulated the concentration of CO2. The bubbling reactor designed in this paper was used to study the reaserch of CO2absorption. Firstly, orthogonal experiment was used to study the influence law of CO2absorption effect caused by absorbent type, absorbent concentration, CO2concentration in flue gas, gas flow, gas temperature and liquid level height. It turned out that the order of influence factors that is absorbent type>absorbent concentration> CO2concentration in flue gas>liquid level height> gas flow> gas temperature. Based on the results of the orthogonal experiment, ammonia and sodium hydroxide were choosed to carry on single factor experiments. In the bubble absorption process, the influence law of CO2absorption effect was studied on absorbent concentration, the inlet of CO2concentration, gas flow, liquid level height and activator. The results show that, with the increase of the inlet of CO2concentration and gas flow, the CO2removal efficiency gradually decreased and the absorption rate increased; with the increase of liquid level height, the CO2removal efficiency gradually increased and the absorption rate increased firstly and then decreased; With the increase of absorbent concentration, the CO2removel efficiency and absorption rate of ammonia gradually increased and the CO2removel efficiency and absorption rate of sodium hydroxide increased firstly and then decreased; the CO2removal efficiency and absorption rate were improved after adding anhydrous piperazine, diethylenetriamine, triethanolamine, hydroxyethyl ethylenediamine into the absorbent solution, the activation of anhydrous piperazine is the best.