Inexpensive calcium-modified potassium carbonate sorbent for CO_2 capture from flue gas: Improved SO_2 resistance, enhanced capacity and stability

摘要

Many sorbents have been studied for their CO_2 sorption capacities with CO_2 and N_2 mixture. In reality, flue gases contain SO_2. This research was designed to develop and evaluates an inexpensive and robust CO_2 sorbent for actual flue gas. Ca(OH)_2, CaO and CaCO_3 were explored to serve as additives of K_2CO_3/ γ-Al_2O_3 for CO_2 capture. The three additives were characterized using different methods including thermal gravimetric, X-ray diffraction analyses and so on. It was found that Ca(OH)_2 is the best additive of K_2CO_3/γ-AL_2O_3 for CO_2 capture. The performances of K_2CO_3/Ca(OH)_2/γ-Al_2O_3 were evaluated with a flu-idized bed reactor under different conditions including the presence of SO_2. Experimental results show that introduction of Ca(OH)_2 made K_2CO_3/Ca(OH)_2/γ-Al_2O_3 not only more capable in adsorbing CO_2 but also more robust within SO_2-containing flue gas. Thus the research work provides useful information for further development and subsequent commercialization of K_2CO_3/Ca(OH)_2/γ-Al_2O_3 in coal-fired power plants.