REDUCTION KINETICS OF A CaSO4 BASED OXYGEN CARRIER FOR CHEMICAL-LOOPING COMBUSTION
The CaSO4 based oxygen carrier has been proposed as an alternative low cost oxygen carrier for Chemical-looping combustion (CLC) of coal. The reduction of CaSO4 to CaS is an important step for the cyclic process of reduction/oxidation in CLC of coal with CaSO4 based oxygen carrier. Thermodynamic analysis of CaSO4 oxygen carrier with CO based on the principle of Gibbs free energy minimization show that the essentially high purity of CO2 can be obtained, while the solid product is CaS instead of CaO. The intrinsic reduction kinetics of a CaSO4 based oxygen carrier with CO was investigated in a differential fixed bed reactor. The effects of gas partial pressure (20％-70％) and temperature (880-950 ℃) on the reduction were investigated. The reduction was described with shrinking unreacted core model. Experimental results of CO partial pressure on the solid conversion show that the reduction of fresh oxygen carriers is of first order with respect to the CO partial pressure. Both chemical reaction control and product layer diffusion control determine the reduction rate. The dependences of reaction rate constant and effective diffusivity with temperature were both obtained. The kinetic equation well predicted the experimental data.
CO2 capture chemical-looping combustion ozygen carrier kinetics CaSO4
R.Xiao Q.L.Song W.G.Zheng Z.Y.Deng L.H.Shen M.Y.Zhang
Department of Thermal Engineering, Southeast University, Nanjing, 210096,China
国际会议
第20届国际流化床燃烧会议(20th International Conference on Fluidized Bed Combustion)
西安
英文
519-526
2009-05-18（万方平台首次上网日期，不代表论文的发表时间）