Abstract
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°C) 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.
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References
Abad, A., Adánez, J., García-Labiano, E, de Diego, L. E, Gayán, P. and Celaya, J.: Chern. Eng. Sci. 62 (2007a), pp.533–549.
Abad, A., García-Labiano, E, de Diego, L. E, Gayán, P. and Adánez, J.: Energy Fuels 21 (2007b), pp.1843–1853.
Abad, A., Mattisson, T., Lyngfelt, A. and Johansson, M.: Fuel 86 (2007c), pp.1021–1035.
Adánez, J., Abad, A., de Diego, L. E, García-Labiano, E and Gayán, P.: Ind. Eng. Chern. Res. 43 (2004), pp.4132–4139.
Chuang, S. Y., Dennis, J. S., Hayhurst, A. N. and Scott, S. A.: Combust. Flame 154 (2008), pp.109–121.
Jung, J. and Gamwo, I. K.: Powder Technol. 183 (2008), pp401–409.
Leion, H., Lyngfelt, A., Johansson, M., Jemdal, E. and Mattisson, T.: Chern. Eng. Res. Des. 86 (2008a), pp.1017–1026.
Leion, H., Mattisson, T. and Lyngfelt, A.: International Journal of Greenhouse Gas Control 2 (2008b), pp.180–193.
Lyngfelt, A., Leckner, B. and Mattisson, T.: Chern. Eng. Sci. 56 (2001), pp.3101–3113.
Ryu, H. J., Bae, D. H., Han, K. H., Lee, S. Y., Jin, G. T. and Choi, J. H.: Korean J. Chern. Eng. 18 (2001), pp.831–837.
Shen, L. H., Zheng, M., Xiao, J. and Xiao, R: Combust. Flame 154 (2008), pp.489–506.
Song, Q. L., Xiao, R, Deng, Z. Y., Shen, L. H., Xiao, J. and Zhang, M. Y.: Ind. Eng. Chern. Res. 47 (2008a), pp.8148–8159.
Song, Q. L., Xiao, R, Deng, Z. Y., Zheng, W.G., Shen, L. H. and Xiao, J.: Energy Fuels 22 (2008b), pp.3661–3672.
Wang, J. S. and Anthony, E. J.: Applied Energy 85 (2008), pp.73–79.
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© 2009 Tsinghua University Press, Beijing and Springer-Verlag Berlin Heidelberg
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Xiao, R., Song, Q.L., Zheng, W.G., Deng, Z.Y., Shen, L.H., Zhang, M.Y. (2009). Reduction Kinetics of a CasO4 Based Oxygen Carrier for Chemical-Looping Combustion. In: Yue, G., Zhang, H., Zhao, C., Luo, Z. (eds) Proceedings of the 20th International Conference on Fluidized Bed Combustion. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-02682-9_79
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DOI: https://doi.org/10.1007/978-3-642-02682-9_79
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