Industrial & Engineering Chemistry Research, Vol.46, No.12, 4212-4220, 2007
Packed bed reactor technology for chemical-looping combustion
Chemical-looping combustion (CLC) has emerged as an alternative for conventional power production processes to intrinsically integrate power production and CO2 capture. In this work a new reactor concept for CLC is proposed, based on dynamically operated packed bed reactors. With analytical expressions validated with a more detailed numerical model, it is demonstrated that a constant, very high temperature air stream can be generated efficiently using packed bed CLC reactors to drive a downstream gas turbine. The process consists of alternate oxidation and reduction cycles, intermittently alternated with short periods of mild fluidization of the bed after each cycle to level off temperature and concentration profiles. Oxygen carriers based on nickel, iron, and manganese oxide show the highest potential for use in packed bed CLC. Compared to the interconnected fluidized bed system proposed in the literature (Lyngfelt, A.; Leckner, B.; Mattisson, T. A fluidized-bed combustion process with inherent CO2 separation; application of chemical-looping combustion. Chem. Eng. Sci. 2001, 56, 3101), the difficult separation of gas and particles is intrinsically avoided and the oxygen carrier can be utilized over the entire range of oxidation states.