Fluidized bed desulfurization using an activated carbonate sorbent.

In this work we have tested the fluidized bed desulfurization performance of an activated carbonate sorbent obtained with a limestone pre-treatment/activation technique. This performance was compared with that of the parent untreated limestone particles. The occurrence of particle fragmentation and attrition during the fluidized bed operation was also investigated with a specific test protocol for both limestone and activated carbonate sorbent. Two particle size ranges were tested under typical fluidized bed coal combustion conditions (T = 850°C; SO2 = 1800 ppm). Results showed that the treatment/activation technique was able to preserve after calcination the initial particle size distribution of the parent particles. In addition, high calcium reactivity and final conversion were observed for the activated carbonate particles, leading to a much better SO2 capture capacity per unit mass of sorbent than that obtained with the untreated limestone. Simple economic evaluations suggest that the use of this pre-treated sorbent in place of limestone can involve significant savings for fluidized bed coal combustor operators.