PM combustion enhancement to reduce continuous regeneration temperature of fluidized bed type PM removal device using catalyst-doped bed particle

Abstract

A fluidized bed type PM removal device was developed by focusing on adhesion force as a highly efficient device for PM collection and low-temperature continuous regeneration. To further reduce the continuous regeneration temperature of this device, catalytic PM combustion was investigated. Alkaline and alkaline earth metals (potassium and calcium, respectively) are effective for PM combustion and are among the least expensive catalysts. The positive effects of these catalysts on PM combustion were compared. As their catalytic performances are almost identical, potassium was used for the continuous regeneration of this device. Potassium was doped on the bed particle via the impregnation method. Moreover, the amounts of doped potassium were compared based on the effects of PM combustion on collection efficiency, and the optimum value was determined to be 1.58 g-catalyst/kg-bed particle. Catalyst characterization was conducted via XRD and FTIR analysis of the cleaned gas. K2CO3 is detected on bed particle surface from the XRD patterns. The FTIR results show that potassium promotes PM combustion and selectively enhanced CO2 generation. CO2 is generated from the oxidation of K2CO3 and transformation of K2O2 to K2O with the consumption of PM. K2O is converted to K2CO3 with the re-absorption of CO2. The lowest continuous regeneration temperature decreases to 350 °C with maintaining the collection efficiency 100% owing to the catalytic PM combustion. Furthermore, the effect of water vapor, which is present in exhaust gas, was investigated. It promotes PM combustion and further reduces the continuous regeneration temperature to 330 °C.