A comparative ammonia recovery study of solid wastes discharged from rice husk gasifi cation and combustion plants

Abstract

Large amounts of rice husk char (RHC) and rice husk ash (RHA) are generated in rice husk-based power plants, and development of an effective recycling method for the RHC and the RHA wastes would be desirable. The main components of RHC were carbon (37.2 mass%) and silica (47.72 mass%), while that of RHA was silica (88.59 mass%). Both RHC and RHA had a reticulate porous structure with specifi c surface areas of 207.0 and 7.9 m²/g, respectively. Their ammonia recovery capacities were evaluated by adsorption capacities of ammonia in gas phase (50 ppm) and its desorption capacities in water at 25°C and ambient pressure. The adsorption capacity of ammonia in gas phase was higher for the RHC than for the RHA.