Optimum conditions for preparation of flue gas desulfurization absorbent from rice husk ash

Several previous studies have reported the preparation of absorbents from coal fly ash variations as a source of siliceous material for the preparation of absorbents for flue gas desulfurization. On the other hand, this study presents findings from an experimental investigation of the preparation of absorbents from rice husk ash as the source of the siliceous material. The effect of various absorbent preparation variables such as hydration period, amount of rice husk ash, amount of calcium sulfate (CaSO4) and hydration temperature on the BET (Brunner-Emmett-Teller) specific surface area of the absorbent were investigated. Based on the Central Composite Design (CCD) of experiments, a third order mathematical model was developed to correlate the absorbent preparation variables to the surface area of the absorbent. The predicted surface area was found to agree satisfactory with the experimental values. The model indicated that lower hydration period and temperature favor the formation of absorbent with higher surface area. Sulfation activity test on the absorbent revealed that the absorbent prepared from rice husk ash does have a high capacity in sulfur dioxide (SO2) absorption. (C) 2004 Elsevier Ltd. All rights reserved.