Elimination/Reduction of discharged pollutants on environment is an essential requirement for human life. Combustion of fossil fuel is the main source for pollution of air by emission of a variety of substances such as sulphur dioxide (SO 2 ). Its emission is source of various hazards for environment, such as the formation of acid rain. There are various flue gas desulphurization (FGD) processes. They have ). By increasing ammonia concentration, efficiency of desulphurization had increased but resulted in reduction of ammonium sulphate purity. Based on a published research resulted the effect of temperature on desulphurization's efficiency was high, but in this research the temperature parameter was not effective, due to limited range of parameters. Increasing of temperature as same as increasing of inlet sulphur dioxide concentration, reduced the purity of ammonium sulfate product. Experimental results showed that, in up and down range of inlet sulphur dioxide concentration, the efficiency of desulphurization became Maximum. Also effect of pollutant air flow variable on both responses is not independent and this variable increases other parameters effect. Keywords : flue gas, sulphur dioxide, ammonia scrubbing, ammonium sulfate, fertilizer, response surface methodology.
