Abstract: In the simulation of flue gas, free ammonia at the export of spray tower was used as the monitoring object. Factors of influence including pH value and concentration of absorption liquid, volume ratio of liquid to gas (L/G) and inlet gas temperature on the efficiency of flue gas desulphurization (FGD) were studied. Experimental results show that the amount of ammonia escape increases as the pH value, concentration of absorption liquid and L/G increase. To control ammonia escape and the high rate of desulphurization, appropriate parameters should be used, including pH value of 6.0, concentration of  absorption ((NH4)2SO3) of 1%, L/G of 4 L/m³, and inlet gas temperature of 90~110  ℃.

Key words: ammonia escape, ammonia method, flue gas desulphurization (FGD)