Simultaneous removal of SO_2 and NO_x with ammonia absorbent in a packed column

摘要

Catalytic oxidation of NO followed by simultaneous removal of SO_2 and NO_x with ammonia is a promising method for control of coal-fired flue gas pollutants. We investigated simultaneous absorption of SO_2 and NO_x in a packed column with ammonia, and found that SO_2 and NO_x could promote absorption with each other in the process of simultaneous removal SO_2 and NO_x. The removal efficiency of SO_2 and NO_x was, respectively, about 98% and 70.9% at pH 5.5, temperature 323.15 K, SO_2 concentration 1,800× 10~(-6), NO_x concentration 400× 10~(-6) and m_(NO_2)/m_(NO) 1 in our experimental system. The experimental results also show that the formation of sulfite oxidized by reacting with dissolved NO_2 and the molar ratio of sulfite to total sulfur is more than 0.8 in the solution. Accordingly, the energy consumption for sulfite oxidation would be greatly reduced in the process of simultaneous desulfurization and denitrification with ammonia.