| 摘要 |
Ammonia is removed from gases containing it together with acrylonitrile, obtained from the vapour phase oxidation of propylene, by quenching the gases, at a temperature above their dew point, with an aqueous solution at at least 70 DEG C. and containing (NH4)2SO4 and an excess of H2SO4 above that necessary for neutralization of the ammonia. At least a portion of the resulting spent solution is cooled to precipitate ammonium sulphate crystals and the molten liquor, together with fish H2SO4 returned to the quenching stage. The concentration of H2SO4 in the spent solution may be 0.5 to 5%. A portion of the spent liquor may be recycled to the quenching stage without crystallization of (NH4)2SO4. |
