Method for lowering content of organic matters in absorption liquid in ammonium sulfate-free acrylonitrile technology

The invention relates to a method for lowering the content of organic matters in an absorption liquid in ammonia sulfate-free acrylonitrile technology, which mainly solves problems that the energy consumption is high and the removal efficiency of organic impurities in the absorption liquid is low in the prior art. The method comprises the steps of allowing reaction gas I and ammonia-poor absorption liquid I to contact with unreacted ammonia so as to obtain ammonia-rich absorption liquid II and ammonia-free reaction gas II not containing ammonia; (2) steam stripping the absorption liquid II rich in ammonia in a steam stripping tower, adding acid for regulating pH value, then carrying out oil-water separation so as to obtain ammonia-rich absorption liquid III; then heating up the ammonia-rich absorption liquid III in a resolution tower, carrying out steam stripping so as to obtain ammonia gas flow III and ammonia-poor absorption liquid IV, and returning the ammonia-poor absorption liquid IV back to a quench tower for absorbing unreacted ammonia; and (3) rectifying and separating the ammonia gas flow III in an ammonia rectification tower so as to obtain high-purity ammonia IV, and returning the high-purity ammonia IV back to an ammonia oxidation reactor for reaction. The method adopting the technical scheme well solves the problems and can be used by an industrial device of acrylonitrile.