GB1365268A - Disposal of waste material from unsaturated nitrile plant - Google Patents

Abstract

1365268 Disposal of waste material from unsaturated nitrile plant BADGER CO Inc 30 June 1972 [2 Aug 1971] 30687/72 Heading C2C In the ammoxidation of olefines to nitriles, e.g. of propylene or isobutylene to acrylonitrile or methacrylonitrile respectively, an improved process for recovering and disposing of waste materials is described. The unsaturated nitrile, ammonia and waste materials formed as byproducts of the reaction are adiabatically cooled in a quenching chamber by evaporation of at least one vaporizable liquid medium selected from water and a hydrocarbon solvent, to condense any polymers formed as by-products of the reaction. The condensed polymers and any entrained catalyst fines are flushed out of the system in a small stream of unvaporized solvent. The partially quenched effluent recovered from the quench column is then optionally treated to condense water and hydrocarbon solvent which are recycled to the quench column and passed to an absorber column operating at a temperature above the dew point of the water in the effluent and using a hydrocarbon solvent as absorption medium for the unsaturated nitrile. The solution formed by the unsaturated nitrile together with small amounts of by-product and the hydrocarbon solvent is recovered and the byproduct removed as overhead in a lights distallation column and recycled to the absorber. The unsaturated nitrile bottoms product is recovered as high purity product in a succeeding product column, the hydrocarbon solvent being recycled to the absorber and lights column. The hot absorber off gases are treated to recover any hydrocarbon solvent and incinerated, ammonia, HCN, acetonitrile and some vaporized solvent furnishing the fuel. To minimize loss of solvent to the incinerator, the off-gases from the absorber may be scrubbed with a scrubbing oil to remove the solvent.