| 摘要 |
PROBLEM TO BE SOLVED: To provide a monomer-recovering method capable of increasing recovery efficiency of unreacted monomer components recovered in a recovery process of acrylonitrile monomers, and a recovery system of an acrylonitrile polymer. SOLUTION: The monomer components are recovered by vaporizingly separating the monomer components and water from the polymer by distillation of a monomer/polymer/water solution obtained by polymerization in a polymerization reaction tank (5) and subsequently condensing the vaporized monomer components and water, where a deaeration tube part (6) having a tube body (9) of a small diameter is interveningly disposed between the polymerization reaction tank (5) and a distillation column (7) and the polymer/unreacted monomer/water solution obtained in the polymerization reaction tank (5) is continuously fed directly to the distillation column (7) through the deaeration tube part (6). Thus, the amount of AAP (Acrylonitrile Addition Products), formed by the reaction of acrylonitrile (AN) with sodium hydrogen sulfite as a reducing agent for a polymerization initiation reaction and subsequently discharged outside the system, is remarkably decreased thereby to increase the recovery efficiency of AN. COPYRIGHT: (C)2006,JPO&NCIPI
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