| 摘要 |
PURPOSE:To recover unsaturated nitrile from ammoxidation reaction gas composed mainly of unsaturated nitrile, in the absorption of gaseous component with absorbing water, by extracting the absorbing water fed to the top of an absorption column, and cooling and recycling the extracted water. CONSTITUTION:Ammoxidation reaction gas composed mainly of unsaturated nitrile is supplied through the line 2 to the absorption column 1, and the gaseous component is absorbed with absorbing water supplied to the column top through the line 3. In the above process, the absorbing water is extracted from the middle stage of the absorption column via the line 6, and separated into an oil layer and an aqueous layer by the decanter 7. The aqueous layer is cooled with the cooler 8, and fed to the absorption column via the line 9. The excess water layer is fed to the recovery column 4, and the oil layer is supplied directly to the decyanation column 5 through the line 11. The amount of absorbing water can be decreased to enable the reduction of the installation and energy cost of the following distillation and purification step.
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