| 摘要 |
PURPOSE:To increase the energy efficiency in the preparation of the titled compound by the ammoxidation reaction of an olefin, by utilizing the relatively low-temperature sensible heat or latent heat generated in the reaction system and wasted so far, as a cooling source or a heating source. CONSTITUTION:The ammoxidation reaction product of an olefin is quenched with water in a quenching tower 3, and absorbed in absorbing water in the absorption tower 8. The absorbing liquid is subjected to the extractive distillation with water solvent in the recovery tower 13, and the distillate from the top of the tower is sent successively to the hydrogen cyanide-removal tower 21, the dehydration tower 25 and the product tower 28, etc. and the unsaturated nitrile is separated by distillation. In the above process, the absorption refrigerator 31 is driven e.g. by the used cooling circulation water discharged from the bottom of the quenching tower 3, and the obtained coolant is used for the cooling of the cooler 9 for the absorbing water of the absorption tower and the condenser 23 of the hydrogen cyanide-removal tower. As an alternative method, the quenching tower is divided into two stages, the absorption heat pump 33 is driven by the circulation water discharged from the lower cooling zone, and the obtained hot water is utilized as the heat source of the reboilers 22, 26, and 29 for the distillation columns. |
