我国环己烷氧化分解液碱水分离技术研究进展

Advances in lye separation of cyclohexane oxidative decomposition liquid in China

废碱液的分离是环己烷氧化法制备环己酮的关键处理环节,若分离不彻底,将直接导致烷蒸馏塔再沸器结垢,造成物料消耗增加及装置运行周期大幅度缩短;因此如何高效降低环己烷氧化分解液中废碱含量一直是各个企业所面临的难题。本文对环己烷氧化分解液碱水分离技术进展进行了综述,分析了重力沉降+斜板分离工艺、重力沉降+聚结分离工艺、重力沉降+旋流分离+聚结分离工艺、斜板分离+旋流分离+聚结分离工艺技术的原理、特点及其应用效果。随着深度分离技术的升级,进入烷蒸馏塔物料中Na+含量从50~100mg/kg降至0.2mg/kg以下,环己酮装置开车周期从2~3个月延长到24个月以上。从工业应用效果来看,重力沉降+旋流分离+聚结分离工艺碱水分离效率最高、工业应用效果最好,值得大力推广应用。此外,斜板分离+旋流分离+聚结分离工艺作为新型组合分离技术,其分离效果有待进一步工业验证。

The separation of waste lye is the key processing step in the preparation of cyclohexanone by the cyclohexane oxidation method.If the separation is incomplete,it will directly cause the scaling of the reboiler of the alkane distillation tower,resulting in increased material consumption and greatly short operating cycle of the cyclohexanone unit.Therefore,how to efficiently reducing the waste alkali content in cyclohexane oxidation decomposition liquid has always been a difficult problem faced by various enterprises.This article reviews the progress of advances in lye separation technology of cyclohexane oxidative decomposition liquid,and analyzes the principle,characteristics and application effects of the gravity sedimentation+inclined plate separation process,the gravity sedimentation+coalescence separation process,the gravity sedimentation+hydrocyclone separation+coalescence separation process,and the inclined plate separation+hydrocyclone separation+coalescence separation process.With the upgrading of deep separation technology,the Na^(+)content in the material entering the alkane distillation tower has dropped from 50-100mg/kg to less than 0.2mg/kg,and the start-up cycle of the cyclohexanone unit has been extended from 2-3 months to more than 24 months.From the perspective of industrial application effect,the gravity sedimentation+hydrocyclone separation+coalescence separation process has the highest lye separation efficiency and the best industrial application effect,which is worthy of vigorous promotion and application.In addition,the inclined plate separation+hydrocyclone separation+coalescence separation process is a novel combined separation technology,and its separation effect needs further industrial verification.