己内酰胺单体回收浓缩液蒸发工艺的优化

Optimization of evaporation process for caprolactam monomer recovery concentrated solution

介绍了己内酰胺回收的三效蒸发工艺，在己内酰胺单体回收三效蒸发过程中，通过添加新鲜己内酰胺，实现蒸发系统及聚合生产的安全稳定运行，讨论了添加新鲜己内酰胺对蒸发工艺的影响。结果表明：随着新鲜己内酰胺添加量的增加，蒸发液中己内酰胺的含量迅速增加，导致蒸发液的电导率下降，低于液位计的正常工作值，液位显示失真，蒸发液浓度波动大；当添加新鲜己内酰胺质量分数在2％～5％时，二级蒸发塔蒸发液的电导率可控制在40～110μS／cm，蒸发液位和蒸发液浓度正常，蒸发系统运行稳定。

The triple effect evaporation process for caprolactam recovery was introduced. The safety and stable operation of evaporation system and polymerization plant can be guaranteed by adding fresh caprolactam during the triple effect evaporation process for caprolactam monomer recovery. The effect of fresh caprolactam addition on evaporation process was discussed. The results showed that the caprolactam content of evaporating liquid was rapidly increased with the increase of fresh caprolactam addition, causing the conductivity inclination of evaporating liquid; the level gauge failed to indicate as the conductivity was lower than the normal value, which led to the great fluctuation of evaporating liquid concentration; the conductivity of evaporating liquid in the secondary evaporator was 40 - 110 μS/cm, the evaporating liquid level and concentration kept normal and the evaporation system ran steadily when the mass fraction of fresh caprolactam was 2% -5%.