影响PA6萃取水蒸发效果的因素探讨

Discussion of factors affecting vaporization efficiency of PA6 extraction water

讨论了在己内酰胺聚合过程中,三效蒸发工艺对PA6萃取水浓缩液浓度的影响,为蒸发系统节能降耗提供依据。结果表明:温度和真空度相互制约,温度98～118℃,真空度0．040～0．085 MPa,一效蒸发塔底部物料温度与二效蒸发塔的二次蒸汽温度差为6～8℃,回流水量75～105 L/h,调节浓度梯度,控制蒸汽调节阀开度为55%～80%,可得到己内酰胺质量分数约80%的萃取水浓缩液,且一效蒸发塔出料温度稳定,有利于节能。

The effect of triple effect evaporation process on the concentration of PA6 concentrated extraction water was discussed during the polymerization of caprolactam, which provided a basis of the energy saving and consumption reducing for evaporation system. The experimental results showed that the temperature and the vacuum degree were restricted with each other. The con- centrated extraction water with 80% caprolactam by mass fraction can be obtained under the conditions as followed： temperature 98 -118℃, vacuum degree 0.040 -0. 085 MPa, the difference between feedstock temperature at the bottom of the first effect evaporation tower and the steam temperature of the secondary effect evaporation tower of 6 - 8℃, the reflux water flow 75 - 105 L/ h, adjusting the concentration gradient, controlling steam governing valve opening 55% -80%. The first effect evaporation tower had a stable discharging temperature, helping to energy saving.