不同类型双效精馏流程节能特性的研究

Study on energy saving of different types of double effect distillation process

本研究利用工程模拟软件,选择乙醇-水二元物系为模型,对不同类型的3种双效精馏流程(平流双效精馏、顺流双效精馏和逆流双效精馏)进行了流程模拟,考查了不同的原料组成、不同的进料温度在分离要求相同的情况下,与普通精馏塔相比,各类型流程节能率的变化情况。结果表明,(1)原料组成变化对平流双效精馏节能率基本没影响,进料温度在泡点下,平流双效精馏节能率更高;(2)对于顺流双效精馏,进料温度的变化对其节能率的影响较大,进料温度越高两种流程的节能率越低,原进料组成中轻组分含量越多,节能率越高;(3)逆流双效精馏流程适合进料中低沸组分浓度高于高沸组分浓度的物系精馏分离。低沸组分的浓度越大,应用逆流双效精馏流程的节能率会越高。对于逆流双效精馏流程的3种不同流程的节能率均随着进料温度的升高而下降。

Engineering simulation softwarewas used to simulate double effect distillation with the ethanol - water system as a model. Different types of double effect distillation were simulated including double effect distillation with parallel feed, double effect distillation with feed from lower pressure tower and double effect distillation with feed from higher pressure tower. The influence of different feed composition and different feed temperature on energy saving effect of various distillation processes was investigated. The results showed that （ 1 ） for the double effect distillation with parallel feed, the changes of feed composition have little effect on energy saving rate, feed temperature, below the bubble point is the appropriate feed temperature, （2） for the double effect distillation with feed from higher pressure tower, energy saving rate decreased with the increase of the feed temperature, increased with light group content increased, （3） for double effect distillation with feed from lower pressure tower, the greater the concentration of light components, the better the energy saving effect, the lower the feed temperaturethe better the energy saving effect.