乙醇胺反应工艺模拟与分析

Simulation and analysis of ethanolamine reaction process

国内乙醇胺生产大多采用低温低浓度氨水和环氧乙烷进行反应,反应体系中氨和水的循环量大、反应速度慢、不能按市场要求控制产品分布。本文通过比较不同的反应动力学表达式,选择了较好的反应动力学方法,在Aspen plus中建立了乙醇胺反应过程的模型,对影响反应速度和产品分布的反应温度、氨水浓度、物料混合方式、以及物料配比等因素进行了分析,得出了该反应工艺温度提高到90℃可以使反应速度差不多处于最大值,氨水浓度增大使反应停留时间减少,生产负荷提高。由于氨／环氧乙烷进料摩尔比较大,使物料混合形式对反应速度影响不大,反应过程前后反应速度变化不大。物料返混越大, 氨／环氧乙烷进料摩尔比越大,产品中三乙醇胺占的比例越大,一乙醇胺比例越小。这些反应规律为实际的生产提供了有益的指导。

Most domestic factories produce ethanolamines from low concentration aqueous ammonia and ethylene oxide. Large volume of recycling aqueous ammonia, slow reaction rate and difficuh： control of the product profile are main disadvantages. In this paper, suitable reaction dynamic equations are compared and selected from deferent literatures for ethanolamines reaction process. Affective factors are analyzed which are related to the reaction rate and final product distribution. The calculations show the follows results. The reaction rate reach maximum at 90℃. The higher concentration of aqueous ammonia, the rest time is shorter. The deferent flow mixing types nearly affect the reaction rate and the reaction rate change little along the whole process due to large ratio of ammonia and ethylene oxide. When more back mixing and bigger feed ratio of ammonia and ethylene oxide, the percent of tri-ethanolamine is more and the percent of mon-ethanolamine is less. The analysis results can be referred to improve the performance of the actual ethanolamine process.