摘要
使用Van’t Hoff方程、Hildebrand方程和冰点降低常数法计算了PX-MX二元体系的固液平衡相图,计算结果表明,3种计算方法均与实验结果吻合很好。使用冰点降低常数法计算混合二甲苯多元体系的低共熔点组成,计算结果表明,含有EB的多元体系,其液相不能当作是理想溶液,不含EB的多元体系,其液相可以近似当作是理想溶液,在工业生产分析时,PX-MX-OX-EB可以近似为PX-MX-OX三元体系。根据冰点降低常数法的计算结果,绘制了PX-MX-OX三元体系的固液平衡立体相图,并分析了不同工业原料中对二甲苯的结晶过程,计算结果表明,PX结晶过程的回收率都受到低共熔点的限制,对于PX质量分数为21.5%的低含量进料,PX最大回收率为67%,对于PX质量分数为83.72%的高含量进料,PX最大回收率为97%。
The solid-liquid equilibrium （SLE） diagram of PX-MX was calculated with Van l Hoff equation, Hilde- brand equation and eryoscopie method respectively and all the calculation results agree very well with the published experimental data. Due to its simple form, cryoscopic method was used to calculate the eutectic composition of multi-component xylol systems and the results suggested that, if there is no ethylbenzene in the xylol mixture, the liquid phase can be treated as ideal solution, otherwise it should be considered as nonideal solution. In the industrial process, the quaternary system of PX-MX-OX-EB can be treated as a quasi-ternary system PX-MX-OX if the concentration of EB is very small, which is usually true in an industrial process. Based on the calculation results, the 3 D ternary SLE diagram of PX-MX-OX system was developed. The PX crystallization process was analyzed at different PX concentration conditions under the help of the 3D SLE phase diagram and the results suggested that the yield of PX during the crystallization process is limited by the eutectic point of the system. The maximum yield of PX is 67% and 97% while the feed PX concentration is 21.5% and 83.72% respectively.
出处
《聚酯工业》
CAS
2009年第1期7-11,共5页
Polyester Industry
关键词
对二甲苯
结晶
固液相平衡
p-Xylene
crystallization
solid-liquid equilibrium
作者简介
陈亮（1981-，男，安徽池州人，博士，从事结晶分离技术的研究工作。
