苯乙烯装置塔系热集成

精馏作为过程工业中最重要和最常用的分离手段, 是耗能最大的单元操作。精馏塔一般从再沸器输入热量, 从冷凝器取走热量, 利用某些塔高温位的冷凝热加热其他塔的再沸器, 并将单塔节能技术与过程集成相结合, 实现塔系的热集成, 可充分挖掘系统内部的节能潜力, 达到减少公用工程消耗的目的。本文通过对某化工厂的苯乙烯装置精馏塔系的分析, 通过各个塔的温焓图之间的关系, 提出了精馏塔系内部热集成的措施, 包括直接热集成、调压热集成和双效精馏与间接热集成耦合等3种方案。对于后两个热集成方案, 采用Aspen Plus模拟改造后精馏塔的变化并验证了方案的可行性。结果表明, 苯乙烯装置采用该热集成措施能明显节省高品位蒸汽的消耗, 降低能量费用。

Heat integration of columns in styrene plant

Distillation is the most important and commonly used separation method in the process industry, and is the operation unit with maximal energy consumption. For a column, heat is generally supplied from a reboiler, and rejected from a condenser. Using the condensing heat of one column to heat another column’s reboiler, and combining energy saving measures of a single column with process integration, namely heat integration of columns, is an effective way to reduce utilities consumption. In this paper, by analyzing the distillation system in a styrene plant, with the relative position of T-H diagram for each column, three measures of heat integration schemes were proposed for the columns system, including direct heat integration, heat integration with pressure adjustment and coupling double-effect distillation with indirect integration. For the last two measures, Aspen Plus was used to simulate the operation changes and verify the feasibility of the schemes. The consumption of high quality steams and related cost could be significantly reduced.