甲醇精馏系统模拟与优化

Simulation and optimization of methanol distillation system

本文应用过程模拟软件Aspen Plus,采用Wilson和PSRK相结合的物性方法,实现了对某厂甲醇四塔双效精馏系统的模拟。为降低生产成本,本文通过对系统模拟与分析,对生产的工艺流程进行进一步改进,并提出3个优化方案:(1)增加加压精馏塔侧线采出送常压精馏塔作为进料;(2)对常压精馏塔塔底和回收塔塔底部分废水进行循环;(3)采用加压精馏塔与预精馏塔双效精馏。经过模拟计算,改进后的新工艺流程在保证甲醇产品的产量与质量的前提下,共能节省公用工程热量21 173 kW,节省公用工程冷量16 268 kW,节省工业用水10 375 kg/hr,污水处理量减少10 375 kg/hr。本文所选用的单元操作模型及物性方法对于模拟甲醇精馏系统是准确可靠的,因此本文所提出的优化方案能为甲醇工业生产节能、节水以及减少废水排放的改造和新工艺流程的开发提供理论依据。

By combining Wilson and PSRK equation of state model in the process simulation software Aspen Plus, the simulation of the 4-column double-effect methanol distillation system was accomplished in this paper. In order to reduce the production cost, it provided 3 optimized solutions to improve the production process by simulating and analyzing the system has been developed： （1） increase pressurized column side stream output as the feed for the normal pressure column, （2） recycling part of the waste water at the bottom of the normal pressure column and recovery column, and （2） utilizing double-effect distillation between pressurized column and pre-distillation column. By simulating calculation, newly improved process flow can save public project amount of heat 21 173 kW, public project cooling capacity 16 268 kW, industrial water 10 375 kg/hr, and decrease waste water treatment 10 375 kg/hr. The unit operation model and equation of state model used in this paper are accurate and reliable to simulate of the methanol distillation system. So the optimized solution in this paper can provide theoretical basis to the improvement of saving energy, water and decreasing waste water discharge, and to the development of the new production process.