甲醇精馏自控稳定性的提高方法

The application of Advanced Process Control System in Methanol Rectification

甲醇精馏是因粗甲醇混合物中各个不同组分之间的相对挥发度不相同,经过加热,是在同一个温度基准下,在粗甲醇中的各种不相同的组分多次通过一部分气化和一部分冷凝,其中在粗甲醇中的不相同的杂质组分会被除去,最终会得到符合GB/T 338-2011标准的精甲醇,这样就实现了粗甲醇中各种混合物的分离。由于甲醇混合物进料流量及组成存在波动,用于精馏的蒸汽温度、压力亦不稳定,对于这种多变量耦合、大时滞的系统,PID单回路的常规的操作和控制很难达到理想的控制效果。为了解决以上问题,迫切需要采用先进控制技术。介绍了利用先进控制系统提高甲醇精馏自控稳定性的方法,在保证精甲醇符合产品质量的情况下,还能提高精馏装置关键工艺参数的稳定性,通过运用优化控制策略,实现了产品单耗降低、收率提高。

The rectification of methanol is due to the differing relative volatilities of components in the crude methanol mixture.Upon heating,various components in the crude methanol undergo multiple cycles of partial vaporization and condensation at a consistent temperature,leading to the removal of different impurity groups.Ultimately,refined methanol meeting the GB/T 338-2011 standard is obtained,allowing for separation of various mixtures within the crude methanol.The fluctuating feed flow and composition of the methanol mixture result in unstable steam temperature and pressure during distillation.Conventional PID single loop operation and control are inadequate for achieving ideal control in this multi-variable coupling system with significant time delay.Therefore,adoption of advanced control technology is imperative to address these challenges.This paper introduces an advanced control system to enhance automatic stability in methanol distillation,thereby improving key process parameter stability while maintaining product quality in refined methanol production.Implementation of optimal control strategies can reduce unit consumption and increase yield.