以三甲氧基硅烷-甲醇最大共沸物萃取精馏系统为例,利用三元相图分析了传统控制策略不适用于最大共沸物萃取精馏系统过程控制的原因,在稳态计算的基础上,利用Aspen Dynamics软件建立了多种控制结构,通过引入±20%的进料流量和组成扰动考察控制结构的动态可控性。动态响应结果表明,在固定溶剂比的前提下,塔釜热负荷/进料流量前馈控制结构在超调量、响应时间等方面优于基础控制结构,但三甲氧基硅烷产品的摩尔分数为99.3%,未达到设计值。为保证产品纯度,提出一种固定萃取剂流量/产品流量的新型控制结构,该控制结构无需使用昂贵的在线组分分析仪器即可保证产品摩尔分数稳定在99.6%。

Taking trimethoxysilane-methanol maximum azeotrope extractive distillation system as an example,the reason for that the traditional control strategy is not suitable for the process control of the maximum azeotrope extractive distillation system is analyzed by means of ternary phase diagram.On the basis of steady-state calculation,different control structures are established by using Aspen dynamics software.The dynamic controllability of the control structure is investigated by using ±20% disturbances in the feed flow rate and methanol concentration.Dynamic response results show that the QR/FF (reboiler heat duty to feed flowrate ratio) feedforward control structure outperforms the basic control structure in terms of overshoot and response time under the premise of a fixed solvent ratio,but the purity of trimethoxysilane drops from 99.6 mol% to 99.3 mol%,failing to meet the design requirements.To ensure the purity of the product,a new control structure with fixed extractant flow/product flow is proposed,which can effectively ensure the purity of trimethoxysilane to be stable at 99.6 mol% without using online component analyzer.

尹民(1996-),男,硕士生