【作者】 曾涵卫；

【导师】 潘海天；

【作者基本信息】 浙江工业大学 ， 化学工程， 2011， 硕士

【摘要】 精馏塔是分离过程中应用最为广泛的一种分离混合物的设备,在石油、化工过程生产中具有举足轻重的地位。然而精馏过程是以热能的消耗来换取石油化工产品的高耗能过程,其操作的优化对于提高产品的质量、降低能耗有着重要的意义。过程模拟、控制与优化技术是提高石油化工企业的经济效益、降低生产成本的主要技术手段。但精馏过程的塔系优化问题属于大规模复杂系统的非线性规划问题,其中基于机理方法建立的模型因经较多假设与精简而失其精确性,并且目标函数构建复杂,决策变量多且耦合严重,可行域不易确定,优化操作困难,因此在实际应用中存在很大困难。本文以某化工公司直接合成法生产乙腈为案例,在熟悉乙腈合成精制的工艺基础上,分析物性方法和精馏机理,对粗乙腈三元体系分离进行工艺模拟优化和控制的研究,以寻求简易可行的优化操作方法。主要内容和结果如下:1、针对高纯乙腈连续精制过程,深入分析精馏原理,对乙腈三元体系进行热力学气液平衡计算,并且最终选择NRTL模型计算物质的热力学参数。然后将之应用于乙腈连续精制体系的模拟上,深入剖析,模拟结果与生产数据相接近,确定先进模拟系统、工艺知识和生产经验相结合可以较好模拟精馏过程。2、介绍了三元气液平衡相图,并对乙腈精馏三元共沸体系进行了研究,分析模拟数据,对模拟过程提出优化方案。主要考查进料板、压力因素、出料量和回流比等因素对乙腈产品品质及精馏过程中能耗的影响,从中找出较为可行的优化操作控制区域,并确定了最适合操作参数。3、将优化操作参数应用于生产,针对该化工厂蒸汽供应不稳,干扰较大,特别是对象存在大时滞,并具有非线性与时变性等特点提出了控制方案,并付诸实践,根据生产反馈信息,乙腈纯度达到99.9%以上,回收率达到90%以上,节约能耗达30%。更多还原

【Abstract】 As separation equipments, rectification columns are widely applied in the separation process, and they play an important role in petrochemical industry. However, petrochemicals paid energy-intensively for their production in rectification process, so the optimization of operation is significant to improve the quality of the products and reduce the energy consumption.This article attempts to take a chemical company directly synthesising acetonitrile as a case, at the base of be familiar with synthesis process of acetonitrile, analysising material properties and the mechanism of distillation, study the process simulation, optimization and control of the separation of acetonitrile ternary system, and try to find a easy way to optimizing the operation. The main content and the results are as follows: At the base of being familiar with acetonitrile synthesis process, analysising material properties and the mechanism of distillation, the process simulation, optimization and control in the separation of acetonitrile ternary system is studied, in order to find a easy way to optimizing the operation. The main content and the results are as follows:1, For the continuous refining process of high purity acetonitrile, this work deeply analyzed the mechanism of distillation, and solved the gas-liquid equilibrium equation of the ternary systems (acetonitrile-water- methanol), and employed the NRTL model to get the thermodynamic parameters of material. This method was applied to the simulation of continuous refining process of acetonitrile, the simulation results were close to practical data. This result confirmed that the combination of advanced simulation system, technology and experiences can forecast the variation of operating parameters in the rectifying process.2, The phase diagram of ternary vapor-liquid equilibrium was applied to analysis the triple azeotropic system in the distillation of acetonitrile. This work investigates the effect of stage, pressure, out stream and reflux ratio on the properties of the concentration of acetonitrile and energy consumption during distillation process, the most appropriate operation parameters were determined by the feasible control region of optimize operation. 3, The optimal parameters were applied to put forward control scheme in the production in chemical factory which had some problems such as the supplement of steam was unstable, especially existed larger time-delay which was nonlinear and time-variable. According to the feedback from production, the concentration and recovery of acetonitrile was 99.9% and 90%, respectively, while reduce energy consumption up to 30%.更多还原