芳烃精制流程的模拟与控制

发布时间：2018-11-03 17:23

【摘要】：目前国内苯加氢已成为粗苯精制的必然趋势。其中萃取剂N-甲酰吗啉(NFM)以其以其优良的化学和热力学稳定性,以及无毒、无腐蚀性,越来越被国内外的学者关注。以NFM为溶剂的芳烃萃取精馏工艺也受到普遍关注。本文研究了国内外芳烃精制工艺,优选了以N-甲酰吗啉(NFM)为萃取剂的萃取精馏工艺流程。利用Aspen Plus软件,对某焦化厂的实际工艺建立芳烃萃取精馏工艺流程模型,模拟结果与工业实际状况吻合。在稳态模拟的基础上,提取出各物流数据。进而利用Aspen Energy Analyzer软件对该物流数据进行分析,确定合适的最小夹点温差。并针对此工艺流程设计出适宜的换热网络。综合考虑设备投资费用和操作费用,经过换热网络改造后,该工艺可使热公用工程的能耗降低30.93%,冷公用工程的能耗降低31.66%,在换热部分的年度总费用总费用可减少13.7%。为了满足控制精度的要求,对稳态流程进行了灵敏度分析,得到合适的理论板数、进料板位置以及回流比参数。对经过处理的稳态流程,利用Aspen Dynamic软件,分别对独立控制方案、关联控制方案进行流量和组分的扰动性能测试。独立控制方案中对各个操作单元进行独立控制,彼此间没有联系。关联控制方案有两种:一种是将初始进料作为后续所有控制单元的前馈补偿信息;另一种是将前一个操作单元的进料作为后一个操作单元的前馈补偿信息。结果表明,前馈补偿信息的远近对操作单元控制的影响也不同。最后结合两种关联控制方案中的优点,提出一种改进的控制方案。在改进的控制方案中,不仅优选了关联方案中的控制结构,并将各塔板温度控制器和塔底再沸器热负荷与进料的比值(QR/F)进行串级控制,加强了进料、塔板温度和塔底再沸器之间的联系。动态性能测试表明改进的控制方案具有较好的控制效果。
[Abstract]:At present domestic benzene hydrogenation has become the inevitable trend of crude benzene refining. Among them, the extractant N-formylmorpholine (NFM) has been paid more and more attention by scholars at home and abroad for its excellent chemical and thermodynamic stability, nontoxic and non-corrosive. The extraction distillation process of aromatic hydrocarbons using NFM as solvent has also received widespread attention. In this paper, the refining process of aromatic hydrocarbons at home and abroad was studied, and the extractive distillation process using N-formylmorpholine (NFM) as extractant was selected. The model of aromatic hydrocarbon extractive distillation process was established by using Aspen Plus software. The simulation results were in agreement with the actual industrial conditions. On the basis of steady state simulation, each logistics data is extracted. Then the Aspen Energy Analyzer software is used to analyze the material flow data to determine the appropriate minimum pinch temperature difference. A suitable heat exchange network is designed for this process. Considering the cost of equipment investment and operation, the process can reduce the energy consumption of hot public works by 30.933and that of cold public works by 31.66after the heat exchange network is reformed. The total annual cost of the heat transfer portion can be reduced by 13. 7%. In order to meet the requirements of control accuracy, the sensitivity analysis of steady state flow is carried out, and the appropriate theoretical plate number, feed plate position and reflux ratio parameters are obtained. Aspen Dynamic software is used to test the flow rate and disturbance performance of the independent control scheme and the associated control scheme respectively. In the independent control scheme, each operation unit is controlled independently and has no relation with each other. There are two associated control schemes: one is to take the initial feed forward as feedforward compensation information for all subsequent control units, and the other is to take the feedforward compensation information of the former operation unit as the feedforward compensation information of the latter operation unit. The results show that the influence of feedforward compensation information on operation unit control is different. Finally, an improved control scheme is proposed by combining the advantages of the two schemes. In the improved control scheme, not only the control structure of the correlation scheme is selected, but also the temperature controller of each tray and the ratio of heat load to feed (QR/F) of the bottom reboiler (QR/F) are controlled cascade to strengthen the feed. The relation between tray temperature and bottom reboiler. The dynamic performance test shows that the improved control scheme has better control effect.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ241

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