本文選題：共沸物分離 + 萃取精餾�。� 參考：《青島科技大學(xué)》2017年碩士論文

【摘要】：乙酸乙酯和乙腈是化工工業(yè)和制藥工業(yè)中用途廣泛的化工原料和良好的有機溶劑。本文利用特殊精餾法對乙酸乙酯-乙腈共沸物系進行分離。利用化工流程軟件Aspen Plus及Aspen Dynamics對該物系的工藝流程分別進行優(yōu)化設(shè)計及動態(tài)控制研究。最終實現(xiàn)該物系分離的嚴(yán)格經(jīng)濟優(yōu)化及穩(wěn)健的動態(tài)控制。首先提出常規(guī)雙塔萃取精餾分離法對乙酸乙酯-乙腈共沸物系進行分離,以最低年度總費用TAC(Total Annual Cost)為目標(biāo)函數(shù),設(shè)計并優(yōu)化工藝流程,獲得最佳工藝流程參數(shù),進而開始動態(tài)控制的研究。首先提出了固定回流比的基本控制結(jié)構(gòu),對其進行流量和組成的擾動,擾動結(jié)果存在乙腈產(chǎn)品純度波動過大,再沸器熱負荷的響應(yīng)速度較慢等問題,進而提出改進的回流量與進料量(R/Fn)及再沸器熱負荷與進料量(QR/Fn)比例控制的動態(tài)控制方案,該方案在對產(chǎn)品純度控制方面有明顯優(yōu)勢,最終實現(xiàn)了動態(tài)的穩(wěn)健控制。由于常規(guī)雙塔萃取精餾工藝能耗較高,而隔壁塔的節(jié)能優(yōu)勢明顯,所以將其引入萃取精餾中,探究該物系分離的萃取精餾隔壁塔的穩(wěn)態(tài)工藝流程及其動態(tài)控制。首先建立熱力學(xué)等價雙塔段模型的萃取精餾隔壁塔的分離方案,對其進行工藝優(yōu)化,與常規(guī)萃取精餾流程比較,其TAC減少約19.7%。但由于熱力學(xué)等價雙塔段模型的分離方案存在氣相分配比不易調(diào)節(jié)的缺陷,不易對其進行更靈活的動態(tài)控制研究,因此在熱力學(xué)等價雙塔段模型的基礎(chǔ)上建立了熱力學(xué)等價三塔段模型的萃取精餾隔壁塔分離方案。在穩(wěn)態(tài)模擬優(yōu)化基礎(chǔ)上對其進行動態(tài)控制研究,首先建立帶有氣相分配比的控制結(jié)構(gòu),進行流量和組成擾動。結(jié)果顯示乙酸乙酯和乙腈產(chǎn)品純度較低,所以在此基礎(chǔ)上進一步改進,固定回流比改為帶有回流量和采出量(R/Vn)前饋比例控制,添加組成控制器CC2,與氣相分配比構(gòu)成串級,進行擾動,結(jié)果顯示兩產(chǎn)品純度偏差減小,但仍達不到分離要求。對其進一步改進,在溫度控制器基礎(chǔ)上,添加QR/F比例控制,最終控制結(jié)構(gòu)對進料流量和組成的擾動都能實現(xiàn)穩(wěn)健處理。本文對乙酸乙酯-乙腈共沸物系分離的穩(wěn)態(tài)及動態(tài)控制研究將對采用特殊精餾法分離二元共沸物系的實際工業(yè)設(shè)計及生產(chǎn)控制提供一定的理論依據(jù)。
[Abstract]:Ethyl acetate and acetonitrile are widely used chemical raw materials and good organic solvents in chemical and pharmaceutical industries.The azeotrope system of ethyl acetate and acetonitrile was separated by special distillation method.The optimization design and dynamic control of the process were studied by using the chemical process software Aspen Plus and Aspen Dynamics respectively.Finally, strict economic optimization and robust dynamic control are realized.Firstly, the conventional two-tower extraction distillation separation method was proposed to separate ethyl acetate and acetonitrile azeotrope system. The minimum annual total cost TAC(Total Annual cost was used as the objective function to design and optimize the process flow and obtain the best technological process parameters.And then start the research of dynamic control.Firstly, the basic control structure of fixed reflux ratio is put forward, and the flow rate and composition are disturbed. The result of disturbance is that the purity of acetonitrile product fluctuates too much, the response speed of reboiler heat load is slow, and so on.Furthermore, an improved dynamic control scheme for reflow volume and feed volume (R / Fn) and reboiler heat load / feed ratio control is proposed. The scheme has obvious advantages in product purity control, and finally realizes dynamic robust control.Due to the high energy consumption of the conventional two-tower extractive distillation process and the obvious energy-saving advantage of the next-wall column, the steady state process and its dynamic control of the adjoining column of the separated extractive distillation column are explored.In this paper, the separation scheme of extraction distillation next door column with thermodynamic equivalent two-column model is established, and the process is optimized. Compared with the conventional extractive distillation process, the TAC is reduced by about 19.7.However, because the separation scheme of thermodynamic equivalent two-tower model is not easy to adjust the gas-phase distribution ratio, it is not easy to carry out a more flexible dynamic control study.On the basis of the thermodynamic equivalent two-column model, the separation scheme of the extraction distillation next-wall column for the thermodynamic equivalent three-column model is established.On the basis of steady state simulation optimization, the dynamic control is studied. Firstly, a control structure with gas phase distribution ratio is established, and the flow rate and composition disturbance are carried out.The results show that the purity of ethyl acetate and acetonitrile products is low, so the fixed reflux ratio is changed to feed forward ratio control with reflux and yield R / V _ n, and the composition controller CC2 is added to form cascade with gas phase distribution ratio.The results show that the purity deviation of the two products is reduced, but the separation requirements are still not met.On the basis of temperature controller and adding QR/F proportional control, the control structure can deal with the disturbance of feed flow and composition.In this paper, the steady state and dynamic control of the separation of ethyl acetate and acetonitrile azeotrope system will provide a certain theoretical basis for the practical industrial design and production control of separation of binary azeotrope system by special distillation method.
【學(xué)位授予單位】：青島科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ028.31

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