發(fā)布時間：2018-04-09 22:33

  本文選題：分隔壁塔　切入點：混合醇　出處：《太原理工大學》2017年碩士論文

【摘要】：低碳醇作為重要的化工產(chǎn)品和潛在的替代燃料具有較大應(yīng)用潛力。合成氣制低碳醇是煤間接液化和清潔利用的重要手段之一,對其產(chǎn)物的分離是該技術(shù)實現(xiàn)工業(yè)化的重點。本文以課題組前期研究為基礎(chǔ),進料中甲醇265kg/h,乙醇255.8kg/h,正丙醇197.4kg/h,正丁醇110.3kg/h,要求產(chǎn)品純度均為0.99。采用先脫水后分離得到單醇的策略,利用普通精餾分離甲醇,再利用分隔壁塔分離乙醇-正丙醇-正丁醇的工藝流程�；谀M軟件Aspen Plus和Aspen Dynamics對該過程的穩(wěn)態(tài)設(shè)計和動態(tài)控制做了全面研究。通過軟件自帶函數(shù)和全年總費用法(TAC)得到了分隔壁塔最優(yōu)操作參數(shù),并找到了最佳熱集成方式和操作壓力;在穩(wěn)態(tài)運行的基礎(chǔ)上,添加流量變化±5%的恒定擾動,對比考察了4種控制結(jié)構(gòu)的動態(tài)響應(yīng)效果。主要結(jié)論如下:(1)通過軟件自帶函數(shù)對隔壁塔分離的穩(wěn)態(tài)過程進行計算和調(diào)優(yōu),在滿足分離要求的情況下對工藝參數(shù)進行優(yōu)化。研究發(fā)現(xiàn)4個參數(shù)存在最佳范圍,其中液相分配比LR最佳范圍為0.38-0.42,氣相分配比VR最佳范圍為0.6-0.63,最佳進料位置與初餾塔塔板數(shù)的比約為0.33,最佳出料位置與主塔塔板數(shù)的比為0.5;固定上述4個參數(shù)后,通過TAC法求出主塔塔板數(shù)為54塊,初餾塔塔板數(shù)為27塊,側(cè)線抽出位置為第12塊,分隔壁塔回流比為2.17。在此條件下,全年總費用174478美元。(2)以節(jié)能為目標,研究了不同的熱集成方式,發(fā)現(xiàn)兩塔最優(yōu)方式為逆流型,最優(yōu)壓力組合方式為低壓(前效壓力,0.3atm)-常壓(后效壓力,1atm)。相對于傳統(tǒng)兩塔流程,整個過程耗能265.2kW,總節(jié)能效率為51.4%。(3)采用塔頂冷凝器負荷QC控制主塔塔頂壓力,并且考慮塔板存在滯后效應(yīng),得出以下4種控制結(jié)構(gòu):LQR/DSB、LB/DSQR、DB/LSQR、DQR/LSB,來分析其抗干擾性能。在忽略液相分配量LL控制初餾塔壓力的情況下發(fā)現(xiàn)純度控制不理想,原因是初餾塔塔頂壓力的不可控。在添加LL控制初餾塔壓力后,發(fā)現(xiàn)上述4種控制策略中DB/LSQR(塔頂采出量D控制塔頂液位、塔釜采出量B控制塔釜液位、回流量L控制塔頂產(chǎn)品純度、側(cè)線采出量S控制側(cè)線產(chǎn)品純度、再沸器負荷QR控制塔釜產(chǎn)品純度)在面臨流量擾動時,控制效果最理想,且通過添加溫度-組成串級控制可以進一步縮短調(diào)節(jié)時間,減小最大偏差。
[Abstract]:Low-carbon alcohols as important chemical products and potential alternative fuels have great application potential.The synthesis of low carbon alcohols from syngas is one of the important methods for indirect liquefaction and clean utilization of coal, and the separation of its products is the focus of industrialization.Based on the previous research of our group, the purity of methanol in feed was 265kg / h, ethanol was 255.8 kg / h, n-propanol 197.4kg / h, n-butanol 110.3kg / h, and the purity of product was 0.99kg / h.The strategy of dehydration and then separation of monool was adopted, methanol was separated by ordinary distillation, and the process of separation of ethanol-n-propanol-n-butanol in the next row column was used.Based on the simulation software Aspen Plus and Aspen Dynamics, the steady state design and dynamic control of the process are studied.The optimal operating parameters of the adjacent tower are obtained by using the software self-contained function and the annual total cost method, and the optimal thermal integration mode and operating pressure are found, and a constant disturbance of 鹵5% flow rate is added on the basis of steady-state operation.The dynamic response effects of four control structures are compared and investigated.The main conclusions are as follows: (1) the steady-state process of the separation of the adjacent tower is calculated and optimized by the software self-contained function, and the process parameters are optimized under the condition of satisfying the separation requirements.The study found that there is an optimal range of four parameters.The optimum range of LR is 0.38-0.42, the best range of Vapor partition ratio VR is 0.6-0.63, the ratio of the best feed position to the number of plates in the primary column is about 0.33, the ratio of the optimal discharge position to the number of main tray is 0.5.By TAC method, the main tower plate number is 54, the primary column plate number is 27, the side line extraction position is the 12th block, and the reflux ratio of the next column is 2.17.Under this condition, the total cost of the whole year is $174478. The purpose of energy saving is to study different thermal integration methods. It is found that the optimal mode of two towers is countercurrent and the optimal pressure combination is low pressure (pre-effect pressure 0.3atmg-normal pressure).It is found that the purity control is not ideal because the top pressure of the primary distillation tower is not controllable.After adding LL to control the pressure of the primary distillation tower, it is found that among the four control strategies mentioned above, DB-LSQR (top recovery D) controls the top liquid level of the tower, the tank yield B controls the liquid level of the tower, and the reflux L controls the purity of the top product of the tower.The side line yield S controls the purity of the side line product and the product purity of the reboiler load QR control tower. When the flow is disturbed, the control effect is the most ideal, and the adjustment time can be further shortened by adding temperature and composition cascade control.Reduce the maximum deviation.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TQ223.1;TQ028.31

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本文編號：1728488