本文選題：聚氯乙烯 + 精餾��； 參考：《北京化工大學(xué)》2015年碩士論文

【摘要】：聚氯乙烯(PVC)是我國(guó)國(guó)民經(jīng)濟(jì)中不可或缺的重要原材料,由氯乙烯單體(VCM)聚合而成。目前我國(guó)PVC分離提純過程普遍存在分離效率低、產(chǎn)品純度差、能耗高、操作控制不穩(wěn)定、高附加值釜液未有效回收。對(duì)于以上關(guān)鍵技術(shù)難題,本文從工藝流程、能量集成、過程控制三個(gè)方面著手,利用計(jì)算機(jī)模擬技術(shù)對(duì)年產(chǎn)40萬(wàn)噸PVC的精餾系統(tǒng)進(jìn)行模擬分析、能量集成優(yōu)化以及動(dòng)態(tài)控制,得到最優(yōu)的工藝參數(shù)、換熱網(wǎng)絡(luò)和控制方案,達(dá)到節(jié)能減排的目標(biāo)。根據(jù)熱力學(xué)一致性檢驗(yàn)結(jié)果,驗(yàn)證了氯乙烯(VCM)-二氯乙烷(EDC)體系汽液相平衡(VLE)數(shù)據(jù)的可靠性。對(duì)NRTL、WILSON、UNIQUAC熱力學(xué)模型的交互作用參數(shù)擬合回歸,通過比較發(fā)現(xiàn)NRTL模型的模擬數(shù)據(jù)與實(shí)驗(yàn)數(shù)據(jù)的平均相對(duì)偏差最小。同時(shí)用回歸后各個(gè)模型的計(jì)算數(shù)值與工程采集值對(duì)比,驗(yàn)證了NRTL模型可以準(zhǔn)確的模擬VCM-EDC體系。對(duì)低沸塔(TQ201)、高沸塔(TQ202)和高沸物回收塔(TQ203)進(jìn)行模擬優(yōu)化。通過單因素靈敏度和正交試驗(yàn)的分析得到TQ201、TQ202塔的最佳工藝參數(shù),包括操作壓力、進(jìn)料狀態(tài)、進(jìn)料位置、回流比及餾出比。結(jié)果表明TQ201塔回流比由5.0降為3.6,節(jié)能28.0%；TQ201塔回流比由1.0降為0.6,節(jié)能40.0%。VCM產(chǎn)品純度達(dá)到99.999%,低沸點(diǎn)雜質(zhì)含量小于1 ppm,高沸點(diǎn)雜質(zhì)含量小于3 ppm。同時(shí),冷卻介質(zhì)由32℃循環(huán)水替代5℃冷凍水,節(jié)省了電耗。兩塔共節(jié)約操作費(fèi)用3472.1萬(wàn)元／年。TQ203塔采用恒回流比式間歇精餾,通過分析塔頂、塔釜及儲(chǔ)罐成分隨時(shí)間的動(dòng)態(tài)變化,產(chǎn)品收益、操作費(fèi)用和經(jīng)濟(jì)效益的影響因素,得到最佳塔板數(shù)、回流比和操作周期。最終得到質(zhì)量分?jǐn)?shù)大于99.9%的氯乙烯、質(zhì)量分?jǐn)?shù)大于99.0%的二氯乙烯和二氯乙烷,年經(jīng)濟(jì)效益為735.3萬(wàn)元,同時(shí)環(huán)境效益顯著。對(duì)于PVC精餾工段能耗較高、余熱利用不充分的問題,建立公用工程用量最低和換熱器數(shù)目最少兩個(gè)目標(biāo)函數(shù),通過分析△Tmin與設(shè)備費(fèi)、操作費(fèi)和年度總成本目標(biāo)的關(guān)系,求得最佳的△Tmin,利用夾點(diǎn)技術(shù)獲得冷、熱物流夾點(diǎn)位置和最小公用工程用量。方案一公用工程用量最低,投資回收期為6個(gè)月；方案二最大化利用現(xiàn)有設(shè)備,投資回收期為4個(gè)月,對(duì)于實(shí)際工廠改造更為適宜。對(duì)于PVC精餾工段操作控制不穩(wěn)定的問題,從產(chǎn)品純度、操作穩(wěn)定及節(jié)能環(huán)保的角度確定適用于PVC精餾系統(tǒng)的最佳控制方案。通過分析動(dòng)態(tài)數(shù)學(xué)模型,確定控制變量,對(duì)TQ201塔提出三種控制方案；對(duì)TQ202塔提出兩種控制方案；對(duì)TQ203塔提出各組分采出的控制條件。對(duì)比不同控制方案下精餾塔在受到擾動(dòng)后的動(dòng)態(tài)響應(yīng),結(jié)果表明TQ201塔更適用于回流量與餾出量比值恒定的控制,TQ202塔宜選擇回流量與進(jìn)料量比值恒定的操作。
[Abstract]:Polyvinyl chloride (PVC) is an indispensable raw material in our national economy, which is polymerized by vinyl chloride monomer (VCM). At present, the separation and purification process of PVC in China is generally characterized by low separation efficiency, poor product purity, high energy consumption, unstable operation control and inefficient recovery of high value-added kettle liquid. For the above key technical problems, this paper starts from three aspects of technological process, energy integration and process control, and makes use of computer simulation technology to simulate and analyze the distillation system with an annual output of 400000 tons PVC, and optimize the energy integration and dynamic control. The optimal process parameters, heat exchange network and control scheme are obtained to achieve the goal of energy saving and emission reduction. Based on the results of thermodynamic consistency test, the reliability of the Vapor-liquid equilibrium VLEs data of vinyl chloride (VCM) -dichloroethane (EDCC) system was verified. By fitting the interaction parameters of NRTL WILSONNU UNIQUAC thermodynamic model, it is found that the average relative deviation between the simulated data and experimental data of NRTL model is the smallest. At the same time, the calculation value of each model after regression is compared with the data collected in engineering, which verifies that the NRTL model can accurately simulate the VCM-EDC system. The low boiling tower TQ201, high boiling tower TQ202 and high boiling recovery tower TQ203) were simulated and optimized. Through the analysis of single factor sensitivity and orthogonal test, the optimum process parameters of TQ201 TQ202 tower were obtained, including operating pressure, feed state, feed position, reflux ratio and distillation ratio. The results show that the reflux ratio of TQ201 column is decreased from 5.0 to 3.6, the reflux ratio of energy-saving TQ201 tower is reduced from 1.0 to 0.6, the purity of energy-saving 40.0%.VCM product is 99.999, the impurity content of low boiling point is less than 1 ppm, and the impurity content of high boiling point is less than 3 ppm. At the same time, the cooling medium is replaced by 32 鈩，

本文編號(hào)：1814440