本文選題：醋酸乙烯　切入點(diǎn)：甲醇　出處：《北京化工大學(xué)》2016年碩士論文

【摘要】：目前我國(guó)聚乙烯醇(PVA)生產(chǎn)企業(yè)在生產(chǎn)過程中會(huì)產(chǎn)生大量的醋酸乙烯(VAc)和甲醇(MeOH)的共沸物,而在分離提純過程中普遍存在產(chǎn)品純度不高、萃取劑用量大、能耗高、設(shè)備投資費(fèi)用大、過程控制不穩(wěn)定等技術(shù)難題。本文從工藝流程、能量節(jié)約、過程控制、經(jīng)濟(jì)效益四個(gè)方面著手,利用計(jì)算機(jī)模擬技術(shù)對(duì)年產(chǎn)10萬噸PVA中用水作為萃取劑萃取精餾分離醋酸乙烯-甲醇共沸體系的過程進(jìn)行模擬計(jì)算、經(jīng)濟(jì)優(yōu)化及動(dòng)態(tài)控制,分別采用連續(xù)萃取精餾、間歇萃取精餾和隔壁萃取精餾三種工藝流程,通過對(duì)比獲得最佳工藝流程和最優(yōu)的工藝參數(shù)及控制方案,達(dá)到節(jié)能增效的目標(biāo)。通過熱力學(xué)一致性檢驗(yàn),驗(yàn)證了實(shí)驗(yàn)所得醋酸乙烯-甲醇共沸體系汽液相平衡(VLE)數(shù)據(jù)的可靠性。對(duì)Wilson、NRTL、UNIQUAC熱力學(xué)模型的二元交互作用參數(shù)擬合回歸,通過對(duì)比實(shí)驗(yàn)與回歸的數(shù)據(jù)偏差和圖像吻合度,得到UNIQUAC模型的效果最好。同時(shí)用回歸后各個(gè)模型的計(jì)算數(shù)值與實(shí)際生產(chǎn)數(shù)據(jù)進(jìn)行對(duì)比,驗(yàn)證了UNIQUAC模型可以準(zhǔn)確的用于醋酸乙烯-甲醇-水體系的萃取精餾模擬研究。對(duì)原有雙塔連續(xù)萃取精餾進(jìn)行模擬優(yōu)化,通過靈敏度分析及經(jīng)濟(jì)優(yōu)化,得到萃取精餾塔49塊塔板(理論板),萃取劑進(jìn)料流量17800 kg/h,溫度76℃,塔頂采出量18477 kg/h,萃取劑進(jìn)料位置第2塊塔板,物料進(jìn)料位置第18塊塔板,回流比0.27；溶劑回收塔32塊塔板,塔頂采出量12626 kg/h,物料進(jìn)料位置第22塊,回流比1.08；醋酸乙烯產(chǎn)品純度從90%提高到93.5%,甲醇產(chǎn)品純度從95%提高到99.9%；連續(xù)萃取精餾工藝的“全年總費(fèi)用”(TAC)為2370萬元/a。對(duì)于設(shè)備投資費(fèi)用大和過程控制不穩(wěn)定,采用恒定回流比的間歇萃取精餾工藝,得到間歇萃取精餾塔16塊塔板,萃取劑進(jìn)料流量24673 kg/h,溫度100℃,萃取劑進(jìn)料位置第5塊塔板,回流比10,間歇萃取精餾操作時(shí)間1.75 h；間歇萃取精餾工藝的TAC為8363萬元/a。對(duì)于能耗高,采取熱耦合精餾原理的隔壁萃取精餾工藝,得到隔壁萃取精餾塔主塔51塊塔板,萃取劑進(jìn)料流量17800 kg/h,溫度75℃,塔頂采出量18477 kg/h,萃取劑進(jìn)料位置第2塊塔板,物料進(jìn)料位置第18塊塔板,側(cè)線汽相采出位置第43塊塔板,側(cè)線汽相采出量16325 kg/h,回流比0.22；側(cè)線精餾塔30塊塔板,塔頂采出量12874 kg/h,回流比1.0；隔壁萃取精餾工藝的TAC為2037萬元/a。從經(jīng)濟(jì)角度分析,隔壁萃取精餾過程比連續(xù)萃取精餾過程固定成本投資節(jié)省約9.99%,能耗成本投資節(jié)省約14.19%,TAC減少了14.06%,隔壁萃取精餾工藝具有很大的經(jīng)濟(jì)優(yōu)勢(shì)。從動(dòng)態(tài)控制角度分析,對(duì)于連續(xù)萃取精餾過程雙溫度控制結(jié)構(gòu)更加有效,對(duì)于隔壁萃取精餾過程R/F恒定的控制結(jié)構(gòu)更有效,二者對(duì)于進(jìn)料流量擾動(dòng)和進(jìn)料組成擾動(dòng)都能產(chǎn)生較好的控制效果。綜合比較,隔壁萃取精餾過程更加適合該體系的分離。
[Abstract]:At present, a large number of azeotropic compounds of vinyl acetate (VAC) and methanol (MeOH) will be produced in the production process of polyvinyl alcohol (PVA) production enterprises in China. However, in the process of separation and purification, the purity of the product is not high, the amount of extractant is large, and the energy consumption is high.Equipment investment costs, process control instability and other technical problems.This paper starts from four aspects: technological process, energy saving, process control and economic benefits.The process of separation of vinyl acetate and methanol azeotropic system with water used as extractant in PVA with annual output of 100000 tons was simulated and calculated by computer simulation technology.By comparing the three processes of batch extractive distillation and adjoining extractive distillation, the optimal technological process, the optimal technological parameters and the control scheme are obtained to achieve the goal of saving energy and increasing efficiency.The reliability of the VLEE data of the azeotropic system of vinyl acetate and methanol was verified by the thermodynamic consistency test.The fitting regression of binary interaction parameters of Wilsonian NRTLUAC UNIQUAC thermodynamic model is carried out. By comparing the data deviation and image coincidence between the experiment and the regression, the best result of UNIQUAC model is obtained.At the same time, the calculated values of each model after regression were compared with the actual production data, which verified that UNIQUAC model could be used to simulate the extractive distillation of vinyl acetate methanol-water system accurately.Through sensitivity analysis and economic optimization, 49 trays of extraction distillation column (theoretical plate, feed rate of extractant 17800 kg / h, temperature 76 鈩，

本文編號(hào)：1712883