第38卷第5期化學(xué)工程vl.38N.5010年5月CHEMICAL ENGINEERING( CHINA)May 2010乙醇胺精餾過程五塔流程模擬分析李清元,朱志亮,黃明祥(上?；ぱ芯吭?上海200062)摘要:用 ASPEN1L.1化工流程模擬軟件,對乙醇胺分離工藝中的蒸氨塔、脫水塔、一乙醇胺塔、二乙醇胺塔、三乙醇胺塔進(jìn)行了模擬計(jì)算,釆用非隨機(jī)雙液體(NRTL)熱力學(xué)計(jì)算模型,并進(jìn)行了熱力學(xué)參數(shù)修正,通過調(diào)整各塔的理論板數(shù)、進(jìn)料位置和回流比,以及后二塔的塔頂回路質(zhì)量流量等操作參數(shù)得出各塔的最佳工藝條件。在最佳工藝條件下,分析了此分離過程的能耗問題。模擬結(jié)果表明:五塔流程分離得到的乙醇胺均能達(dá)到產(chǎn)品質(zhì)量要求,T藝流程合理、可靠,對工程設(shè)計(jì)和T藝操作具有較強(qiáng)的指導(dǎo)作用關(guān)鍵詞:乙醇胺; ASPEN.1;精餾;模擬分析中圖分類號:TQ028文獻(xiàn)標(biāo)識碼:A文章編號:10059954(2010)0508704Simulation analysis of ethanolamine distillation process of five columns flowLI Qing- yuan, ZHU Zhi-liang, HUANG Ming-xingShanghai Research Institute of Chemical Industry, Shanghai 200062, China)Abstract: The design and optimization were carried out for ammon distillation column, dehydeethanolamine column, diethanolymine column and triethanolmine column in the ethanolamine separation process bythe chemical simulation software of ASPENIl. 1 model respectively. Non-random two liquids NrTLthermodynamic calculation model was adopted and somewhat thermodynamics parameters were modified. Howevertheoretical perfect plates, feed stage, and reflux ratio were calculated and the operating parameters of top reflux ofthe two latter columns were adjusted in order to get optimal results for five columns. Under the optimum conditionsthe energy consumption in the distillation was analyzed. The results demonstrate that the ethanolamine products offive-column process meet the quality requirement. The process is reasonable and reliable, and has some referencesignificance for engineering and operationKey words: ethanolamine; ASPEN ll. 1; distillation; simulation analysis乙醇胺是一乙醇胺(MEA)、二乙醇胺(DEA)、1乙醇胺精制五塔流程工藝簡述乙醇胺(TEA)的統(tǒng)稱,是重要的精細(xì)化工原料乙醇胺五塔精餾工藝流程依次由脫氨塔、脫水被廣泛用于合成洗滌劑、各種氣體的吸收劑及乳塔、一乙醇胺塔(簡稱一乙塔)、二乙醇胺塔(簡稱二化劑,也可用于紡織工業(yè)作增白劑、軟化劑、清凈乙塔)、三乙醇胺塔(簡稱三乙塔)組成。原料經(jīng)預(yù)劑,還可用于合成醫(yī)藥驅(qū)蟲藥,建筑水泥增強(qiáng)劑,熱后進(jìn)脫氨塔,脫氨塔采用加壓操作,控制塔底溫度制備染料和合成橡膠的中間體等。另外,乙醇·不高于200℃,經(jīng)過脫氨塔分離塔頂餾出大部分氨胺在國防工業(yè)也有著重要的用途,用作火箭的除氣,經(jīng)過冷卻后進(jìn)入儲罐。塔底物料進(jìn)蒸發(fā)器,進(jìn)一灰劑和燃料組分。步脫氨,蒸發(fā)器底部物料進(jìn)脫水塔,經(jīng)過脫水塔分隨著國內(nèi)外乙醇胺需求量的增加,研究高效離,塔頂分離出水,塔底含有乙醇胺和聚合物,然后分離工藝的可行性有著重要的意義。本文采用進(jìn)入一乙塔塔頂?shù)玫礁呒兌纫掖及樊a(chǎn)品,塔底物料ASPEN1.1化工流程模擬軟件,對乙醇胺精餾五進(jìn)入二乙塔,由于含有少量的一乙醇胺,在二乙塔塔塔流程進(jìn)行了模擬計(jì)算與分析,確定了工藝優(yōu)化頂餾操作條件。中國煤化工塔進(jìn)料物流混合采出高純度二乙CNMHG作者簡介:李清元(1978-),男,碩士工程師從事化工過程分離模擬研究工作,電話:13636460881,(021)52804906,E-mail:lish3600@88化學(xué)工程2010年第38卷第5期醇胺產(chǎn)品。塔底物料進(jìn)入三乙塔,同樣由于含有少度三乙醇胺產(chǎn)品,塔底產(chǎn)品含有少量聚合物冷卻到量二乙醇胺進(jìn)入三乙塔,塔頂物流和二乙塔進(jìn)料物室溫后裝罐。乙醇胺五塔精餾工藝流程如圖1流混合后進(jìn)入二乙塔。在三乙塔上部側(cè)線采出高純所示。氣乙醇胺原料乙醇胺乙醇酸拿聚合物圖1乙醇胺精餾五塔流程Fig. 1 Ethanolamine five-column rectifing flowsheet diagram2乙醇胺原料組成時塔底溫度為195-189℃。由于脫氨塔底物料還乙醇胺原料組成如表1所示。含有一定量的氨,直接加入脫水塔會影響脫水塔的分離效果和熱負(fù)荷,由此脫氨塔底物料經(jīng)過一個蒸發(fā)器表1乙醇胺原料組成后蒸出剩余的氨然后進(jìn)入脫水塔分離。脫水塔采Table 1 Crude ethanolamine compositions用13塊理論板(包括冷凝器和再沸器,下同),進(jìn)料位氨氣環(huán)氧乙烷水一乙醇胺置在第4塊塔板,操作壓力為17.3kPa,脫水塔采用沸點(diǎn)/℃33.5170.3低壓操作控制塔底物料溫度不高于140℃,經(jīng)過脫質(zhì)量分?jǐn)?shù)%400.00132.52·46—水塔的分離,水基本從脫水塔塔頂餾出二乙醇胺三乙醇胺聚合物210沸點(diǎn)℃268.4335.4300-500質(zhì)量分?jǐn)?shù)%23.450.33模擬模型建立乙醇胺精餾工藝過程是一個復(fù)雜的多組分汽液相平衡(2),采用非隨機(jī)雙液體(NRTL)熱力學(xué)計(jì)算模型,并對各塔進(jìn)行了熱力學(xué)參數(shù)修正,通過參數(shù)優(yōu)140120140160180200220240化確定了各塔進(jìn)料位置、回流比和側(cè)線采出位置。塔底氨質(zhì)量流量/(kg·h)采用 DSWTU模塊對各塔估算所需的最小理論板圖2塔底氨質(zhì)量流量和溫度關(guān)系數(shù),據(jù)此確定所需的理論板數(shù)ation of ammoniaow with temperature at column bottom模擬過程4.2乙醇胺塔4.1脫氨塔和脫水塔同樣乙醇胺塔也采用低壓操作,一乙塔采用脫氨塔采用5塊理論板(包括再沸器),原料預(yù)5塊理論板進(jìn)料位置在第3塊板操作壓力約為熱后在塔頂加入,操作壓力1.55MPa,脫氨塔采用加1kPa,經(jīng)過一乙塔塔頂?shù)玫劫|(zhì)量分?jǐn)?shù)約為99.8%壓操作主要是為了提高混合氨氣的冷凝溫度,以便可的一乙醇胺產(chǎn)品,塔底物料自流進(jìn)入二乙塔。二乙用工藝水來冷凝,從而降低冷凝劑制冷能耗。塔頂蒸塔采用10塊理論板,進(jìn)料位置在第7塊板操作壓出大部分的氨調(diào)節(jié)塔底氨質(zhì)量分?jǐn)?shù),由于乙醇胺具力為V凵中國煤化工少量的一乙醇胺有熱敏性控制塔底溫度不高于200℃,塔底氨質(zhì)量進(jìn)入CNMHG頂蒸出少量的流量和塔底溫度如圖2所示。隨著氨質(zhì)量流量的增乙醇胺,通過調(diào)節(jié)塔頂流量使進(jìn)入的一乙醇胺完全加塔底溫度下降,當(dāng)氨質(zhì)量流量為110-120kg/h脫除,然后返回一乙塔進(jìn)行分離在二乙塔第3塊板李清元等乙醇胺精餾過程五塔流程模擬分析側(cè)線采出質(zhì)量分?jǐn)?shù)為9.86%的二乙醇胺產(chǎn)品,塔5.1模擬操作參數(shù)和物料平衡結(jié)果底物料自流進(jìn)入三乙塔。三乙塔采用16塊理論板,物料平衡見表2,各塔的主要操作參數(shù)模擬優(yōu)進(jìn)料位置在第11塊操作壓力為0.4kPa,同樣調(diào)節(jié)化值見表3。塔頂物流采出量,然后返回到二乙塔進(jìn)行分離,由于對三乙醇胺產(chǎn)品質(zhì)量要求不同,在該塔分離得到表2物料平衡2個不同級別的產(chǎn)品。在三乙塔第4塊板側(cè)線采出Table 2 Material equilibrium質(zhì)量分?jǐn)?shù)為99.93%的三乙醇胺產(chǎn)品,塔底產(chǎn)品三流量進(jìn)料類別組分收率/%乙醇胺質(zhì)量分?jǐn)?shù)為90%,含有少量的聚合物,冷卻到室溫后裝罐。進(jìn)方粗乙醇胺7666.365.52氨水3282.512.3642.5模擬結(jié)果分析乙醇胺產(chǎn)品2021.211.4626.36模擬采用某廠生產(chǎn)精乙醇胺2.2萬ta,年操作出方二乙醇胺產(chǎn)品1800.041.3023三乙醇胺產(chǎn)品7200h,粗乙醇胺總進(jìn)料量為3835kgh,重要工藝合計(jì)7666.365.52100指標(biāo):乙醇胺產(chǎn)品純度均達(dá)到99.8%質(zhì)量指標(biāo)。表3模擬優(yōu)化各塔主要工藝操作參數(shù)結(jié)果Table 3 Optimized results of main process operation parameters of columns蒸氨塔脫水塔乙塔二乙塔三乙塔理論板數(shù)10回流比(質(zhì)量比)0.582.860.2135.58進(jìn)料位置塔頂壓力/kP1549.8塔底壓力/kPa1550.118.1進(jìn)料溫度/℃143.4180.3塔頂溫度℃147.6塔底溫度/℃192.9133.5180.2194.3冷凝器負(fù)荷/(k·h-)666434.12410012.4-1604238.0-3343878.8再沸器負(fù)荷/(k·h1917905.2451498.52070663.31551741.43344418.05.2產(chǎn)品質(zhì)量分析產(chǎn)品質(zhì)量如表4所示表4產(chǎn)品質(zhì)量Table 4 Quality of products乙醇胺產(chǎn)品二乙醇胺產(chǎn)品三乙醇胺產(chǎn)品1三乙醇胺產(chǎn)品2產(chǎn)品質(zhì)量流量/(kg·h2021.211800.04233.6副產(chǎn)品質(zhì)量流量/(kg·h-)(一乙醇胺)/%1(二乙醇胺)%v(三乙醇胺)%(聚合物)/(水)/%5.850.17中國煤化工一乙醇胺回收率/%二乙醇胺回收率/%CNMHG三乙醇胺回收率/%化學(xué)工程2010年第38卷第5期表4中氨水主要由脫氨塔塔頂汽和蒸發(fā)器氣相五塔精餾工藝流程進(jìn)行模擬研究,對各種工況操作物料以及脫水塔塔頂物料冷卻混合后組成,氨水中條件和各種工藝流程都可以有效地進(jìn)行比較,然后主要含有氨和水以及微量的一乙醇胺。一乙醇胺產(chǎn)確定最佳值。品代表一乙塔塔頂產(chǎn)品,二乙醇胺產(chǎn)品代表二乙塔(2)通過模擬計(jì)算可知,乙醇胺五塔精餾工藝流側(cè)線產(chǎn)品,三乙醇胺產(chǎn)品1代表三乙塔側(cè)線產(chǎn)品,三程合理,對工程設(shè)計(jì)和工藝操作具有較強(qiáng)的指導(dǎo)作乙醇胺產(chǎn)品2代表三乙塔塔底產(chǎn)品。由表4可看用,有效節(jié)能對工藝的操作費(fèi)用可以有較大的降低。出,乙醇胺產(chǎn)品均能達(dá)到質(zhì)量要求。(3)模擬計(jì)算中選擇合適的熱力學(xué)模型,同時5.3模擬工藝耗能分析對熱力學(xué)模型進(jìn)行適當(dāng)?shù)膮?shù)修正,這對冷凝器和乙醇胺精餾五塔塔底溫位不同需要采用不同再沸器的熱負(fù)荷有直接影響可以顯著降低冷凝器壓力的高溫水蒸氣來供給熱量蒸氨塔和三乙塔采和再沸器熱負(fù)荷用的高溫高壓蒸汽可以再用來給脫水塔供熱,這樣(4)模擬過程中,可以對各塔進(jìn)行參數(shù)優(yōu)化,降可以節(jié)省一部分蒸汽消耗,同時利用二乙塔和三乙低塔的熱負(fù)荷,也可以有效提高塔的分離效率。同塔塔頂冷凝熱來預(yù)熱總進(jìn)料至90℃,這樣可以節(jié)省時利用二乙塔和三乙塔頂冷凝熱來預(yù)熱進(jìn)料以及采部分工藝用水。用脫氨塔和三乙塔加熱蒸汽來供給脫水塔熱量,可由表3可以看出,二乙塔和三乙塔回流比較大,以有效提高熱能利用。分別為30.38和35.58,在塔頂冋路質(zhì)量流量分別在50-100kg/h的情況下,仍需要較大回流比,這就增加了塔頂塔底的熱負(fù)荷,在乙醇胺精餾工藝能參考文獻(xiàn):[1]賀繼銘國內(nèi)外乙醇胺生產(chǎn)現(xiàn)狀及發(fā)展趨勢[].石油耗中占有較大的比重,仍有可以調(diào)節(jié)的余地?；ぜ夹g(shù)經(jīng)濟(jì),2007,23(4):5862每t精乙醇胺耗冷卻水量為3141t,每,[2]郭天民多元?dú)庖浩胶夂途s([M北京:石油工業(yè)出版社,2002精乙醇胺消耗飽和蒸汽[0.8MPa(g)]量為1.05t。[3]宋海華多級分離理論(一)精餾模擬[M].天津*:天津大學(xué)出版社,20056結(jié)論4]陳敏恒,叢德滋,方圖南等化工原理:下冊[M]北1)采用 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