三相床中合成氣制二甲醚宏觀(guān)動(dòng)力學(xué)研究

天然氣化工2010年第35卷三相床中合成氣制二甲醚宏觀(guān)動(dòng)力學(xué)研究曹曉路,陳振,張海濤,應衛勇,房鼎業(yè)(華東理工大學(xué)大型工業(yè)反應器工程教育部工程研究中化學(xué)工程聯(lián)合國家重點(diǎn)實(shí)驗室,上海200237)摘要:在三相高壓攪拌釜中,使用KR型復合催化劑,在溫度為220℃-260°℃,空速為0.75Lgh-1,35Lgh',壓力為3MPa~MPa反應進(jìn)口m小m為401-49的范圍內攪拌轉速為9omin的條件下研究了合成氣一步法制二甲醚宏觀(guān)動(dòng)力學(xué)考察了溫度、空速、壓力條件的變化對反應性能的影響。選取 langmuir雙曲型動(dòng)力學(xué)模型,采用遺傳算法和單純形法對宏觀(guān)動(dòng)力學(xué)模型進(jìn)行了參數估值獲得動(dòng)力學(xué)模型的參數統計檢驗和殘差分析證實(shí)模型是適宜的。關(guān)鍵詞:合成氣;二甲醚;直接合成;XR催化劑;三相床;宏觀(guān)動(dòng)力學(xué)中圖分類(lèi)號:T013.2文獻標識碼:A文章編號:10019219(2010)01-06507在常溫常壓下,二甲醚(DME)是一種無(wú)色氣力學(xué)模型參數。體,無(wú)毒,無(wú)腐蝕性,可作為燃料和化工原料。二甲醚的十六烷值高,具有優(yōu)良的燃燒性能叫,可替代柴1實(shí)驗部分油作為車(chē)用燃料能降低尾氣中NOx的排放量。二1.1原料甲醚易壓縮,可作為替代液化石油氣(LPG)的民用原料氣是由含量99%以上的H2、N2、CO、CO2純清潔燃料。二甲醚是重要的化工原料可制備低碳氣體按一定的比例充入原料氣鋼瓶配制放置一周烯烴,生產(chǎn)乙酸甲酯、乙酸、乙酐、甲氧基乙酸等?；旌暇鶆蚝蠼?jīng)過(guò)分析組成用于實(shí)驗。實(shí)驗用復合由于其沸點(diǎn)低,可廣泛用作制冷劑氣霧劑。催化劑經(jīng)研磨至100目~150目,即粒度為0lmm二甲醚的生產(chǎn)工藝主要有:()甲醇氣相或液0154mm,然后準確稱(chēng)量催化劑,與液體石蠟油裝入相在酸性催化劑上脫水生成;(2)合成氣在具有甲反應釜混合均勻。用H2體積分數為5%的H2N2混醇合成和甲醇脫水作用的雙功能催化劑上一步法合氣程序升溫還原,升溫速率小于0℃min,在直接制取二甲醚。一步法由于雙功能催化劑的協(xié)同240℃維持10h。還原結束后在實(shí)驗溫度下切人原料效應使甲醇合成、甲醇脫水反應相互耦合,打破了氣進(jìn)行反應。熱力學(xué)平衡的限制能夠提高CO的轉化率及DME12實(shí)驗流程及主要設備固相的收率。根據反應器型式,一步法反應可在氣固實(shí)驗流程如圖1所示,原料氣經(jīng)減壓閥減壓至固定床反應器及三相淤漿反應器中進(jìn)行,三相床存所需壓力經(jīng)質(zhì)量流量計控制其流量然后經(jīng)脫氧在大量導熱性能好、熱容大的惰性液相介質(zhì)使反器脫氧后進(jìn)入反應器,反應后的氣體經(jīng)保溫帶保應與傳熱相耦合便于達到均勻的反應溫度并維持溫經(jīng)背壓閥減壓以氣體形式經(jīng)過(guò)切換閥進(jìn)人兩臺恒溫。色譜儀進(jìn)行分析,也可經(jīng)切換閥切換經(jīng)過(guò)冷凝后進(jìn)催化劑采用西南化工研究設計院的甲醇合成皂膜流量計計量尾氣。反應器為高壓自吸式攪拌和甲醇脫水雙功能XR系列催化劑,對三相床中合反應釜,該反應器的攪拌軸為中空結構,在攪拌軸成氣一步法制二甲醚的宏觀(guān)動(dòng)力學(xué)進(jìn)行了研究,考靠近密封蓋的地方開(kāi)有2個(gè)直徑3mm的孔,攪拌察了溫度、空速和壓力條件對反應性能的影響。在槳在兩圓盤(pán)之間有肋板在攪拌槳與軸連接處的兩實(shí)驗的基礎上,確定了宏觀(guān)動(dòng)力學(xué)模型,獲得了動(dòng)圓盤(pán)間有4個(gè)直徑2m的孔。其技術(shù)參數為:容積mV凵中國煤化工最高工作壓力收稿日期:200907-24;薔金項目:國家科技支撐計劃項目2006BAE02B02);作者簡(jiǎn)介:曹曉路(1983-),男,碩士生,電郵20MPCNMH G: 0-1000 rmin.caoxiaolu2007@163com;*聯(lián)系人:應衛勇,教授,電郵科氣及反應后氣體甲的H2、N2、CO、CO2均由wing@ecust.edu.cn熱導池(TCD)檢測器色譜儀分析,型號為GC900B,第1期曹曉路等:三相床中合成氣制二甲醚宏觀(guān)動(dòng)力學(xué)研究載氣為Ar氣,色譜柱規格為3m×3mm(OD)。反應后器色譜儀檢測,型號為GC900,載氣為N2,色譜柱的有機物甲醇、二甲醚等由氫火焰離子(FD)檢測規格為30m×0.32mm(OD)毛細管色譜柱。一I-Reducing gas cylinder: 2-N2 cylinder: 3-Syngas cylinder: 4-Pressure gauge: 5-PresBure reducer: 6-Mass flowmeter: 7-Ball valve: 8-Non retumvalve:9-Deoxidation vessel 10-Slurry reacter: 11-Thermocouple: 12-Back pressure regulator: 13-Six-channel switch valve; 14-Heat preservationbelt: 15-Condencer tube: 16-Separatory funnel: 17-Soap flowmeter圖1三相床合成氣制二甲醚工藝流程1.3工藝條件的影響13.1反應溫度的影響在反應壓力3MPa~TMPa,反應空速075Lg在空速為075Lgh2壓力為5MPa的條件下h-1.35Lgh",溫度220℃-260℃,攪拌器轉速為考察了溫度對反應的影響由圖2可以看出在220900mim,原料氣各組分摩爾分率為y=0.7225y%260℃的溫度范圍內,CO的轉化率隨溫度的升高而00759,yo=0.1450,y4=005660條件下考察了溫度、空速和壓力條件對反應性能的影響cO的轉化率及產(chǎn)物二甲醚和甲醇的選擇性由076下式計算:Nin co, inou /co,os.(1)0.74N,yco0.72nOu yoMEBOME N, jm -Nou cow0中國煤化工52CNMHG圖2反應溫度對Co轉化率的影響on conversion of c天然氣化工2010年第35卷上升,因為溫度升高增加了活化分子數,加快了反一DME一·M應速率,使CO的轉化率增加。圖3為二甲醚DME)和甲醇M的選擇性隨溫度的變化關(guān)系。二甲醚的選擇性隨溫度升高而提高,甲醇的選擇性隨溫度升高而降低,這是因為隨著(zhù)溫度的升高,甲醇脫水反應增強,而使二甲醚的選擇性增加,甲醇選擇性下降。0.42040071-DME一·M0.6圖5反應空速對產(chǎn)物選擇性的影響Fig 5 Effect of WHSV on selectivity of DME and133反應壓力的影響在溫度為240℃、空速為05Lgh的條件下考察了壓力對反應的影響,實(shí)驗結果見(jiàn)圖6和圖7。Temperature/t圖3反應溫度對產(chǎn)物選擇性的影響在3MPa~7MPa的范圍內,CO的轉化率隨壓力升高Fig-3 Effect of temperature on selectivity of DME andmethanol0.81.3.2反應空速的影響在壓力5MPa溫度為240℃的條件下考察了質(zhì)量空速(WHSV對反應的影響。圖4和圖5分別為CO轉化率、二甲醚和甲醇選擇性隨空速的變化關(guān)系。在WHSV=0.75Lg2h2-1.35Lgh2的范圍內,CO的轉化率隨空速的增加而下降。這是因為隨空速增加,反應氣體在催化劑上的停留時(shí)間變短,而Pressure /MPa導致轉化率下降。隨空速增加,二甲醚選擇性下降,圖6壓力對co轉化率的影響甲醇選擇性增加。Fig, 6 Effect of pressure on conversion of CO0.75DME06503中國煤化工0708091.01.11.21.314CNMH GWHSV/L·gh圖7壓力對產(chǎn)物選擇性的影響圖4反應空速對Co轉化率的影響Fig7 Enect ofe on selectivity of DMEFig 4 Efect of WHsv on conversion of Coethanol第1期曹曉路等:三相床中合成氣制二甲醚宏觀(guān)動(dòng)力學(xué)研究而升高,這是因為CO加氫反應是體積縮小的反應在反應壓力3MPa-7MPa、反應空速075Lg4h而CO變換反應前后體積不變,升高壓力有利于C0-135Lgh、溫度220℃-260℃、攪拌轉速為900r加氫反應正向進(jìn)行從而提高了CO的轉化率從總min,原料氣個(gè)組分摩爾分率為y=0.658-0708的反應講,CO加氫直接制取二甲醚的反應是體積y=076-0093105-0.171,ya005101,縮小的反應當壓力升高時(shí),有利于二甲醚的生成,催化劑質(zhì)量為75006g的條件下測得了宏觀(guān)動(dòng)力學(xué)甲醚選擇性增加,甲醇選擇性下降。數據,如表1所示。2宏觀(guān)動(dòng)力學(xué)模型及參數估值衰1宏觀(guān)動(dòng)力學(xué)數據表Table 1 Experimental data of global kineticsNo. T/C P/MPa N/mol mina Jca yoo,Yxe )se12298500000419070780.1546004965400483007950.035300621001912240.15010.004190707801546004960658700446008560.04090046400181250.1501070780.1546004960.67350.0415008940043900328001560.004190.707801546004960.67520038300922740023800158521994990.005010684201708006110.67310.0639008210023600584000786240.250000050168420.1708006110678800505008300034400464001697250.150000001068420170800611066109580041400402001598260.1501068420.17080061106620004600.1076004530.02990.0099920.16990.00419068201556010804918004110.19050063200530004370004190658201550100568004960160300460004670030711250.1000419065820.556010805830006200.158100379004230020612250006582015560.11080.5434004860.166400488005390034913250.5010000106582015601108057440.0559015630040200499026314250.13.9900001065820.155601108060250063201463003290045001915250.1300000501065820.15560110806200007850.1406002560035900125162399601070340.153100506063090.0392008340046900489002940041907034015310050606537004400085200395004470017318240.1401000419070340531000606641005230088000328004260006619220.0502000419070340153100506063640055200708002470079300172202299501070340.153100506065680.04750081100313005770012021240.05.010.00419070340.153100506066090.040088500375004300011322240.1501070340.15310.05060.6729003870092400408003340.009623240050107034015310050606744004600091100360003530005624240.1500070340.15310.05060670004570094500337003730000225240.1499070340.153100506068060.051300888002940.040400000721宏觀(guān)動(dòng)力學(xué)模型的建立此反應體系涉及的反應物及產(chǎn)物主要有6種,合成氣一步法制二甲醚反應體系的主要反應元素數為3,獨立反應數為3選取反應式(4)(5)、(6有即CO加氫反應、CO2加氫反應和甲醇脫水反應為Co+2H,PCH,OH(4)獨立反應。CO, +3H, +CH, OH+H,O選取的動(dòng)力學(xué)模型為 Langmuir雙曲型動(dòng)力學(xué)模型2CH, OHFCH,OCH, +H,oHa中國煤化工CNMHGSICofco+kco, fco, +kH, H,天然氣化工2010年第35卷k3=182005exp(dW“a+K。后。+kl0+kn陰19l6953、其中KM=18.3245exp(3997,40RTKn、Ka、K0為3個(gè)獨立反應以逸度計算的平衡23統計檢驗常數。各組分的逸度用 SHBWR狀態(tài)方程計算。式(8)至(10的統計量列于表2。當p>09,F模型中各參數用下述方程表示:10FT時(shí),模型是適宜的k,=koy exp(-E,/RT).(al, 2, 3)11)表2動(dòng)力學(xué)模型的統計量Table 2 The statistics of the global kinetics modelK=K exp E/RT).(i=CO, CO, Ha CH OH) (12) Equation Mr10xFT其中: ka KaCie均為參數099522模型參數估值170995452468255(10)09961410.19628以CO、CO2、DME為關(guān)鍵組分,給定參數初值和關(guān)鍵組分的出口摩爾分率可由式(8)、(9)、(10)計算表中M為實(shí)驗組數,MP為參數個(gè)數決定性指出一定反應條件下的反應速率。三相床反應器是全標p2的計算式如下式混流反應器,3個(gè)獨立反應的反應速率又可以表示p2=1-2∑-n)/∑成催化劑質(zhì)量及進(jìn)出口摩爾流量和關(guān)鍵組分進(jìn)出口摩爾分率的函數:F為回歸均方和模型殘差均方和之比。(14∑(-,)3/M-M)FT為顯著(zhù)水平為5%的相對自由度下的F表值。(15)24殘差分析將反應速率的實(shí)驗值與模型計算值的殘差對參數估值時(shí),選取關(guān)鍵組分出口反應速率的計算值和實(shí)驗值的加權殘差平方和的最小值為目標函數盡(y-6o)2+wo(oy-y(16)用遺傳算法和單純形法相結合的方法進(jìn)行參數估值,得到模型參數如下:3675869k1=11487537exp(中國煤化工一1CNMHgmn=82331c9Px90503圖8殘差圖Fig8 The residual error of Too第1期曹曉路等:三相床中合成氣制二甲醚宏觀(guān)動(dòng)力學(xué)研究圍內,隨著(zhù)壓力增加C0轉化率提高,二甲醚選擇性增加,甲醇選擇性下降。(2)選取了 Langmuir雙曲型動(dòng)力學(xué)方程,利用遺傳算法與單純形法相結合進(jìn)行了參數估值,通過(guò)數理統計的檢驗,實(shí)驗值與模型計算值吻合較好,表明模型是適宜的。符號說(shuō)明45E反應活化能kmof逸度MPa;k-反應速率常數;K-吸x105/mog·mio附平衡常數;N-摩爾流量, mol. min;P-壓力MPa;r-反應速圖9@殘差圖率 mol ming2;S-目標函數;溫度,℃;T-溫度,K;-目標函數中組分權值;即一催化劑質(zhì)量,g;x-轉化率;y-摩爾分率BFig 9 The residual error of roa選擇性;-偏離平衡系數下標:c-模型計算值;DME-二甲醚;-組分;-反應器進(jìn)口;M-甲醇;out-反應器出口;w-水參考文獻倪維斗,靳暉,李政等二甲醚經(jīng)濟是解決中國能源與環(huán)境問(wèn)題的關(guān)鍵選擇科技導報2002,(:58-602 Adachi A, Komoto M, Watanabe Let al, Eective utilizationcoal through dimethyl ether synthesis [].Fu2000,79:229-234.[3] Takeguchi T, Yanggisawa K, Inui T, Inoue M Efect of theconversion on the hybrid catalysts composed of Cu-Zn-Ga圖10殘差圖and solid acids [). Appl Catal A, 2000, 192: 201-209Fig 10 The residual error of roM]常雁紅,韓怡卓,王心葵二甲醚的生產(chǎn)、應用及下游產(chǎn)品的開(kāi)發(fā)天然氣化工,2000,253):4549計算值作圖,如圖89、10所示,殘差分布在0%水5王表良,王金福刁杰等漿態(tài)床二甲醚合成中的過(guò)程耦平線(xiàn)的兩側,表明動(dòng)力學(xué)模型計算值與實(shí)驗值吻合合協(xié)同效應卩化學(xué)反應工程與工藝,2001,17(3):233較好。237.[6] Peng X D, Toseland B A, Tijim P J AKinetic understanding3結論f the chemical synergy under LPDME condition(1)在0.5L的高壓攪拌反應釜中,壓力3MPaoncethrough applications UChem Eng Sci1999, 54: 278727927MPa、質(zhì)量空速075Lgh-1.35Lg!h、溫度四劉宏偉,劉殿華,應衛勇三相床中含氮合成氣直接合成220℃-260℃、攪拌器轉速為900mn4,原料氣各組二甲醚門(mén)石油化工,2004,334):3l1-315分摩爾分率范圍y=06580723,yx=0076-093,{8]聶兆廣,劉殿華應衛勇等三相床中雙功能混合催化劑y=0.1450.171,ya4=0.051-0.1測定了宏觀(guān)動(dòng)力上含氮合成氣直接制取二甲醚的宏觀(guān)動(dòng)力學(xué)化學(xué)反學(xué)數據。并對催化劑性能隨工藝條件的變化進(jìn)行了應工程與工藝2004,30(1):11-14考察,在實(shí)驗溫度范圍內,隨著(zhù)溫度上升,CO轉化9張琦,楊靜,應衛勇,房鼎業(yè)合成氣合成二甲醚平衡轉率提高,二甲醚選擇性增加甲醇選擇性下降。在實(shí)10化率及選擇性計算模型化學(xué)工程,2005,32):6468中國煤化工據處理與實(shí)驗設計驗空速范圍內,隨著(zhù)空速增加,CO轉化率降低,二甲醚選擇性下降,甲醇選擇性增加。在實(shí)驗壓力范CNMHG石化出原社,202天然氣化工2010年第35卷Global kinetics of dimethyl ether direct synthesis'from syngas in three-phase slurry reactorCAO Xiao-Lu, CHEN Zhen, ZHANG Hai-tao, YING Wei-yong, FANG Ding-ye(Engineering Research Center of Large Scale Reactor Engineering and Technology of Ministry of Education, State Key Laboratory ofChemical Engineering, East China University of Science and Technology, Shanghai 200237, China)Abstract: The global kinetics of direct synthesis of dimethyl ether (DMe) from syngas was investigated in a high-pressure stirredtank under the conditions of temperature 220C-260'C, space velocity 0.75L-g' b-135 L-g. h, pressure 3MPa-7MPa, molar ratioH, to CO in the feed gas 4.01-4.59, and stir speed 900, min-1. The XR dual function catalyst was used. The effects of temperature,space velocity and pressure on the reaction were studied. The hyperbolic kinetic model based on Langmuir's theory of adsorptionwas selected. The genetic algorithm combined with simplex method was utilized to estimate the parameters of the kinetic equations toobtain a global kinetic model. Statistical tests and residual analysis confirmed that the model is appropriateKey words: syngas; dimethyl ether; direct synthesis; XR catalyst; three-phase slurry reactor, global kinetics(上接第5頁(yè))Catal Today,2004,96:155-160.模型門(mén)煤炭轉化,1994,17(2):1412] Zeng D L Yang J, Wang J Q, et al Solid-state NMR studies圖]齊國禎謝在庫,鐘思青等甲醇制低碳烯烴(MT0)反of methanol-to-aromatics reaction over silver exchange應熱力學(xué)研究石油與天然氣化工,2005,34(5):349HZSM-5 zeolite[J]Microporous Mesoporous Mater, 2007, 98353.214-219⑨9]楊明平羅娟甲醇制低碳烯烴反應體系的熱力學(xué)計算3 Bjorgen M, Svelle S, Joensen Fet al. Conversion of分析U煤化工,200836(3):448methanol to hydrocarbons over zeolite H-ZSM5: On the o-[10]于海衛劉盛林,劉偉成等汽油中烯烴異構和芳構化偶rigin of the olefinic species Catal, 2007, 249: 195-207.合熱力學(xué)分析門(mén)石油學(xué)報(石油加工),2007,23(2):[4] Kanazirev V, Tsoncheva T. A study of the nonstationarycharacter of the methanol to hydrocarbons conversion[毛在砂陳家鏞化學(xué)反應工程學(xué)基礎M]北京:科學(xué)出Can J Chem,1992,70:1997-2002版社,20048-1l[5] Chang C D. A kinetic model for methanol conversion to [12] Reid R C, Prausnitz J M, Poling B E. The Properties ofhydrocarbons J).Chem Eng Sci, 1980, 35: 619-622.Gases and Liquids [M].New York: Mcgraw-Hill, Appendix[6] Sedran U, Mahay A, Delasa H IModelling methanol con-A,1987ersion to hydrocarbons: revision and testing of a simple[13]姜玄珍, Howe R F.在HZSM5沸石上甲醇轉化為汽油kinetic model[J] Chem Eng Sci, 1990. 45(5: 1161-1165.的初始產(chǎn)物分布分子催化,1994,8(3):237-241⑦杜明仙郝栩胡惠民等甲醇制汽油(MTG)集總動(dòng)力學(xué)Thermodynamic analysis for dMe conversion to n-octane and p-xylene of gasoline via light olefinsHU Qian-qian", TAN Yi-sheng, HAN Yi-zhuo, MAN Jian-ming"?(1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; 2.Graduate University of The Chinese Academy of Sciences, Beijing 100039, China)Abstract: The number of independent reactions of dimethyl ether DMe)to n-octane and p-xylene via light olefins was obtainedby atomic matrix method. Reactions heat, equilibrium constants, equilibrium relationships among the products of all those reactionswere calculated through building equilibrium relationships with the methods from literatures. The results show that most of the reac-tions are exothermic reactions. Most of the reactions in models could proceed spontaneously with high equilibrium conversion. Lowmperature and high pressure are beneficial to improve the yield of n-oct中國煤化工improve the yield of p-xylene; conversion rates of propylene to n-octaneethane and butlerThe product yield could be improved through controlling the content of proCNMHGKey words: DME to lower olefins; lower olefins to gasoline; thermodynamic calculation; n-octane; p-xylene; equilibnation