天然氣化工2010年第35卷三相床中合成氣制二甲醚宏觀動(dòng)力學(xué)研究曹曉路,陳振,張海濤,應(yīng)衛(wèi)勇,房鼎業(yè)(華東理工大學(xué)大型工業(yè)反應(yīng)器工程教育部工程研究中化學(xué)工程聯(lián)合國(guó)家重點(diǎn)實(shí)驗(yàn)室,上海200237)摘要:在三相高壓攪拌釜中,使用KR型復(fù)合催化劑,在溫度為220℃-260°℃,空速為0.75Lgh-1,35Lgh',壓力為3MPa~MPa反應(yīng)進(jìn)口m小m為401-49的范圍內(nèi)攪拌轉(zhuǎn)速為9omin的條件下研究了合成氣一步法制二甲醚宏觀動(dòng)力學(xué)考察了溫度、空速、壓力條件的變化對(duì)反應(yīng)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(duì)宏觀動(dòng)力學(xué)模型進(jìn)行了參數(shù)估值獲得動(dòng)力學(xué)模型的參數(shù)統(tǒng)計(jì)檢驗(yàn)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;宏觀動(dòng)力學(xué)中圖分類號(hào):T013.2文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):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(shù)。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(yàn)部分油作為車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?xì)怏w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(yàn)。實(shí)驗(yàn)用復(fù)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?xì)庀嗷蛞?154mm,然后準(zhǔn)確稱量催化劑,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(yīng)釜混合均勻。用H2體積分?jǐn)?shù)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(jié)束后在實(shí)驗(yàn)溫度下切人原料效應(yīng)使甲醇合成、甲醇脫水反應(yīng)相互耦合,打破了氣進(jìn)行反應(yīng)。熱力學(xué)平衡的限制能夠提高CO的轉(zhuǎn)化率及DME12實(shí)驗(yàn)流程及主要設(shè)備固相的收率。根據(jù)反應(yīng)器型式,一步法反應(yīng)可在氣固實(shí)驗(yàn)流程如圖1所示,原料氣經(jīng)減壓閥減壓至固定床反應(yīng)器及三相淤漿反應(yīng)器中進(jìn)行,三相床存所需壓力經(jīng)質(zhì)量流量計(jì)控制其流量然后經(jīng)脫氧在大量導(dǎo)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(yīng)器,反應(yīng)后的氣體經(jīng)保溫帶保應(yīng)與傳熱相耦合便于達(dá)到均勻的反應(yīng)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(tái)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(shè)計(jì)院的甲醇合成皂膜流量計(jì)計(jì)量尾氣。反應(yīng)器為高壓自吸式攪拌和甲醇脫水雙功能XR系列催化劑,對(duì)三相床中合反應(yīng)釜,該反應(yīng)器的攪拌軸為中空結(jié)構(gòu),在攪拌軸成氣一步法制二甲醚的宏觀動(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(duì)反應(yīng)性能的影響。在槳在兩圓盤之間有肋板在攪拌槳與軸連接處的兩實(shí)驗(yàn)的基礎(chǔ)上,確定了宏觀動(dòng)力學(xué)模型,獲得了動(dòng)圓盤間有4個(gè)直徑2m的孔。其技術(shù)參數(shù)為:容積mV凵中國(guó)煤化工最高工作壓力收稿日期:200907-24;薔金項(xiàng)目:國(guó)家科技支撐計(jì)劃項(xiàng)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(yīng)衛(wèi)勇,教授,電郵科氣及反應(yīng)后氣體甲的H2、N2、CO、CO2均由wing@ecust.edu.cn熱導(dǎo)池(TCD)檢測(cè)器色譜儀分析,型號(hào)為GC900B,第1期曹曉路等:三相床中合成氣制二甲醚宏觀動(dòng)力學(xué)研究載氣為Ar氣,色譜柱規(guī)格為3m×3mm(OD)。反應(yīng)后器色譜儀檢測(cè),型號(hào)為GC900,載氣為N2,色譜柱的有機(jī)物甲醇、二甲醚等由氫火焰離子(FD)檢測(cè)規(guī)格為30m×0.32mm(OD)毛細(xì)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(yīng)溫度的影響在反應(yīng)壓力3MPa~TMPa,反應(yīng)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(zhuǎn)速為考察了溫度對(duì)反應(yīng)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(nèi),CO的轉(zhuǎn)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(duì)反應(yīng)性能的影響cO的轉(zhuǎn)化率及產(chǎn)物二甲醚和甲醇的選擇性由076下式計(jì)算:Nin co, inou /co,os.(1)0.74N,yco0.72nOu yoMEBOME N, jm -Nou cow0中國(guó)煤化工52CNMHG圖2反應(yīng)溫度對(duì)Co轉(zhuǎn)化率的影響on conversion of c天然氣化工2010年第35卷上升,因?yàn)闇囟壬咴黾恿嘶罨肿訑?shù),加快了反一DME一·M應(yīng)速率,使CO的轉(zhuǎn)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?yàn)殡S著溫度的升高,甲醇脫水反應(yīng)增強(qiáng),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(yīng)空速對(duì)產(chǎn)物選擇性的影響Fig 5 Effect of WHSV on selectivity of DME and133反應(yīng)壓力的影響在溫度為240℃、空速為05Lgh的條件下考察了壓力對(duì)反應(yīng)的影響,實(shí)驗(yàn)結(jié)果見(jiàn)圖6和圖7。Temperature/t圖3反應(yīng)溫度對(duì)產(chǎn)物選擇性的影響在3MPa~7MPa的范圍內(nèi),CO的轉(zhuǎn)化率隨壓力升高Fig-3 Effect of temperature on selectivity of DME andmethanol0.81.3.2反應(yīng)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(duì)反應(yīng)的影響。圖4和圖5分別為CO轉(zhuǎn)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(nèi),CO的轉(zhuǎn)化率隨空速的增加而下降。這是因?yàn)殡S空速增加,反應(yīng)氣體在催化劑上的停留時(shí)間變短,而Pressure /MPa導(dǎo)致轉(zhuǎn)化率下降。隨空速增加,二甲醚選擇性下降,圖6壓力對(duì)co轉(zhuǎn)化率的影響甲醇選擇性增加。Fig, 6 Effect of pressure on conversion of CO0.75DME06503中國(guó)煤化工0708091.01.11.21.314CNMH GWHSV/L·gh圖7壓力對(duì)產(chǎn)物選擇性的影響圖4反應(yīng)空速對(duì)Co轉(zhuǎn)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動(dòng)力學(xué)研究而升高,這是因?yàn)镃O加氫反應(yīng)是體積縮小的反應(yīng)在反應(yīng)壓力3MPa-7MPa、反應(yīng)空速075Lg4h而CO變換反應(yīng)前后體積不變,升高壓力有利于C0-135Lgh、溫度220℃-260℃、攪拌轉(zhuǎn)速為900r加氫反應(yīng)正向進(jìn)行從而提高了CO的轉(zhuǎn)化率從總min,原料氣個(gè)組分摩爾分率為y=0.658-0708的反應(yīng)講,CO加氫直接制取二甲醚的反應(yīng)是體積y=076-0093105-0.171,ya005101,縮小的反應(yīng)當(dāng)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(cè)得了宏觀動(dòng)力學(xué)甲醚選擇性增加,甲醇選擇性下降。數(shù)據(jù),如表1所示。2宏觀動(dòng)力學(xué)模型及參數(shù)估值衰1宏觀動(dòng)力學(xué)數(shù)據(jù)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宏觀動(dòng)力學(xué)模型的建立此反應(yīng)體系涉及的反應(yīng)物及產(chǎn)物主要有6種,合成氣一步法制二甲醚反應(yīng)體系的主要反應(yīng)元素?cái)?shù)為3,獨(dú)立反應(yīng)數(shù)為3選取反應(yīng)式(4)(5)、(6有即CO加氫反應(yīng)、CO2加氫反應(yīng)和甲醇脫水反應(yīng)為Co+2H,PCH,OH(4)獨(dú)立反應(yīng)。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(guó)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(dú)立反應(yīng)以逸度計(jì)算的平衡23統(tǒng)計(jì)檢驗(yàn)常數(shù)。各組分的逸度用 SHBWR狀態(tài)方程計(jì)算。式(8)至(10的統(tǒng)計(jì)量列于表2。當(dāng)p>09,F模型中各參數(shù)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(tǒng)計(jì)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(shù)099522模型參數(shù)估值170995452468255(10)09961410.19628以CO、CO2、DME為關(guān)鍵組分,給定參數(shù)初值和關(guān)鍵組分的出口摩爾分率可由式(8)、(9)、(10)計(jì)算表中M為實(shí)驗(yàn)組數(shù),MP為參數(shù)個(gè)數(shù)決定性指出一定反應(yīng)條件下的反應(yīng)速率。三相床反應(yīng)器是全標(biāo)p2的計(jì)算式如下式混流反應(yīng)器,3個(gè)獨(dú)立反應(yīng)的反應(yīng)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(shù):F為回歸均方和模型殘差均方和之比。(14∑(-,)3/M-M)FT為顯著水平為5%的相對(duì)自由度下的F表值。(15)24殘差分析將反應(yīng)速率的實(shí)驗(yàn)值與模型計(jì)算值的殘差對(duì)參數(shù)估值時(shí),選取關(guān)鍵組分出口反應(yīng)速率的計(jì)算值和實(shí)驗(yàn)值的加權(quán)殘差平方和的最小值為目標(biāo)函數(shù)盡(y-6o)2+wo(oy-y(16)用遺傳算法和單純形法相結(jié)合的方法進(jìn)行參數(shù)估值,得到模型參數(shù)如下:3675869k1=11487537exp(中國(guó)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動(dòng)力學(xué)研究圍內(nèi),隨著壓力增加C0轉(zhuǎn)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(jié)合進(jìn)行了參數(shù)估值,通過(guò)數(shù)理統(tǒng)計(jì)的檢驗(yàn),實(shí)驗(yàn)值與模型計(jì)算值吻合較好,表明模型是適宜的。符號(hào)說(shuō)明45E反應(yīng)活化能kmof逸度MPa;k-反應(yīng)速率常數(shù);K-吸x105/mog·mio附平衡常數(shù);N-摩爾流量, mol. min;P-壓力MPa;r-反應(yīng)速圖9@殘差圖率 mol ming2;S-目標(biāo)函數(shù);溫度,℃;T-溫度,K;-目標(biāo)函數(shù)中組分權(quán)值;即一催化劑質(zhì)量,g;x-轉(zhuǎn)化率;y-摩爾分率BFig 9 The residual error of roa選擇性;-偏離平衡系數(shù)下標(biāo):c-模型計(jì)算值;DME-二甲醚;-組分;-反應(yīng)器進(jìn)口;M-甲醇;out-反應(yīng)器出口;w-水參考文獻(xiàn)倪維斗,靳暉,李政等二甲醚經(jīng)濟(jì)是解決中國(guó)能源與環(huán)境問(wèn)題的關(guān)鍵選擇科技導(dǎo)報(bào)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(yīng)用及下游產(chǎn)品的開(kāi)發(fā)天然氣化工,2000,253):4549計(jì)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)程耦平線的兩側(cè),表明動(dòng)力學(xué)模型計(jì)算值與實(shí)驗(yàn)值吻合合協(xié)同效應(yīng)卩化學(xué)反應(yīng)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(jié)論f the chemical synergy under LPDME condition(1)在0.5L的高壓攪拌反應(yīng)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(yīng)衛(wèi)勇三相床中含氮合成氣直接合成220℃-260℃、攪拌器轉(zhuǎn)速為900mn4,原料氣各組二甲醚門石油化工,2004,334):3l1-315分摩爾分率范圍y=06580723,yx=0076-093,{8]聶兆廣,劉殿華應(yīng)衛(wèi)勇等三相床中雙功能混合催化劑y=0.1450.171,ya4=0.051-0.1測(cè)定了宏觀動(dòng)力上含氮合成氣直接制取二甲醚的宏觀動(dòng)力學(xué)化學(xué)反學(xué)數(shù)據(jù)。并對(duì)催化劑性能隨工藝條件的變化進(jìn)行了應(yīng)工程與工藝2004,30(1):11-14考察,在實(shí)驗(yàn)溫度范圍內(nèi),隨著溫度上升,CO轉(zhuǎn)化9張琦,楊靜,應(yīng)衛(wèi)勇,房鼎業(yè)合成氣合成二甲醚平衡轉(zhuǎn)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(jì)算模型化學(xué)工程,2005,32):6468中國(guó)煤化工據(jù)處理與實(shí)驗(yàn)設(shè)計(jì)驗(yàn)空速范圍內(nèi),隨著空速增加,CO轉(zhuǎn)化率降低,二甲醚選擇性下降,甲醇選擇性增加。在實(shí)驗(yàn)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.模型門煤炭轉(zhuǎn)化,1994,17(2):1412] Zeng D L Yang J, Wang J Q, et al Solid-state NMR studies圖]齊國(guó)禎謝在庫(kù),鐘思青等甲醇制低碳烯烴(MT0)反of methanol-to-aromatics reaction over silver exchange應(yīng)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(yīng)體系的熱力學(xué)計(jì)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(wèi)劉盛林,劉偉成等汽油中烯烴異構(gòu)和芳構(gòu)化偶rigin of the olefinic species Catal, 2007, 249: 195-207.合熱力學(xué)分析門石油學(xué)報(bào)(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(yīng)工程學(xué)基礎(chǔ)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(zhuǎn)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(guó)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