第29卷Vol 29 No. 2OLRNAL OF FLEL CHEMISTRY AND TECHNOLOGY文章號:02532409(2001)0208104煤瀝青改質(zhì)非等溫動力學(xué)研究王錦平,水恒福,馮映桐華東冶金學(xué)院化學(xué)工程系,安徽嗎鞍山243002)關(guān)鍵詞:煤焦油瀝青;中間相;非等溫動力學(xué);菲殘油中圍分類號:mQ622.65文獻(xiàn)標(biāo)識碼:A煤焦油的組成和性質(zhì)受配煤的組成和煉焦條1.2軟瀝膏的制備將寶鋼I期焦油經(jīng)離心法預(yù)件,如煤階、配比和煉焦溫度等的影響,因此各個生處理脫除其原生Q≤0.1%,再經(jīng)蒸餾制得精制瀝青產(chǎn)廠的焦油組成和性質(zhì)迥然相異。寶鋼為獲得優(yōu)質(zhì)(編號bO),以該瀝青各配加18%30%菲殘油后得到針狀焦原料,對原料改質(zhì),添加菲殘油進(jìn)行了研究。軟瀝青(編號 bpl, bp2),作為中間相轉(zhuǎn)化非等溫動力生產(chǎn)針狀焦的原料瀝青在熱轉(zhuǎn)化過程中經(jīng)歷了中間學(xué)試驗原料。所得各軟瀝青性質(zhì)如表2所示相生成階段。為了生成較好的中間相結(jié)構(gòu)和組分表1原料性質(zhì)要求原料的反應(yīng)性適中。因此,首先對原料進(jìn)行動Table 1 properties of feedstock力學(xué)研究,測定其活化能和反應(yīng)速率常數(shù)。對此國Density vis80℃Primary quinoline內(nèi)外學(xué)者進(jìn)行了較多的研究,均得出了煤焦油瀝青FeedstockAsh/%insoluble/ %c的中間相生成為一級反應(yīng), Honda等求得活化能為-CTP1.1720.08147-189kJ/mol, n Huttinger等得出活化能為186kPRO1433.62m(Ar)和183kJml(H2)2。水恒福等對煤焦油瀝 tar pitc; o-phenanthrene residue o青進(jìn)行試驗,結(jié)果表明該反應(yīng)可表示為自催化反應(yīng),表2軟瀝青性質(zhì)活化能為175.8k/mol3。以上這些研究大都為等Table 2 properties of coal tar pitches sadie溫動力學(xué),溫度不超過40℃,而對于包含中間相在 mple Softening Content of Ultimate analysis w%,d40℃之后的重排、固化、分解等反應(yīng)特征的整個中.pm℃QW% c H s o(diff)0.4692.374.981.040.490.12間相生成過程研究較少。本文采用寶鋼Ⅰ期焦油l410.6292.424.811.020.461.29配加菲殘油改質(zhì)通過非等溫動力學(xué)研究,對400℃bp2390.7192404901010.471.25500℃的中間相生成全過程特征進(jìn)行了探討。為了解幾種瀝青結(jié)構(gòu)差異,采用Knr公司產(chǎn)ⅴPO1實(shí)驗部分分子量測定儀測定其分子量, BrukeTAn0核磁共振儀1.1實(shí)驗原料采用寶鋼I期焦油、菲殘油為原進(jìn)行HNM分析運(yùn)用B-L法計算結(jié)構(gòu)參數(shù),對瀝料,其性質(zhì)如表1所示。青結(jié)構(gòu)進(jìn)行表征。所得各瀝青的結(jié)構(gòu)參數(shù)列于表3表3軟瀝膏及菲殘油結(jié)構(gòu)參數(shù)Table 3 structural parameters of soft pitch and PROSampleCP C/CA RAb1022.014.20.93420.512.30.605085.650.570.981.47pl23414.60.94222.012.70.585666.100.440.751RRO14.411.40.9013.19.60.742.733.140.410.831.58Cr- total carbons per average molecule Hr -total hydrogens per aver中國煤化工CA aromaticcarbons per average molecule; CP-peripheral carbons in mucleus; CP/CAage molecule: Rr- total rings per average molecule: Ro-naphthenic riCN MHGstituents on aro-matic nucleus per average molecule; l-average carbons per alkyl side chain收稿日期:2000024:修回日期:20001-13金項目:安徽省自然科學(xué)基金作者簡介:工錦平(1975),男,江西東鄉(xiāng)人,硬士研究生,化學(xué)工藝專業(yè),主要從事煤焦油的深加工和炭材料的開發(fā)燃料化學(xué)學(xué)報卷13中間相熱轉(zhuǎn)化試驗瀝青中間相熱轉(zhuǎn)化試驗應(yīng),則積分處理公式為:在8×φ25×265試管爐中進(jìn)行,用A708P智能溫控儀控制加熱,從400℃起以恒定的升溫速率加熱In(lo-MV)=2.(1-D )exp(-p)直至終溫。然后測定中間相瀝青中的中間相含量兩邊取自然對數(shù)并整理:中間相產(chǎn)率采用下式計算In(lo1r1(1)=如中間相產(chǎn)率=中間相含量×殘留物產(chǎn)率式中各向同性基質(zhì)l,中間相產(chǎn)率M,揮發(fā)份V升2非等溫動力學(xué)數(shù)據(jù)處理函數(shù)溫速率β和溫度均可由實(shí)驗測得中問相轉(zhuǎn)化過程就是瀝青中各向同性基質(zhì)(1)轉(zhuǎn)化為各向異性的中間相(M),同時析出揮發(fā)分?jǐn)?shù)據(jù)處理時,首先以加(mMY)對1/r(V)的這樣一個過程,該過程可表示為:作圖時,由直線斜率可求出初始活化能B0,然后把Bn代人1(M)(12B)中,并以血(則根據(jù)質(zhì)量速率方程有:hM2)h(12R)(注:令其等于Y值)對1/T=k(Iu-M-V(1)作圖,根據(jù)斜率求出一個新的Ea,如此反復(fù)疊代,直其中,為光學(xué)各向同性基質(zhì)含量,=FM0,M為瀝到前后的a值相差小于103為止(瀝青中問相轉(zhuǎn)青由室溫升至400開始恒速升溫時的中間相產(chǎn)率化動力學(xué)曲線見圖1)求出最終的Fa后,根據(jù)最根據(jù) Arrhenius定律有終的直線截距與h[RA/(BEa)]求出指前因子A(2)積分法求得的結(jié)果見表4在恒速升溫條件下升溫速率為:3=d7/dt(3)l】5把(2)、(3)代入(1)式,整理并兩端積分:dM A(4)-13.5若反應(yīng)級數(shù)n=1時,則(4)式左邊積分得:0(l0-Mv)In(Lu-M-v)若反應(yīng)級數(shù)n=m時,則(4)式左邊積分得1261.301341.381.421461.500(J-MV)”你了(b-MV)m)(6)l7·10°方程(4)式右邊在數(shù)學(xué)上為不可積函數(shù),對其采圖1瀝青中間相轉(zhuǎn)化動力學(xué)曲線用積分近似6,得Kinetic curves for mesophase transformationRT 2Rthree coal tar pitchesexp( Rt )dT fa(- ea ) expe)(7)1)bl;(2)b0;(3)bp2根據(jù)以上(5)式與(7)式或者(6)式與(7)式,即表4三種軟瀝青中間相轉(zhuǎn)化動力學(xué)參數(shù)可進(jìn)行中間相轉(zhuǎn)化的非等溫動力學(xué)數(shù)據(jù)處理。Table 4 Kinetic parameter for mesophase transformationof three pitches3結(jié)果與討論3.1中間相轉(zhuǎn)化動力學(xué)瀝青的中間相轉(zhuǎn)化過程中國煤化工coefficient由于瀝青組成和結(jié)構(gòu)相當(dāng)復(fù)雜,反應(yīng)包括脫氫、裂CNMHGxl0-0,9977解、縮合等多步反應(yīng),同時也經(jīng)歷了中間相的形成、309.485×100.995長大、融并、重排等過程,但從總的反應(yīng)來看,國內(nèi)外99.29138075,221×10多數(shù)學(xué)者均的熱轉(zhuǎn)化反應(yīng)為一級反從圖1的曲線可以看出,三種瀝青采用積分法設(shè)瀝青的中間相轉(zhuǎn)化為級反級反應(yīng)動力學(xué)處理,擬合曲線的線性相關(guān)性較好,王錦平等:煤瀝青改質(zhì)非等溫動力學(xué)研究相關(guān)系數(shù)均在099以上,這說明三種瀝青中間相轉(zhuǎn)的中間相生成特征溫度區(qū)間△T與bpo均相差不化過程均附合一級反應(yīng)。由表觀活化能和指前因子大。表明18%菲殘油的加入對I期焦油的中間相數(shù)據(jù)可以得到三種軟瀝青的反應(yīng)速度常數(shù)表達(dá)式:轉(zhuǎn)化影響不大,30%菲殘油的加入使得瀝青反應(yīng)性k:=165×1081130加大,在熱轉(zhuǎn)化過程中中間相小球出現(xiàn)過早,不利于后期整體中間相的顯微組分形成。表6給出了三種k=9.485×10°exp(185300軟瀝青試樣熱轉(zhuǎn)化終溫殘留物的光學(xué)顯微組分。從長6中可以看出,bp0與bpl相比,對針狀焦不利的k,=521×10ecp(-130小片和鑲嵌結(jié)構(gòu)數(shù)目及對針狀焦生產(chǎn)有利的粗纖維瀝青中間相的轉(zhuǎn)化過程一般包括中間相小球體和大片結(jié)構(gòu)數(shù)月差不多,bp2與bp0相比,則小片和的生成、長大、遷移、融并、重排和整體中間相形成等鑲嵌結(jié)構(gòu)明顯增多,增加了15.5%,可見,由于菲殘過程,在此過程中發(fā)生了裂解、脫氫縮合、氫轉(zhuǎn)移等多種復(fù)雜反應(yīng)。因此只能從宏觀上描述中間相生成特征:從瀝青的動力學(xué)參數(shù)可以看出,bpO的活化能為180.02kJ/mol,加入18%菲殘油的bpl活化能為185.30k/mol,基本上與bp0活化能接近。加入30%菲殘油的bp2活化能為138.07kJ/mol,與bpo相比明顯降低,叮見30%非殘油的加入提高了原料瀝青的反應(yīng)性,使得原料瀝青的中間相生成速率明400420440460480500顯加快,這對于中間相生成過程是不利的。Temperature f/℃3.2原料瀝青結(jié)構(gòu)分析從原料瀝青的結(jié)構(gòu)參數(shù)(表3)來看,各原料瀝青的芳香度均在090以上,由25個芳環(huán)組成的芳核,周圍有一定數(shù)量的烷基側(cè)鏈,且側(cè)鏈長度較短,平均長度不超過2個碳原子,幾60種原料的組成具有一定的差異。以bp0(即期焦油瀝青)為比較基準(zhǔn),菲殘油與之相比,總體上者結(jié)構(gòu)相似取代基長度和數(shù)目相近,但芳香度較低為0910分子的平面性稍差。對中間相轉(zhuǎn)化過程具有重要影響的環(huán)烷數(shù)有所降低,這對中間相轉(zhuǎn)化過程不利。60480500bp1所得瀝青結(jié)構(gòu)與bp0相近,沒有對期原料焦油瀝青的結(jié)構(gòu)產(chǎn)生太大的變化,故對中間相形成過程影響不大:但由于菲殘油的壞烷數(shù)較少,加入30%的菲殘油則明顯改變了期焦油瀝青的結(jié)構(gòu),提高了其反應(yīng)飛/性,加快了中間相轉(zhuǎn)化的速率。對中間相生成已經(jīng)產(chǎn)生不利的影響。因此,在對期焦油用菲殘油改質(zhì)時,菲殘油的加入量應(yīng)加以控制3.3中間相熱轉(zhuǎn)化曲線中間相小球體的形成、長大、融并、重排、固化一般是在400℃~500的溫度中國煤化工50區(qū)間內(nèi)進(jìn)行,在此溫度區(qū)間恒速升溫的熱轉(zhuǎn)化曲線CNMHG如圖2所示。從圖2的曲線中可以得出中間相生成圖2三種瀝青中間相(殘留物)產(chǎn)率與熱轉(zhuǎn)化時間的關(guān)系的特征溫度,如表5所示。從表5可以看出,bpl與 Figure2 Relation between mesophase( residue) yield and timbp0的To、Ts接近,bp2與bp0的To、7s則差別較of thermal reaction of(a) bpO;(b)bpl:(c) bp2大,了要喜,6℃c,7x小14,面(1)-mesophase yield:(2)-residue yield29卷表5中間相轉(zhuǎn)化特征溫度油加入的量過大使得原料的反應(yīng)活性加大,生成中Iahk5 Characteristic temperature of mesophase transformation間相小球體過早,最終不利于中間相的轉(zhuǎn)化過程。Characteristic temperature△Ts4結(jié)論435.8459,0(1)瀝青中間相轉(zhuǎn)化過程可以用級反應(yīng)動力433.5460.5478,0學(xué)來描述。采用積分法處理的實(shí)驗結(jié)果,反映了整428.2472.844.6個中間相生成過程的反應(yīng)特征。表6熱轉(zhuǎn)化終溫殘留物的光學(xué)顯微組分(2)采用非等溫動力學(xué)所得寶鋼I期焦油瀝青Table 6 Optical microstructure component of thermal-conversion的中間相生成活化能為180.02/mol(3)添加18%菲殘油的原料瀝青活化能為Sample Fine Coarse185.30kJ/mol,添加30%菲殘油的原料瀝青活化能Mosaicfibrous fibrous為13807 k/mol。30%菲殘油加入提高了原料的反4.217.567.46.53,7應(yīng)性,加速了中間相熱轉(zhuǎn)化速率,對最終生成整體中bl5.020.06326.65.2間相的顯微結(jié)構(gòu)結(jié)果有明顯不利影響。6.035.532.t: Honda H, Kimura H, Sanada Y, Optical mesophase texture and x-ray diffraction pattem of the early-stage carbonatation of pitches2. Huttinger K J, Wang JP. Kinctics of mesophase formation in a stirred tank reactor and properties of the kinetics[ J;.Carbon, 19913 Shui Hengfu, Feng Yingtong et al. Kinetics of mesophase transformation of coal tar pitch[J]. Fuel Pmcess Technol, 1998, 55(2)4. Brown J K, Ladner W P. A study of the hydrogen distribution in coal-like materials by high-resolution nuclear magnetic resonancespectroscopy a comparison with infra-red measurement and the conversion to carbon structure [ J].Fuel, 1960, 39(2):87-965. Yue C, Watkinson A P. Pyrolysis of pitch[ J]. Fuel, 1998, 77(7):695-7116.楊繼濤陳廷蕤.茂名油頁巖非等溫?zé)峤獾膭恿W(xué)研究[J.石油煉制,1983,12:41-477. Azami K, Yamamoto S. Kinetics of mesofase formation of petroleum pitch[J]. Carbon, 1994, 32(5):947-951STUDY ON NON-ISOTHERMAL KINETICS FOR MODIFIED COAL TAR PITCHWANG Jin-ping, SHUI Heng-fu, FENG Ying-tongDepartment of Chemical Engineering, East China Instinte of Metallurgy, Maanshan 243002, China)Abstract: The non- isothermal kinetics for mesophase transformation of Baogang-I coal tar pitch(I-CTP), soft pitchconsisted of 1-CTP and 18% phenanthrene residue oil(PRO)or I-CTP and 30% PRo have been studied in a thermalconversion unit. Kinetic parameters were calculated by using an integral method. Results showed that the process ofmesophase pitch transformation could be described in first order reaction. The activation energy of I-CTP is 17536k/mol. But adding 30% PRO, which improved the reactivity of I-CTP with activation energy is 138. 07 k/mol, is notbeneficial to mesophase transformationKey words: coal tar pitch; mesophase; non-isothemmal kinetics; phenanthrene residue oilFoundation item Nature Science Foundation of Anhui provinceAuthor introduction: WANG Jin-ping(I975-), male, Master StudentH中國煤化工CNMHGof coal tar pitch further