王文清等小分子物質在聚烯烴粒 子內的傳質●15.Q小分子物質在聚烯烴粒子內的傳質王文清②馬青山馮連芳王凱(浙江大學材料與化工學院聚合反應工程國家重點實驗室,杭州310027)通過實驗與理論分析相結合，對小分子物質在聚合物粒子內的傳質進行了研究。傳質過程分為小分子物質在流體主體相與粒子孔洞間的傳質和小分子物質在流體主體相與聚合物相間的傳質。文中著重討論”了不同條件對后一-過程的影響，并發(fā)現(xiàn)該過程雖然由孔洞內擴散阻力控制，但其規(guī)律可用傳質系數(shù)的方法進行處理。文中還提出了一修正的Sherwood準數(shù)，對于小分子物質在流體主體相與聚合物間的傳質，可用該準數(shù)與Reynolds準數(shù)很好地關聯(lián)。關鍵詞:傳質小分子物質聚合物粒子中圖分類號: TQ021.4A聚合物工業(yè)中，涉及小分子物質在聚合物中的曲折因子 A的關系為"，傳質現(xiàn)象很多，如多相聚合反應、聚合物系脫揮、D. = D,(e/2)(1)增塑劑及其他添加劑的分散等。本研究所涉及的傳其中. λ由下式給出2，質過程包括氣相聚合反應和聚合物粒子的脫揮，它λ= of D(r)()dr(2)們共同的特點是由聚合物粒子和小分子物質組成的體系，體系壓力為常壓或低壓(<1.013 x其中,f(r)為粒子內孔徑密度分布函數(shù), ε和10'kPa),體系溫度比較低(T0. 03m/s時，粒子層D。有效擴散系數(shù)， m2/s .已經(jīng)開始鼓動，所以屬湍流傳質。DL單體在粒子內擴 散系數(shù), m2/s將Sh"對Re回歸得到D。單體在聚合物內擴散系數(shù), m2/sSh'= 0.017Re.s7(11)dp 粒子粒徑，m回歸結果如圖6所示。由圖可見，不同溫度相E。吸收_擴散活化能， J/mol同氣速下的Re和Sh'都相差很小。k Henry 系數(shù), mol/ (m' ●Pa)0.121hy傳質系數(shù), s"M單體濃度, mol/m3 .。M。飽和濃度， mol/m'0.08eg00Mgg單體平衡濃度， mol/m'M。反應器內單體濃度， molm'0.04R傳質速率, mol/ (m'●s)T溫度,C0.00T，沸點,C20 25RT。玻璃化轉變溫度,T時間，s或min圍6 Sh" 與Re回歸結果Fig,6 Calculated reults of Sh" at diferent Re5。特征時間， su表觀氣速， m/s本研究用的是沸騰床傳質,但是由上式可以看λ孔洞曲折因子出，Re的方次接近于0.5,這是層流傳質的特征。p氮氣密度，kg/m'這是因為小分子物質在聚合物粒子內的傳質，其控μ氮氣粘度，Pa.s制步驟是小分子物質在聚合物粒子空洞內的擴散，.Re Reynolds 準數(shù)而該步驟為層流傳質,所以整個過程也表現(xiàn)出層流Se Schmidt 準數(shù)傳質的特征。Sh"修正的 Sherwood準數(shù)I下轉第56頁]●56.化學工程2001 年第29卷第6期136.19 TnlebM. etal. Cstllizain of pocins under an exter12 NimuraN, Minezaki Y, et al. Polar structure of lysornal electic feld. ICirystal Cromth, 999, 200; 575.zyme agrgates in unseturated solurion delermined by20 YunYY, Neve RS. Cllis M W. The cfer of an eesmall-angle neutron scteringcontrast variation melthod..trie field on heat and mass trausfer for dieletric crstaliza-Crystal Growth, 199 200: 265.tin. Trus lchemE, 1997, 75, P'ant A: 668.13 BairdJ K. Theary o protein cytal muleation and growth21 LipusL, KopeJ, el l. Magneie water tealment forcontolld by solvent evaporation. 了Crystal Crowth,scale prevenion. HungJ Ind Chem, 1998. 26: 109.1999，204: 553.22 WakayamaN1, Ataka M, Abe H. Eiteer of a magetie14 Takeuchi H. Structure frmation during the crstlizationfield on the crslalization of hen lyozyme. 」Crystalinduction period of a sbhort chain molecule system: a morGrowth, 1997. 178: 653.lecular dynanics study. J Cherm Phys， 1998， 10923 SaakiC, Yohida E, etal. ffetr ol a magneic field on(13): 5614.the ersalization of biological maronpoleules. J Crystal15 CrantML Efets of temodynamie nideaity in proceinGrowth. 1997. 173: 231.crystal growth. J Crystal Crowth, 2000, 209: 13024 SuzkiC, YanagiyaS, et ul. Efer of a megnetie fed on16 WangYP, HanY, etal. Prolein cystal gowth in micro.the prolein rylalizain. Intemnatioul Sympoium on Ingarity using a liqpid liquid difusion method. Microgai- .lstrial Crslliatinn Waseda Unierit， Jpan.ty Sci Technol, 1996, 9 (4): 281.1998, 363.I7 McPbersn A. Recent advancs in the mingngieysal 25 AlakaM, KaohE, WakeyamaNl. Etea of the hoan-lization of bologial macomolecules. Trends in Biotech-geneous magnetic field on protein erysalization. J Crystalnology, 1997, I5 (6): 197.Crwth, 1997, 173: 592.18 Sohnel0, CarsideJ. Peipatin.n (xford: Butereorh. 26 Banel PA, etal. Laser seine for bomolcular cystaHeineman, 1992, 65.liation. 」Crystal Crowth, 1998, 191: 537.[上接第19頁]10 Floyds, Huthinson RA, Ray W H. Polymeirzaton of參考文獻Olefins throughb heterogencous calysis- V. J Appl PolymSei, 1986, 32: 5451.1 FloydS, Choi KR, TaglorTW, el al. Polyncrization of11 FloydS, Heiskanen T, Taylor 1 w. e1 al. Polymeiza-Olefins through heterngeneous catalysis- m.」Appl Polymtiomu of Olefins through beleogeneous catalysis-VI.」Ap-Sei, 1986 (32): 2935.pl PolymSei, 1987. 33: 1021.2 WangCr, Smith J M. Totuosily facors for difusion in 12 馬青山 氣相原位共聚制備粒狀聚烯烴臺金工程研究catalyst plls. AIChEJ. 1983, 29 <1): 132.[博士學位論文。。杭州:浙江大學化工系. 19993 Michaels AS, Bisler H J. Flow of gases through polyethy13 KimKJ, Choi K Y. Continuous olefin cplymerzrinene. J Polym Sei, 1961, 50: 413.with soluble Ziepler-Natta calalysts. AICnEJ, 1991, 37Michaels AS, Bixler H J. Slobliy of gaes in palyehy-(8): 1255.lene. J PolymSci, 1961, 50: 393.14 Hamba M. Han-AdebekunGC, Ray W H. Kinetic study5 Frensdod H K. Polymerization in expanding calyst parti.of gas phase olecfin polymerization with a TiCL//4/MgC1//cles. J PolymnSei, A-2, 1964, I: 341.2 catalyst I. Kinetie paraneter eination and mode!6 Takenchi Y, Okamure H. The role of difusion in the Xie-building J Polym Sci, A: Plym Chem， 1997. 35:gler polymerzaion of ethylene.」Chem Fng Japan, 1976,2075.9: 136.15 Singh D, Mrill R P. Molecular weight disnibution of po-7 LongR B. A particle growth thory for heterogneus Zie-lyetlhylene produced by Ziegler Natta eatalysts. Macromole-gler polyeriztion. Ind Eng Chem，1965, 4 (4): 445.xules, 1971,4 (5): 599.8 MeCal D W. Sicher w P. Difusion in ethylene poly.16 Y'emakov v A. Chunaerski N B. On the mechauism ofmers.0 Efects of temperature and pressure. J Am Chcmolein polymeriration by Zieler-Natta catalysts. PlastSoe, 1958. 80: 1861.Massy, 1970, 9: 7.9 Schmeal W R, Sret J R. Polymerization in expnding cat.17馬青山， 馮連芳，張立鋒等，丙烯為土單體的烯烴共alyst paricles. AIChEJ, 1971 (17) 5, 188.聚合金的研究，石油化工， 199 28 (10): 66.6..