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1、天津大學(xué)碩士學(xué)位論文淀粉質(zhì)吸附劑選擇性分離醇/水共沸物實(shí)驗(yàn)研究姓名:鄭帥申請(qǐng)學(xué)位級(jí)別:碩士專業(yè):化學(xué)工程指導(dǎo)教師:孫津生20080601中文摘要低級(jí)醇(乙醇、異丙醇、正丙醇等)/水的混合物在常壓時(shí)存在共沸點(diǎn),是最典型的共沸系統(tǒng)。本文以乙醇/水溶液為研究對(duì)象,用一種新型環(huán)??苫厥盏膹?fù)合擠壓型淀粉質(zhì)吸附劑——ZSG.1,用恒溫吸附蒸餾方法對(duì)乙醇/水溶液進(jìn)行選擇性分離,得到99.7叭%以上純度的乙醇。從實(shí)驗(yàn)和理論兩方面對(duì)分離效果進(jìn)行了研究。首先,通過(guò)篩選,選定玉米和薯粉為基本原料,混合擠壓作為處理方法,過(guò)程中要加入發(fā)泡劑。制備出的ZSG.1是一種中空、富含微孔、尺寸
2、為西3×3mm并且能通過(guò)313kPa靜壓實(shí)驗(yàn)的吸附劑。該吸附劑對(duì)水分子具有很強(qiáng)的吸附作用,對(duì)乙醇分子則很弱,當(dāng)含水乙醇蒸氣通過(guò)吸附劑后即達(dá)到脫水的目的。本實(shí)驗(yàn)通過(guò)測(cè)定該吸附劑的吸附穿透曲線,來(lái)衡量其對(duì)水的吸附能力。結(jié)果顯示:在氣相吸附過(guò)程中,進(jìn)料濃度、表觀氣速、床層溫度為敏感因素。當(dāng)三個(gè)主要參數(shù)都為理想值時(shí),能得到較高的對(duì)水吸附量。通過(guò)實(shí)驗(yàn)測(cè)定,89℃時(shí)H20對(duì)ZSG.1的傳質(zhì)速率常數(shù)為13.6m3·k91.h~,偏?。晃饺萘繛?1.8蠅·m一。又因?yàn)閆SG-1的動(dòng)態(tài)飽和吸附量為O.15119(H20)儋,已經(jīng)接近3A分子篩。根據(jù)反氣相色譜實(shí)驗(yàn)的數(shù)據(jù),計(jì)算可
3、知:水在zSG.1上的凈保留時(shí)間遠(yuǎn)大于乙醇;水在ZSG.1上的吸附熱△H。b。=3.16×104J·mol~。關(guān)鍵詞:共沸、淀粉質(zhì)吸附劑、傳質(zhì)速率常數(shù)、動(dòng)態(tài)飽和吸附量、吸附熱ABSTRACTLoweralcohol(ethanol,isopropanol,n—propanolandsoon)—.watersysytemisthemosttypicalazeotrope.Inthispaper,ethanol-waterseparationbythe瑚ostatadso巾tiVedistillationwithasqueezedcompoundstarchine
4、ssadsorbent-一ZSG.1,whichisnovel,environmentalandrecoverable.Ethanolof99.7叭%inpurityisachieVedinthismethod.AnditisinVestigatedbothexperimentallyandtheoretically.First,comandsweetpotatoareselectedasthebasicrawmaterialsthroughscreening·Thent11eyaremixed,squeezedandjoinedtheprocessoffo鋤
5、ingagenttoprepareanadsorbent。Thehollow①3×3mmabsorbentpieces,richi力microspore,isn鋤edZSG-1,andpassesatestunderthepressureof3l3I①a.Theadsorbentabsorbedwaterstrongly,withalcoholsbeingscreenedoutsimultaneously.Thepu甲o(hù)seofdehydrationcanreachedduringethanol-watervaporflowthrou曲theadsorbent
6、bed.Theexperimentsareperfonnedtomeasurethemassofadsorptivewaterandethanol,adso甲tiVebreakthroughcun,es.Itissho、ⅣnthatthesensitivefactorsfortheVaporabso叩tionprocessincludethefixedbedtemperamre,thewaterconcentration,andthesupe而cialVelocity.Whenalloftheparametersweresetatsuitablevalue,h
7、igerc印acityofwaterabsorptionwouldbeattained.AccordingtoexperimentalthemasstransferrateconstantofH20toZSG.1is13。6m3’k分1.h叫at89℃.Itisrelativelysmall.Atthes鋤etime,theadsorptioncapacityofZSG-1forH20is51.8k‘m一.Saturatedcapacity0.151lg(H20)儋,whichisclosetothecapacityof3AzeoIite.InVersegas
8、chromato伊aphymethod