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1、本科學(xué)生畢業(yè)設(shè)計(jì)(論文)燃煤煙氣中汞的氧化劑開發(fā)摘要燃煤過程排放出的汞對(duì)生態(tài)環(huán)境具有巨大危害，必須對(duì)其進(jìn)行有效控制。然而，煤燃燒過程排放的汞絕大部分為單質(zhì)汞（Hg0），具有易揮發(fā)和不溶于水的特點(diǎn)，不易通過吸附或吸收手段脫除。目前，通常采取將單質(zhì)汞氧化為高價(jià)態(tài)汞，再通過吸附或吸收手段進(jìn)行脫除。因此，開展燃煤煙氣中單質(zhì)汞氧化劑的研究，具有重要的理論意義和實(shí)際價(jià)值。論文采用Gibbs自由能最小化方法，對(duì)煙氣溫度為50℃－450℃圍的單質(zhì)汞氧化條件進(jìn)行了計(jì)算。計(jì)算結(jié)果表明，在論文涉及的計(jì)算條件下，單質(zhì)汞的適宜氧化條件為高的氧氣濃度、較低的溫度、存在SO2等酸性氧化物等，適宜的氧化劑為NaB
2、r。以熱力學(xué)計(jì)算為基礎(chǔ)，采用浸漬方法對(duì)粉煤灰基脫汞吸附劑基體進(jìn)行了改性，并進(jìn)行了單質(zhì)汞氧化性能實(shí)驗(yàn)研究。實(shí)驗(yàn)結(jié)果表明，由NaBr所制備的改性溶液，當(dāng)其濃度為5%、浸漬時(shí)間為3min時(shí)，所得改性吸附劑的單質(zhì)汞氧化能力最高，可達(dá)79.43%；在本實(shí)驗(yàn)條件下，該單質(zhì)汞氧化劑的適宜使用條件為氧氣濃度8%、溫度80℃、SO2濃度0.7%。關(guān)鍵詞:脫汞，煙氣，改性吸附劑，鹵族化合物ABSTRACTMercurypollutioncomesmainlyfromtheburningfossilfuels.Thereisagreatimmediateandpotentialhazardontheec
3、ologicalenvironment.Theemissionofmercuryduringtheprocessofthecoalcombustionhasagreatharmtotheecologicalenvironmentsothatitmustbeeffectivelycontrolled.However,themajorityofthemercuryemissionfromcoalcombustionprocessisthezero-valentmercury(Hg0).Asthezero-valentmercuryhasahighvolatilityanddonotdi
4、ssolvedinwaterfeatures,theabsorptionandremovaloftheitwouldbemoredifficult.Atpresent,thezero-valentmercuryusuallytobetransformedintodivalentmercurycompoundswhichismoreefficientabsorption.Therefore,theresearchofthemercuryoxidantinfluegasisveryimportant.Thisarticleshavehadthethermodynamiccalculat
5、ioninmercuryoxidationconditionsbyGibbsfreeenergyminimizationmethodtothefluegastemperatureduring50℃-450℃.Theresultsshowthatthecalculationsinvolvedinthepaperundertheconditionsofthezero-valentmercuryoxidationintheappropriateconditionsisthehighoxygenconcentration,thelowtemperature,theexistenceofac
6、idicoxidessuchasSO2.Thesuitableoxidantofthezero-valentmercuryisNaBr.Theflyash-basedsorbentmatrixwasmodifiedbydippinginthemodifiedsolutionaccordingtothethermodynamiccalculations.Theexperimentalresultsshowthatthetheproceedsofmodifiedadsorptionforoxidationofthezero-valentmercuryis79.43%whichisthe
7、highestwhenthepreparedbythemodifiedNaBrsolution,theconcentrationof5%,dippingtimeof3min.Intheexperimentalconditions,theappropriateconditionsofthezero-valentmercuryoxidantsistheoxygenconcentrationof8%,temperatureof80℃andSO2concentrationof
