第32卷第12期北京工業(yè)大學(xué)學(xué)報Vol 32 No 122006年12月JOURNAL OF BEIJING UNIVERSITY OF TECHNOLOGYDec.2006貴金屬纖維催化劑的H4催化燃燒活性何洪,張建霞,戴洪興,訾學(xué)紅〔北京工業(yè)大學(xué)環(huán)境與能源工程學(xué)院催化化學(xué)與納米科學(xué)研究室,北京100022)摘要∶為了得到活性高、成本低的CH催化燃燒催化劑制備了一種P、P負(fù)載在硅鋁纖維棉載體上的催化劑考察了CH4催化燃燒的活性及抗老化性能研究了載體旳組成、預(yù)處理方法及貴金屬負(fù)載量對催化劑活性的影響.結(jié)果表明利用淄博華巖耐火纖維公司生產(chǎn)的高鋁型纖維棉作為載體制備的催化劑的活性最好載體預(yù)處理方法影響催化劑活性其中用質(zhì)量分?jǐn)?shù)為1%的鹽酸常溫浸泡30min得到的纖維載體最佳;當(dāng)負(fù)載的P的質(zhì)量分?jǐn)?shù)為1.5%負(fù)載的Pd的質(zhì)量分?jǐn)?shù)為2%時催化劑活性最好1.5%P/Z3催化劑的CH4完全轉(zhuǎn)化溫度為600℃C2%Pd/Z3催化劑的CH4完全轉(zhuǎn)化溫度為450℃2%PZ3催化劑在800℃經(jīng)過100h老化后其to僅提高了50℃該催化劑具有良好的抗老化性能關(guān)鍵詞∶貴金屬纖維催化劑;甲烷催化燃燒;硅鋁纖維載體中圖分類號:0643文獻(xiàn)標(biāo)識碼:A文章編號:0254-0037(2006)2-1097-0環(huán)境和能源問題是當(dāng)今世界兩大重要問題.天然氣被認(rèn)為是目前最清潔的能源之一但天然氣的主要成分CH4的燃燒溫度很蠃Ⅰ600℃)高溫產(chǎn)物NO,和未完全燃燒產(chǎn)物CO、HC等會造成環(huán)境污染催化燃燒被認(rèn)為是解決這一問題最有效的途徑1!目前CH4催化燃燒催化劑的研究主要集中在負(fù)載型貴金屬催化劑、鈣鈦礦型催化劑和六鋁酸鹽型催化劑.貴金屬催化劑具有良好的低溫起燃活性和催化性能.負(fù)載型貴金屬催化劑通常采用陶瓷蜂窩載體活性涂層一般采用γ-A2O3但高溫下-Al2O,會向αr-Al2O3轉(zhuǎn)化導(dǎo)致比表面積劇烈減少引起表面負(fù)載的活性組分聚集使催化劑活性明顯下降.硅鋁纖維材料旳抗熱沖擊性能和杋械柔韌性優(yōu)于陶瓷蜂窩載體材料并可根據(jù)反應(yīng)器的形狀仼意成形滿足不同需要23.同時纖維材料的制備費(fèi)用低化學(xué)穩(wěn)定性和高溫穩(wěn)定性好.以硅鋁纖維氈為載體負(fù)載不同活性組分可制備適合不同用途的催化劑其特點(diǎn)為活性組分用量少、空速大、成本低但硅鋁纖維材料的比表面積很小通常在10m2/g以下遠(yuǎn)小于γ-A2O3的比表面積.作者在硅鋁纖維棉上負(fù)載了P和P得到了高活性的催化劑其中負(fù)載質(zhì)量分?jǐn)?shù)為2%的Pd催化劑活性最好CH4完全轉(zhuǎn)化溫度為450℃1實(shí)驗(yàn)部分1.1催化劑的制備采用5個廠家的商用硅鋁纖維棉作為催化劑載體纖維棉型號及化學(xué)組成見表1.制備纖維催化劑時采用的化學(xué)試劑為H2PCl·H2Q分析純北京試劑公司)PdCl(分析純北京試劑公司)質(zhì)量分?jǐn)?shù)為36%~38%的HC溶液(分析純北京化工廠)催化劑的制備采用傳統(tǒng)的浸漬法.先用一定質(zhì)量分?jǐn)?shù)的HCl溶液對纖維棉進(jìn)行預(yù)處理處理后用蒸餾水沖洗干凈烘τ備用.測定纖維棉載體的吸水率按纖維棉的吸水量配制等體積的貴金屬浸漬液.浸漬纖維棉10℃烘干于馬弗爐內(nèi)500℃焙燒3h得到貴n中國煤化工中催化劑的負(fù)載量均按單質(zhì)態(tài)金屬質(zhì)量計HHCNMHG收稿日期:2005-11409作者簡介:何洪(1956-),男,北京人,教授,博士生導(dǎo)師1098北京工業(yè)大學(xué)學(xué)報2006年表1纖維棉的型號及化學(xué)組成Tab 1 Types and chemical composition of fibers載體編號纖維棉型號SO2+AOMO3載體編號纖維棉型號SiO2+AL,O3 AL, OZH9浙江1000淄博HPZH10浙江1260淄博HA浙江142074淄博32-3317-18zH2浙江72河南STDZH13浙江80河南HP上海50河南HA上海51河南ZA382~10‖L16魯陽ZA39-4015-171.2催化劑活性評價及老化實(shí)驗(yàn)催化劑活性評價在固定床石英管反應(yīng)器中進(jìn)行.催化劑用量為0.1g.反應(yīng)氣中CH4O2和N2的體積分?jǐn)?shù)分別為2%、8%和90%反應(yīng)氣體總流量100m/min空速60L(gh)反應(yīng)從300℃開始每隔50℃進(jìn)1次樣直至檢測不到CH4為止.反應(yīng)產(chǎn)物采用日本島津GC-14C色譜儀進(jìn)行在線檢測利用5A分子篩柱分離反應(yīng)產(chǎn)物.其色譜分析條件為He為載氣柱溫100℃,TCD檢測器檢測器溫度為110℃為考察催化劑的抗老化性能將催化劑在800℃反應(yīng)氣氛下連續(xù)老化100h每隔10h測定催化劑的活性情況1.3空白實(shí)驗(yàn)CH4燃燒的空白實(shí)驗(yàn)結(jié)果表明CH完全轉(zhuǎn)化溫度為900℃.未負(fù)載貴金屬的纖維棉的CH4燃燒實(shí)驗(yàn)結(jié)果表明CH4完全轉(zhuǎn)化溫度為950℃2結(jié)果與討論2.1載體的不同組分對催化劑活性的影響本實(shí)驗(yàn)選用16種商用硅鋁纖維棉作為催化劑載體這些纖維棉分為不含鋯和含鋯2類.由表1可看出不含鋯纖維棉的SO2和Al2O3總的質(zhì)量分?jǐn)?shù)大多在97%以上(浙江1420除外),Al2O3的質(zhì)量分?jǐn)?shù)與型號有關(guān)含鋯纖維棉的ZO,質(zhì)量分?jǐn)?shù)不同最高不超過18%用這些纖維棉作為載體在上面負(fù)載質(zhì)量分?jǐn)?shù)為1%的Pt纖維棉預(yù)處理方法都采用質(zhì)量分?jǐn)?shù)為3%的HCl溶液煮沸20min.圖1是這些催化劑的CH4轉(zhuǎn)化率曲線.可以看出A個活性最好的催化劑分別是1%PUZ3、1%P/H7、1%PtZH10和1%P/S14.由表1可見前3種催化劑對應(yīng)的載體Z3、H7和ZH10的Al2O3的質(zhì)量分?jǐn)?shù)都在52%~55%之間但1%PS14催化劑所用纖維棉S14的A2O3的質(zhì)量分?jǐn)?shù)為4%仍具有高的活性.在所有催化劑中由含鋯纖維棉作載體制備旳催化劑的活性低于不含鋯纖維棉制備的催化劑說明纖維棉中的鋯元素對催化劑活性無促進(jìn)V凵中國煤化工表2給出了各催化劑的CH4催化燃燒的起燃溫度loCNMH⑦為50%時的反應(yīng)溫度從表2可看出J%P/3催化劑的CH4催化燃燒的起燃溫度最低為578℃其次是1%P/S14催化劑;581℃第12期何洪等:貴金屬纖維催化劑的CH4催化燃燒活性1099→1%PUZ1→1%PtH5Q-H-1%Pt/Z2i-1%Pt/H61%Pt/Z31%Pt/H7t-1%Pt/Z41%Pt/H8200040050060070000400500600700t/℃(a)用淄博纖維棉作載體制備(b)用河南纖維棉作載體制備的催化劑活性比較的催化劑活性比較◆1%PZH9→1%PtS14+1%PU/ZH10a1%PU/S15t-1%Pt/ZHIl-1%PU/L161%Pt/ZH121%Pt/ZH13300400500600700900400500600700t/℃t/℃(c)用漸江纖維棉作載體制備(d用上海纖維棉作載體制備的催化劑活性比較的催化劑活性比較圖1用不同纖維棉載體制備的P催化劑的CH4轉(zhuǎn)化率Fig. 1 CH conversion rate curves over Pt catalysts with different fiber表2催化劑活性評價數(shù)據(jù)Tab 2 Catalytic activities estimate data of catalysts載體名稱催化劑名稱載體名稱催化劑名稱淄博ST1%0 Pt/ZI610浙江1000%o PtZH9淄博HP%o PtZ2590浙江1261% Pt/ZH1O淄博HA1%Pt73578浙江1420I %o Pt/ZHII6l0淄博ZA1%o PtZ620浙江721%o Pt/ZH12河南STD1% Pt/H500浙江80I%0 Pt/ZH13河南HP1 %0 Pt/H6619上海501%0 Pt/S14河南HAI%0 Pt/H7590上海511%o Pt/S15河南ZA1%o Pt/H8621魯陽ZA1%0 Pt/L166202.2載體預(yù)處理方法對催化劑活性的影響在2.1實(shí)驗(yàn)基礎(chǔ)上考察載體預(yù)處理方法對催化劑活性的影響蕺體選用淄博華巖耐火纖維有限公司生產(chǎn)的高鋁HA型纖維棉負(fù)載質(zhì)量分?jǐn)?shù)為1%的P分別采用表3的6種方法對載體進(jìn)行預(yù)處理.用HCI溶液處理除去載體中的Al2O3形成多孔結(jié)構(gòu)提高纖維棉的比表面積3].從表3可看出1%PZ3-4催化劑的CH4催化燃燒的掃物催化劑但1%PZ3-4催化劑的CH4完全轉(zhuǎn)化溫度比1%中國煤化xC其次是1%Pv73-3因此,%PUZ3-3催化劑的活性最好其CH完全轉(zhuǎn)化的溫度為600℃比其他人星CNMHG」∴A應(yīng)載體的預(yù)處理方法為用質(zhì)量分?jǐn)?shù)為1%的HCl溶液常溫浸泡3σmin延長lC溶液處理時間和提高HCl溶液濃度并沒有提高催化劑活性反而使活性下降同時載體強(qiáng)度也遭到破壞.1100北京工業(yè)大學(xué)學(xué)報2006年表3纖維棉預(yù)處理方法及催化劑活性評價數(shù)據(jù)Tab 3 Pre-treatment of fibers and catalytic activities estimate data of catalysts體編號載體預(yù)處理方法催化劑名稱℃10℃用蒸餾水洗滌%PU/Z3-1577用質(zhì)量分?jǐn)?shù)為1%的HCI溶液常溫浸泡15min1%Pt/Z3-2用質(zhì)量分?jǐn)?shù)為1%的HC溶液常溫浸泡30min1%Pt/Z3-3600質(zhì)量分?jǐn)?shù)為1%的HC溶液常溫浸泡45min1%PtZ3-473-5用質(zhì)量分?jǐn)?shù)為3%的HCl溶液煮10min1%PUZ3-5570650736用質(zhì)量分?jǐn)?shù)為3%的HC溶液煮20min1%PU/Z3-6580652.3貴金屬負(fù)載量對催化劑活性的影響考察了不同負(fù)載量的P和P纖維催化劑對CH催化燃燒活性的影響載體采用淄博華巖耐火纖維有限公司生產(chǎn)的高鋁HA型纖維棉預(yù)處理用質(zhì)量分?jǐn)?shù)為1%的HCl溶液常溫浸泡30min.圖2給出了各催化劑CH4催化燃燒的起燃溫度隨負(fù)載量的變化曲線.從實(shí)驗(yàn)結(jié)果可看岀P催化劑的活性不如Pd催化劑這與文獻(xiàn)6]報道的在CO、CH4和烯烴的氧化中P的活性更高的結(jié)果是一致的.從圖2可看出Pt催化劑的最佳負(fù)載的質(zhì)量分?jǐn)?shù)為1.5%CH4催化燃燒的起燃溫度為530℃P的最佳負(fù)載的質(zhì)量分?jǐn)?shù)為2%CH4催化燃燒的起燃溫度為370℃洇此2%PdZ3催化劑的活性最好,它的CH4完全轉(zhuǎn)化溫度為450℃. KIyana等人報道的質(zhì)量分?jǐn)?shù)為2%的Pd纖維催化劑的CH4完全轉(zhuǎn)化溫度為512℃質(zhì)量分?jǐn)?shù)為2%的P纖維催化劑的CH4完全轉(zhuǎn)化溫度為637℃7其空速為12L(gh)遠(yuǎn)遠(yuǎn)小于本實(shí)驗(yàn)的空速60L(g·h)而其反應(yīng)氣CH4的體積分?jǐn)?shù)為3%比本實(shí)驗(yàn)CH4的體積分?jǐn)?shù)2%略大可見其催化劑活性比本文制備的催化劑活性差.從圖2還可看出催化劑的活性并不是隨負(fù)載量的增加而線性提高的,它有一個最佳值.當(dāng)超過此值時催化劑活性反而下降這是因?yàn)樨?fù)載量小時提供的金屬活性表面積小而負(fù)載量大時會引起金屬顆粒積聚活性組分分散度降低使反應(yīng)接觸表面積減少8.而CH4完全氧化反應(yīng)屬于結(jié)構(gòu)敏感反應(yīng)活性組分顆粒的大小對催化劑活性影響很大.因此,負(fù)載量大時催化劑活性降低同時高的負(fù)載量也會引起催化劑成本的增加不利于實(shí)際應(yīng)用370.01.52.0253.001.52.02.53.0Pt負(fù)載量%Pd負(fù)載量/%a)Pt負(fù)載量對PZ3催化劑活性的影響b)Pd負(fù)載量對PdZ3催化劑活性的影響圖2貴金屬負(fù)載量對CH4氧化催化劑活性影響Fig. 2 The effect of noble metal loading on the catalysts s activit2.4老化實(shí)驗(yàn)結(jié)果催化劑的抗老化性能是催化劑是否具有應(yīng)用價值廠V中國煤化了測試了活性最好的2%PM/73催化劑在80℃反應(yīng)氣氛下連續(xù)老化10h后HHCNMHGd/3催化劑經(jīng)不同時間老化后的t和tm從表4可看出催化劑經(jīng)10h老化以后l只提高了12℃繼續(xù)增加催化劑老化時間至30h催化劑活性情況幾乎不變化當(dāng)老化40h時催化劑活性又略有降低;而當(dāng)老化時間增至50h時催化劑活性明顯下降但t也只提高了41℃J則提高了75℃催化劑繼續(xù)進(jìn)行老化至100h,與新鮮催化劑相比只提高了50℃;提高了75℃可見2%PdZ3催化劑具有良好的抗老化性能第12期何洪等:貴金屬纖維催化劑的CH4催化燃燒活性l101表42%Pd/⑦3催化劑不同老化時間后的活性評價數(shù)據(jù)Tab. 4 The catalytic activities estimate data of 2 %Pd/z3 catalysts aged for different time老化時間/h老化時間/h/℃4575254274605253結(jié)論1)纖維棉載體中的A2O3的質(zhì)量分?jǐn)?shù)對催化劑活性有影響,當(dāng)Al2O3的質(zhì)量分?jǐn)?shù)在50%左右時得到的催化劑活性最好2)用適當(dāng)質(zhì)量分?jǐn)?shù)的HC溶液處理載體可提高催化劑活性最佳處理?xiàng)l件為用質(zhì)量分?jǐn)?shù)為1%的HCI溶液常溫浸泡30min;3)貴金屬負(fù)載量對催化劑活性也有影響其中1.5%P3和2.0%PdZ3催化劑活性最好CH4完全轉(zhuǎn)化溫度分別為600℃和450℃C4)2.0%PdZ3催化劑在高的空速60L/(g·h))下對CH4氧化具有很高的活性5)2.0%PdZ3催化劑具有良好的抗老化性能在800℃反應(yīng)氣氛下老化100h后s僅提高50℃;6)纖維載體的比表面積遠(yuǎn)小于y-A2O3但仍具有很高的活性7)貴金屬纖維催化劑制備工藝簡單不需涂覆活性涂層費(fèi)用低具有廣闊的應(yīng)用前景.參考文獻(xiàn)[1]嚴(yán)河清,張?zhí)?王鄂鳳,等.甲烷催化燃燒催化劑的研究進(jìn)罳J]武漢大學(xué)學(xué)報,2005,51(2):161-166YAN He-qing, ZHANG Tian, WANG E-feng et al. 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Prescription and preparation condition optimizationCoal Mine, 1997(6): 11-12. in ChineseTHE中國煤化工CNMHG(下轉(zhuǎn)第1110頁)l10北京工業(yè)大學(xué)學(xué)報2006年Anti-fouling Experimental Study of a green Compound ScaleInhibitor PASP/POCA for Heat Transfer EnhancementQUAN Zhen-hua, ChEn Yong-chang WANG Chun-ming, LI BingKey Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education and Key Laboratory of HeatTransfer and Energy Conversion Beijing Education Commission, College of Environmental and Energy EngineeringBeijing University of Technology, Beijing 100022 ChinaAbstract: In this paper, the anti-fouling experiment of green compound scale inhibitor PASP/POCA for heattransfer enhancement is conducted in the dynamic system. The result indicates that the performance of scale in-hibiting of the compound scale inhibitor is very excellent. Little compound scale inhibitor into the solution canmake fouling thermal resistance decrease extraordinarily and the scale inhibition rate can reach to about 98%0SEM photographs show that the shape of CaCO, crystle changes from the compact structure to the relax structurethus scale is not easy to form on heat transfer surfaceKey words: polyaspartic acid phosphonocarboxylic compound scale inhibitor fouling thermal resistance(上接第1101頁)Catalvtic Combustion of methane Over Noble metalsSupported on Fibers catalystsHE Hong ZHANG Jian-xia, DAI Hong-xing ZI Xue-hongLaboratory of Catalysis Chemistry and Nanoscience ollege of Environmental and Energy EngineeringBeijing University of Technology, Beijing 100022, ChinaAbstract: To get the high activity and low price methane combustion catalyst a fiber-supported Pd or Pt com-ustion catalyst has been developed. The influences of fiber composition, pre-treatment process of support, andnoble metal loading on the catalyst activity have been investigated. The thermal stability of catalysts has also beerinvestigated. The experiment results have revealed as follows 1)the catalytic activities of the Pt and Pd supported on the high alumina fiber of Huayan catalysts are higher than that supported on other fibers. 2)The catalyticactivity depends on the pre-treatment process, such as temperature treatment time and concentration of HCl solution and the best treatment condition is impregnation in HCI solution that the mass fraction is 1% for 30min atroom temperature. 3)1.5%0 Pt/Z3 and 2. 0%Pd/Z3 catalysts possessed more activities than those with otherloadings. The methane completed conversion has been obtained over 1. 5%Pt/Z3 and 2. 0% Pd/Z3 catalysts attemperatures of 600C and 450 C, respectively. 4)2. 0% Pd/ 3 catalyst has high thermal stability tso only in-creases 50C when 2. 0%Pd/73 catalyst has been aged for 100 h at 8000Key words: fiber-supported noble metal catalyst methaneTYH中國煤化工aluminum fiber-supportCNMHG