第25卷第12期農(nóng)業(yè)工程學(xué)報(bào)VoL 25 No 1282009年12月Transactions of the csaeDec.2009金屬元素對(duì)木屑快速熱解的影響牛艷青,王學(xué)斌,譚厚章,徐通模,惠世恩,趙欽新,周屈蘭(西安交通大學(xué)動(dòng)力工程多相流國(guó)家重點(diǎn)實(shí)驗(yàn)室,西安710049)摘要:采用傅立葉紅外光譜(FIIR)分析,以木屑為研究對(duì)象,在管式爐中研究了AJCa/Fe/K/Na/Zn金屬元素對(duì)生物質(zhì)快速熱解過(guò)程中熱解速率以及CO和CH4析出規(guī)律的影響。FIR分析表明:加入含金屬元素添加劑抑制了CO和CH4的產(chǎn)量,添加劑對(duì)CO產(chǎn)量和CH4產(chǎn)量的抑制能力依次為Fe2O3>ZnO>NaCl>CaO>KC1>A2O3;Al2OyFe2O3ZnO作為添加劑可縮短CO和CH4的析出時(shí)間,其中Fe2O3作用最為顯著,其他添加劑對(duì)析出時(shí)間的影響相對(duì)較小。對(duì)熱解速率的統(tǒng)計(jì)分析表明:加入金屬元素降低了生物質(zhì)的快速熱解速率,熱解反應(yīng)速率大小依次為:不加添加劑>Al2O3>Fe O3>Zno>KcI> Cao> NaCl關(guān)鍵詞:生物質(zhì),熱解,一氧化碳,甲烷,木屑,金屬元素,傅立葉紅外光譜doi:10.3969/jiss.1002-6819.2009.12.040中圖分類號(hào):TK6文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1002-6819(2009)-12-022806牛艷青,王學(xué)斌,譚厚章,等.金屬元素對(duì)木屑快速熱解的影響[].農(nóng)業(yè)工程學(xué)報(bào),2009,25(12):228-233Niu Yanqing, Wang Xuebin, Tan Houzhang, et al. Effect of metal elements on sawdust fast-pyrolysis[J]. Transactions of theCSAE, 2009, 25(12): 228-233. (in Chinese with English abstract)言1試驗(yàn)原料與裝置生物質(zhì)燃料不僅氮硫含量低,而且可再生能實(shí)現(xiàn)1.1試驗(yàn)裝置氧化碳的零排放,因此對(duì)生物質(zhì)燃料的利用成為近年來(lái)試驗(yàn)系統(tǒng)如圖1所示:99,9%的高純氮?dú)?室溫)研究的熱點(diǎn)。目前世界各國(guó)對(duì)生物質(zhì)能的利用主要集中分為兩路進(jìn)入石英反應(yīng)器中,使反應(yīng)器內(nèi)保持還原氣氛在生物質(zhì)熱化學(xué)轉(zhuǎn)變的研究,而熱解則是生物質(zhì)在熱化木屑和添加物通過(guò)石英反應(yīng)器正上方的給料口由一路氮學(xué)轉(zhuǎn)變中最基本和重要的過(guò)程14由于生物質(zhì)中灰份高,氣送入,沉降在反應(yīng)器中部的孔板上進(jìn)行反應(yīng),物料混金屬元素含量豐富,其對(duì)生物質(zhì)大分子分解的影響很合均勻:熱解產(chǎn)物引岀后經(jīng)過(guò)二級(jí)過(guò)濾裝置以脫除煙氣大5,因此有必要對(duì)生物質(zhì)熱解過(guò)程中金屬元素的影響進(jìn)攜帶的固體和焦油等,進(jìn)入傅立葉紅外分析儀(FTIR行硏究。已有學(xué)者對(duì)生物質(zhì)熱解過(guò)程中金屬元素的影響進(jìn)行在線分析。通過(guò)溫控儀控制反應(yīng)器內(nèi)溫度,反應(yīng)結(jié)進(jìn)行了研究,但由于反應(yīng)條件差異很大,得出的結(jié)論未束通入氧氣使反應(yīng)器內(nèi)殘余固體物質(zhì)燃燒后再將反應(yīng)器盡一致: Pen gmei L和 Desmond研究表明白云石(主內(nèi)的固體清空;并對(duì)每種工況均進(jìn)行重復(fù)性驗(yàn)證試驗(yàn)兩要組分為碳酸鎂與碳酸鈣)可以明顯降低生物質(zhì)熱解過(guò)次,誤差不超過(guò)5%程中的CO和CH4產(chǎn)量;肖軍和楊昌炎等81的研究則分別指出NO和CaO可以促進(jìn)CO和CH4的生成,Ca和K1.管式爐對(duì)CO和CH4析出的影響不大,溫度對(duì)催化作用的影響2.孔板很大; Demirall2的研究則表明A和Na對(duì)生物質(zhì)熱解氣析出量的影響在不同升溫速率下差別也很大。木屑熱解4.氮?dú)馄?.溫控儀產(chǎn)物主要為CO、CH4、CO2、H,且CO和CH4占絕對(duì)6.給料口優(yōu)勢(shì)。文獻(xiàn)[8,13-14]均表明溫度673K時(shí),生物質(zhì)已開(kāi)始7.石英反應(yīng)器劇烈熱解,因此本文在管式爐上研究了溫度為673K時(shí)8.過(guò)濾裝置1不同金屬元素AlCa/le/KNa/Zn對(duì)木屑快速熱解的影響,9.過(guò)濾裝置210用傅立葉紅外光譜(FTIR)分析熱解產(chǎn)物—CO和CH4,10.PC機(jī)并對(duì)添加劑對(duì)木屑熱解速率的影響進(jìn)行了統(tǒng)計(jì)分析。11.FTR分析儀圖1試驗(yàn)系統(tǒng)圖收稿日期:20090409修訂日期:200908-17leccrintion nf tect system基金項(xiàng)目:973國(guó)家基礎(chǔ)研究發(fā)展項(xiàng)目(No.2005CB221206);十一五科技中國(guó)煤化工支撐計(jì)劃(No.2006BAK02B03)石英反應(yīng)CNMH Gn,由于物料少作者簡(jiǎn)介:牛艷青(195-),男,山西長(zhǎng)治人,主要從事清潔燃燒技木研避免了物料在孔極上堆:試驗(yàn)前物料于105℃處于烘干究。西安西安交通大學(xué)熱能工程系,710049。 Email: yqniut00l@ yahoo.cl箱內(nèi),試驗(yàn)期間放于干燥器中。電爐由S讠C元件加熱,第12期牛艷青等:金屬元素對(duì)木屑快速熱解的影響石英管中部600mm處于恒溫區(qū)。鉑銠鉑熱電偶用于測(cè)量密度差,為盡量混合充分加入添加劑100mg反應(yīng)區(qū)溫度,該溫度由希曼頓FP93PID溫控儀控制,精表1木屑的工業(yè)分析和元素分析度為士2K,測(cè)點(diǎn)處石英管內(nèi)外溫度相差小于5K。試驗(yàn) Table 1 Industrial analysis and elementary analysis on sav用FTIR為芬蘭 Temet Instruments helsinki公司生產(chǎn)的工業(yè)分析(質(zhì)量分?jǐn)?shù))/%元素分析(質(zhì)量分?jǐn)?shù))/%DX-400系列煙氣分析儀,該儀器可以實(shí)現(xiàn)對(duì)CO和CH水分Ma灰分Aa揮發(fā)份V固定碳Ca氫Had氧Oa4氮Na硫Sad等氣體高精度的在線測(cè)量,測(cè)量精度為測(cè)量值的0.01%。本文選取673K作為研究金屬元素對(duì)木屑熱解影響9.8776.7744.7549839850.120.01的固定溫度。保護(hù)氣流量恒定為200mL/min1.2試驗(yàn)原料2結(jié)果與分析試驗(yàn)所用木屑來(lái)源于陜西省西安市某木材工廠,該圖2選取了無(wú)添加劑以及NaC1作為添加劑時(shí)木屑快木屑的工業(yè)分析和元素分析見(jiàn)表1:由于金屬元素氧化物速熱解的兩譜圖,譜圖均取自熱解過(guò)程中CO和CH4具較碳酸鹽穩(wěn)定,且不會(huì)產(chǎn)生附加CO,故本試驗(yàn)中加入的有最大峰值的時(shí)刻。由圖可見(jiàn):加入金屬元素添加劑后金屬元素添加物分別為Fe2O3/ ZnO/NaCl/cao/KCl/A2O3,CO在2000~2200cm之間的特征峰值降低顯著;CH46種物質(zhì)的純度均為分析純。其中木屑和添加劑的粒徑在1300cm和3000cm處的兩個(gè)特征峰也有明顯降均<148/m,每次加入木屑20mg,考慮添加劑與木屑的低?？梢?jiàn),添加劑的加入抑制了木屑熱解氣體的析出0.400.400.350.35400035003000250020001500100030002500200015001000峰值/cm1峰值/cma.無(wú)添加劑b, NaCl添加劑圖2木屑快速熱解的紅外光譜圖Fig 2 IR spectra of Fast pyrolysis sawdust2.1金屬元素對(duì)CO的影響式中:—反應(yīng)時(shí)間,s:Qt—截止到反應(yīng)時(shí)間為τ時(shí)圖3為加入添加劑后木屑快速熱解過(guò)程中CO的濃CO的產(chǎn)量,106;Q0反應(yīng)結(jié)束時(shí)CO的總產(chǎn)量,10度變化以及CO相對(duì)產(chǎn)量的積分曲線與不加添加劑時(shí)的Q定義為對(duì)比(2)相對(duì)產(chǎn)量q為Q式中:C—CO濃度,10;V—保護(hù)氣流量200mL/minqM—CO的分子量。1800l40012000-AlO3CO濃度-CaO-CO濃度元添加劑一CO濃度06細(xì)無(wú)添加劑CO濃度06ALO3相對(duì)產(chǎn)量CaO相對(duì)產(chǎn)量無(wú)澤加劑相對(duì)產(chǎn)量04無(wú)添加劑相對(duì)產(chǎn)量04中國(guó)煤化工2000200400600800100012001400160018006001800時(shí)間/sCNMHGa,AlO3添加劑bCaO澤加劑農(nóng)業(yè)工程學(xué)報(bào)2009年l80014000-Fe2O3CO濃度一無(wú)澤加劑一CO濃度-無(wú)加利C0濃度06FeO3相對(duì)產(chǎn)量KC1相對(duì)產(chǎn)量無(wú)添加剎相對(duì)產(chǎn)量04是一無(wú)添加劑相對(duì)產(chǎn)量104應(yīng)2000200020040060080010001200140016001800200020040060080010001200140016001800時(shí)間/s寸間/scFeO3添加剎d,KC添加劑1800160016004000.81200NaC|CO濃度1200Zno-Co濃度81000無(wú)添加劑CO濃度0-無(wú)添加劑CO濃度106一NaC相對(duì)產(chǎn)量一ZnO相對(duì)產(chǎn)量無(wú)添加劑相對(duì)產(chǎn)量爛800000無(wú)添加劑相對(duì)產(chǎn)量000020040060080010001200140016001800200020040060080010001200140016001800時(shí)間/s時(shí)間/se.NaCl添加劑r.ZnO添加剎圖3金屬元素對(duì)CO析出的影響Fig 3 Effects of metal elements on the release of co由圖3及表2可見(jiàn):Al2O/Fe2O/ZnO作為添加劑時(shí)CO開(kāi)始析出的時(shí)間提前; Cao/Nacl/KCl對(duì)CO的開(kāi)始無(wú)如加相多多多多多析出時(shí)間影響不大。而對(duì)于CO析出的結(jié)束時(shí)間,加入Fe2O3可顯著縮短,NaCl/ZnO也有縮短,而其他添加劑影響不大。表2金屬元素對(duì)CO析出時(shí)間的影響Nb多Table 2 effects of metal elements on co release time開(kāi)始時(shí)間時(shí)間間隔無(wú)添加劑105.94654.352AlO31532.141532.1400.51.01.5202.53040103.7101533.306429.596CO總產(chǎn)量/mg121.6831672.6111550928圖4金屬元素對(duì)CO總產(chǎn)量的影響I278.167l208.148Fig 4 Effects of metal elements on the total release of co1153.491表3金屬元素對(duì)CH4析出時(shí)間的影響對(duì)比圖3中加入添加劑與不加添加劑CO濃度峰值的Table 3 Effects of metal elements on Cha release time影響,可見(jiàn)除Al2O3外的其他添加劑對(duì)峰值的影響均較大。圖4為添加劑對(duì)CO總產(chǎn)量 Total的影響,可見(jiàn)re2O3無(wú)添加劑1902.000對(duì)CO總產(chǎn)量的影響最大,Al2O3的影響最小。1641.0001641.0002.2金屬元素對(duì)cH4的影響CaoFe O3中國(guó)煤化工101700添加劑對(duì)CH4析出的影響見(jiàn)圖5及表3,其中加入CNMHG 611.442Al2O3Fe2O3/ZnO時(shí)CH4的析出時(shí)間提前,而其他添加劑NaClTYH171.746對(duì)CH4的析出時(shí)間影響不大,甚至延遲了CH4的析出1361.000136100第12期牛艷青等:金屬元素對(duì)木屑快速熱解的影響23180-AMO-CH濃度0.650- Cao-CH4濃度0000一0—無(wú)添加劑一CH4濃度無(wú)添加劑-H4濃度ALO3相對(duì)產(chǎn)量-CaO相對(duì)產(chǎn)量一無(wú)添加劑相對(duì)產(chǎn)量無(wú)添加劑相對(duì)產(chǎn)量100.220002004006008001000120014001600180000020040060080010001200140016001800時(shí)間/s時(shí)間/saAlO3添加劑bCaO添加劑FeO3CH4濃度a-KCCH4濃度—無(wú)添加劑一CH濃度無(wú)添加劑-CH4濃度一一Fe2O3相對(duì)產(chǎn)量KCl相對(duì)產(chǎn)量無(wú)添加劑相對(duì)產(chǎn)量無(wú)添加劑相對(duì)產(chǎn)量200020040060080010001200140016001800-200020040060080010001200140016001800時(shí)間/s時(shí)間/sc.FeO3添加劑d.KC1添加劑NaCl-CH4濃度無(wú)添加劑CH4濃度0.6a- ZnO-CH濃度06恒無(wú)澤加利CH濃度NaC相對(duì)產(chǎn)量ZnO相對(duì)產(chǎn)量無(wú)澤加劑相對(duì)產(chǎn)量無(wú)添加劑相對(duì)產(chǎn)量200020040060080010001200140016001800200020040060080010001200140016001800時(shí)間/se,NaC1添加劑f,ZnO添加劑圖5金屬元素對(duì)CH4析出的影響Fig 5 Effects of metal elements on the release of CHa添加劑對(duì)CH4總產(chǎn)量的影響如圖6所示:可見(jiàn)添加CO析出時(shí)間兩個(gè)物理量,定義熱解平均速率κ9劑對(duì)CH4總產(chǎn)量的影響和對(duì)CO總產(chǎn)量的影響一樣,產(chǎn)量由小到大均為:Fe2O3A2O3>re2O3>∠nO>KCl>CaO>理地反映添加劑對(duì)木屑熱解的影響,綜合CO總產(chǎn)量和NaCl農(nóng)業(yè)工程學(xué)報(bào)2009年2008,87(8/9):1492-1502無(wú)添加劑D[4] Zheng Jilu, Yi Weiming, Wang Nana Bio-oil production fromAl acotton stalk[J]. 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FuelTechnical rTHaCNMHG第12期牛艷青等:金屬元素對(duì)木屑快速熱解的影響233Effect of metal elements on sawdust fast-pyrolysisNiu Yanqing Wang Xuebin, Tan Houzhang Xu Tongmo, Hui Shien, Zhao Qinxin, Zhou QulanState Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi'an 710049, China)Abstract: Influence of metal elements such as Al/Ca/Fe/K/Na/Zn on the pyrolysis rate and production of CO and CH4was investigated using Fourier Transform Infrared Analyzer(FTIR) in the process of sawdust fast-pyrolysis in anentrained flow reactor. The results show that the addition of metal elements inhibits the production of co/CH4, and theinhibiting ability order is Fe2O3>ZnO>NaCI>Cao>KCI> ALO3. The addition of Al2O3/ Fe2O3/ZnO shortens theescaping time of CO and CH4, especially for Fe2O3. The statistical analysis suggests that the addition of metal elementsgenerally decreases the reaction rate in the process of biomass fast-pyrolysis, and the reaction rate order is no-additionAlO3>Fe2O3>Zno>KCI> Cao> NaclKey words: biomass, pyrolysis, carbon monoxide, methane, sawdust, metal elements, Fourier transform infraredanalyzer(FTIR中國(guó)煤化工CNMHG