甲烷与正丁烷微小尺度催化燃烧性能比较
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摘要
对微圆管内甲烷和正丁烷在Pt/ZSM-5上的催化燃烧进行实验研究,获得并分析了二者的稳燃范围、产物浓度、壁温分布和壁面散热等燃烧性能。发现在富燃条件下甲烷和正丁烷能够在大当量比下实现催化自稳燃烧。相同流量下正丁烷稳燃当量比范围宽于甲烷,贫燃范围在0.4附近。流量由200 ml·min~(-1)增大至1000 ml·min-1,甲烷和正丁烷转化率出现大幅下降。在实验范围内,正丁烷和甲烷的转化率差异不大。化学当量比条件下随流量增大,正丁烷的转化率在600 ml·min~(-1)开始高于甲烷。甲烷和正丁烷能够在散热比例高达70%的情况下自稳催化燃烧且转化率在95%以上。相同流量下,与甲烷相比,正丁烷催化燃烧的壁温、散热功率和散热比例都更高。整体来看,正丁烷催化稳燃范围较甲烷略宽,两者转化率曲线相近,放热功率和壁面散热功率相差较小,正丁烷在必要时可作为甲烷的替代燃料。
Catalytic combustion of methane and n-butane with Pt/ZSM-5 in a microtube was studied on self-sustaining combustion limits, product concentrations, wall temperature, and surface heat loss. The catalytic combustion of methane and n-butane could be sustained at very high molar ratio(Φ) in rich burn condition. At the same flow rate, n-butane had broader self-sustaining combustion limit than methane with lean burn limit around 0.4. Conversion of the two fuels decreased steeply with flow rate increased from 200 to 1000 ml·min~(-1), which were largely due to decrease of residence time and increase of weight hourly space velocity(WHSV). The combustion conversion of methane and n-butane showed minimal difference within the range of experiments. As a result of activation of gas-phase reactions posterior to catalyst and its feedback effect to catalytic reaction, n-butane had higher conversion than methane at the same chemical normality upon flow rate reaching to 600 ml·min~(-1). Both methane and n-butane could have self-sustaining combustion with above 95% conversion even when ratio of through-wall heat loss to input power was reached to 70%. Compared to that of methane, n-butane combustion produced higher wall temperature, through-wall heat loss rate, and ratio of through-wall heat loss rate to input power, which was directly related to the activation of gas-phase reactions in n-butane combustion. Overall, considered broader combustion limit, similar conversion curve, minimal difference in heat generate rate and through-wall heat loss, n-butane could be an alternative fuel to methane when necessary.
Catalytic combustion of methane and n-butane with Pt/ZSM-5 in a microtube was studied on self-sustaining combustion limits, product concentrations, wall temperature, and surface heat loss. The catalytic combustion of methane and n-butane could be sustained at very high molar ratio(Φ) in rich burn condition. At the same flow rate, n-butane had broader self-sustaining combustion limit than methane with lean burn limit around 0.4. Conversion of the two fuels decreased steeply with flow rate increased from 200 to 1000 ml·min~(-1), which were largely due to decrease of residence time and increase of weight hourly space velocity(WHSV). The combustion conversion of methane and n-butane showed minimal difference within the range of experiments. As a result of activation of gas-phase reactions posterior to catalyst and its feedback effect to catalytic reaction, n-butane had higher conversion than methane at the same chemical normality upon flow rate reaching to 600 ml·min~(-1). Both methane and n-butane could have self-sustaining combustion with above 95% conversion even when ratio of through-wall heat loss to input power was reached to 70%. Compared to that of methane, n-butane combustion produced higher wall temperature, through-wall heat loss rate, and ratio of through-wall heat loss rate to input power, which was directly related to the activation of gas-phase reactions in n-butane combustion. Overall, considered broader combustion limit, similar conversion curve, minimal difference in heat generate rate and through-wall heat loss, n-butane could be an alternative fuel to methane when necessary.
引文
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[30]LI J,ZHONG B.Experimental investigation on heat loss and combustion in methane/oxygen micro-tube combustor[J].Applied Thermal Engineering,2008,28(7):707-716.
[2]MIKAMI M,MAEDA Y,MATSUI K,et al.Combustion of gaseous and liquid fuels in meso-scale tubes with wire mesh[J].Proceedings of the Combustion Institute,2013,34(2):3387-3394.
[3]李军伟,钟北京.微细直管燃烧器的散热损失研究[J].中国电机工程学报,2007,27(20):59-64.LI J W,ZHONG B J.Investigation on heat loss of microtube combustor[J].Proceedings of the CSEE,2007,27(20):59-64.
[4]KAISARE N S,VLACHOS D G.A review on microcombustion:fundamentals,devices and applications[J].Progress in Energy and Combustion Science,2012,38(3):321-359.
[5]CHOU S K,YANG W M,CHUA K J,et al.Development of micro power generators—a review[J].Applied Energy,2011,88(1):1-16.
[6]邓元望,刘放浪,刘学英.天然气及其在内燃机中的应用技术[J].拖拉机与农用运输车,2004,(5):5-6.DENG Y W,LIU F L,LIU X Y.Natural gas and its application to engine[J].Tractor&Farm Transporter,2004,(5):5-6.
[7]QU Z G,FENG X B.Catalytic combustion of premixed methane/air in a two-zone perovskite-based alumina pileup-pellets burner with different pellet diameters[J].Fuel,2015,159:128-140.
[8]周明月,杨卫娟,邓尘,等.微型圆管内氢气/甲烷/空气催化燃烧实验[J].浙江大学学报(工学版),2015,49(12):2276-2281.ZHOU M Y,YANG W J,DENG C,et al.Experiments on hydrogen/methane/air catalytic combustion in micro tube[J].Journal of Zhejiang University(Engineering Science),2015,49(12):2276-2281.
[9]张力,闫云飞,李丽仙,等.微型燃烧器内甲烷预混催化燃烧的数值研究[J].化工学报,2009,60(3):627-633.ZHANG L,YAN Y F,LI L X,et al.Numerical investigation of premixed catalytic combustion of methane in micro-combustor[J].CIESC Journal,2009,60(3):627-633.
[10]孙路石,秦晓楠,逄鹏,等.La/Mn改性Pd/γ-Al2O3催化剂对甲烷催化燃烧的影响[J].中国电机工程学报,2009,29(11):26-31.SUN L S,QIN X N,PANG P,et al.Influence of Pd/γ-Al2O3 catalyst modified by La/Mn on methane catalytic combustion[J].Proceedings of the CSEE,2009,29(11):26-31.
[11]YANG H,FENG Y,WANG X,et al.OH-PLIF investigation of wall effects on the flame quenching in a slit burner[J].Proceedings of the Combustion Institute,2013,34(2):3379-3386.
[12]YAN Y,HUANG W,TANG W,et al.Numerical study on catalytic combustion and extinction characteristics of pre-mixed methane-air in micro flatbed channel under different parameters of operation and wall[J].Fuel,2016,180:659-667.
[13]LI Y H,CHEN G B,WU F H,et al.Effects of catalyst segmentation with cavities on combustion enhancement of blended fuels in a micro channel[J].Combustion&Flame,2012,159(4):1644-1651.
[14]BURCH R,CRITTLE D J,HAYES M J.C—H bond activation in hydrocarbon oxidation on heterogeneous catalysts[J].Catalysis Today,1999,47(1/2/3/4):229-234.
[15]CIMINO S,BENEDETTO A D,PIRONE R,et al.CO,H2 or C3H8assisted catalytic combustion of methane over supported La Mn O3monoliths[J].Catalysis Today,2003,83(1):33-43.
[16]DEMOULIN O,CLEF B L,NAVEZ M,et al.Combustion of methane,ethane and propane and of mixtures of methane with ethane or propane on Pd/γ-Al2O3 catalysts[J].Applied Catalysis A General,2008,344(s1/2):1-9.
[17]GOLODETS G I.Heterogeneous Catalytic Reactions Involving Molecular Oxygen[M].Amsterdam·New York:Elsevier,1983.
[18]VESER G,ZIAUDDIN M,SCHMIDT L D.Ignition in alkane oxidation on noble-metal catalysts[J].Catalysis Today,1999,47(1/2/3/4):219-228.
[19]BEKAT T,INAL F.Effects of dimethyl ether on n-butane oxidation[J].Fuel,2014,115(1):861-869.
[20]ZHONG B J,FAN Y.Characteristics of hydrogen-assisted catalytic ignition of n-butane/air mixtures[J].International Journal of Hydrogen Energy,2012,37(10):8716-8723.
[21]胡二江,黄佐华,姜雪,等.C1~C4烷烃预混层流燃烧与着火特性研究[J].工程热物理学报,2013,34(3):558-562.HU E J,HUANG Z H,JIANG X,et al.Kinetic study on laminar velocities and ignition delay time of C1—C4 alkanes[J].Journal of Engineering Thermophysics,2013,34(3):558-562.
[22]曹玉春,冯珍珍,李晓东.丁烷层流预混火焰多环芳烃生成化学动力学模拟[J].中国电机工程学报,2012,32(8):71-77.CAO Y C,FENG Z Z,LI X D.Detailed chemical kinetic modeling of polycyclic aromatic hydrocarbons formation in a laminar premixed n-butane flame[J].Proceedings of the CSEE,2012,32(8):71-77.
[23]杨帆,杨庆涛,钟北京.微尺度正丁烷催化反应的实验研究[J].工程热物理学报,2009,30(5):890-892.YANG F,YANG Q T,ZHONG B J.Experimental study on micro-scale n-butane catalytic reaction characteristics[J].Journal of Engineering Thermophysics,2009,30(5):890-892.
[24]DEUTSCHMANN O,SCHMIDT R,BEHRENDT F,et al.Numerical modeling of catalytic ignition[J].Symposium on Combustion,1970,26(1):1747-1754.
[25]XIN Y,WANG H,LAW C K.Kinetics of catalytic oxidation of methane,ethane and propane over palladium oxide[J].Combustion&Flame,2014,161(4):1048-1054.
[26]DENG C,YANG W,ZHOU J,et al.Catalytic combustion of methane,methanol,and ethanol in microscale combustors with Pt/ZSM-5 packed beds[J].Fuel,2015,150:339-346.
[27]熊鹏飞,钟北京,杨帆.C1~C4在Pt催化剂上的多相反应机理[J].物理化学学报,2011,27(9):2200-2208.XIONG P F,ZHONG B J,YANG F.Heterogeneous mechanism of C1—C4 on a platinum catalyst[J].Acta Physico-Chimica Sinica,2011,27(9):2200-2208.
[28]杨帆.正丁烷的微尺度催化着火与燃烧[D].北京:清华大学,2013.YANG F.Micro-scale catalytic ignition and combustion of n-butane[D].Beijing:Tsinghua University,2013
[29]YANG W,WANG Y,ZHOU J,et al.Catalytic self-sustaining combustion of the alkanes with Pt/ZSM-5 packed bed in a microscale tube[J].Chemical Engineering Science,2017,158:30-36.
[30]LI J,ZHONG B.Experimental investigation on heat loss and combustion in methane/oxygen micro-tube combustor[J].Applied Thermal Engineering,2008,28(7):707-716.