摘要
人类社会现在面临着巨大的能源及环境危机,能源消耗以及污染物的排放屡创新高。能源关系着一个国家的兴衰,能源问题已经成为各国争端的焦点。由于环境的污染近几年各种极端恶劣的天气接踵而至。发展可再生能源已经成为关系人类发展的重大问题。我国生物质能源发展起步晚,技术落后,并没有形成相应产业。借鉴国外经验,参照我国基本国情,在我国非常适合于发展生物质颗粒燃料。现阶段我国主要发展的是农作物秸秆类生物质颗粒燃料,这种生物质颗粒燃料有生物质燃料所具有的突出优点,但是其也具有明显的缺点,主要表现在燃烧过程中极容易发生积灰结渣阻碍燃烧的顺利进行,严重制约了生物质颗粒燃料的发展。
本文针对生物质颗粒燃料容易积灰结渣这一问题,依据东北地区特点,选用玉米秸秆,大豆秸秆以及花生壳进行复合生物质颗粒燃料的研究,以解决玉米秸秆的灰分熔点过低问题。本文选用CaO,SiO2,MgO,Fe2O3,Al2O3以及长春当地粘土作为添加剂,以提高玉米秸秆颗粒燃料的灰分熔点,解决玉米秸秆燃烧过程中容易结块粘连的问题。并且通过热重试验对复合生物质颗粒燃料进行燃烧特性及燃烧动力学分析。其主要研究结果概括如下:
1)复合生物质颗粒燃料的灰分熔融特性
花生壳以及大豆秸秆这两种生物质其软化温度都很高,分别达1399℃以及1520℃,远远超过了玉米秸秆的1102℃。但是花生壳以及大豆秸秆分别与玉米秸秆混合燃料软化温度不高。试验研究发现,添加剂对于改善玉米秸秆的灰分熔融特性效果明显,MgO的含量达到3%时,玉米秸秆颗粒燃料灰分的软化温度(ST)达到1445℃,Al2O3的含量达到3%时,软化温度(ST)达到1450℃,CaO的含量为3%时,软化温度(ST)达到1355℃。
2)复合生物质颗粒燃料的结渣特性
在对复合生物质颗粒燃料进行模拟实际燃烧试验中发现,利用复合生物质颗粒燃料灰分的软化温度对生物质颗粒燃料进行灰熔融性评价,并不能准确地反映生物质颗粒燃料燃烧过程中的真实积灰结渣情况。运用模拟燃烧试验能够准确反映复合生物质颗粒燃料的结渣特性。玉米秸秆在900℃时已经表现出结渣倾向,在1000℃时已经完全结成硬块,而当MgO的含量达到3%时,复合生物质颗粒燃料在1200℃时也完全不结焦,其它添加剂在不同含量时亦能保证提高50~100℃。
在对复合生物质颗粒燃料进行模拟实际燃烧试验中发现,利用复合生物质颗粒燃料灰分的软化温度对生物质颗粒燃料进行灰熔融性评价,并不能准确地反映生物质颗粒燃料燃烧过程中的真实积灰结渣情况。运用模拟燃烧试验能够准确反映复合生物质颗粒燃料的结渣特性。
3)复合生物质颗粒燃料的燃烧特性
利用O2及N2两种气氛进行热重试验,通过两种曲线进行结合分析,判断颗粒燃料的着火点,并分析研究认为复合生物质颗粒燃料的各种特性都要比玉米秸秆颗粒燃料的燃烧特性优异。
4)复合生物质颗粒燃料的燃烧动力学特性
生物质颗粒燃料的燃烧过程是一个非等温的过程,在对热重数据进行处理分析时,选用积分法的Coats-Redfern方法。利用Coats-Redfern方程进行线性拟合得到的回归方程求的“动力学三因子”中的表观活化能E以及频率因子A,通过分析认为Coats-Redfern方程能够很好的反应生物质颗粒燃料的燃烧过程。并且通过分析验证了复合生物质颗粒燃料燃烧特性的优异性。
复合生物质颗粒燃料其结渣特性以及燃烧特性都要比玉米秸秆颗粒燃料好得多。优化配比得到的复合生物质颗粒燃料较好的解决了玉米秸秆燃烧过程中出现的结渣问题,并且研制的复合生物质颗粒燃料燃烧特性优越,对于复合生物质颗粒燃料的推广有积极作用,对于我国生物质能源的发展具有使用价值。
Our society is facing huge energy and environmental crises now. Energyconsumption and discharge of pollutant are repeatedly break records. Energy affectsthe rise and fall of a country and energy problems has become the focus of all disputes.Extremely bad weathers come one after another in recent years due to theenvironmental pollution. The development of renewable energy sources has become abig issue that influences human progress.As a eximious and clean renewable energy,biomass has draw the attention of more and more countries. Biomass hasn't formed acorresponding industry in China due to its late starting and backward technology.After learning from abroad and researching China's basic conditions we find thatChina is propitious to develop biomass particle fuel. At present in China the mainbiomass particle fuel is that takes crops' straw as material. This kind of biomassparticle fuel tents to produces slagging which hinder burning. And thus restricts thedevelopment of biomass particle fuel.
This article aims to solve the problem of biomass's slagging and ash fouling.According to the regional characteristics of northeast, corn straw, soybean straw andpeanut shells are used in the research of composite biomass particle fuel hoping tosolve the problem of corn straw ash's low melting point. CaO,SiO2,MgO,Fe2O3,Al2O3and ChangChun's local clay are taken as additives in order to heighten the cornstraw ash's melting point and prevent agglomerate adhesion during burning process.Thermo-gravimetric experiment are conducted to analysis combustion characteristicand combustion kinetics of composite biomass particle fuel.
1) Ash melting characteristics of composite biomass particle fuels
Peanut shells and soybean straw these two kinds of biomass the softeningtemperature are very high, up to139℃9and m ore than1520℃,far m ore than the corn straw1102℃. But peanut shells and soybean straw respectively with the cornstraw mixed fuel softening temperature is not high. Test study found, using additive toimprove corn stalk ash melting characteristics effect is obvious. The content of MgOreached3%, corn straw pellet fuel of ash softening temperature (ST) to144℃5, thecontent of Al2O3reached3%, softening temperature (ST) to1450℃, the content ofCaO reached3%, softening temperature (ST) to1355℃.
2)Slagging characteristics of composite biomass particle fuels
Simulation of the actual combustion texts of composite biomass particle fuelsshows that evaluation of biomass particle fuel's ash melting couldn't reflect the realash slagging during its burning. Because the evaluation is based on compositebiomass particle fuel's ash softening temperature. Application of simulation burningexperiment can accurately reflect the composite biomass particle fuel's slaggingcharacteristics. Corn straw in900℃is show ing slagging tendency,in1000℃havebeen fully formed lumps. But when the content of MgO reached3%, compositebiomass pellet fuel in12℃00is com pletely not anti-coking, other additives indifferent content can also improve more than50to100℃.
3) combustion characteristics of composite biomass particle fuels
O2and N2are used to conduct thermo-gravimetric experiment and produced twocurves. Particle fuel ignition is judged by combined analysis of this two curves.Research proved that all characteristics of composite biomass particle fuels are betterthan that of the corn straw particle fuels.
4)Combustion kinetics characteristics of composite biomass particle fuels
Combustion process of composite biomass particle fuels is a non-isothermalprocess. The Coasts-Redfern method which belongs to integration is adopted todealing with the thermo-gravimetric data. The use of coats-Redfern equation areobtained by linear regression equation of the return of get "dynamic three factors" ofthe apparent activation energy E and frequency factor A. Based on analysis i thinkCoats-Redfern equation can give a good reflection on biomass particle fuelscombustion process. Analysis proved the excellent combustion characteristics of composite biomass particle fuels.
The slagging and combusion characteristics of composite biomass particle fuelsare far better than corn straw particle fuel's. Some composite biomass particle fuel hassolve the slagging problem during the corn straw combustion. The combustioncharacteristics of composite biomass particle fuel are extremely advantageous. Thisplays a positive role in spreading composite biomass fuel and has great significancefor the development of biomass energy in China.
引文
[1]刘润生.能源消耗与产业结构变迁[D].合肥工业大学硕士学位论文,2009,4.
[2] SAXENARC, ADHIKARIDK, GOYALHB. Biomass based energy fuel through biochemicalroutes: A review[J].Renewable and Sustainable Energy Review,2009,13(l):167-178.
[3]朱清时,阎立峰,郭庆祥,等.生物质洁净能源[M].北京:化学工业出版社,2002.
[4] Ayhan Demirbas. Combustion characteristics of different biomass fuels [J]. Progress inEnergy and Combustion Science,2004(30):219-230.
[5]田贺忠,郝吉明,陆永琪,等.中国生物质燃烧排放量的估算[J].环境科学学报,2002,22(2):204-208.
[6] LEUNG DENN IS Y C,CHANG J,WU C Z,etal.A review on the energy productionconsumption and prospect of renewable energy in China[J].Renewable and Sustainable EnergyRe2views,2003,7(5):453-463.
[7]岳跃国.《“十二五”节能减排综合性工作方案》解读减排量远超“双八双十”[EB/OL].
[2011-10-27]. http://www.mep.gov.cn/zhxx/hjyw/201110/t20111027_218884.htm
[8]中华人民共和国国家统计局.《中华人民共和国2010年国民经济和社会发展统计公报》.[2011-2-28].http://www.stats.gov.cn/tjgb/ndtjgb/qgndtjgb/t20110228_402705692.htm
[9]张军.中国能源发展战略和能源政策[J].能源与节能,2011,5:3-5.
[10]骆仲泱,周劲松,王树荣,余春江,方梦祥,岑可法.中国生物质能利用技术评价[J].中国能源,2004,26(9):39-41.
[11] PAR IKKA. Global biomass fuel resources [J].Biomass and Bioenergy,2004,27(6):613-620.
[12]赵廷林,舒伟,邓大军,等.生物质致密成型技术研究现状与发展[J].农机化研究,2010,12(4):29-33.
[13]陈彦宏,武佩,田雪艳,等.生物质致密成型燃料制造技术研究现状[J].特别关注,2007,1:206-210.
[14]肃林湘.多种方式开发利用生物质能源[J].中国林业,2006,11:120-125.
[15]刘宇刚.关于利用生物质能技术的思考[J].佳木斯大学学报,2005,23(3):443-445
[16]贾小黎,丁航.中国生物质发电产业现状、问题和建议[J].太阳能,2007,5:10-13.
[17]黄英超,李文哲,张波.生物质能发电技术现状与展望[J].东北农业大学学报,2007,38(2):270-274.
[18]李改莲,等.中国生物质能的利用状况及展望[J].河南农业大学学报,2004,38(1):100-104.
[19] Nielsen H. P., Frandsen F. J., Dam-Johansen K, et al. The implications of chlorine-associatedcorrosion on the operation of biomass-fired boilers[J]. Process in Energy and Combustion Science,2000,26:283-298.
[20] LIN W,SONG W. Power production from biomass in Denmark[J].Journal chemistry andtechnology,2005,33(6):650-655.
[21]张百良.农村能源工程学[M].北京:中国农业出版社,1999.
[22]中国科学技术协会.2006-2007农业工程学科发展报告[M].北京:中国科学技术出版社,2007,第一版.
[23]李美华,俞国胜.生物质燃料成型技术研究现状[J].木材加工机械,2005,16(2):36-40.
[24] Husain Z,Zainac Z,Abdullah Z.Briquetting of palm fibre and shell from the processing ofpalm nuts to palm oil[J].Biomass and Bioenergy,2002,20:505-509.
[25] P D Grover,S K Mishra.Proceedings of the international workshop on biomassbriquetting[C].New Delhi,India,1996.
[26]赵武子.生物质混合颗粒燃料热工特性研究[D].吉林大学硕士论文,2010,4.
[27]《煤的工业分析方法》(GB/T212-2008)
[28]《生物质固体成型燃料试验方法》(NY/T1881-2010)
[29]叶贻杰.生物质灰特性及其结渣机理的研究[D].华中科技大学硕士论文,2007,1.
[30] R. S. Miller, Bellan J. A Generalized Biomass Pyrolysis Model Based on SuperimposedCellulose, Hemicellulose, and Lignin Kinetics[J]. Combust. Sci. and Tech.,1997,126:97-107
[31]徐婧.生物质燃烧过程中碱金属析出的实验研究[D].浙江大学硕士论文,2006,5.
[32] A. Williams, M Pourkashanian, J M jones. Combustion of Pulverized Coal and Biomass[J].Progress in Energy and Combustion Science,2001(27):587-610.
[33]宋鸿伟,等.生物质燃烧过程中的积灰结渣特性[J].节能与环保,2003,9:29-31.
[34]王晓岚,那峙雄.基于燃料特性的秸秆积灰结渣[J].赤峰学院学报,2008,2(24):76-77.
[35]袁艳文,林聪,等.生物质固体成型燃料抗结渣研究进展[J].可再生能源,2009,10(27):48-51.
[36] Easterly J L,Burnham M.Overview of Biomass and Waster Fuel Resources for PowerProduction[J].Biomass and Bioenergy,1996:79-92.
[37]李润东,聂永丰,李爱民,王雷.垃圾焚烧飞灰理化特性研究[J].燃料化学学报,2004,32(2):175-179.
[38]陈国艳,张忠孝,等.添加剂对煤灰熔融特性的影响[J].锅炉技术,2009,5(40):18-26.
[39] Ingwald Obernbergr, Friendrich Biedrmann,Walter Widmann and Rudolf Riedl,Concertrations of inorganic elements in biomass fuels and recovery in the different ashfractions[J].Biomass and Bioenergy,1997,3:211-224.
[40] Nielsen, H.P. Frandsen, F.J. Dam-Johansen, K.,etc. The implications of chlorine-associatedcorrosion on the operation of biomass-fired boilers [J].Progress in Energy and CombustionScience,2000(26):283-293.
[41] Valmari T, Lind T M, Kauppinen E I. Field study on ash behavior during circulatingfluidized-bed combustion of biomass[J].Ash Formation, Energy&Fuels,1999,13:379-389.
[42]卞素芳.生物质与煤混合燃烧过程中灰沉积特性的试验研究[D]山东大学硕士论文.2011,5.
[43]郝丽芬,李东雄,靳智平,等.灰成分与灰熔融性关系的研究[J].电力学报,2006,21(3):294-296.
[44] Blander M. and Pelton A.D. The Inorganic Cemistry of the Combusti on of WheatStraw [J]. Biomass and Bioenergy,1997,12(4):295-29.
[45]张浩.基于灰成分的生物质结渣特性研究[D].山东大学硕士学位论文.2010.4.
[46]朗芳,马晓茜,王晶晶.秸秆灰特性的研究[J].可再生能源,2007,25(4):25-28.
[47]张艳平,金宝升.生物质热化学转化过程中碱金属问题的相关研究[J].能源研究与利用.2007,(3):27-31.
[48] Xiaolin Wei, Uwe Schnell, Klaus Hein R G. Behaviour of gaseous chlorine and alkali metalsduring biomass thermal utilization[J].Fuel,2005,84:841-848.
[49]叶贻杰.生物质灰特性及其结渣机理研究[D].武汉:华中科技大学,2007.
[50]孙巍.流化床垃圾焚烧积灰特性研究及冷态积灰模拟实验[D].杭州:浙江大学机械与能源工程学院,2006.
[51]叶贻杰,陈汉平,王贤华,等.生物质流化床燃烧过程中的结渣特性[J].可再生能源,2007,3:50-53.
[52] Larry L B, Thomas R M, Thomas R M. The Behavior of Inorganic Material in Biomass-firedPower Boilers: Field and Laboratory Experiences [J]. Fuel Processing Technology,1998,54:47-78.
[53] Khanh-Quang Tran, Kristiina Iisa, Britt-Marie Steenari, etal. A kinetic study of gaseousalkali capture by kaolin in the fixed bed reactor equipped with an alkali detector[J].Fuel,2005,(84):169-175.
[54] Nielsen H P, Baxter L L, Sclippab G. Deposition of Potassium Salts on Heat TransferSurfaces Instraw-fired Boilers: a pilot-scale study[J]. Fuel.2000,79:131-139.
[55] Wei X L Uwe S, Klaus H R. Behaviour of Gaseous Chlorine and Alkali Metals DuringBiomass Thermal Utilization[J]. Fuel,2005,84:841-848.
[56] Mohamed Gabra, Anders Nordin, Marcus Ohman, Bjorn Kjellstrom. Alkaliretention/separation during bagasse gasication:a comparison between a fluidized bed and acyclone gasifier[J]. Biomass and Bioenergy2001,(21)461–476.
[57]李宝霞,张济宁.煤灰渣熔融特性的研究进展[J].现代化工,2005,25(5):23-26.
[58]阎维平,陈颖吟.TK6生物质燃料结渣特性分析与判别[J].华北电力大学学报,2007,34(1):49-54.
[59] Larry L.Baxter, Thomas R.Miles, Thomas R.Miles Jr., etal The behavior of inorganic materialin biomass-fired power boilers: field and laboratory experiences [J].Fuel Processing Technology1998,(54):47-78.
[60]刘乃安.生物质材料热解失重动力学及其分析方法研究[D].合肥:中国科学技术大学,2000.
[61]洪兴.差热、热重分析与非等温固相反应动力学[M].北京:冶金工业出版社,1995,第一版.
[62]于伯龄,姜胶东.实用热分析[M].北京:纺织工业出版社,1990,第一版.
[63]胡荣祖,高胜利,等.热分析动力学[M].北京:科学出版社,2008,第二版.
[64]宋春财,胡浩权,朱盛维,等.生物质秸杆热重分析及几种动力学模型结果比较[J].燃料化学学报,2003,31(4):311-316.
[65] Baxter L. Biomass-coal co-combustion: opportunity for affordable renewable energy[C].International Symposium on Utilization of Coal and Biomass, Newcastle, Australia,2003
[66] Eleni Kastanaki,Despina Vamvuka. A comparative reactivity and kinetic study on thecombustion of coal-biomass char blends [J]. Fuel,2006,85:1186-1193
[67]黄海珍.煤与生物质混合动力学特性及成型燃料固硫特性研究[D].吉林大学博士论文,2007,4.
[68]矫振伟.燃料燃烧热重试验台的研制[M].吉林大学,2006,9.
[69]乐园,李龙生.秸秆类生物质燃烧特性的研究[J].能源工艺,2006(4):30-33.
[70] Demirabas A.Combustion characteristics of different biomass fuels[J].Progress in Energy andCombustion Science,2004,30:219-230.
[71]傅维镳,张永康,王清安.燃烧学[M].高等教育出版社,1989,4(1).
[72] Demirabas A.Combustion characteristics of different biomass fuels[J].Progress in Energy andCombustion Science,2004,30:219-230.
[73] Fenkins BM,BaxterL L,Miles JrTR,etal.Combustion properties of biomass[J].Fuel ProcessingTechnology,1998,54:17-46.
[74]戴文仪.生物质颗粒燃料燃烧特性及燃烧动力学实验研究[D].吉林大学硕士论文,2007,6.
[75] Fenkins BM,BaxterL L,Miles JrTR,etal.Combustion properties of biomass[J].Fuel ProcessingTechnology,1998,54:17-46.
[76]韩昭沧.燃料及燃烧[M].北京:冶金工业出版社,1994,第二版.