配煤对气化焦孔隙结构及分形特征的影响
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摘要
依据不同配比的焦煤、焦煤洗中煤和神木长焰煤配煤制备气化焦,利用低温氮气吸附法、压汞法和扫描电镜分析焦炭孔隙结构的变化规律,使用FHH模型在p/p0为0～0.5和0.5～0.9的相对压力下分别计算两个分形维数D_1和D_2,分析了配煤对焦炭孔隙分形特征的影响。结果表明:焦炭的微孔孔径主要分布在0.5nm～1.0nm之间,中孔孔径主要分布在2.0nm～12.0nm之间。随配煤灰分的增加,配煤灰分对焦炭孔隙的形成既有促进作用又有阻碍作用,焦炭中微孔的孔径分布呈现向孔径更大位置移动的趋势,微孔和中孔数量先增加后减少,与焦炭比表面积和孔体积变化规律一致,焦炭大孔数量先增加后略微减少;焦炭孔隙有两种分形特征D_1和D_2,D_1反映孔隙表面的粗糙度,配煤灰分增高导致更多的矿物质在高温分解成球形颗粒析出在孔隙表面,从而使得D_1增大;D_2和焦炭孔体积变化规律相似,随着配煤灰分的增高,焦炭孔隙内部复杂程度先增高后减小,D_2先增大后减小。
The gasification coke was prepared from coking coal,coking middlings and Shenmu long flame coal with different blending ratio.The change law of coke pore structure was analyzed by low temperature nitrogen adsorption method,mercury intrusion method and scanning electron microscope.Fractal dimensions D_1 and D_2 were calculated by using the FHH model under the relative pressures p/p0 range of 0-0.5 and 0.5-0.9,the effects of different blended coal on the pore fractal dimension of coke were analyzed.The results show that the pore diameter of microporous is mainly distributed between 0.5nm and 1.0nm,and the pore diameter of mesopores is mainly distributed between 2.0nm and 12.0nm.With the increase of ash of blended coal,the ash of blended coal has both promoting and hindering effect on coke porosity,and the pore size distribution of micropores in coke shows a tendency to move toward a larger pore size.And the micropores and mesopores of coke increase firstly and then decrease,which are consistent with the change of coke specific surface area and pore volume.The number of macropores firstly increases and then decreases slightly.There are two fractal characteristics of coke pores D_1 and D_2,D_1 reflects the roughness of the pore surface,and the increase of coal ash leads to more minerals decomposing into small spheres at high temperature,which causes D_1 to increase.The changes in D_2 are similar to micropore pore volume,indicating the volumetric roughness of micropore.As the ash of blended coal increases,D_2 increases firstly and then decreases.
The gasification coke was prepared from coking coal,coking middlings and Shenmu long flame coal with different blending ratio.The change law of coke pore structure was analyzed by low temperature nitrogen adsorption method,mercury intrusion method and scanning electron microscope.Fractal dimensions D_1 and D_2 were calculated by using the FHH model under the relative pressures p/p0 range of 0-0.5 and 0.5-0.9,the effects of different blended coal on the pore fractal dimension of coke were analyzed.The results show that the pore diameter of microporous is mainly distributed between 0.5nm and 1.0nm,and the pore diameter of mesopores is mainly distributed between 2.0nm and 12.0nm.With the increase of ash of blended coal,the ash of blended coal has both promoting and hindering effect on coke porosity,and the pore size distribution of micropores in coke shows a tendency to move toward a larger pore size.And the micropores and mesopores of coke increase firstly and then decrease,which are consistent with the change of coke specific surface area and pore volume.The number of macropores firstly increases and then decreases slightly.There are two fractal characteristics of coke pores D_1 and D_2,D_1 reflects the roughness of the pore surface,and the increase of coal ash leads to more minerals decomposing into small spheres at high temperature,which causes D_1 to increase.The changes in D_2 are similar to micropore pore volume,indicating the volumetric roughness of micropore.As the ash of blended coal increases,D_2 increases firstly and then decreases.
引文
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[19]MENG Haiyu,WANG Shuzhong,CHEN Lin,et al.Study on Product Distributions and Char Morphology During Rapid Copyrolysis of Platanus Wood and Lignite in a Drop Tube Fixed-bed Reactor[J].Bioresource Technology,2016,209:273-281.
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[21]YE D P,AGNEW J B,ZHANG D K.Gasification of a South Australian Low-rank Coal with Carbon Dioxide and Steam:Kinetics and Reactivity Studies[J].Fuel,1998,77(11):1209-1219.
[22]POMONIS J P,TSAOUSI E T,Frenkel-Halsey-Hill Equation,Dimensionality of Adsorption,and Pore Anisotropy[J].Langmuir the Acs Journal of Surfaces and Colloids,2009,25(17):9986-9994.
[23]季斌,位革老,张凤桐,等.气煤配煤炼焦对焦炭热性质及孔结构的影响[J].煤炭科学技术,2015,43(5):139-143.JI Bin,WEI Gelao,ZHANG Fengtong,et al.Coking with Gas Coal Blended Affected to Thermal Property and Pore Structure of Coke[J].Coal Science and Technology,2015,43(5):139-143.
[24]张洪,李迎,哈斯,等.煤粉中内在矿物对煤焦孔隙结构的影响[J].中国矿业大学学报,2009,38(6):810-814.ZHANG Hong,LI Ying,HA Si,et al.Effects of Included Minerals in Pulverized Coals on the Pore Structure of Chars[J].Journal of China University of Mining and Technology,2009,38(6):810-814.
[25]王聪,江成发,储伟.煤的分形维数及其影响因素分析[J].中国矿业大学学报,2013,42(6):1009-1014.WANG Cong,JIANG Chengfa,CHU Wei.Fractal Dimension of Coals and Analysis of Its Influencing Factors[J].Journal of China University of Mining and Technology,2013,42(6):1009-1014.
[2]王胜春,张德祥,陆鑫,等.中国炼焦煤资源与焦炭质量的现状与展望[J].煤炭转化,2011,34(3):92-96.WANG Shengchun,ZHANG Dexiang,LU Xin,et al.Current Status and Prospects of Coking Coal Resources and Coke Quality in China[J].Coal Conversion,2011,34(3):92-96.
[3]孟庆岩,杨志荣,黄戒介,等.神木煤与黏结煤配伍制气化焦的黏结特性[J].煤炭转化,2017,40(5):45-49.MENG Qingyan,YANG Zhirong,HUANG Jiejie,et al.Bonding Characteristics of Gasification Coke in Combination with Shenmu Coal and Bonded Coal[J].Coal Conversion,2017,40(5):45-49.
[4]崔强,孙体昌,余文,等.用煤泥为还原剂制备海滨砂矿含碳球团[J].金属矿山,2014(10):86-90.CUI Qiang,SUN Tichang,YU Wen,et al.Preparation of Carbon-containing Briquettes Made from Beach Placer Using Coalslime as Reductant[J].Mental Mine,2014(10):86-90.
[5]张磊,刘文礼,马克富,等.炼焦中煤再选技术试验研究[J].煤炭科学技术,2011,39(3):125-128.ZHANG Lei,LIU Wenli,MA Kefu,et al.Experiment Study on Repreparation Technology of Coking Middlings[J].Journal of Coal Science and Technology,2011,39(3):125-128.
[6]刘清泉,侯作民.快速灰分测定仪的应用[J].燃料与化工,1994,25(4):183-184.LIU Qingquan,HOU Zuomin.Application of Fast Ash Analyzer[J].Fuel and Chemical Processes,1994,25(4):183-184.
[7]GORNOSTAYEV S S,HRKKI J J.Mechanism of Physical Transformations of Mineral Matter in the Blast Furnace Coke with Reference to Its Reactivity and Strength[J].Energy and Fuels,2006,20(6):2632-2635.
[8]常娜,陈延信,甘艳萍.微负压系统中不同粒径煤粉热解半焦特性研究[J].煤炭转化,2014,37(1):65-68.CHANG Na,CHEN Yanxin,GAN Yanping.Characteristics Study on Semicoke from Coal Fast Pyrolysis with Different Particle Size Micro-negative Pressure[J].Coal Conversion,2014,37(1):65-68.
[9]徐秀峰,顾永达.焦炭的比表面积与CO2气化反应性的关系[J].燃料与化工,1996,27(3):122-124.XU Xiufeng,GU Yongda.The Relationship Between the Specific Area of Coal Chars and Their Gasification Reactivity by CO2[J].Fuel and Chemical Processes,1996,27(3):122-124.
[10]张文成,任学延,张小勇,等.废橡胶共焦化对焦炭结构影响[J].化工进展,2017,36(增刊1):339-345.ZHANG Wencheng,REN Xueyan,ZHANG Xiaoyong,et al.Study on Influence of Coking with Used Rubber on Coke Microstructure[J].Chemical Industry and Engineering Progress,2017,36(Supplement 1):339-345.
[11]陆云婷,倪明江,吴荣兵,等.KOH活化对焦炭孔隙结构以及导电特性影响[J].工程热物理学报,2014,35(7):1448-1452.LU Yunting,NI Mingjiang,WU Rongbing,et al.Characteristics of Pore Structure and Electrical Conductivity of Charcoal Prepared by KOH Activation[J].Journal of Engineering Thermophysics,2014,35(7):1448-1452.
[12]鞠付栋,陈汉平,杨海平,等.煤气化过程中焦炭的表面孔隙结构及其分形特征[J].中国电机工程学报,2010,30(8):9-14.JU Fudong,CHEN Hanping,YANG Haiping,et al.Char Surface Pore Structure and Its Fractal Characteristics During Coal Gasification[J].Proceedings of the CSEE,2010,30(8):9-14.
[13]邹涛,徐宏伟,袁善录,等.配入低阶煤对制得气化焦气化特性的影响[J].煤炭学报,2017,42(增刊2):512-517.ZOU Tao,XU Hongwei,YUAN Shanlu,et al.Influence of Blending Low-rank Coals on Gasification Characteristics of Gasification Coke[J].Journal of China Coal Society,2017,42(Supplement 2):512-517.
[14]JENKINS D R,MAHONEY M R.Fissure Formation in Coke(2):Effect of Heating Rate,Shrinkage and Coke Strength[J].Fuel,2010,89(7):1663-1674.
[15]李文军,焦子阳,刘丽丽,等.甲醇萃取对大雁褐煤孔隙结构的影响[J].煤炭转化,2009,32(4):5-7.LI Wenjun,JIAO Ziyang,LIU Lili,et al.Effect of Methanol Extraction on Pore Character of Dayan Lignite[J].Coal Conversion,2009,32(4):5-7.
[16]么玉鹏,姜波,李明,等.淮北朱仙庄矿构造煤孔隙结构及其分形表征研究[J].煤炭工程,2016,48(5):98-101.YAO Yupeng,JIANG Bo,LI Ming,et al.Pore Structure and Fractal Characteristic of Tectonic Coals from Zhuxianzhuang Coal Mine in Huaibei Coalfield[J].Coal Engineering,2016,48(5):98-101.
[17]戚灵灵,王兆丰,杨宏民,等.基于低温氮吸附法和压汞法的煤样孔隙研究[J].煤炭科学技术,2012,40(8):36-39.QI Lingling,WANG Zhaofeng,YANG Hongmin,et al.Study on Porosity of Coal Samples Based on Low Temperature Nitrogen Adsorption Method and Mercury Porosimetry[J].Coal Science and Technology,2012,40(8):36-39.
[18]QI Ying,HOADLEY A F A,CHAFFEE A L,et al.Characterization of Lignite as an Industrial Adsorbent[J].Fuel,2011,90(4):1567-1574.
[19]MENG Haiyu,WANG Shuzhong,CHEN Lin,et al.Study on Product Distributions and Char Morphology During Rapid Copyrolysis of Platanus Wood and Lignite in a Drop Tube Fixed-bed Reactor[J].Bioresource Technology,2016,209:273-281.
[20]TANG Jiewu,FENG Li,LI Yajun,et al.Fractal and Pore Structure Analysis of Shengli Lignite During Drying Process[J].Powder Technology,2016,303:251-259.
[21]YE D P,AGNEW J B,ZHANG D K.Gasification of a South Australian Low-rank Coal with Carbon Dioxide and Steam:Kinetics and Reactivity Studies[J].Fuel,1998,77(11):1209-1219.
[22]POMONIS J P,TSAOUSI E T,Frenkel-Halsey-Hill Equation,Dimensionality of Adsorption,and Pore Anisotropy[J].Langmuir the Acs Journal of Surfaces and Colloids,2009,25(17):9986-9994.
[23]季斌,位革老,张凤桐,等.气煤配煤炼焦对焦炭热性质及孔结构的影响[J].煤炭科学技术,2015,43(5):139-143.JI Bin,WEI Gelao,ZHANG Fengtong,et al.Coking with Gas Coal Blended Affected to Thermal Property and Pore Structure of Coke[J].Coal Science and Technology,2015,43(5):139-143.
[24]张洪,李迎,哈斯,等.煤粉中内在矿物对煤焦孔隙结构的影响[J].中国矿业大学学报,2009,38(6):810-814.ZHANG Hong,LI Ying,HA Si,et al.Effects of Included Minerals in Pulverized Coals on the Pore Structure of Chars[J].Journal of China University of Mining and Technology,2009,38(6):810-814.
[25]王聪,江成发,储伟.煤的分形维数及其影响因素分析[J].中国矿业大学学报,2013,42(6):1009-1014.WANG Cong,JIANG Chengfa,CHU Wei.Fractal Dimension of Coals and Analysis of Its Influencing Factors[J].Journal of China University of Mining and Technology,2013,42(6):1009-1014.