气化细渣基础燃烧特性试验研究
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摘要
煤气化过程中产生大量含碳量较高的气化细渣,其填埋处理不仅占用大量土地,污染土壤和水体,同时造成能源浪费,如何高效环保地对气化细渣进行资源化利用是目前研究的热点。在获得气化细渣工业分析、元素分析、粒径分布、灰成分和微观形貌等基础上,利用热重对气化细渣单独燃烧及与燃料煤混合燃烧特性进行研究,对比了气化细渣与典型煤种燃烧特性的差异,并考虑掺混比例对混燃的影响。研究结果表明:气化细渣的M_(ar)=69. 7%,A_d=54. 5%,w(C_d)=43. 4%,Q_(gr,d)=16. 14 MJ/kg,干化后的气化细渣中碳含量和发热量与对比劣质烟煤相当;干燥后的气化细渣粒径普遍小于200μm,且孔隙结构发达,电镜结果显示其微观结构由球形颗粒和不规则多孔形状颗粒组成。气化细渣与其他煤种燃烧特性对比表明:气化细渣的着火温度和燃尽温度分别为601. 6℃和680. 8℃,着火和燃尽特性比对比煤样和对应的原煤略差。气化细渣和原煤在不同掺烧比例下的热重燃烧试验结果表明,气化细渣和原煤掺烧存在显著的协同效应,与原煤掺烧能显著改进气化细渣的燃烧特性,在25%气化细渣掺烧比例下,气化细渣的燃烧特性得到显著改善,且相比于纯烧原煤,掺烧气化细渣后混煤的燃烧特性未显著下降。研究结果表明,干化后高含碳量的气化细渣极具应用价值,且与原煤掺烧对混煤的燃烧特性影响较小,还能显著改进混煤的燃烧特性,将干化后的气化细渣与原煤掺烧是一种可行的利用气化细渣热值的技术方案。
In the process of coal gasification,a large amount of fine gasification slag( HC-ash) with high carbon content is produced.The ash-waste landfilling occupies a lot of land,causes the pollution of soil and water,and also wastes the energy.How to utilize the coal-gasification ash( HC-ash) is attracting more and more attentions recently.Based on the proximate and ultimate analysis,particle size distribution,ash compositions,and micro-morphologies of HC-ash,the characteristics of HC-ash combustion alone and combustion with raw coal were studied by thermos gravimetric analysis( TGA).The difference of combustion characteristics between HC-ash and typical coal was compared.The influence of mixing ratio on mixture combustion was also considered.The results show that the moisture of HC-ash( as received basis) reaches 69.7%,the ash of dried HC-ash is 54.5%,the carbon content in dried HC-ash is 43.4% with a heating value of 16.14 MJ/kg.The carbon content and calorific value of dried HC-ash are equivalent to that of inferior bituminous coal.The particle size of dried HC-ash is generally smaller than 200 μm,but with a very developed porous structure.The results of SEM show that the microstructure of HC-ash is composed of sphere and porous irregular shapes.HC-ash compared with other types of combustion characteristics show that the ignition temperature and burnout temperature of HC-ash is 601.6 ℃ and 680.8 ℃,respectively,which are slightly worse than those of contrastive coal samples.The TGA results with different mixing ratio of HC-ash and raw coal show that a significant synergistic effect is observed during the co-combustion of HC-ash and raw coal,which can significantly improve the combustion property of HC-ash.When mixing ratio is 25%,the combustion property of HC-ash is significantly improved and the combustion characteristics of mixed coal with HC-ash decreases slightly compared with pure raw coal.This study indicates that the dried HC-ash is of great application value,its co-firing with raw coal has little influence on the combustion characteristics of mixed coal and is able to improve the overall combustion properties.The overall results suggest that combustion of dried HC-ash with raw coal is a feasible technical scheme to utilize the calorific value of HC-ash.
In the process of coal gasification,a large amount of fine gasification slag( HC-ash) with high carbon content is produced.The ash-waste landfilling occupies a lot of land,causes the pollution of soil and water,and also wastes the energy.How to utilize the coal-gasification ash( HC-ash) is attracting more and more attentions recently.Based on the proximate and ultimate analysis,particle size distribution,ash compositions,and micro-morphologies of HC-ash,the characteristics of HC-ash combustion alone and combustion with raw coal were studied by thermos gravimetric analysis( TGA).The difference of combustion characteristics between HC-ash and typical coal was compared.The influence of mixing ratio on mixture combustion was also considered.The results show that the moisture of HC-ash( as received basis) reaches 69.7%,the ash of dried HC-ash is 54.5%,the carbon content in dried HC-ash is 43.4% with a heating value of 16.14 MJ/kg.The carbon content and calorific value of dried HC-ash are equivalent to that of inferior bituminous coal.The particle size of dried HC-ash is generally smaller than 200 μm,but with a very developed porous structure.The results of SEM show that the microstructure of HC-ash is composed of sphere and porous irregular shapes.HC-ash compared with other types of combustion characteristics show that the ignition temperature and burnout temperature of HC-ash is 601.6 ℃ and 680.8 ℃,respectively,which are slightly worse than those of contrastive coal samples.The TGA results with different mixing ratio of HC-ash and raw coal show that a significant synergistic effect is observed during the co-combustion of HC-ash and raw coal,which can significantly improve the combustion property of HC-ash.When mixing ratio is 25%,the combustion property of HC-ash is significantly improved and the combustion characteristics of mixed coal with HC-ash decreases slightly compared with pure raw coal.This study indicates that the dried HC-ash is of great application value,its co-firing with raw coal has little influence on the combustion characteristics of mixed coal and is able to improve the overall combustion properties.The overall results suggest that combustion of dried HC-ash with raw coal is a feasible technical scheme to utilize the calorific value of HC-ash.
引文
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[17]WANG X,LI S,ADEOSUN A,et al.Effect of potassium-doping and oxygen concentration on soot oxidation in O2/CO2 atmosphere:A kinetics study by thermogravimetric analysis[J].Energy Conversion and Management,2017,149:686-697.
[18]张锦萍,王长安,贾晓威,等.半焦-烟煤混燃特性及动力学分析[J].化工学报,2018,69(8):3611-3618.ZHANG Jinping,WANG Chang'an,JIA Xiaowei,et al.Co-combustion characteristics and kinetic analysis of semi-coke and bituminous coal[J].CIESC Journal,2018,69(8):3611-3618.
[2]商晓甫,游洋洋,周金倩,等.煤气化渣利用技术研究现状及应用趋势浅析[C]//2016中国环境科学学会学术年会论文集(第3卷).北京:[s.n.],2016:823-826.
[3]赵世永,吴阳,李博.Texaco气化炉灰渣理化特性与脱碳研究[J].煤炭工程,2016,48(9):29-32.ZHAO Shiyong,WU Yang,LI Bo.Study on residue features and decarbonization of Eexaco entrained flow gasifier[J].Coal Engineering,2016,48(9):29-32.
[4]刘嘉鹏.气流床气化细灰燃烧特性及再利用探讨[J].煤炭加工与综合利用,2017(6):17-20.LIU Jiapeng.Discussion on combustion characteristics and reuse of entrained-flow gasified fine ash[J].Coal Processing&Comprehensive Utilization,2017(6):17-20.
[5]XU S,ZHOU Z,GAO X,et al.The gasification reactivity of unburned carbon present in gasification slag from entrained-flow gasifier[J].Fuel Processing Technology,2009,90(9):1062-1070.
[6]高旭霞,郭晓镭,龚欣.气流床煤气化渣的特征[J].华东理工大学学报,2009,35(5):677-683.GAO Xuxia,GUO Xiaolei,GONG Xin.Characterizarion fof slag from entrained flow coal gasification[J].Journal of East China University of Science and Technology(Natural Science Edition),2009,35(5):677-683.
[7]TAO W,MEI G,LESTER E,et al.Characterisation of residual carbon from entrained-bed coal water slurry gasifiers[J].Fuel,2007,86(7):972-982.
[8]MONTAGNARO F,BRACHI P,SALATINO P.Char-wall interaction and properties of slag waste in entrained-flow gasification of coal[J].Energy&Fuels,2011,25(8):3671-3677.
[9]刘家利,郭孟狮,李炎.135 MW机组锅炉掺烧半焦试验及经济性分析[J].洁净煤技术,2017,23(2):86-91.LIU Jiali,GUO Mengshi,LI Yan.Economic analysis for a 135 MWpulverized coal fired boiler blending with semi-cok[J].Clean Coal Technology,2017,23(2):86-91.
[10]杨忠灿,程国安,李炎,等.电站煤粉锅炉掺烧兰炭试验研究[J].洁净煤技术,2017,23(1):80-85.YANG Zhongcan,CHENG Guoan,LI Yan,et al.Experimental research on pulverized coal power station blending with semi-coke[J].Clean Coal Technology,2017,23(1):80-85.
[11]刘家利,姚伟,杨忠灿,等.半焦与不同制粉系统的适应性分析[J].热力发电,2017,46(2):7-14.LIU Jiali,YAO Wei,YANG Zhongcan,et al.Adaptability analysis for semi-coke in different mill systems[J].Thermal Power Generation,2017,46(2):7-14.
[12]杨忠灿,刘家利,王志超,等.半焦着火性能评价指标在电站锅炉上的应用[J].热力发电,2017,46(3):109-113,120.YANG Zhongcan,LIU Jiali,WANG Zhichao,et al.Application of ignition performance evaluation indicator of semi-coke in utility boilers[J].Thermal Power Generation,2017,46(3):109-113,120.
[13]张旻晓.气化半焦在流化床实验台上燃烧特性研究[D].哈尔滨:哈尔滨工业大学,2011.
[14]HUANG Q,LI S,LI G,et al.Reduction of fine particulate matter by blending lignite with semi-char in a down-fired pulverized coal combustor[J].Fuel,2016,181:1162-1169.
[15]WANG X,SI J,TAN H,et al.Kinetics investigation on the combustion of waste capsicum stalks in Western China using thermogravimetric analysis[J].Journal of Thermal Analysis and Calorimetry,2012,109(1):403-412.
[16]姜秀民,李巨斌,邱健荣.超细化煤粉燃烧特性的研究[J].中国电机工程学报,2000,20(6):71-74.JIANG Xiumin,LI Jubin,QIU Jianrong.Study on combustion characteristic of micro pulverized coal[J].Proceedings of the CSEE,2000,20(6):71-74.
[17]WANG X,LI S,ADEOSUN A,et al.Effect of potassium-doping and oxygen concentration on soot oxidation in O2/CO2 atmosphere:A kinetics study by thermogravimetric analysis[J].Energy Conversion and Management,2017,149:686-697.
[18]张锦萍,王长安,贾晓威,等.半焦-烟煤混燃特性及动力学分析[J].化工学报,2018,69(8):3611-3618.ZHANG Jinping,WANG Chang'an,JIA Xiaowei,et al.Co-combustion characteristics and kinetic analysis of semi-coke and bituminous coal[J].CIESC Journal,2018,69(8):3611-3618.