煤粉流态化预热气态组分CO/CO2生成转化特性研究Study on the formation and conversion characteristics of gaseous component CO/CO2 with fluidized preheating pulverized coal
刘玉华,刘敬樟,吕清刚,朱建国,朱书骏
LIU Yuhua,LIU Jingzhang,LYU Qinggang,ZHU Jianguo,ZHU Shujun
摘要(Abstract):
基于循环流化床预热的燃烧系统是一种新型的清洁燃烧技术,其流态化预热后煤气中CO/CO_2比值对后续燃烧和排放影响较大,研究正确反映CO/CO_2比值的焦炭燃烧模型有助于进一步了解该流态化预热过程。笔者基于燃料流态化预热转化过程,研究典型的预热空气富氧气氛(O_2/N2)、富氧气氛(O_2/CO_2)以及燃料种类变化对预热后气态组分中CO/CO_2生成转化特性的影响,分析现有焦炭燃烧模型与流态化预热过程的匹配程度。试验数据和模型预测对比分析表明,空气富氧气氛下,氧气浓度从21%增至28.2%的过程中,神木半焦流态化预热过程产生的预热气体中CO_2占比减少,CO占比增多,CO/CO_2比值从0.81增至1.45;神木烟煤在该气氛预热时,各参数与神木半焦呈现同样的变化趋势,且随氧气浓度从21.0%增至24.4%,CO/CO_2比值从0.51增至0.76。富氧气氛时神木半焦预热产生的CO与神木烟煤相比产量更高,CO/CO_2比值随氧气浓度增大而增大,但与空气富氧气氛下相比递增幅度较小。神木烟煤预热气体组分CO/CO_2的试验数据与Tognotti提出的焦炭燃烧模型预测值吻合度最高,富氧气氛下试验与预测结果误差在9%以内。
The preheating combustion technology based on circulating fluidized bed proposed is one of the new clean coal combustion technologies.The O_2/CO_2 ratio in the gas after fluidized preheating process has a great influence on the subsequent combustion and emissions.Exploring the coke combustion model that can correctly reflect the O_2/CO_2 ratio will help to further understand the fluidized preheating process.Based on the pulverized coal fluidized preheating conversion process,the typical preheated air-rich atmosphere( O_2/N2),oxygenrich atmosphere( O_2/CO_2),and fuel type change were used to study the conversion characteristics of the gaseous component CO/CO_2 after preheating.Moreover,the degree of matching between the existing coke combustion model and the fluidized preheating process was analyzed.The experimental data and model predictions show that in the air-rich oxygen atmosphere,as the oxygen concentration increases from 21% to 28.2%,the proportion of CO_2 in the preheated gas produced by Shenmu semi-coke fluidized preheating process decreases,the proportion of CO increases,and the CO/CO_2 ratio increases from 0.81 to 1.45.When Shenmu bituminous coal is preheated in the same atmosphere,the above-mentioned parameters show the same tendency as Shenmu semi-coke,and the CO/CO_2 ratio increases from 0.51 to0.76 as the oxygen concentration increases from 21.0% to 24.4%.In the oxygen-rich atmosphere,the CO produced by Shenmu semi-coke preheating is higher than that of Shenmu bituminous coal. The CO/CO_2 ratio also increases with the increase of oxygen concentration,but compared with the air-enriched atmosphere,the increasing degree is smaller. The experimental data of the preheated gas component CO/CO_2 of Shenmu bituminous coal is the most consistent with the prediction of the coke combustion model proposed by Tognotti,and the error of experiment and prediction results is within 9% under oxygen-rich atmosphere
关键词(KeyWords):
预热燃烧;空气富氧;富氧气氛;CO/CO_2
preheating combustion;air-rich oxygen;oxygen-rich atmosphere;CO/CO_2
基金项目(Foundation): 国家重点研发计划资助项目(2017YFB0602001);; 国家自然科学基金资助项目(51876204)
作者(Author):
刘玉华,刘敬樟,吕清刚,朱建国,朱书骏
LIU Yuhua,LIU Jingzhang,LYU Qinggang,ZHU Jianguo,ZHU Shujun
DOI: 10.13226/j.issn.1006-6772.19110602
参考文献(References):
- [1]吕清刚,李诗媛,黄粲然.工业领域煤炭清洁高效燃烧利用技术现状与发展建议[J].中国科学院院刊,2019,34(4):392-400.LYU Qinggang,LI Shiyuan,HUANG Canran.Current situation and development suggestions of coal clean and efficient combustion technology in industry field[J]. Bulletin of Chinese Academy of Sciences,2019,34(4):392-400.
- [2] MAN Chengbo,ZHU Jianguo,OUYANG Ziqu,et al.Experimental study on combustion characteristics of pulverized coal preheated in a circulating fluidized bed[J].Fuel Processing Technology,2018,172:72-78.
- [3] ZHU Shujun,ZHU Jianguo,LYU Qinggang,et al.NO emissions under pulverized char combustion in O2/CO2/H2O preheated by a circulating fluidized bed[J].Fuel,2019,252:512-521.
- [4]朱书骏,吕清刚,朱建国,等.基于循环流化床预热的半焦燃烧试验研究[J].工程热物理学报,2018,39(4):887-892.ZHU Shujun,LYU Qinggang,ZHU Jianguo,et al. Experimental study on pulverized char combustion preheated by a circulating fluidized bed[J]. Journal of Engineering Thermophysics,2018,39(4):887-892.
- [5]刘敬樟,李百航,朱建国,等.焦炭颗粒群氧燃烧速率特性[J].中国科学:科学技术,2017,47(12):1265-1272.LIU Jingzhang,LI Baihang,ZHU Jianguo,et al. Investigation on char cloud burning rates under oxy-combustion[J]. Scientia Sinica(Technologica),2017,47(12):1265-1272.
- [6] WALL T,LIU Y,SPERO C,et al.An overview on oxyfuel coal combustion-state of the art research and technology development[J].Chemical Engineering Research&Design,2009,87:1003-1016.
- [7] CHRISTOPHER R Shaddix,FRANZ Holzleithner,MANFRED Geier,et al. Numerical assessment of Tognotti determination of CO2/CO production ration during char oxidation[J]. Combustion and Flame,2013,160:1827-1834.
- [8] ARTHOR J A.Reactions between carbon and oxygen[J].Transactions of the Faraday Society,1951,47:164-178.
- [9] JAKUB Bibrzycki,MARCO Mancini,ANDRZEJ Szlek,et al.A char combustion sub-model for CFD-predictions of fluidized bed combustion-experiments and mathematical modeling[J]. Combustion and Flame,2016,163:188-201.
- [10] ROBERT Hurt,SUN Jiankuan,MELISSA Lunden.A kinetic model of carbon burnout in pulverized coal combustion[J]. Combustion and Flame,1998,113:181-197.
- [11] LIU Jingzhang,LI Baihang,ZHU Jianguo.Investigation on pulverized coal char oxy-combustion behavior at moderate and high temperatures:Experiments and a novel developed kinetics modeling[J]. Industrial&Engineering Chemistry Research,2018,57(36):12264-12277.
- [12]张志,李振山,蔡宁生.煤粉燃烧中焦炭燃烧模型的比较与分析[J].燃烧科学与技术,2014,20(5):393-400.ZHANG Zhi,LI Zhenshan,CAI Ningsheng. Comparison and analysis of different models of pulverized coal char combustion[J]. Journal of Combustion Science and Technology,2014,20(5):393-400.
- [13]欧阳子区.基于循环流化床预热的无烟煤粉燃烧及污染物生成特性实验研究[D].北京:中国科学院工程热物理研究所,2014:50-70.OUYANG Ziqu.Experimental study on combustion characteristics and pollutants emission of pulverized anthracite preheated by circulating fluidized bed[D]. Beijing:Institute of engineering thermophysics,Chinese academy of sciences,2014:50-70.
- [14]朱书骏.煤/半焦富氧预热燃烧特性及NOx排放特性实验研究[D].北京:中国科学院工程热物理研究所,2019:28-70.ZHU Shujun.Experimental study on preheating oxy-fuel combustion and NOxemission characteristics of coal/char[D]. Beijing:Institute of Engineering Thermophysics,Chinese Academy of Sciences,2019:28-70.
- [15]岑可法,姚强,骆仲泱,等.高等燃烧学[M].杭州:浙江大学出版社,2002:372-374.CEN Kefa,YAO Qiang,LUO Zhongyang,et al.Advanced combustion[M].Hangzhou:Zhejiang University Press,2002:372-374.
- [16] ARTHUR J R.Reactions between carbon and oxygen[J].Transactions of the Faraday Society,1951,47:164-178.
- [17] TOGNOTTI L,LONGWELL J P,SAROFIM A F.The products of the high temperature oxidation of a single char particle in an electrodynamic balance[J]. Proceedings of the Combustion Institute,1990,23(1):1207-1213.
- [18] OTTERBEIN M,BONNETAIN L.Combustion d'un carbon vitreux sous basses pressions d'oxygene[J].Carbon,1968,6(6):877-885.
- [19] PHILLIPS R,VASTOLA F J,WALKER Jr P L.Factors affecting the product ration of the carbon-oxygen reaction(Ⅱ):Reaction temperature[J].Carbon,1970,8(2):205-210.
- [20]巩志强.低阶煤热解半焦的燃烧特性和NOx排放特性实验研究[D].北京:中国科学院工程热物理研究所,2016.GONG Zhiqiang. Experimental study on combustion and NOx emission characteristics of char from pyrolysis of low rank coal[D]. Beijing:Institute of Engineering Thermophysics,Chinese Academy of Sciences,2016:28-70.