摘要
作为温室效应的主要来源,CO_(2)的循环再利用成为研究的热点。在矿山灾害防治技术领域,液态CO_(2)在煤自燃灾害防治和煤层瓦斯置换驱替方面发挥了重要作用。低温液态CO_(2)(-56^-20℃)与煤体接触产生对流换热,煤体内部受到热应力作用产生损伤破坏,煤体的孔裂隙发育及比表面积发生变化,氧化过程与空气中氧的结合能力改变,氧化性发生显著变化。为了分析液态CO_(2)低温损伤煤体后的氧化特征,以河南永城矿区无烟煤为对象,开展热重分析实验,研究了原煤样及液态CO_(2)处理煤样的氧化过程特征温度,采用FWO和KAS两种非等温方法计算了氧化动力学参数,分析了液态CO_(2)影响煤体氧化特征。结果表明:液态CO_(2)溶浸后无烟煤的临界温度和干裂温度比原煤样降低了2~8℃,增速温度、失重温度、着火温度、最大失重温度和燃尽温度提前了100~140℃,各特征温度对应的失重质量百分比较原煤样降低了0.8%~10.0%。煤样在失水失重、吸氧增重、热解和燃烧4个阶段的温度跨度区间均变小,煤样氧化活性增强,吸附氧气速度和吸氧量增加,燃烧反应速度加快。溶浸煤样的表观活化能在4个氧化阶段较原煤样均降低10~30 kJ/mol,指前因子ln A与表观活化能Ea表现为正相关性。液态CO_(2)溶浸处理煤体的自燃倾向性增加,加速了煤的氧化自燃进程。采用液态CO_(2)进行煤层瓦斯驱替或煤自燃灾害灭火后,应当更加注意防范煤自燃发火灾害的发生。
As one of most important sources on greenhouse effect,the CO_(2)recycling and utilization have become a hot spot in research.In the field of mine disaster prevention and control technology,the technologies for controlling spontaneous coal combustion and displacing coal bed methane by liquid CO_(2)have achieved a great success.However,the liquid CO_(2)with low-temperature(from-56℃to-20℃)forms a heat transfer after injecting into coal seam,and causes a damaged effect by thermal stress.Specific surface area and volume in coal pore are changed,and then the adsorption capacity of coal-oxygen is transformed and the tendency of spontaneous coal combustion is varied.To study the oxidation characteristics of coal infiltrated by liquid CO_(2),a thermo gravimetric analysis was carried out with anthracite in Yongcheng mining area of Henan,China.The characteristic temperatures of original and liquid CO_(2)infiltrated coal oxidation were analyzed.The oxidation kinetics parameters were calculated by non-isothermal methods(FWO and KAS methods),and the influence of liquid CO_(2)on coal oxidation was obtained.The study shows that the critical temperature and crack temperature of anthracite infiltrated by liquid CO_(2)were decreased by 2-8℃compared with raw coal.The growth temperature,weight loss temperature,ignition temperature,maximum weight loss rate temperature and burnout temperature were advanced by 100-140℃.The weight loss percentage corresponding to each characteristic temperature was reduced by 0.8%-10.0%.The interval ranges of four oxidation stages(water evaporation and physical adsorption of oxygen,mass gain through oxygen chemisorption,pyrogenic decomposition and combustion)were reduced.The rate and quantity of oxygen adsorption on infiltrated coal were increased,and the combustion reaction speed of was improved.The apparent activation energy of infiltrated coal sample was decreased by 10-30 kJ/mol in four oxidation stages compared with that of raw coal samples.A positive correlation was shown between pre-exponential factor and apparent activation energy.The spontaneous combustion tendency of coal treated by liquid CO_(2)was increased,and the process of coal oxidation was accelerated.More stringent measures for preventing spontaneous coal combustion should be carried out after controlling coal fire in gob and displacing coal bed methane by liquid CO_(2).
作者
李珍宝
王凤双
魏高明
马砺
安满林
俞树荣
LI Zhenbao;WANG Fengshuang;WEI Gaoming;MA Li;AN Manlin;YU Shurong(College of Petrochemical Technology,Lanzhou University of Technology,Lanzhou 730050,China;Yancon Group Co.,Ltd.,Zoucheng 272100,China;College of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2020年第S01期330-335,共6页
Journal of China Coal Society
基金
国家自然科学青年基金资助项目(51904138)
兰州理工大学红柳优秀青年人才支持计划资助项目(062001)
甘肃省高等学校创新能力提升资助项目(2019A-018)
关键词
氧化动力学
无烟煤
热重分析
特征温度
表观活化能
oxidation kinetics
anthracite
thermogravimetric analysis
characteristic temperature
apparent activation energy
作者简介
李珍宝(1987-),男,陕西凤翔人,讲师。E-mail:lizb@lut.edu.cn;通讯作者:王凤双(1987-),女,河北威县人,讲师。E-mail:735872503@qq.com
