高温贫氧下不同温度阶段煤体自燃指标气体测试

(1.西安科技大学 安全科学与工程学院,陕西 西安 710054; 2.西安科技大学 陕西省煤火防控重点实验室,陕西 西安 710054; 3.新疆大学 干旱生态环境研究所和新疆大学生态学博士后流动站,新疆 乌鲁木齐 830046)

高温贫氧; 指标气体; 特征温度; 温度阶段

Coal spontaneous combustion indicator gases analysis of different temperature stages upon high-temperature and low-oxygen condition
ZHAO Jing-yu1,2,3,ZHANG Yu-xuan1,2,SONG Jia-jia1,2,ZHANG Yan-ni1,2 ,WANG Kai1,2

(1.College of Safety Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Shaanxi Key Laboratory of Prevention and Control of Coal Fire,Xi'an University of Science and Technology,Xi'an 710054,China; 3.Post-Doctoral Research Center for Ecology,Institute for Arid Ecology and Environment,Xinjiang University,Urumqi,830046,China)

high-temperature and low-oxygen; indictor gases; characteristic temperatures; temperature stages

DOI: 10.13800/j.cnki.xakjdxxb.2019.0202

备注

为了研究高温贫氧条件对煤自燃指标气体释放的影响,利用西安科技大学自主研发的高温氧化燃烧特性测试装置,测试30~500 ℃过程中煤自燃气体变化规律,通过使用指标气体的增长率分析法,并参考热分析实验温度区间划分准则,得出5个特征温度点,以此作为划分煤样常温至高温不同氧化阶段的依据,分为4个阶段:分别是临界温度阶段,干裂-活性-增速温度阶段,增速-燃点温度阶段和燃烧阶段。分析不同阶段的指标气体的变化规律,实验结果表明,CO气体在第1阶段增长较为缓慢,在第2,第3阶段增长较为迅速,呈现出指数级增长态势,当温度超过燃烧温度后,CO气体浓度开始呈现出下降的态势,后由于稳定官能团的断裂,气体浓度有所回升。C2H4气体在干裂-活性-增速温度阶段前增长较为缓慢,而后急剧增长,当温度到达燃烧温度时,C2H4气体浓度达到顶峰,随后随着温度的上升,气体浓度急剧下降。

To study the characteristics of high temperature and oxygen-poor conditions on indicator gases of coal spontaneous combustion,the independently designed high-temperature programmed experimental system was used to test the changes of gaseous products during 30 ℃ to 500 ℃.Growth rate analysis method of the indicator gases was adopted to calculate the characteristic temperatures.With reference of thermal gravimetric analysis on temperature division,the five characteristic temperature points are confirmed.Four different oxidation stages were divided by the five temperatures,i.e, as critical temperature stage,crack-active-speedup temperature stage,speedup-ignite temperature stage and combustion stage.Moreover,the variation of indicator gases at different stages were studied.The results showed that the concentration of CO gas increases slowly in the critical temperature stage,and rapidly in the second and third stage with trend of exponential liner.When the temperature exceeded the combustion temperature,the CO gas begins to decrease firstly,and then increase again because of the fracture of the stable functional groups.The C2H4 gas released slowly before crack-active-speedup temperature,then increased sharply,and when the temperature reached the combustion temperature,the C2H4 gas concentration reached the peak value.