煤矸石人工热储的建造及自燃热能潜力分析

Constraction of coal gangue artificial thermal storage and analysis of spontaneous combustion thermal energy potential

针对山西省阳泉市荫营煤矿矸石山自燃造成的环境污染和能源浪费问题,提出了以煤矸石为原材料建造人工热储并利用内部自燃热能的方案;研究了煤矸石自燃耗氧速率、放热速率和可燃物剩余量的动态变化规律;建立了温度场、渗流场、氧气浓度和可燃物剩余量分布的多物理场数学模型;评价了煤矸石热储的供热潜力。研究结果表明:人工热储内空间分布不均匀的温度场会产生烟囱效应,使渗流速度增大、对流换热增强;高温区的煤矸石氧化反应较快,可燃物剩余量较少和氧气浓度衰减幅度较大。连续取热720 d后,“U”形管进出口温度差超过10℃,出风口流出的空气温度超过55℃;同时可燃物剩余量超过60%的煤矸石体积占比依旧超过94%。研究认为,利用煤矸石建造的人工热储可以长时间提供优质热量。

Aiming at the problems of environmental pollution and energy waste caused by spontaneous combustion of coal gangue mountain in Yinying Coal Mine in Yangquan City,Shanxi Province,a scheme of constructing artificial thermal storage with coal gangue as raw material and utilizing internal spontaneous combustion thermal energy was proposed.The dynamic change law of oxygen consumption rate,heat release rate and residual amount of combustibles in spontaneous combustion of coal gangue was quantified.A multi-physics mathematical model of temperature field,seepage field,oxygen concentration and residual amount of combustibles was established.The heat-supply potential of coal gangue heat storage was evaluated.The results show that the temperature field with uneven spatial distribution in the artificial thermal storage produces the chimney effect,which increases the seepage velocity and enhances the convective heat transfer.The oxidation reaction of coal gangue in the high temperature area is faster,the residual amount of combustibles is less and the attenuation of oxygen concentration is larger.After 720 d of continuous heating,the temperature difference between the inlet and outlet of the U-tube exceeds 10℃,and the temperature of the air flowing out of the outlet exceeds 55℃.At the same time,the volume of coal gangue with more than 60% of the remaining combustibles still exceeds 94%.The study believes that artificial thermal storage built with coal gangue can provide high-quality heat for a long time.