煤自燃与瓦斯耦合致灾作用机理及协同防控技术研究

In view of the disaster caused by coal spontaneous combustion and gas having the characteristics of inducement to each other, complicated variety, sudden and so on, the methods of the theories of blasting, gas flow field and coal spontaneous combustion are combined to adopt, and the means of laboratory experiments, numerical simulation, theoretical analysis and field test are taken. A systemic research is conducted on the two key scientific problems: one is the coal oxidation property under gas environment, the other is the multi-field coupling mechanism under the co-existence environment of coal spontaneous combustion and gas. The variation characteristics of heat, products and micro-group in the process of coal oxidation under gas environment have been emphatically analyzed, the index gases and warning index of coal spontaneous combustion are put forward, and the internal mechanism of oxidation property differences is revealed as well. The emission feature and transport dispersion law of gas are respectively analyzed in the process of coal spontaneous combustion environment and fire zone close down. Moreover, not only the space-time coupling distribution of temperature field, gas concentration filed and air leakage flow field are studied, but the thermodynamics process and characteristics inducing gas explosion are researched, revealing the evolution mechanism of coupling disaster. The experimental device of gas monitoring and supervision system is utilized to make a research on the concentration changes of gas, carbonic oxide and so on, before and after the coal spontaneous combustion covering the aqueous film forming colloidal aphrons. The action process and mechanisms of aqueous film forming colloidal aphrons preventing coupling disaster are revealed, and thus the key coordinated prevention and control technologies are mastered. By above researches, the theoretical basis and technical means are provided for the safe and efficient mining of coal in our country.

针对煤矿煤自燃与瓦斯灾害互为诱因、复杂多变及突发性等特点，采用爆炸作用原理与瓦斯流场理论、煤炭自燃理论相结合的方法，借助实验室实验、数值模拟、理论分析与现场试验相结合的综合手段，对瓦斯环境煤氧化特性、煤自燃与瓦斯共生环境多场耦合作用机制两个关键科学问题进行研究。着重分析瓦斯环境煤氧化过程的产热产物和微观基团变化特性，提出瓦斯环境煤自燃指标气体及预警指标，揭示其氧化特性差异的内在机制；分析煤自燃环境及火区封闭过程中瓦斯的涌出特性及运移扩散规律，研究温度场、气体浓度场、漏风流场时空耦合分布及其诱发瓦斯爆炸的热动力学过程及特征，揭示共生灾害的演化机制。利用半封闭空间气体监测监控系统，研究自燃煤体覆盖水成膜胶体泡沫前后瓦斯、一氧化碳等气体浓度变化特征，揭示水成膜胶体泡沫防治共生灾害的作用过程及机理，掌握耦合灾害的关键协同防控技术。为我国高瓦斯易自燃煤层矿井的安全高效开采提供理论依据和技术手段。

针对煤矿煤自燃与瓦斯灾害互为诱因、复杂多变及突发性等特点，采用煤自燃理论与爆炸作用原理相结合的方法，借助实验室实验、数值模拟与理论分析相结合的综合手段，对不同条件下煤自燃特性与瓦斯爆炸特性进行研究。结果表明，氧气浓度越大，煤氧复合反应越剧烈，气体生成物的浓度也越大。当氧气浓度较高时，煤样耗氧速率均随着煤温的升高而增加，且在整体升温过程中，升高单位温度的煤样的耗氧速率增加量基本呈增大的趋势；然而当后期氧气浓度较低时，耗氧速率又呈现降低趋势。CO和CO、H2混合气体对瓦斯爆炸极限的影响规律相似，瓦斯爆炸浓度上限和下限都随着CO、H2混合气体浓度的增大呈逐渐减小的变化趋势，且其对瓦斯爆炸下限影响较大；与CO对瓦斯爆炸极限的影响相比，有H2加入的混合气体瓦斯爆炸的浓度范围变大。以朱集西煤矿13502工作面采空区为研究对象，采用 FLUENT 数值模拟软件研究了采空区煤自燃与瓦斯耦合灾害分布范围。得出采空区氧气浓度与瓦斯浓度的分布均呈现非对称性，进风侧氧气浓度大于回风侧，而进风侧瓦斯浓度则明显低于回风侧，并且越深入采空区，靠近顶板，氧气浓度低，瓦斯浓度越高。在改变通风量的情况下，氧气浓度分布及瓦斯浓度分布规律也发生变化，随着通风量的增加，氧化带的区域向着采空区深部移动；与此同时，瓦斯向回风侧运移的趋势愈加明显。根据耦合灾害区域判定的相关理论，对采空区氧化带的边界进行处理，并进一步确定了耦合灾害危险区域范围及面积。得出当通风量为1100m3/min时，耦合灾害危险区域分布范围较小，但距离工作面较近，若此时发生爆炸事故，对工作面人、机影响较为严重；当通风量为1300m3/min时，耦合灾害危险区域虽然远离了工作面，但其分布宽度和广度也增大，从而增大了耦合灾害发生的可能性。综合考虑，当通风量为1200m3/min时，耦合灾害区域最小。最后，提出采用水成膜胶体泡沫与纳米氢氧化铝泡沫协同防控技术，为高瓦斯易自燃煤层矿井的安全高效开采提供一种理论依据和技术手段。