水成膜胶体泡沫形成机制及抑制采空区瓦斯涌出特性研究

Due to the characteristics of great mining intensity, production concentration and fast exploitation velocity of comprehensive mechanized coal mining, the widespread mined-out area is formed, aggregating abundant gas, and thus it easier to cause the problem of exceeding gas in working face and return air flow. The aqueous film forming colloidal aphrons with the features of well stability, high viscosity, no dehydration and surface filming was put forward so as to prevent the gas emission in goaf. By using the principal of mechanical foaming and the theories of colloid chemistry and polymer, through laboratory testing, computer numerical simulation and theoretical analysis, researches are conducted on the effect of physico-chemical characteristics of different kinds of materials forming aqueous film forming colloidal aphrons on foaming process, foaming multiple and the properties of surface film. Then the mechanism of interaction between various components and the chemical kinetics process of forming aqueous film forming colloidal aphrons are studied. Moreover, the mechanism of delay crosslinking and surface filming is revealed. The experimental device of fluid mechanics and gas monitoring and supervision system are further established and improved. The apparent viscosity, shear stress, flow resistance, viscoelasticity of aqueous film forming colloidal aphrons and characteristics of airtightness and sealing of surface film are also carried out. The properties of flowing diffusion in loosing coal-rock body and preventing gas emission are disclosed. Through the studies in the project, a new method for preventing gas emission in goaf is provided.

针对综合机械化采煤开采强度大、生产集中、推进速度快，形成较大面积采空区，从而聚集大量瓦斯，易造成工作面及回风流瓦斯超限等问题。本项目提出稳定性好、粘性高、不脱水且能表面成膜的水成膜胶体泡沫来防治采空区瓦斯涌出。采用机械发泡原理与胶体化学理论、高分子聚合物理论相结合的方法，借助实验室试验、计算机数值模拟与理论分析相结合的综合手段，研究水成膜胶体泡沫各材料自身的物理化学特性对发泡过程、发泡倍数和泡沫表面成膜性能的影响；研究各组分之间相互作用的机理，提出水成膜胶体泡沫形成的化学动力学过程，揭示聚合物间延迟交联和表面成膜机制；建立和完善测试水成膜胶体泡沫流体力学的实验装置和瓦斯气体的监测监控实验系统，研究水成膜胶体泡沫的表观粘度、剪切应力、流动阻力、粘弹性及表面膜的密闭性和封堵性等，揭示水成膜胶体泡沫在松散煤岩多孔介质中的流动扩散特性和抑制瓦斯涌出性能。为防治采空区瓦斯涌出提供新的手段和技术基础。

矿井瓦斯是煤矿安全生产的主要自然灾害之一。针对现有采空区瓦斯防治技术存在的不足，本课题提出来水成膜胶体泡沫防治技术。针对水成膜胶体泡沫交联特征及发泡工艺对交联聚合物的要求，研制出适合制备水成膜胶体泡沫的稠化剂和交联剂；同时，依据稠化剂和交联剂对表面活性剂的作用特点，复配出一种发泡倍数高的水成膜胶体泡沫发泡剂。对水成膜胶体泡沫的成胶时间以及稳定性进行了实验研究，得出水成膜胶体泡沫成胶时间在10~20min可调，泡沫静置24h仍能稳定存在。在实验室构建了制备水成膜胶体泡沫的系统并确定了其制备的工艺流程，通过大量实验研究，当溶液复配发泡剂质量浓度为4‰、稠化剂和交联剂质量浓度均为3‰，pH值为7~9时，所形成的水成膜胶体泡沫性能最佳。研究了水成膜胶体泡沫的流变学特性，结果表明水成膜胶体泡沫具有剪切变稀的性质。依据表观黏度和屈服应力测定结果，分别得到了剪切应力—剪切速率的曲线和公式模型。在此基础上，研究了水成膜胶体泡沫在多孔介质中的渗透特性，采用Fluent软件对其在不同倾角采空区的流动扩散与堆积特性进行了数值模拟，弄清了水成膜胶体泡沫在采空区的堆积高度、扩散宽度和扩散长度等参数。研究了水成膜胶体泡沫的成膜特性，包括成膜微观形貌、水蒸气透过性和堵漏性等。利用AFM观测了水成膜胶体泡沫所成膜的微观形貌，探讨了不同聚合物配比对成膜形貌及性能的影响，实验发现有且仅当稠化剂和交联剂按质量比1:1共混使用时才能够充分交联形成致密平坦的薄膜；同时共混聚合物浓度越大，成膜性越好。通过对薄膜水蒸气透过率和封堵性进行了测试，结果表明，水成膜胶体泡沫表面膜在持续一周内水蒸气透过率均为零；表面膜能承受2500Pa以上的风压，对采空区瓦斯具有一定的封堵能力。最后，水成膜胶体泡沫防瓦斯技术在新集二矿和布尔台煤矿进行了工业性试验，现场的工程应用效果表明，水成膜胶体泡沫防瓦斯效果显著，优点突出，是一种具有广阔应用前景和推广价值的新型矿用防瓦斯材料。