Reserch On Non-interval Nitrogen Injection For Fire Control

At present, the buried nitrogen injection process is commonly used to prevent the coal spontaneous combustion in gobs, there are two serious defects using the way, the first one is nitrogen injection sites have interval in the space, which results that nitrogen gas is not formed continuity distribution in the god and the effect of nitrogen injection is poor, then leads to the required injection rate is large; the second is the nitrogen injection pipes are alternately discarded in the gob and the material cannot be recycled, which results in a great waste of resources and large input cost. Considering the main problem of traditional nitrogen injection process, the technology of non-interval nitrogen injection for fire control was proposed that making the nitrogen injection sites keep pace with working face to cause the nitrogen injection sites maintain a continuous space. According to the relevant principles of material mechanics, the new technology of non-interval nitrogen for fire control, which was designed to drag with rotating, makes use of anti-shearing ability for the injection pipe to overcome the biggest obstacle in the towing process. FLAC3D was used to analyze the wall stress distribution of the nitrogen injection buried pipe in the goaf, then based on elasticity mechanics, structural mechanics, unloading arch principle and some related theories, the theoretical calculation method of calculating for load caused by overlying roak to buried pipe wall in the goaf, and calculating for dynamic value of the technology of non-interval nitrogen injection for fire control could be obtained. Based on the coal-oxygen comlex theory, the discriminant model of high temperature area distribution in goaf was built, which provides theoretical basis to confirm the best nitrogen injection position in goaf during the process of non-interval nitrogen injection for fire control. And the mode of traction for the non-interval nitrogen injection for fire control device was studied by theoretical analysis, various parameters nitrogen injection pipes were calculated, and the connection ways among pipes were determined. The device of non-interval nitrogen injection for fire control was designed and processed, and field experiment check and optimization of device design parameters were made.