The Research On Pyrolysis-penteation And Microstructure Of Lignite

Some current coal mining methods have serious impact on the life environment of the human, animal and plant. In order to green utilization high efficiently of coal resources, scientists have proposed clean coal mining, namely the underground pyrolysis vaporization or liquefaction. In the process of coal gasification underground and the exploitation of coal-bed methane, there will be a lot of gas in the coal layer diffusion, education. It is more important to study the way to transporting these flammable gases to the surface by gasification channel of rock. Based on coal penetration theory and microscopic mechanism, we obtained the change rule of permeability, microscopic structure and gases of lignite in the process of underground in-situ. All conclusion will be use of finding the effective way, effectively controlling the influence factors of coal and rock permeability character, improving its permeability, and further improving the gas production lignite in situ in the process of pyrolysis lignite underground.Paper mainly studies on the following aspects of the coal pyrolysis:(1)Summarized the influence factors character of permeability and Microscopic changes of coal in theory, and analyzed and summarized in depth the effects mechanism.(2) By using self-developed triaxial stress permeation experiment bed simulated the permeability character of lignite under low temperature period state (less than200℃) in underground in-situ stress. I studied the permeability character of lignite under different temperature and infiltration pressure by experiment, summed up the change relationship of temperature, pore pressure and permeability under low temperature stage, and summered on the reason.(3) By using another one self-developed penetration test bed simulated the permeability character of lignite under the stress of in situ in high temperature period (200℃--400℃). The relationship of temperature, pore pressure and permeability of lignite under high temperature pyrolysis provides the basis for controlling the temperature and pore pressure when coal pyrolysis.(4) By using the microscopic CT machine researched the thermal cracking lignite rule and its the phenomenon under different temperature period. The change law of pore and fracture in internal of lignite in different temperature period provide theoretical basis for the research on the transformation of pyrolysis products from underground in-situ pyrolysis, and thus pyrolysis products will be obtained to the maximum limited.(5) Through a large number of experimental research lignite hair with the rise of temperature of the gas produced amount and different temperature period the change of gas production, and analyze gas produced components under different temperature period. These provide certain basis for the control of temperature to increase gas production of lignite in the progress of underground gasification.(6) For the center with underground in-situ pyrolysis, by summing up the relationship of the penetration properties of lignite and the temperature, and the micro structure rule and the amount of gas released rules in different temperature period, and expounds the penetration of lignite and structural change in situ pyrolysis, control effectively the influence factors in lignite pyrolysis permeability character, increases permeability character in the process of pyrolysis, so as to improve the gas production of the lignite.