Study On Mechanism And Technology Process Simulation Of Reverse Combustion Gasification Of Coal Seam

The reverse combustion gasification method is applied to the underground coal gasificationprocess in order to solve the problem occurred in the late stage of forward gasification which thehigh intensity gasification process is difficult to be continued. The technology of reversecombustion gasification technique combined with forward combustion gasification is creativelyput forward through the study of reverse combustion phenomenon, gasification flame movementand its main influence factors. At the same time the coal gas of heat value and quality same asforward gasification can be obtained to improve the energy efficiency using reverse combustiongasification technique. The properties of reverse combustion in the seepage channel are studiedwith high temperature coal gasification reaction furnace based on the characteristics of reversecombustion gasification process in the thesis. The forward and reverse combustion gasificationtechnology of gasifying coal with oxygen-steam gasification agent is investigated through themodel tests and numerical simulation. The feasibility of technology was tested. The results showthat the relationship between the inject gas flow within certain limits and velocity of thegasification flame was linear during reverse combustion. And equation of flame speed andoxygen flow can be expressed first-order Arrhenius kinetics. The gasification temperature of thereaction furnace can control by adjusting the ratio of steam to oxygen. The optimal ranges ofgasifying lignite and bituminous coal were found to be1.5–2.0and1.3–1.75, respectively. Thegasification time was extended more than25%and using the reverse combustion approach. Theaverage effective content (H2and CO) of syngas was in the range of60–70%, meetingthe requirement of synthesis gas.