Numerical study on the underground coal gasification for inclined seams

According to the characteristics for combustion and gasification reactions occurring in the gasification gallery, the mathematical functional relationship between the chemical reaction rate and every influencing factor is studied. The dynamic nonlinear coupling mathematical models on underground coal gasification of inclined seams are established. The determination methods of major model parameters are introduced. Additionally, the control volume method is adopted to find the numerical solution to the mathematical models. The patterns of development and variation for temperature field, concentration field and pressure field in gasification panel are studied. On the basis of the model test, calculation results are analyzed. From the distribution of temperature field, its calculation value is a little higher than the experimental one, with the relative error of every measuring point virtually within 17%. Research shows that, the experiment value of gas heat value and calculated value take on a good conformity; due to the influence of temperature, in the high temperature zone, the change gradient of the experiment value for concentration field of gas compositions is greater than that of the calculation value. The simulated results indicate that the relative error of the pressure field calculation is 4.13%-12.69% and 8.25%-17.47%, respectively, 7 h and 45 h after the ignition. The drop rate for the fluid pressure is 6 01 % and 10. 91 %, respectively. Research shows that the simulated values conform with experimental values comparatively well, which demonstrates that the numerical simulation on the "three fields" in underground coal gasification is correct. (c) 2005 American Institute of Chemical Engineers.