Abstract
Complex multiphase flow, heat transfer and reaction process in entrained flow gasifier can't be measured directly. The numerical simulation and process investigation will supply technical support for gasifier design and operation. SG-Vortex gasifier is a new type entrained flow coal gasifier developed by SBWL. Numerical simulation and process investigation of three-stage SG-Vortex gasifier have been carried out in this study. A comprehensive three-dimensional numerical model is developed for simulation of the industrial scale SG-Vortex gasifier. The dry pulverized gasification process is divided into several submodels. The Realizable k-ε model is applied to close the Reynolds-averaged Navier-Stokes equation for gas phase, and the Random-Trajectory model is used to simulate the behavior of particle flow in gasifier. Water evaporation, coal pyrolysis, and homogeneous and heterogeneous char reactions are all considered. The P1 model is adopted to calculate the radiative heat transfer in gasifier. Otherwise, the water shift reaction process in second stage of gasifier is studied. The results indicated that the coal particle enrich on the wall above the burner and bottom of gasifier, the particle is effected by centrifugal force. So steady slagging flow can be formed on the surface of the membrane wall. Furthermore, the eddy effect also led the particle flow to the wall of gasifier and deposited, and the slagging formed on the wall of gasifier molted and flow down from the top of gasifier. Temperature and syngas composition distribution in the gasifier is agreed well with similar industrial gasifier. Water shift reaction exists in second stage of gasifier, and the shift efficiency over than 20%. So the H_2/CO will increase more than 100% compared to general entrained flow pulverized coal gasifier. This advantage led a significant cost saving of investment and operation cost from shift unit.
