Abstract: In this paper,three-dimensional computational fluid dynamics( CFD) simulation of a large-scale high-temperature Fischer-Tropsch fluidized bed reactor was carried out. The traditional two-fluid model is based on the assumption of homogeneity at the level of computational cells,which assumes that the gas and solid phases are uniformly distributed within a cell and the mesh size must be small enough to properly reveal all the details of the local heterogeneous structure. When the two fluid model is used to simulate large-scale industrial fluidized bed reactors,the number of grids will be too large,which is far beyond the existing computing capacity. In order to improve the simulation efficiency without losing the simulation accuracy,a pseudo bubble-emulsion triple-phase drag( PBTD) model based on the assumption of local heterogeneity and applicable to coarse meshes was proposed. In this model,the fluidized bed is divided into three phases:emulsified phase gas,emulsified phase particle and bubble. A conservation equation is established for each of the three phases to reflect the effect of the heterogeneous characteristics of the bubbles on the gas-solid drag force. The gas-solid drag force within the emulsion phase and the drag force between the bubble phase and the particles in the emulsion phase are considered separately. A three-dimensional flowtransfer-reaction model of the high-temperature Fischer-Tropsch reactor based on the assumption of local heterogeneity is established using the PBTD model coupled with the mass transfer and reaction models,including the conservation control equations of each phase,the bubble size model,the interphase mass and momentum exchange model,the high-temperature Fischer-Tropsch reaction kinetics model,and the initial and boundary conditions to predict the flow hydrodynamics and gas component concentration distribution. The results show that under the condition of coarse grid,the proposed heterogeneous drag model can obtain good results of the distribution of phase holdup in the bed,and the predicted bed expansion height is in good agreement with empirical correlation with a deviation of 1.2%. The mass fraction of the gas compositions at the reactor outlet is close to measurement values,and the deviations are in the range of 1.5%-16.0%. The simulation results show that the PBTD model is suitable for simulating industrial scale bubbling fluidized bed reactors,which has guiding value for application in the design and operation of industrial reactor.