Numerical simulation of flow and heat transfer in connection of gasif ier to the radiant syngas cooler

摘要

The connection of gasifier to the radiant syngas cooler has been regarded as a key technology for heat recovery system. Multiphase flow and heat transfer processes presented in this work considers particle deposition and radiation model to mixture of non-gray gas with particles. An axisymmetric simulation of the multiphase flow in an industrial scale connection is performed. The standard k-ε model, Renormalization group (RNG) k-ε model and Realizable k-ε model turbulence model are proposed. The particle motion is modeled by discrete random walk model. The discrete ordinates model (DOM), P-1 and discrete transfer model (DTRM) are used to model the radiative heat transfer. The effect of particles on the radiative heat transfer was taken into account when the DOM and P-1 model were used. The absorption coefficient of the gas mixture is calculated by means of a weighted-sum-of-gray-gas (WSGG) model. The results with the DOM and P-l model are very similar and close to practical condition. A large number of particles are deposited on the cone of gasifier which is the top of connection. Maximum temperature difference is approximate 7 K when the cooling tube heights change from 0.5 m to 1.5 m. The temperature inside has a linear relationship with operating temperature.