45000 m^(3)/h恩德气化炉气固流动特性模拟

Numerical simulation of gas-solid two-phase flow characteristics in a 45000 m^(3)/h Ende gasifier

将常规45000 m^(3)/h恩德气化炉对冲布置的喷嘴结构改良为旋切均布喷嘴结构,炉膛内流场发生了变化。为了研究旋切结构喷嘴恩德气化炉炉内的流场结构以及喷嘴气化剂速度对气固流动特性的影响,应用欧拉-欧拉双流体模型(TFM)对炉膛内的流场进行冷态数值模拟。得到了炉膛内颗粒轴向速度分布、颗粒体积分数分布以及流场结构分布结果。研究表明:旋切喷嘴结构下恩德气化炉炉内颗粒流动轨迹为螺旋上升式结构,并在炉膛中下部形成颗粒内循环;增大喷嘴气化剂速度能够提升颗粒内循环倍率;随喷嘴气化剂速度的增加,炉内气固流动特性越佳,喷嘴速度为50,60 m/s时,炉内流场较为紊乱,喷嘴速度增加到70,80 m/s时,颗粒分布更加规则,但气固流动特性变化已不明显,考虑到喷嘴速度过大会影响系统的稳定性,则喷嘴速度70 m/s时,为较优工况。模拟结果为热态数值模拟以及提高工业气化炉气化效率的研究提供一定的理论依据。

The nozzle structure of conventional Ende gasifier was improved to the rotary nozzle structure,and the flow field in the furnace changed.In order to study the flow field structure and the influence of gasifying agent velocity on the gas-solid two-phase flow characteristics in the rotary nozzle Ende gasifier,the Eulerian-Eulerian two-fluid model(TFM)was used to simulate the cold flow field in the furnace.The particle axial velocity distribution,particle volume fraction distribution and flow field structure distribution in the furnace were obtained.The results show that the particle flow trajectory in the Ende gasifier with the rotary-cut nozzle structure is a spiral upward structure,and the particle internal circulation is formed in the middle and lower part of the furnace,and the particle internal circulation ratio can be improved by increasing the gasification agent velocity of the nozzle;With the increase of the gasifying agent velocity in the nozzle,the gas-solid flow characteristics in the furnace become better.When the nozzle velocity is 50 m/s and 60 m/s,the flow field in the furnace is more disordered,and when the nozzle velocity increases to 70 m/s and 80 m/s,the particle distribution is more regular,but the change of gas-solid flow characteristics is not obvious.Considering that too high nozzle velocity will affect the stability of the system,the nozzle velocity of 70 m/s is the optimal working condition.The simulation results provide a theoretical basis for the thermal numerical simulation and the study of improving the gasification efficiency of industrial gasifier.