新型干煤粉气流床气化炉的冷态数值模拟

Cold model numerical simulation of new dry-feed entrained-flow coal gasifier

为了考察基于无焰氧化技术所提出的新型干煤粉气流床气化炉的流场和颗粒停留时间分布特性,对该气化炉进行三维冷态数值模拟研究,得到了不同工况下的模拟结果,可知:单喷嘴切向进气工况导致炉内速度场发生了偏移;双喷嘴中心对称切向进气工况导致炉内形成外圈速度大、内圈速度小的对称旋转梯度场。随着进口总气速、颗粒平均直径和颗粒密度的增大,气化炉内颗粒停留时间逐渐减小。颗粒停留时间随颗粒平均直径增大的减幅较随颗粒密度增大的减幅更大。当颗粒入射角度为正时,随着入射角度的增加,颗粒停留时间逐渐增大;当入射角度为负时,随着入射角度的增加,颗粒停留时间逐渐减小。

In order to study the flow field and particle residence time distribution characteristic of a new dry-feed entrained-flow coal gasifier which was put forward based on flameless oxidation technology, three-dimensional cold model numerical simulation research on the gasifier was conducted and the simulation results on different working conditions were achieved. The resuhs show that deviation occurs in the flow field of the gasifier on single nozzle working condition; rotational symmetric velocity gradient field occurs in the gasifier on double centrosymmetric nozzles working condition with larger speed outside and smaller speed inside. Besides, the particle residence time decreases with the increase of the total inlet gas velocity, particle mean diameter and particle density, and the particle residence time experiences a more significant decrease with the increase of the particle mean diameter than that of the particle density. In addition, the particle residence time increases with the increase of the positive particle jet angle; the particle residence time decreases with the increase of the negative particle jet angle.