生物质气化焦油分离器气相流场数值模拟

Numerical Simulation on Biomass Gasification Tar Separator

根据焦油的物性和分离要求设计了一种适用于干法脱除焦油的新型焦油分离器,该焦油分离器同时具有冷却降温促焦油冷凝析出和分离焦油液滴的作用。通过对其气相流场的数值模拟发现,壁面降温对其内部的温度场影响明显,这是气体运动传热的结果。旋风分离器内气体温度随着周边气流下行温度逐渐降低,随着中心气流上行而逐渐升高,在径向呈现驼峰状分布。温度降低导致了气体密度增加和粘度减小,以及焦油液滴粘度增加,通过对焦油液滴分离理论和焦油的物性分析得出,壁面降温可以减小切割粒径,有利于提高生物质气化燃气中焦油的分离效率。

According to physical properties of the tar and separate requirements, a type of tar separator which is applicable to dry method of removing the tar was designed. This type of tar separator can cool and condensing the tar, at the same time separates the droplets of the tar. It can be seen from the numerical simulation results of gas flow field, the results of gas movement of heat transfer show that wall cooling has a great influence on temperature field in the cyclone separator. The temperature field also presents the characteristics that the surrounding area gradually reducing with surrounding downward flow, and the central zone rising up with centering upward flow, and the radial temperature gradually reducing in the cyclone separator. The decrease of temperature leads to the increase in gas density and the decrease in gas viscosity and the increase in the tar droplets viscosity. Wall cooling can reduce the cut size, as well as improve the separation efficiency of biomass gasification gas tar through the tar droplet separation theory and the physical analysis of tar.