生物质气与煤粉混燃过程数值模拟

Co-firing process of biomass gas with coal:numerical simulation

为了分析生物质气与煤粉混燃对锅炉燃烧过程的影响,利用Gambit软件对锅炉的炉膛结构进行网格划分,并基于Fluent软件,搭建生物质气和煤粉混合燃烧模型,对混合燃烧过程进行数值模拟和计算,分析随着生物质气掺烧比的变化,炉内温度场、速度场以及一次风喷口的气流场等的分布特征。结果表明,随着生物质气掺烧比的增大,炉膛中心截面最高温度逐渐降低,燃烧器区域的温度逐渐升高,炉膛中心部分气流速度及旋转强度增强,但对一次风口处的流场影响不大。

In order to analyze the influence of co-firing process of biomass gas with coal on combustion process in boiler, the furnace structure was meshed by the GAMBIT software. On the basis of Fluent soft- ware,the model for co-combusiton of biomass gas and coal was established,and the co-firing process was numerically investigated. The temperature field, velocity field and flow field around the primary air nozzles were analyzed,under conditions with varying biomass gas co-firing ratios. The results show that,when the biomass gas ratio increased, the peak temperature in the furnace cross section decreased gradually,while the temperature at the burner area increased. The air velocity and rotation strength in the center part of the furnace enhanced and the flow field of the primary air changed little with increase of the biomass gas co-firing ratio.