燃煤锅炉掺烧生物质对于碳减排具有积极的作用，同时还能够实现生物质的高效利用。因此，燃煤锅炉掺烧生物质一直是国内外关注的热点。目前已经开展了大量关于燃煤锅炉中掺烧污泥等物质的实验与模拟研究，而鲜见有关燃煤锅炉中掺烧酒糟的数值模拟研究。为了研究燃煤锅炉中掺烧酒糟对于炉内温度场、组分浓度场以及NO_x排放等的影响，运用数值模拟手段，采用计算流体力学软件FLUENT中的涡耗散模型模拟煤粉与酒糟颗粒的混燃。首先验证了模拟手段的可靠性：在满负荷下，模拟得到的出口氧量、飞灰含碳量和NO_x排放与相同条件下的实验结果吻合的较好。随后，进行了酒糟掺烧质量比例分别为0%、3%、6%、8%、10%的模拟计算。结果显示，掺烧酒糟后，燃烧器喷口附近着火距离有所缩短，但炉膛整体温度场无明显变化。掺烧酒糟对炉膛内的O₂浓度分布无太大影响，但是，由于受到酒糟含水量的影响，H₂O浓度在燃烧器喷口附近有所提升。最后，我们发现掺混酒糟对NO_x的排放影响较为明显，其是掺混燃料氮含量和生物质挥发分释放造成的还原性氛围交互作用的结果。

Biomass co-firing in coal-fired power plants has the advantages of low conversion cost,flexible peak shaving,and safe operation,which has a positive effect on carbon emission reduction and can realize the efficient utilization of biomass. At present,a large number of experiments and simulation studies have been carried out on the blending of sludge and other substances in coal-fired boilers,but there are few numerical simulation studies on the blending of distiller′s grains in coal-fired boilers. In order to study the influence of blending distiller′s grains in coal-fired boilers on the temperature field,component concentration field and NOx emission in the furnace,the mixed combustion of pulverized coal and distiller′s grains was simulated by numerical simulation and the vortex dissipation model in computational fluid dynamics software FLUENT. The results show that the simulation method is reliable. Under full load,the simulated outlet oxygen,carbon content of fly ash and NOx emission are in good agreement with the experimental results under the same conditions. The simulation results of 0,3%,6%,8% and 10% of the mass fraction of distiller′s grains show that the ignition distance near the nozzle of the burner is shortened,but the overall temperature field of the furnace does not change significantly. The concentration distribution of O2 in the furnace is not significantly affected by the blending of distiller′s grains,the concentration of H2O is increased near the burner nozzle due to the influence of distiller′s grains water content. Blending distiller′s grains have a significant impact on NOx emission,which is the result of the interaction of reducing atmosphere caused by the nitrogen content of blending fuel and the release of biomass volatiles.

0 引言

1 研究对象

2 数学模型和计算方法

   2.1 数学模型

   2.2 网格划分

   2.3 边界条件

   2.4 研究工况

3 酒糟掺混燃烧数值模拟结果分析

   3.1 模拟结果验证

   3.2 不同酒糟掺混比对温度场的影响

   3.3 不同酒糟掺混比对组分场的影响

   3.4 不同酒糟掺混比对NOx生成的影响

4 结论