煤粉炉C型直流燃烧器的燃烧数值模拟

发布时间：2018-07-31 15:25

【摘要】：燃烧器是电厂锅炉组织燃烧的重要装置,在我国火电厂锅炉中。以煤粉直流燃烧器为主。煤粉颗粒在炉膛内气固两相流的流动和燃烧对于研究炉膛燃烧效率以及煤粉稳燃有着至关重要的影响作用。近年国家对于火电厂制定了更严格的环保标准,低氮燃烧排放成为科研院校研究和电厂实际生产重点研究对象。本文通过商业软件CFD,对新型C型直流燃烧器以及C型直流燃烧器在电厂锅炉的应用进行了燃烧数值模拟研究。首先,本文对单个C型直流燃烧器进行数值模拟,研究煤粉颗粒通过C型燃烧器在炉膛内燃烧的温度云图以及煤粉颗粒在喷射前进方向的着火情况。煤粉通过C型直流燃烧器可以在炉膛内形成C形煤粉射流,在其两个端部会形成小火焰着火区域,这一区域相对表面积较大,煤粉相对浓度较高。两个尖端区域深入并卷吸周围高温烟气,由于其单位体积的表面积大,而形成单位体积最大的烟气卷吸量,从而构成点火性能优越的小火焰着火区,使得煤粉易着火和稳燃。其次,本文单独研究不同尖端折角对C型直流燃烧器性能的影响。可以发现,尖端折角的角度越小,尖端的小火焰效果和双面点火效果越明显。最后,本文采用RNG-湍流模型,将C型直流燃烧器应用于某300MW电厂锅炉,应用并对煤粉的燃烧和污染物的排放进行数值模拟。C型直流在促进煤粉提前着火燃烧,促进煤粉在炉膛内的稳燃和易燃方面有着明显的效果,而且在一定程度上可以促进降低氮氧化物排放。
[Abstract]:Burner is an important device of boiler organization combustion in power plant. Main pulverized coal direct current burner. The flow and combustion of gas-solid two-phase flow of pulverized coal particles in furnace plays an important role in the study of combustion efficiency and steady combustion of pulverized coal. In recent years, more strict environmental protection standards have been established for thermal power plants, and low nitrogen combustion emissions have become the focus of research in scientific research institutions and actual production of power plants. In this paper, the combustion numerical simulation of new type C direct current burner and C type direct current burner in power plant boiler is carried out by commercial software CFDs. Firstly, the numerical simulation of a single C-type direct current burner is carried out to study the temperature cloud pattern of pulverized coal particles burning through the C-type burner and the ignition of the pulverized coal particles in the direction of injection. The pulverized coal can form a C-shaped pulverized coal jet in the furnace through the C-type direct current burner and form a small flame ignition area at the two ends of the pulverized coal. The relative surface area is large and the relative concentration of the pulverized coal is relatively high. Because of the large surface area of the two tip regions and the high temperature smoke around it, the maximum smoke entrainment per unit volume is formed, which forms a small flame ignition area with superior ignition performance, which makes the pulverized coal easily ignite and stable. Secondly, the effect of different tip angle on the performance of C type DC burner is studied separately in this paper. It can be found that the smaller the angle of the tip, the more obvious the effect of small flame and double side ignition. Finally, using RNG-turbulence model, the C type direct current burner is applied to the boiler of a 300MW power plant, and the combustion of pulverized coal and the emission of pollutants are numerically simulated. Promoting pulverized coal combustion stability and flammability in furnace has obvious effect, and can promote the reduction of nitrogen oxide emission to some extent.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM621.2

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