无烟煤混煤煤粉燃烧器的设计及数值仿真分析

发布时间：2017-12-31 08:17

本文关键词：无烟煤混煤煤粉燃烧器的设计及数值仿真分析　出处：《集美大学》2015年硕士论文　论文类型：学位论文

【摘要】：针对福建无烟煤极难燃的问题,本文结合旋流燃烧器的运行优点和超细煤粉良好燃烧效果,利用优质烟煤高效的助燃煤粉特性,开发出一种烟煤助燃超细无烟煤的新燃烧器—新型旋流浓淡煤粉燃烧器(New Type Bias Combustion Swirl Burner,简称(NTBCSB)),并对其燃烧特性进行了详细的研究。新型旋流浓淡煤粉燃烧器充分考虑了影响煤粉着火和燃烧的煤粉气流与高温烟气的迅速强烈混合问题:通过合理的配风和特殊的结构,从而实现了烟煤助燃无烟煤粉的效果。燃烧器一次风通道内设置煤粉浓缩装置,从而实现煤粉的浓淡燃烧;一次风管出口的缩口有利于提高出口煤粉的惯性动量,能够使煤粉颗粒进入炉膛后即能进入回流区,而不会过早地向二次风扩散;中等强度的旋流二次风能促进烟煤与无烟煤混合燃烧,并加强气流扰动;三次直流风的补入能够稳定火焰,并降低火焰温度,减少NOx的排放。对新型旋流浓淡煤粉燃烧器建立了三维数值计算模型,利用专业的计算流体力学软件ANSYS CFX并对采用新型燃烧器的煤粉工业锅炉炉膛燃烧室内的气固两相流场、压力场、温度场和浓度场进行了模拟仿真。并对采用新型旋流浓淡煤粉燃烧器工业锅炉炉膛燃烧室内的回流区进行了立体分析;通过颗粒场模拟,分析了煤粉在喷出燃烧器后在炉膛燃烧室内的分布和运动状态。对采用新型旋流浓淡煤粉燃烧器与改进前的旋流燃烧器的工业锅炉炉膛燃烧室分别进行单烧烟煤、超细无烟煤以及烟煤与超细无烟煤混煤三种工况的燃烧特性分析,仿真结果表明:该燃烧器具有良好的稳燃性能,并且有效的降低NOx排放。
[Abstract]:In order to solve the problem of extremely difficult combustion of anthracite in Fujian province, combined with the operating advantages of swirl burner and the good combustion effect of superfine pulverized coal, the characteristics of high quality bituminous coal with high efficiency for combustion support are utilized in this paper. A new Type Bias Combustion Swirl Burner, a new type of swirl dense and light pulverized coal burner, has been developed for bituminous coal to support the combustion of ultrafine anthracite. Abbreviated as NTB CSB). The combustion characteristics are studied in detail. The new swirl dense and light pulverized coal burner takes into account the rapid and intense mixing of pulverized coal and high temperature flue gas which affects the ignition and combustion of pulverized coal. Through reasonable air distribution and special structure. In order to realize the effect of anthracite pulverized coal combustion supported by bituminous coal, a pulverized coal concentration device is installed in the primary air channel of the burner to realize the dense and light combustion of pulverized coal. The constriction of the outlet of the primary air duct is beneficial to improve the inertia momentum of the outlet pulverized coal, which can make the pulverized coal particles enter the backflow zone after entering the furnace, and not spread to the secondary air prematurely. The secondary wind energy with medium intensity swirl can promote the mixed combustion of bituminous coal and anthracite and enhance the disturbance of air flow. The recharge of the tertiary DC air can stabilize the flame, reduce the flame temperature and reduce the NOx emission. A three-dimensional numerical model for the new swirl thick-light pulverized coal burner is established. The gas-solid two-phase flow field and pressure field in the combustion chamber of pulverized coal fired industrial boiler with a new type burner are analyzed by using the professional computational fluid dynamics software ANSYS CFX. The temperature field and concentration field were simulated, and the reflux zone in the furnace combustion chamber of industrial boiler with a new swirl dense and light pulverized coal burner was analyzed. Through particle field simulation. The distribution and movement state of pulverized coal in the furnace combustion chamber after injection burner are analyzed. The single burning bituminous coal in the furnace combustion chamber of industrial boiler with new swirl dense and light pulverized coal burner and the improved swirl burner is carried out respectively. . The combustion characteristics of ultrafine anthracite and bituminous coal mixed with ultra-fine anthracite are analyzed. The simulation results show that the burner has good combustion stability and effectively reduces NOx emissions.
【学位授予单位】：集美大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK223.23

【参考文献】