循环流化床锅炉二次风射流特性的冷模实验研究

Cold Model Experiments on the Characteristic of Secondary Air Injection in CFB Boiler

循环流化床二次风的主要作用是为燃料补充燃烧所需的氧气和加强燃料在炉内的扰动,对锅炉燃烧效率有重要的影响。在一个可视化的循环流化床实验装置上进行了炉内物料浓度、二次风喷口直径和风速对二次风射程与扩散影响的冷模实验。采用向炉内送入高温二次风,然后通过布置在二次风平面的热电偶来测量炉内温度变化的方法,间接反映二次风的射程和扩散情况。结果表明,在固体颗粒浓度一定时,最大射流深度、扩散程度与二次风动量成正比;二次风动量一定时,最大射流深度、扩散程度与固体颗粒浓度成反比。

In circulating fluidized bed （CFB）, the main motivation of the secondary air （SA） is providing enough oxygen of combustion and enhancing the disturbance of fuel. SA affects the combustion efficiency of circulating fluidized bed obviously. Cold model experiments on the relationship of particle density, SA injection velocity, diameter of nozzle and characteristic of SA injection studied in a visual cold experimental apparatus. The range and diffusion of SA injection is represented by the temperature change of the thermocouple in CFB boiler. The experimental results show that the max range and diffusion of SA injection is in direct ratio to the momentum of SA injection when particle density remains steady, and in inverse ratio to the particle density when the momentum of SA injection remains steady.