Pulverized Coal Burnout Determination in Furnace with Air Staging and It's Comparison with Field Test

2020 Journal of Mechanical Engineering  
Abstract:The traditional zone-by-zone computational approach neglecting particles burnout calculation in furnace heat transfer design is applicable to non air staged combustion. With the extensive air staged low NO x combustion technology, advanced coal combustion model integrated with the heat transfer approach to determine the burnout distribution along the furnace height is of great significance to improve the design accuracy of steam temperature in platen super heater or radiant reheater in
more » ... the upper zone of the furnace. An improved zone-by-zone computational approach incorporated with a more detailed coal combustion model is developed to determine burnout rate of bituminous coal in tangentially fired furnace with air staging, field tests is carried out in the case boiler covering the regular range of variation of operating loads. The tested furnace conditions are used as inputs for the zone-by-zone computational approach coupled with combustion model to predict coal burnout, results of the simulation provide a clear insight into the burnout processes in air staging combustion. The effects of combustion mode and surface reaction kinetics parameters on burnout are also investigated. Results from the simulations are compared against the measured values, showing a reasonable agreement in most test scenarios. Thermal annealing, ash inhibition and inhomogeneous distribution of oxygen content in flue gas are the main cause of the model error. The computational complexity in the incorporated burnout model are equivalent to that of the traditional zone-by-zone computational approach, and suitable for engineering application. Key words:power plant;boiler;air staging;coal combustion;modeling;burnout 0 前言 * 锅炉燃煤经过破碎和研磨形成煤粉,被空气气 流携带喷入炉膛,在数秒内穿过炉膛而完成燃烧过 20200201 收到初稿,20200715 收到修改稿 程。在锅炉运行中,常用飞灰可燃物含量表示煤粉 燃烬程度,是重要的监控参数。飞灰中未燃烬碳损 失降低了锅炉效率,增加燃料消耗 [1-2] ,且飞灰作为 水泥和混凝土的添加剂,可燃物含量过高会降低水 泥的抗冻融性,从而影响飞灰的无害化利用,增加 环境压力 [3-4] 。 月 2020 年 12 月 刘福国等:空气分级炉膛煤粉燃烬模型及实炉试验对比 209 机 械 工 程 学 报 第 56 卷第 24 期期 210
doi:10.3901/jme.2020.24.208 fatcat:jzrxfwdifjgvlmkymhpp7tcbyq