四角切圆锅炉H_2S分布特性及贴壁风喷口研究

Research on H_2S Distribution Characteristics in Tangentially Fired Boiler and Nozzle of Near-wall Air

对四角切圆锅炉内H_2S分布特性进行研究,为切圆燃烧方式下水冷壁壁面区域高温腐蚀问题提供参考,并提出相应的解决方案。采用数值模拟方法对不同负荷下燃烧动力场、SO_2排放值及H_2S分布特性进行模拟,并对贴壁风喷口形状进行分析。结果显示,SO_2模拟结果与锅炉实际SO_2排放数据相符;H_2S质量分数与配风给粉方式有关;任意高度截面H_2S质量分数平均值受炉膛负荷影响不大;高负荷工况炉内动力场旋流强度较强,H_2S主要集中于燃烧器附近水冷壁壁面区域;随负荷增高,壁面区域H_2S分布呈增加趋势。根据H_2S随负荷变化的分布特性可知,锅炉低负荷情况下壁面处H_2S量少,更加安全,同时可配合矩形喷口贴壁风以进一步降低高温腐蚀可能性。在机组调峰过程中,低负荷情况可适当掺烧高硫煤以提高机组经济性。

This paper studied the H 2S distribution characteristics in tangentially fired boiler and proposed solution for high temperature corrosion in water wall.The fields in combustion,SO 2 emission values and H 2S distribution characteristics under different loads were stimulated by numerical simulation method.The paper also analyzed the shape of near-wall nozzle.The results showed that the simulation data of SO 2coincided with the actual data;the mass fraction of H 2S was related to coal quantity and air volume;the influence of firepot load on the mean mass fraction of H 2S was not obvious in arbitrary height cross section;the swirl intensity was stronger in higher load;H 2S mainly concentrated on water wall surface near burners;the H 2S became more with the load increased.According to the H 2S distribution characteristics in different loads,the density of H 2S was less in under load,and it was more secure.The rectangle nozzle of near-wall air can be adopted to further reduce the possibility of high temperature corrosion.When in under load condition,appropriate high-sulphur coal can be blended in to improve the efficiency of units during peak load cycling.