700℃煤电机组锅炉炉内烟气侧热偏差的抑制

Suppression of flue gas side thermal deviation in boiler of :00℃ coal-fired power unit

700℃超超临界锅炉蒸汽参数高,热强度大,要求热偏差尽量小,所以需要确定700℃超超临界锅炉炉内热偏差的优化方法。初步设计了炉膛尺寸,用GAMBIT软件建立了几何模型并进行了网格划分,选取影响其炉膛出口烟气热偏差的3个主要因素:一、二次风入射角度、燃尽风反切角度以及燃尽风率。设计了3因素3水平正交试验表,对正交试验表中的9个工况进行了模拟计算,并对模拟结果进行了极差分析和方差分析,结果表明:燃尽风反切角度和一、二次风入射角度对炉膛出口烟气热偏差影响为高度显著因素,且燃尽风反切角最显著,燃尽风率为显著因素。进一步研究后得出:当一次风偏转2°、二次风偏转17°、燃尽风反切25°、燃尽风率为0.40时,炉膛出口的烟气热偏差最小,此时的烟气热偏差值仅为8.30 K。

The 700℃ ultra supercritical boiler,characterized by high steam parameters and high thermal intensity,requires minimal thermal deviation.It aims to identify an the optimization method of the thermal deviation in the 70o C ultra supercritical boiler.The furnace size was preliminarily designed,and the geometric model was established and meshed using GAMBIT software.Three main factors affecting the thermal deviation of flue gas at the furnace outlet were identified:the incidence angle of primary and secondary air,the reverse tangent angle of burnout air and the burnout air rate.An orthogonal experiment with three factors at three-level was designed,and the simulation calculations were carried out for nine working conditions.The range and variance analysis were carried out for the simulation results.The results show that the reverse tangent angle of burnout air and the incidence angle of primary and secondary air on the thermal deviation of flue gas at the furnace outlet are the highly significant factors,and the reverse tangent angle of burnout air is the most significant factor,and the burnout air rate is the significant factor.Further research revealed that the minimal flue gas thermal deviation at the furnace outlet,at 8.30 K,occurs when the primary air deflects 2°,the secondary air deflects 17°,the burnout air reverses 25°,and the burnout air rate is O.4.