摘要
对220 t/h循环流化床锅炉的石灰石-石膏湿式脱硫塔进行计算流体力学数值模拟,研究液气比、浆液雾化角度及粒径对脱硫效率的影响。模拟结果表明,在正常运行工况下,塔内流场合理,速度与温度分布均匀性较高,出口SO 2浓度为33 mg/m 3,与实际值符合。液气比越高,脱硫效果也越高,但液气比超过23 L/m 3之后,脱硫效率增加不明显。脱硫塔存在最佳雾化半锥角,为35°~50°。当雾化角度过小时,液滴散开角度较小,液雾不能对烟气形成有效覆盖,而雾化角度过大时,更多浆液喷至脱硫塔侧壁,对减弱脱硫作用。浆液的最优平均雾化粒径为1.5~2.5 mm。如果液滴粒径过小,液雾容易受到烟气气流冲击,不能保持原有形状,影响浆液对烟气的覆盖率;反之,液滴粒径较大时,脱硫塔内浆液表面积过小,对SO 2吸收不利,因此,该最优值应是能够保持液雾形状的最小粒径。
The wet desulfurizer of a 220 t/h circulating fluidized bed boiler is numerical simulated,and the influence of liquid-gas ratio,atomization angle and size on desulfurization efficiency is investigated.The result shows that the flow field in the desulfurizer is reasonable,and the distributions of velocity and temperature are quite uniform.The concentration of SO 2 at outlet is calculated to be 33 mg/m 3,which agrees with the actual value.The desulfurization efficiency is increased as the liquid-gas ratio is increased,until it reaches 23 L/m 3.There exists an optimal atomization angle,ranging from 35°to 50°.At small atomization angles,the sprays cannot cover all the flue gas in the desulfurizer.However,the desulfurization liquid will be sprayed on the inner wall of the desulfurizer if the atomization angle is too large.The optimal atomization size of desulfurization liquid is found to be 1.5~2.5 mm.If the droplet size is small,the sprays will be impacted by the gas flow,which reduces the coverage of the desulfurization liquid.On the contrary,the total surface area of desulfurization liquid is too small for the absorption of SO 2 if the droplet size is over large.Therefore,the optimal value should be the minimal droplet size which could keep these cone shapes in the desulfurizer.
出处
《电力科技与环保》
2020年第4期13-18,共6页
Electric Power Technology and Environmental Protection
基金
国家重点研发计划项目(2017YFF0205006)
国家自然科学基金(51876197)。
关键词
湿法脱硫
液气比
覆盖率
数值模拟
运行参数
wet desulphurization
liquid-gas ratio
coverage rate
numerical simulation
operation parameter
