风粉配平论文：煤粉锅炉一次风管风粉配平方案的研究.docVIP

风粉配平论文：煤粉锅炉一次风管风粉配平方案的研究 【中文摘要】对于切向燃烧的煤粉锅炉,一次风管风粉配平(即与一次风管路相连的同层火嘴的出口风量和煤粉量的配平)对锅炉运行的安全性和经济性有重要影响。一次风管风粉分配不均匀使炉膛火焰中心发生偏斜、炉膛局部区域结渣和炉膛燃烧区域燃烧脉动,这不但会引起燃烧不稳定,而且还将引起过热器区域烟气速度场和温度场的分布不均,从而导致汽温偏差甚至造成过热器爆管。改变旋转式粗粉分离器结构提高一次风管风粉均匀性的方案就是将粗粉分离器的转子叶片叶型由直叶片改变成弯扭叶片。论文建立了弯扭叶片式和直叶片式两种旋转粗粉分离器的几何模型,同时建立了气固两相流计算的数学模型,并利用Fluent进行数值计算。计算结果表明:静动叶结合式分离器提高了各个一次风粉管风粉均匀性;同时在分离器运行过程中,弯扭叶片式粗粉分离器减轻了静叶片的磨损程度、降低了最佳分离转速和分离器的通风电耗,对电厂的节能降耗起到一定的作用。通过煤粉管道阻力配平提高一次风管风粉均匀性方案。对于四角切圆燃烧锅炉,与同层火嘴相连的一次风管的管道阻力是不同的,这必然导致了风粉分配的不均匀。通过冷态试验来调整各送粉管道的阻力特性使之一致只能做到纯空气的均匀分配。本文建立了一次风管的动态阻力计算模型,作为在锅炉运行中实时调整一次风管管道阻力的依据,以便提高一次风管风粉的均匀性。利用风粉在线监测提高一次风管风粉均匀性方案。分析了当前风粉在线监测的方法,提出了在线监测风粉浓度的方案。为调平一次风管风粉的均匀性提供准确的数据。 【英文摘要】For tangential firing coal-powder boiler, the air-coal powder balancing of primary air duct will affect the safety and economy of boiler operation.The above mentioned concept means the volume of air and coal powder which is connected with nozzles,and it is on the same floor with primary air duct. Nonuniform distribution of primary air duct will lead to make furnace flame centre in deflection, furnace slagging and combustion pulsation in some local regions.These problems will lead to combustion instability. And it would cause deviation of superheater on its flue-gases velocity field and pressure field, and even will lead temperature to deviate and superheater to break.The solution is to improve the uniformity of primary air duct powder through changing the structure of rotary classifier. By Gambit,we respectively build two kinds of geometrical model.It includes two kinds of segregator, that is twisted blade and straight blade.At the same time,we build a mathematical model of gas-solid:two-phase flow. Then we use fluent to do some numerical calculation. The result indicates that Static and dynamic combination rotary classifier will improve the uniformity of each primary air powder pipe, and the classifier of compound lean blade reduces the degree of wear of stator blade, the best separation speed and the air power consu