一种用于锅炉冷凝式换热器的热力计算方法  

Thermal Calculation Method for Condensing Heat Exchanger in Boilers

作　　者：李建波[1] 吴晓明[1] 陈凯[1] 邓磊[1] 车得福[1] LI Jian-bo WU Xiao-ming CHEN Kai DENG Lei CHE De-fu(State Key Laboratory of Muhiphase Flow in Power Engineering, Xi＇an Jiaotong University, Xi＇ an 710049, China)

机构地区：[1]西安交通大学动力工程及多相流国家重点实验室,陕西西安710049

出　　处：《工业锅炉》2016年第6期35-41,共7页Industrial Boilers

基　　金：国家科技支撑计划资助项目(No.2015BAA04B02)

摘　　要：锅炉冷凝式换热器能深度回收锅炉尾部烟气的水分和热量,在燃气锅炉以及加装了湿法脱硫塔的电站锅炉中得到了一定的应用。对数平均温压法适用于传统非冷凝式换热器的热力计算,但不适用于锅炉冷凝式换热器的热力计算。在目前尚不存在通用性强的锅炉冷凝式换热器热力计算方法的情况下,提出了一种适用于锅炉冷凝式换热器的热力计算方法。采用该方法可分别求出换热器的显热换热量、潜热换热量和冷凝水流量,预测换热器内工质温度、水蒸气体积分数等参数的分布,并判断水蒸气开始发生冷凝的位置。采用文献中的实验数据对该热力计算方法的正确性进行了验证,结果表明烟温和冷凝水流量的计算值和实验值的变化趋势一致,且二者最大偏差在20%以内。该热力计算方法可为锅炉冷凝式换热器的设计和优化提供参考。Condensing heat exchanger has been applied in gas-fired boilers and utility boilers with wet desulfurization for its function of water and heat recovery in flue gas. The log-mean temperature difference method can be applied to ther- mal calculation of the traditional non-condensation heat exchanger, while it is not applicable to thermal calculation of con- densing heat exchanger in boilers. A thermal calculation method was proposed when there is no universal thermal calcula- tion method for condensing heat exchanger in boilers at present. The sensible heat flow rate, latent heat flow rate and con- densate flow rate of the condensing heat exchanger could be calculated through the thermal calculation method. Besides, the distribution of the working medium temperature and the water vapor concentration, and the position where the water vapor starts to condense could be predicted. The accuracy of the thermal calculation method was verified by the experimental data in the literature. It was suggested that the calculated values of the flue gas temperature and the condensate flow rate presen- ted the same changing tendency with the experimental values, and the deviation was less than 20%. The thermal calcula- tion method proposed can provide a reference for the design and optimization of condesing heat exchanger in boilers.

关 键 词：冷凝式换热器 传热 传质 热力计算 

分 类 号：TK212[动力工程及工程热物理—动力机械及工程]