中文摘要：

对1000MW火力发电机组中间热媒体烟气换热器（media gas-gasheater，MGGH）系统中脱硫塔前的氟塑料换热器展开设计计算，从交叉次数的角度对氟塑料换热器模块化以及优化布置展开研究．结果表明：水侧阻力与交叉次数的平方成正比；随着介质交叉次数的增加烟气侧压降降低管外总换热面积、联箱总开孔数和模块单元联箱开孔数均减少，且当交叉次数由2增加到4时上述参数均大幅降低，当交叉次数大于4以后降幅均相对较小，即氟塑料换热器的换热性能、阻力性能及联箱结构在交叉次数为4时得到优化，结合热膨胀因素建议在工程应用中尽量采用2个U形换热模块单元布置成W形．

英文摘要：

A design calculation was implemented for a fluoroplastic heat exchanger set before desulfurizer in the media gas-gas heater （MGGH） system of a 1 000 MW thermal power unit, while an optimal layout of the fluoroplastic heat exchanger was researched based on modularization in terms of gas-water crossover times. Results show that the water side resistance is in direct proportion to the square of crossover times. The total external heat exchange area, the gas-side pressure drop, the total number of header connectors as well as the number ot＂ header connectors in the modular unit reduce with the rise of gas-water crossover times. When the number of crossover times increases from 2 to 4, the above-mentioned parameters signifi- cantly reduce, and when the number rises continually, the reducing tendency lowers gradually, i.e. opti- mum heat exchange performance and optimum resistance characteristics of the fluoroplastic heat exchanger as well as reasonable structure of related headers can be obtained for the crossover times of 4. Considering the thermal expansion factor, double U-shaped heat exchange modules in W-shape arrangement are recom- mended for the fluoroplastic heat exchanger.