The modelling and experimental investigation of a thermally coupled humidification-dehumidification desalination process using a carbon-filled-polypropylene shell-tube column are presented.A heat/mass transfer model is established to study the correlation among productivity,thermal efficiency,physicochemical parameters (gas/liquid phase temperature,heat/mass transfer coefficient,Reynolds number etc.),and operating conditions(the temperature of feed water,the flow rates of external steam,feed water,and carrier air);at the same time,the effects of operating conditions on the productivity and thermal eficiency of the column are investigated both theoretically and experimentally,which indicate that the optimum flow rates of external steam,feed water,and carrier gas are 0.18,60,and 10kg.h- 1,respectively,and the higher the feed water temperature(≤95℃)is,the greater the productivity and the thermal efficiency will be.Furthermore,performance comparison with the previous study shows that the condensate productivity of this carbon-filled-plastic column is not lower than that of the copper column,which demonstrates the practicability and feasibility of applying such a plastic column to the humidification-dehumidification desalination process.
摘要:通过闭式循环冷却水系统中水水换热器的选型, 详细论述了管壳式与板式换热器的结 构性能技术 经济比较,为水水换热器的选型提供参考。 关键词:换热器 性能 比较 从国内已建发电厂来看, 用于闭式循环冷却水系统的水水换热器有两类, 一类是管壳热 换器,另一类是板式换热器。 管壳换热器是常用的换热器形式, 在电厂设计中已得到了广泛 的应用,而在国内一些进口机组的电厂、 燃气蒸汽联合循环电厂和核电站多有采用板式换热 器。由于板式换热器紧凑、重量轻、高传热效率,人们对它的兴趣日益增长。本文针对管壳 式及板式换热器二种型式进行比较,并提出选型参考意见。 1 管壳式及板式换热器结构简介 (1)管壳式换热器 管壳式换热器是由前水室、管束、筒体、后水室等组成。管束采用可抽式管束,它由前 后管板、折流板、拉杆、定距管、换热管组成。拉杆与管板、拆流板采用丝扣连接,换热管 与管板采用胀接加密封焊。 在壳侧水入