基于凝汽器强化传热技术的循环水系统节水研究

从提高凝汽器换热系数出发,在保证真空不变的前提下,引出临界污垢热阻的概念,通过分析临界污垢热阻和循环浓缩倍率的关系,将强化传热和循环水节水问题结合起来研究,并通过实例计算出相应的节水量。研究表明,在凝汽器真空和其它换热条件不变时,增大凝汽器换热管汽侧换热系数可以增大临界污垢热阻,从而提高循环水的浓缩倍率,达到循环水系统节水的目的,并且带来可观的节水效益和环保效益。文中分析了某300 MW机组凝汽器采用强化传热管后,汽侧换热系数显著增大,在达到原设计真空下,该机组每年因此可以节水约86.9×104t。

A Study of the Water Savings of a Circulating Water System Based on the Intensified Heat Transfer Technology of a Condenser

From the standpoint of enhancing the heat transfer coefficient of condensers,a concept of critical fouling heat-resistance is introduced under the precondition of keeping the vacuum unchanged.Through an analysis of the relation between critical fouling heat-resistance and circulation concentration ratio,the intensified heat transfer is studied in conjunction with the issue of circulating water savings.Moreover,through some specific examples,the water saving quantity is calculated.The study results show that when the vacuum of the condenser and other heat exchange conditions are kept unchanged,an increase in heat exchange coefficient at the steam side of condenser heat exchange tubes can raise the critical fouling heat-resistance,thereby enhancing the concentration ratio of the circulating water and attaining the aim of saving water for the circulation water system along with the securing of sizable water-saving and environmental protection benefits.After an analysis had been conducted of a 300 MW power plant condenser that used intensified heat transfer tubes,it is found that the heat exchange coefficient at the steam side has markedly increased.Under the condition of attaining the vacuum set by the original design,the machine unit can as a result save water amounting to 869 000 tons each year.