低温多效蒸发海水淡化系统的变工况性能分析

Off design performance analysis of desalination plant with low temperature distillation

建立了低温多效蒸发系统在变工况运行条件下的数学模型,分析了加热蒸汽温度、加热蒸汽流量和供入海水流量对系统的蒸发产物负荷率和单位蒸发产物热耗率的影响,探讨了各效蒸发器中海水的温度和浓度的变化与装置结垢问题的关系。结果表明,在控制结垢发生的前提下,即盐水浓缩比不超过2.5、顶值盐水温度低于75℃时,降低供入海水流量、增加加热蒸汽流量和提高加热蒸汽温度有利于系统运行。

Mathematical model and performance analysis were presented for a decalination plant with low temperature multi-effect distillation （LT-MED） under off design conditions. Performance analysis is carried out as a function of the heat steam temperature, the heat steam flow rate and the feed seawater flow rate. The results are based on comparison of load ratio （LR） and specific heat consumption. The relationship between scaling and the variation of brine temperature or salinity is also studied. The results indicate that the system performance can be improved by reducing feed seawacer flow rate, increasing heating sleam flow rate and augmenting heating steam temperature when the brine concentration ratio is no more than 2.5 and the tog brine temperature is under 75 ℃.