In this paper, the research was focused on optimizing low-temperature heat recovery to adopt multi-effect distillation (MED) in desalination by pinch technology. And further analysis indicated that phase changes occurred during the heat recovery process. In such case, the feed stream was divided into two streams: the liquid feed stream and the gaseous feed stream. Through calculation, the optimal ΔTmin was established at 26 ℃, and the total cost of heat exchange process was only $1.098×106. By using the Problem Table Algorithm for pinch analysis, the temperature of the hot and the cold steams was 119 ℃ and 93 ℃, respectively. At a temperature higher than 119 ℃, all heat of the hot stream could not be cooled by the condenser, and the minimum heat load of utility (QH,min) was 440457.64 kW; and at a temperature below 93 ℃, all heat of the cold stream could not be provided by the heater, and the minimum cold load of utility (QC,min) was 1965993.85 kW. Finally, the synthesis of heat exchanger network was established through integrating two heat exchanger networks.
展开▼
