关键词: 膜蒸馏, 热泵, 膜通量, 能效比

Abstract: A novel brine solution concentration system based on the heat pump membrane technology was integrated to improve the membrane flux as well as reduce the consumption of cooling water. This proposed system was simulated by the Aspen Plus platform. After experimentally verifying the system simulation model, influences from the feed liquid temperature, temperature at permeate side and feed flow rate on the overall thermal performance indices of the system were studied. The results showed decreasing temperature at permeate side improved the permeability and decreased of the coefficient of performance (COP), and the change of temperature at permeate side played a great effect on the coefficient of performance under the fixed condition of the low temperature at permeate side. With increase of the temperature at permeate side, an optimal temperature value was obtained to maximize the water production ratio and minimize the energy consumption per ton of water, and the maximal water production ratio was 3.42, the minimal energy consumption per ton of water was 463 MJ/t under the working condition in this research. Besides, as the feed liquid temperature increased, the optimal temperature at permeate side increased. As the feed flow rate rised, permeability and coefficient of performance went up, while the energy consumption of tons of water rised and the water production ratio reduced. Moreover, when the feed flow rate was less than 3 L/min, the energy consumption of tons of water and the water production ratio reduced sharply as the feed flow rate increased. When the feed liquid temperature was 50℃, the feed flow rate increased from 1.5 L/min to 3 L/min, the value of GOR (Gained Output Ratio) decreased by 33.5%, while the rise of flow rate from 4.5 L/min to 6 L/min only caused GOR decrease by 10.6%.With increase of the permeation side temperature, an optimal temperature value is obtained to maximize the water production ratio and minimize the energy consumption per ton of water, and the maximal production ratio is of 3.42, the minimal energy consumption is of 463 MJ/t under the working condition in this research. Besides, as the feed temperature increases, the optimal permeation side temperature increases. As the feed liquid flow rises, permeability and energy efficiency ratio go up, while the energy consumption of tons of water rises and the water production ratio reduces. Moreover, when the feed liquid concentration is less than 3L/min, the energy consumption of tons of water and the water production ratio reduce sharply as the feed liquid flow increases.

Key words: membrane distillation, heat pump, membrane flux, COP