| Membrane distillation is the temperature difference across the membrane as a driving force, so that the volatile material can be traveled from one side of the membrane into the other side. Membrane distillation technology can be applied in desalination or brackish water desalination process technologies. In the new membrane distillation system, hydrothermal flow, hydrothermal temperature, semiconductor input current and the cooling water flow affects the membrane flux. Because of the subject has been conducted several experiments to study the factors that affect the flux.In order to save time and reduce the amount of computation relative, so this experiment increases the new factors that is hydrothermal flow.At the same time, the use of orthogonal experiment research analysis the system flux and energy consumption.In the experiment, the cold cavity semiconductor after turning the c urrent 4~5 minutes can be reached a stable cooling effect, the cooling rate relative to other means is rapid. Because the research group has analyzed the semiconductor cold chamber, so in this article we studied the case of the system is a combination of hot and cold cavity. When the hydrothermal temperature roses from 35℃ to 75℃, while the input current is constant, the temperature difference between the membrane surface and aluminum cold-wall temperature is at up to about 25℃. When the hydrothermal temperature is maintained constant 75℃, while the current changes from 14 A to 20 A, the change of temperature is about 3℃;Cooling water flow changes from 600L/h into 1000L/h, and the hydrothermal flow changes from 60L/h to 200L/h, the difference of temperature is about 2.4℃ and 1.89℃. The results varies widely from analysis of semiconductor cold chamber alone, so analyzing the various factors affecting on flux and energy is based on experimental income. In the energy analysis, when the flux of is 15.072 kg/(m2?h), the energy consumption is about 1.78×104/MJ/t, while imports membrane in the same condition derived membrane flux was 34.26 kg/(m2?h), the energy consumption is only 0.8576×104/MJ/t, which shows the influence of the quality of the film on the flux and energy consumption is great. By numerical simulation results, the optimal parameters are: the system tray watershed in the heat chamber slotted heat chamber length 12 mm, with slotted 3mm, slotted angle of 60°,while the interior cavity fluid derived heat flow and temperature, velocity distribution situation. And draw the fluid flow, the temperature and velocity distribution inside the heat capacity chamber.Through experimental analysis, obtained optimum combination of air gap membrane distillation system of cooling water flow is 800L/h, the hydrothermal flow is 80L/h, the hydrothermal temperature is 75℃and the input current is 14 A.The experimental data showed that, when the system has a maximum flux is not the lowest energy consumption: the economy is not very good. Not confirmed semiconductor input current increases, the greater flux. Meanwhile, the system and local membrane also conducted a preliminary current analysis of the entire system, where the semiconductor input current accounting system maximum consumption, the system in many respects have reduced consumption, increase the potential efficiency. Then provide a theoretical basis for the optimization of the new improved membrane distillation system. |
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