الفهرس | Only 14 pages are availabe for public view |
Abstract The present work summarizes a practical study of seawater membrane distillation procedures. This procedure has been carried out using exhaust energy or solar energy, leading to pure water completely free of waste and salt. All the experiments have been done in the labs of the Shoubra faculty of engineering in full simulation of reality. For this purpose, many transactions were accomplished. First of all, a module containing cooling and heating was designed and manufactured in order to obtain the desired temperature difference at the exchanger. The last one contains a chamber for passing the salt water (red sea water; 12,000 ppm), which was heated to 40 to 80 °C. This hot water enters the hot chamber through a locally designed chemical membrane polyvenyldeen fluride (PVDF ). The membrane can withstand a high temperature of up to 260 oC, with hydrophobic pores that repel wastes and salts and allow only water vapor to pass. After passing the membrane, the water vapors are condensed on the cold-water chamber surface. A coldwater tank that has a cooling unit is the one responsible for supplying the cold chamber with cold water (10 to 30 °C). The condensed vapors are collected and analyzed to determine their eligibility for human use. Furthermore, the following variables were utilized and taken into consideration in the present work: Temperature effect on the hot water (the salt water) that enters the hot chamber for distillation, as well as its effect on the water entering the cold chamber. Taking into consideration the water flow rates on both sides and the effect of changing the membrane type and thickness on the permeability. All of that was studied and utilized very carefully, leading to the following results.Increasing the hot water temperature intended to be distilled (seawater) achieved the best findings, especially around 80 °C. Moreover, decreasing the cold-water temperature to the least accomplished temperature of 10 °C led to the best results. Furthermore, the higher the temperature difference between the cold and the hot chamber, the higher the water permeability through the membrane that is achieved and condensed. In addition, various membranes with different characteristics made different chemical substances, were clearly studied. polyvenyldeen fluride ( PVDF ) membrane is the most focused on during the experiences with different thicknesses and different permeabilities to see the effect of these variables on the passing vapours and the amount of condensed and collected water. The rate of the pumped water underneath the cold and hot water tanks is fully studied, leading to the best flow rate between the two chambers without causing any obstacles inside the heating chamber of 6 L/min. Therefore, different (locally made) chemical materials were added to reach the best membrane and enhance its effect, including (PVDF + graphene) and (PVDF + zeolite nanoparticles (Z)). The obtained results were in favour of (PVDF + graphene), which achieved the best results with the highest temperature difference, 6 L/min flow rate, and 0.45 μm permeability. The final obtained results of all experiments were compared in addition to changing all the variables, leading to the best operating circumstances of (PVDF + graphene) membrane, 70 °C temperature and 6 L/min flow rate. With the best achieved result of 13.95 L/hr.m 2 . |