Methanol recovery from transesterification reaction by solar thermal energy

The experimental research was to test the potential of methanol recovery from transesterification reaction by solar distillation process. The flat-plate solar collectors were used as a heat resource to directly increase the temperature of 12 litre biodiesel with a flowing rate at 2.4 litre per minute in the system. The experiment was undertaken in 2 cases. Case 1 , the system in which methanol was distilled from purified diesel and 5% and 10% of methanol added in order to simulate variable condition of methanol quantity, and Case 2, the system in which about 1.3% and 5% of remaining methanol distilled from crude biodiesel after use in the production process reaction was used to test in an actual working condition. The experiments were carried out on the periods of fine weather (solar radiation > 17 MJ/m2day) between 9:00 pm. - 03:00 pm. The result indicated that the temperature of biodiesel in a distillation tank was 80-100 Co varying with solar radiation values. The product of methanol distilled from biodiesel in the both cases yielded the same tendency. In Case 1, extraction efficiency of the system was 85% and 98% with the distillation efficiency of 87% and 98% respectively. In Case 2, extraction efficiency of the system was 84% and 97% with the distillation efficiency of 95% and 98% respectively. The distillation efficiency depended on a quantity of methanol distilled which was varied with temperature and initial amount of methanol whereas quantity of moisture could decrease the extraction efficiency. As clearly seen from the result of the research, it was an appropriate way to promote the use of biodiesel as efficient alternative fuel for thermal energy and as another kind of renewable energy source in a production process.