| Summary: | 碩士 === 國立臺灣海洋大學 === 輪機工程系 === 99 === Excess water existence in the reactant mixture during the strong alkali transesterification process for biodiesel production may deteriorate reacting rate and in turn fuel properties. However, complete removal of water content may result in higher biodiesel production cost. The optimum water content in the animal fat or vegetable oil is therefore significant concern for biodiesel research. This study includes four parts, which are the investigations of the effects of water content in raw lipid on fuel properties of biodiesel, effects of vibrating type and time on water- removal efficiency of molecular sieve, biodiesel properties after water- removal by electrodes, and comparison of water-removal by those two techniques. The raw palm oil was adjusted to contain various water ratios and then underwent alkali transesterification. The experimental results show that the biodiesel product had the highest fatty-acids content of long carbon chains, saturated fatty acids, and total fatty acid methyl esters, highest flash point and ignition point while the lowest acid value, water content and cold filter plugging point when the initial water content of 0.05 wt. % in the raw palm oil was used. In the second experimental part, the water-removal efficiency of molecular sieves along with varied vibrating types for palm oil and ethanol was investigated. It was shown that molecular sieves in a rotating vibrator absorbed more water content than those molecular sieves in a magnetic agitator and in a static beaker by 6 wt. % and 5 wt. %, respectively. The destroying extent of the molecular sieves in the rotating vibrator was less than those in the magnetic agitator. One-pair and two-paired electrodes were thereafter used to continuously electrolyze and remove the water content in the raw lipid. The water content, heating value, specific gravity, flash point and ignition point of the biodiesel product were observed to decrease with the increase of input electrolyzing energy during the transesterification reaction. In addition, the two-paired electrodes appeared to have superior efficiency to reduce acid value and water content, particularly the acid value than the one-paired electrodes. Finally, it was found that molecular sieves in the rotating vibrator removed 9 times of water content in the raw palm oil in comparison with that by two-paired electrodes with input energy of 11 J / g palm oil.
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