HIGH OXIDATION STABILITY OF BIODIESEL AS PREPARED BY SUPERCRITICAL METHANOL METHOD
A non-catalytic supercritical methanol method is an attractive process to convert various oils/fats efficiently into biodiesel. To evaluate oxidation stability of biodiesel, biodiesel produced by alkali-catalyzed method was exposed to supercritical methanol at different temperatures and pressures for 30min. As a result, it was found that the tocopherol in biodiesel is not stable at a temperature higher than 300℃. After the supercritical methanol treatment, hydroperoxides were greatly reduced for biodiesel with initially high in peroxide value, while the tocopherol slightly decreased in its content. Thus, the biodiesel prepared by the supercritical methanol method was enhanced for oxidation stability, compared with that prepared by alkali-catalyzed method. To enhance the oxidation stability, biodiesel prepared from safflower oil was mixed with propyl gallate and studied by Rancimat method and kinetics on its oxidation was described by the first order rate law. In addition, antioxidation effect of lignin-derived products in biodiesel prepared by supercritical methanol (300℃/20MPa) was studied. It was consequently found that lignin could be decomposed to low molecular compounds that have the free radical trapping effect after supercritical methanol treatment. Thus, it was proved that high oxidation stability of biodiesel can be achieved by supercritical methanol method with a very small amount lignin addition.
biodiesel supercritical methanol oxidation stability kinetics lignin
Jiayu XIN Shiro SAKA
Graduate School of Energy Science,Kyoto University,Yoshida-honmachi,Sakyo-ku,Kyoto 606-8501,Japan
国际会议
广州
英文
202-208
2008-12-03（万方平台首次上网日期，不代表论文的发表时间）