餐饮废油生物柴油中甘油和硫含量的同步优化Simultaneous optimization of glycerol and sulfur content in biodiesel prepared from waste cooking oil

为提高餐饮废油生物柴油的品质，降低其甘油和硫含量，分析了离心、静置、水洗-旋蒸3种方法的脱甘油效果，以及氧化、吸附（活性炭作吸附剂）2种方法的脱硫效果，并对甘油和硫含量进行同步优化研究。结果表明：在3种脱甘油方法中，水洗-旋蒸的脱甘油效果最好；氧化脱硫在将硫化物脱除的同时会导致生物柴油的损失，并降低生物柴油的氧化稳定性，与静置和超声氧化脱硫相比，搅拌氧化脱硫的效果较好，脱硫率和生物柴油损失率分别为28.5%和2.0%；在活性炭用量为2%时，脱硫率较高，为23.8%；水洗-旋蒸可以有效地对生物柴油中甘油和硫同时脱除，脱除后的硫、甘油单酯、游离甘油、总甘油含量分别为9.31 mg/kg、0.182%、0.008%、0.054%，脱除率分别达到11.9%、64.3%、78.9%和68.4%，符合GB 25199—2017附录C中BD100生物柴油标准要求。因此，实际生产中可以采用水洗-旋蒸的方法对生物柴油中的甘油和硫进行同步脱除。In order to improve the quality of biodiesel prepared from waste cooking oil and reduce its glycerol and sulfur content, the deglycerol effects of centrifugation, standing, water washing-rotary evaporation, as well as the desulfurization effects of oxidation and adsorption (using activated carbon as adsorbent) were analyzed, and the glycerol and sulfur content were synchronously optimized. The results showed that among the three methods of glycerol removal, water washing-rotary evaporation had the best effect. Oxidative desulfurization could lead to the loss of biodiesel while removing sulfides, and reduce the oxidation stability of biodiesel. Compared with standing and ultrasonic oxidation desulfurization, stirring oxidation desulfurization had a better effect, and the desulfurization rate and biodiesel loss rate were 285% and 2.0%, respectively. When the amount of activated carbon was 2%, the desulfurization rate was relatively high, reaching 23.8%. Water washing-rotary evaporation could effectively remove both glycerol and sulfur simultaneously. The contents of sulfur, monoglyceride, free glycerol, total glycerol in the removed biodiesel were 9.31 mg/kg, 0.182%, 0.008% and 0054%, respectively, and the removal rates were 11.9%, 64.3%, 78.9% and 68.4%, respectively, which met the requirements of BD100 biodiesel standard in GB 25199-2017 appendix C. Therefore, in actual production, the water washing-rotary evaporation method can be used to simultaneously remove glycerol and sulfur from biodiesel.