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利用缫丝蚕蛹获取的蛹油制备生物柴油是生物能源开发的一条新途径,对传统蚕桑产业链多元化深度延伸具有重要意义。在前期采用一步法催化蚕蛹油制备生物柴油的基础上,为提高产品得率,探索采用两步法催化蚕蛹油制备生物柴油的新工艺:第1步利用固体酸性催化剂(离子交换树脂或生物质固体酸)催化蚕蛹油中的游离脂肪酸与甲醇反应生成脂肪酸甲酯;第2步利用氢氧化钾催化甘油三酯与甲醇发生酯交换反应。在预酯化阶段,合适的酸性催化剂为阳离子交换树脂HD-8和桑枝固体酸,最优预酯化反应条件为反应温度70℃,甲醇、油脂摩尔比9∶1,催化剂质量分数3%。在酯交换阶段,最优酯交换反应条件为反应温度40℃,甲醇、油脂摩尔比5∶1,碱催化剂KOH质量分数2%,反应时间10 min。以蚕蛹油为原料,采用上述两步工艺条件制备生物柴油的产率高达95.17%。研究结果表明,初步建立的酸碱两步法新工艺具有操作简单、反应速率快、转化率高等优点,且自制的桑枝固体酸催化剂可循环使用,适合以蚕蛹油为原料规模化制备生物柴油。
The preparation of biodiesel from the pupae obtained from the silkworm pupae is a new approach to bioenergy development and is of great significance to the diversification and extension of the traditional sericulture industry chain. In order to improve the yield of biodiesel by using one-step catalyzed silkworm pupa oil, we explored a new process of preparing biodiesel by using two-step method to catalyze silkworm pupa oil. Step 1: The solid acid catalyst (ion exchange resin or biomass Solid acid) catalyzes the reaction of free fatty acid in silkworm pupa oil with methanol to form fatty acid methyl ester. The second step uses potassium hydroxide to catalyze the transesterification of triglyceride with methanol. In the pre-esterification stage, the suitable acidic catalysts were cation exchange resin HD-8 and mulberry solid acid. The optimal pre-esterification conditions were reaction temperature 70 ℃, molar ratio of methanol to oil 9:1, catalyst mass fraction 3% . In the transesterification stage, the optimum conditions of transesterification were as follows: reaction temperature 40 ℃, molar ratio of methanol to oil 5:1, base KOH mass fraction 2% and reaction time 10 min. Using silkworm pupa oil as raw material, the yield of biodiesel prepared by the above two-step process was as high as 95.17%. The results showed that the newly established acid-base two-step process has the advantages of simple operation, fast reaction rate and high conversion rate. The self-made mulberry solid acid catalyst can be recycled and suitable for preparing biodiesel from silkworm pupa oil .