Direct production of biodiesel from waste oils with a strong solid base from alkalized industrial clay ash
Direct production of biodiesel from waste oils with a strong solid base from alkalized industrial clay ash
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碱化工业粘土灰强固碱废油直接生产生物柴油
DOI：
10.1016/j.apenergy.2020.114735
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发表时间：
2020-04-15
期刊：
影响因子：
11.2
通讯作者：
Xu, Lujiang
中科院分区：
文献类型：
--
作者：
Cong, Wen-Jie;Wang, Yi-Tong;Xu, Lujiang
以废白土(SBC)灰渣为原料，经碱化后的固体碱为催化剂，不经前处理，直接以废油为原料一步法生产生物柴油。采用正交试验设计，优化了大豆油制取生物柴油的工艺条件，生物柴油的产率可达99.1%。碱催化剂在8次循环中稳定(生物柴油收率95%)，抗皂化能力强(AV=9.7mgKOH/g，生物柴油收率96.5%)。用X射线衍射仪、X射线衍射仪、FT-IR、XRF和TPD对其进行了表征，其强碱性与Na2SiO_3相似(0.21对0.22 mmol/g)，活性中心为Na2O和NaAlSiO_4，由NaOH与SBC灰分中的氧化物(如SiO_2、Al_2O_3)反应生成。此外，通过碳化SBC中的渣油作为碳载体和还原剂(将Fe_2O_3转化为磁性Fe_3O_4颗粒)，对基质进行了磁化处理，磁化强度为6.86emu/g。在没有皂化的情况下，大豆油催化合成生物柴油的产率为99.2%，调和油(AV=5.9)的产率为91.9%。该催化剂经磁分离后重复使用3次，收率为87%。非磁性碱还可以有效地催化实际的SBC油生产生物柴油，在AV值为10的情况下，产率为95%。本工作实现了SBC中无机物的充分利用，并实现了SBC油在低温(即65℃对120℃)下直接生产生物柴油，而不产生废物，结果很容易找到废油的实际应用。
Biodiesel was directly one-step produced from waste oils without pretreatment catalyzed by a solid base alkalized from spent bleaching clay (SBC) ash. Optimized conditions were obtained with 99.1% biodiesel yield from soybean oil with an orthogonal design. The base catalyst was stable within 8 cycles (> 95% biodiesel yield) and resistant to saponification (AV = 9.7 mg KOH/g, 96.5% biodiesel yield). The base was characterized with XRD, EDX-mapping, FT-IR, XRF and TPD, and it had similar strong basicity to Na2SiO3 (0.21 vs. 0.22 mmol/g for Na2SiO3) with active sites of Na2O and CH3ONa evolved from Na2SiO3 and NaAlSiO4 by reactions of NaOH with oxides (e.g., SiO2, Al2O3) in SBC ash. Furthermore, the base was magnetized with magnetism of 6.86 emu/g by carbonizing residual oil in SBC as carbon support and reductant (of Fe2O3 to magnetic Fe3O4 particles). It catalyzed soybean oil to produce biodiesel with 99.2% yield and blended oil (AV = 5.9) to biodiesel with 91.9% yield without any saponification. The catalyst was magnetically separated and reused for 3 cycles with 87% yield. The non-magnetic base could also efficiently catalyze actual SBC oil for the production of biodiesel with 95% yield at AV of 10. This work realized the full use of inorganics in SBC, and its oil for direct biodiesel production at a low temperature (i.e., 65 vs. 120 degrees C with sulfuric acid process) without wastes produced and results can easily find practical applications for waste oils.