Abstract:

To enhance the mass transfer efficiency of bio-oil inside the zeolite based catalyst and improve the catalytic selectivity of jet biofuel product, conventional Y zeolite was modified into hierarchical mesoporous Y (meso-Y) zeolite by desilication and loaded with Ni to catalyze the conversion of fatty acid methyl ester (FAME) into jet biofuel. Mesopores in the range of 2 to 10 nm were effectively generated by desilication with NaOH and a certain degree of crystal structure expansion was caused accordingly. When Ni was loaded on meso-Y zeolite treated with 0.4 mol/L NaOH for 1 h, BET surface area and specific pore volume were increased to 554.9 m²/g and 0.340 cm³/g, respectively. A maximum of jet biofuel product selectivity (65.8%) was hence obtained. Iso-alkanes and arenes took up 19.1% and 12.8% within jet biofuel product, guaranteeing the fuel characteristics. As by-products of both hydrodeoxygenation and hydrocracking, the selectivity of CH₄ in the gas phase product was up to 25.2%, and the CO₂ is stable at about 12%. Although the overall selectivity of jet biofuel product varied greatly with NaOH treatment duration, the proportion of each component remained stable. Desilication only modified the physical structure of meso-Y zeolite to enhance the mass transfer of reactants and products. Its chemical properties were preserved to maintain the catalytic activity.

Key words: biofuel, zeolite, catalyst, microalgae, desilication

摘要：

采用NaOH处理Y分子筛脱硅改性为梯度介孔分子筛，并负载镍制成双功能催化剂转化脂肪酸甲酯脱氧断键制成生物航油。微观测试表明：NaOH脱硅分子筛有效形成2~10 nm介孔，并造成一定程度的晶体结构膨胀。镍负载于NaOH处理1 h的脱硅梯度介孔Y分子筛作催化剂时，比表面积和孔容显著提高到554.9 m²/g和0.340 cm³/g。催化十六酸甲酯得到航油产物的选择性达到65.8%，并含有较高的异构烷烃（19.1%）及合适的芳香烃（12.8%），展现出良好的燃料特性。作为脱氧断键反应的副产物，气相产物中CH₄选择性高达25.2%，CO₂稳定在12%左右。虽然航油产物的整体选择性随NaOH处理时间变化较大，但各组分含量相对稳定，说明NaOH脱硅处理的梯度介孔Y分子筛保持了良好的催化转化制航油性能。

关键词: 生物燃料, 沸石, 催化剂, 微藻, 脱硅