脂肪酸甲酯加氢脱氧和加氢脱氮制备生物烷烃

Preparation of Bio-paraffins via Catalytic Hydrodeoxygenation of Fatty Acid Methyl Esters and Subsequent Hydrodenitrogenation

以源于废弃油脂的脂肪酸甲酯(FAMEs)为原料。,以NiMo/Al2O3为催化剂,采用加氢脱氧和加氢脱氮两步法制备生物烷烃并对反应工艺进行了优化。结果表明,加氢脱氧的最佳反应条件为:反应温度380℃、氢气压力2MPa、氢气和FAMEs体积比为1000,空速1h^-1;加氢脱氮的最佳反应条件为:反应温度310℃、氢气压力2MPa、氢气和烷烃体积比为2000,空速0.25h^-1。在该优化反应条件下,硫化后的NiMo/Al2O3催化FAMEs加氢脱氧能够获得正构烷烃质量分数高于97%的生物烷烃,所得产品采用NiMo/Al2O3催化剂进行二次加氢脱氮能够进一步移除超过90%的含氮化合物。硫化后的NiMo/Al2O3催化剂在FAMEs加氢脱氧反应中具有良好的结构稳定性和抗积碳性能,使用1000h后其晶相结构无明显改变且表面积碳量仅为3.18%。

Bio-paraffins were prepared by an integrated process combining hydrodeoxygenation(HDO) of fatty acid methyl esters(FAMEs) and subsequent hydrodenitrogenation(HDN) over NiMo/Al2 O3 catalyst, in which, the FAMEs were derived from waste cooking oils. The reaction conditions were optimized. Optimum reaction conditions of HDO were as follows: temperature 380 ℃, hydrogen pressure 2 MPa, hydrogen/FAMEs volume ratio 1000, space velocity 1 h–1. Under these optimum conditions, presulfided NiMo/Al2 O3 catalyst could convert FAMEs to bio-paraffins with an overall selectivity of normal alkanes above 97%. The subsequent HDN reaction over NiMo/Al2 O3 catalyst could remove more than 90% nitrogen-containing impurities in these bio-paraffins under the optimum conditions of temperature 310 ℃, hydrogen pressure 2 MPa, hydrogen/paraffin volume ratio 2000, space velocity 0.25 h–1. In addition, the presulfided catalyst showed enough structural stability and high resistance to coke formation in the HDO. After this catalyst was used for 1000 h, its crystal structure did not change significantly and the deposited carbon amount was only 3.18%.