Microwave-assisted biodiesel production and hydrothermal gasification of by-product glycerol to hydrogen

Biodiesel, as an environmental-friendly renewable energy, receives continuous attention and is extensively studied. How to improve the efficiency of biodiesel production is a hot research topic. As the biodiesel industry grows rapidly, the discharge of main by-product glycerol increases substantially. Therefore, utilizing by-product glycerol to produce high value-added products has become the new focus of attention.

Solid sodium silicate catalyst was prepared and used to catalyze the transesterification of rapeseed and Jatropha oils to biodiesel under microwave irradiation. Experimental results showed that biodiesel yields of 95.8% and 92.8% were achieved from rapeseed and Jatropha oils, respectively (microwave power of 400 W, methanol/oil molar ratio of 11/1, catalyst amount of 4 wt% and reaction time of 5 min). In addition, a hydrogen yield of 82.8% with a gaseous concentration of 73.6% (v/v) was achieved from hydrothermal gasification of by-product glycerol using Ni-based catalyst and deactivated sodium silicate from biodiesel production (catalyst amounts of Ni-based catalyst 40 wt% and sodium silicate 160 wt%, reaction temperature of 350 oC and reaction time of 30 min).

The research work entitled “Co-production of biodiesel and hydrogen from rapeseed and Jatropha oils with sodium silicate and Ni catalysts” was published in Applied Energy (http://dx.doi.org/10.1016/j.apenergy.2012.12.076).