Hydrogen assisted catalytic biomass pyrolysis. Effect of temperature and pressure

• Published in: Biomass & bioenergy 2018-08, Vol.115, p.97-107
• Main Authors: Stummann, M.Z., Høj, M., Schandel, C.B., Hansen, A.B., Wiwel, P., Gabrielsen, J., Jensen, P.A., Jensen, A.D.
• Format: Article
• Language: English
• Subjects: Biofuel; Catalytic hydropyrolysis; Fluid bed; Hydrodeoxygenation; Oil characterization
• ISSN: 0961-9534; 1873-2909
• DOI: 10.1016/j.biombioe.2018.04.012

Beech wood has been converted into a mixture of oxygen-free naphtha and diesel boiling point range hydrocarbons by using catalytic hydropyrolysis in a fluid bed reactor with a CoMoS/MgAl2O4 catalyst, followed by deep hydrodeoxygenation (HDO) in a fixed bed reactor loaded with a NiMoS/Al2O3 catalyst. The effect of varying the temperature (365–511 °C) and hydrogen pressure (1.6–3.6 MPa) on the product yield and organic composition was studied. The mass balance closed by a mass fraction between 90 and 101% dry ash free basis (daf). The yield of the combined condensed organics and C4+ varied between a mass fraction of 17 and 22% daf, corresponding to an energy recovery of between 40 and 53% in the organic product. The yield of the non-condensable gases varied between a mass fraction of 24 and 32% daf and the char yield varied between 9.6 and 18% daf. The condensed organics contained a mass fraction of 42–75% aromatics, based on GC × GC-FID chromatographic peak area, and the remainder was primarily naphthenes with minor amounts of paraffins. The condensed organics were essentially oxygen free (mass fraction below 0.001%) when both reactors were used. Bypassing the HDO reactor increased the oxygen concentration in the condensed liquid to a mass fraction of 1.8%. The results show that catalytic hydropyrolysis may be a viable way to process solid biomass into liquid and gaseous fuels. [Display omitted] •Catalytic hydropyrolysis of beech wood was studied at 365–511 °C and 1.6–3.6 MPa.•Up to 22% mass yield of condensed organics and C4+ gases has been obtained.•Up to 53% of the energy in biomass was recovered in the condensed organics and C4+.•The organic liquid was essentially oxygen free.•The organic liquid consisted of a volume fraction of 20–40% naphtha and 60–80% diesel.