Catalytic Subcritical Aqueous Phase Conversion of Waste Biomass Into Biofuels

 

Subcritical aqueous phase catalytic processing of waste biomass into potential hydrocarbon fuels was investigated. Experiments with homogeneous catalysts were performed with slurry of 10-20 wt% waste paper in distilled water previously mixed with 5wt% (Cu²⁺ or Ni²⁺ ions) catalyst. Heterogeneous catalytic reactions were performed using the catalyst, which was prepared by the surfactant assisted sol-gel synthesis route involving generation of an ordered mesoporous silicate structure.  The gel formation was accomplished using silica precursor, ethanol, and Brij-76 surfactant well-mixed in acidified solution and finally calcined at 600^oC. The calcined powder was analyzed using TEM, AFM, and powder x-ray diffraction. The mesoporous gels were functionalized with poly(4-vinyl)pyridine and treated with metal ions to establish their binding with the silicate network. Functionalization of the mesoporous silica surface was confirmed using FTIR, and metals were analyzed with the energy dispersive spectroscopy. Next, the catalyst was mixed with the slurry of waste paper (10-20 wt%) in distilled water and heated to 150^o-250^oC in a high pressure reactor. In addition, a catalytic bed was supported on a reactor for selective enrichment of hydrocarbon fuels. Synthesis and characterization of a catalyst, results obtained on the hydropyrolysis of the biomass, and kinetic analysis, including a global reaction network model, will be presented in detail.