Fuel Mixtures from Crude Glycerol, the Bio-oil Water-Soluble Fraction, and Biochar for Stationary Applications

摘要

As-an option for utilizing glycerol in stationary applications (e.g. combustion in boilers or furnaces), fuel mixtures prepared by the current approach of mixing crude glycerol, the whole bio-oil, and/or biochar have limitations of low glycerol blending ratio, high demand of methanol, and still in acidic nature. This study aims to overcome these limitations via preparing fuels from crude glycerol, the bio-oil water-soluble fraction (WSF), and/or biochar. Three types of formulated crude glycerols (FCGs) were used in the experimental program: FCG1 and FCG3 representing crude glycerol without purification and FCG2 representing crude glycerol with an acidification process. The FCGs were mixed with the bio-oil WSF obtained at the water/ bio-oil ratio of 0.5 for preparing fuel mixtures, achieving remarkably high glycerol blending levels (50-70% for FCG1 and FCG3, while completely miscible for FCG2) without methanol addition. Moreover, the FCG/WSF blends have considerably lower acidities and water contents and higher densities and heating values than the WSF. Further addition of biochar into the FCG/ WSF blends results in FCG/WSF/biochar slurry fuels that have similar energy density of bio-oil. The FCG/WSF/biochar slurry fuels exhibit favorably better-viscosity, Ohnesorge number, and acidity than the bio-oil/biothar or glycerol/methanol/bio-oil/ biochar slurries. Therefore, preparing FCG/WSF/biochar slurries is proven to be a good strategy to address the existing key issues associated with fuel mixture preparation from crude glycerol and the whole bio-oil, offering an attractive option of co utilization of bio-oil fractions.