Catalytic co-combustion of biomass and brown coal in a fluidized bed: Economic and environmental benefits.

The work is devoted to the study of combustion of brown coal, pine sawdust, and their mixtures in a fluidized bed of catalyst at 600-750°Ð¡. It is shown that an increase in the content of sawdust in a mixture with brown coal leads to an increase in the burnout degree of solid fuel from 94.4% to 99.9%, while the emission of greenhouse gases in the form of CO2 CO and NOx is reduced (CO2 from the biomass is not included in the balance). The high content of alkaline earth metal oxides (CaO and MgO) in the mineral part of brown coal, sawdust, and their mixtures eliminates the emission of sulfur oxides and the slagging of heat-exchange surfaces during the combustion in a fluidized bed of catalyst. The optimal temperature, when the highest burnout degree of the above fuels is achieved in the combustion is 750°Ð¡. It is also shown that the increase in temperature and the content of sawdust in the composition of the fuel mixtures has a positive effect on the economic and environmental process indicators.

Coupling Hydrogenation of Guaiacol with In Situ Hydrogen Production by Glycerol Aqueous Reforming over Ni/Al2O3 and Ni-X/Al2O3 (X = Cu, Mo, P) Catalysts.

Biomass-derived liquids, such as bio-oil obtained by fast pyrolysis, can be a valuable source of fuels and chemicals. However, these liquids have high oxygen and water content, needing further upgrading typically involving hydrotreating using H2 at high pressure and temperature. The harsh reaction conditions and use of expensive H2 have hindered the progress of this technology and led to the search for alternative processes. In this work, hydrogenation in aqueous phase is investigated using in-situ produced hydrogen from reforming of glycerol, a low-value by-product from biodiesel production, over Ni-based catalysts. Guaiacol was selected as a bio-oil model compound and high conversion (95%) to phenol and aromatic ring hydrogenation products was obtained over Ni/γ-Al2O3 at 250 °C and 2-h reaction time. Seventy percent selectivity to cyclohexanol and cyclohexanone was achieved at this condition. Hydrogenation capacity of P and Mo modified Ni/γ-Al2O3 was inhibited because more hydrogen undergoes methanation, while Cu showed a good performance in suppressing methane formation. These results demonstrate the feasibility of coupling aqueous phase reforming of glycerol with bio-oil hydrogenation, enabling the reaction to be carried out at lower temperatures and pressures and without the need for molecular H2.