Electrocatalytic hydrogenation (ECH) can achieve catalytic hydrogenation at ambient temperature and atmospheric pressure with only a small potential applied between the cathode and the anode. The mild conditions and simplicity make ECH a convenient choice to upgrade bio-oil to combat its intrinsic corrosiveness and chemical instability. This Minireview discusses the recent advances in the ECH of bio-oil and analyzes the mechanism of different bio-oil model compounds during their ECH upgrading. The goal is to demonstrate the viability of ECH as a bio-oil stabilization strategy. The product selectivity control and the effect of electrode selection are also reviewed to explore the design of a more robust electrocatalyst. Lastly, the challenges and opportunities in the ECH of bio-oil are discussed to improve the prospect of the technology in large-scale implementation.

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Different mechanisms of selective electrochemical decarboxylation of acetic acid and butyric acid in aqueous solution and at room temperature.

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Filtration failure occurs when filter media are blocked by accumulated solid particles. Suitable operating conditions were investigated for cake cleaning by partial oxidation of filter-cake particles (FCPs) during biomass gasification. The mechanism of the FCP partial oxidation was investigated in a ceramic filter and by using thermogravimetric analysis through a temperature-programmed route in a 2 vol % O2–N2 environment. Partial oxidation of the FCPs in the simulated product gas environment was examined at 300–600 °C in a ceramic filter that was set and heated in a laboratory-scale fixed reactor. Four reaction stages, namely, drying, preoxidation, complex oxidation, and nonoxidation, occurred in the FCP partial oxidation when the temperature increased from 30 to 800 °C in a 2 vol % O2–N2 environment. Partial oxidation was more effective for FCP mass loss from 275 to 725 °C. Experimental results obtained in a ceramic filter indicated that the best operating temperature and FCP loading occurred at 400 °C and 1.59 g/cm2, respectively. The FCPs were characterized before and after partial oxidation by Fourier-transform infrared spectroscopy, scanning electron microscopy, and Brunaeur–Emmett–Teller analysis. Fourier-transform infrared spectroscopy analysis revealed that partial oxidation of the FCPs can result in a significant decrease in C–H n (alkyl and aromatic) groups and an increase in CO (carboxylic acids) groups. The scanning electron microscopy and Brunaeur–Emmett–Teller analyses suggest that, during partial oxidation, the FCPs underwent pore or pit formation, expansion, amalgamation, and destruction.

Biomass gasification is increasingly attracting interest in the research of biorenewable energy all over the world, as a carbon-neutral supplement to the conventional fossil energy. It can convert biomass to the burnable producer gas for heat and power production or synthesis of fuels and chemicals. However, its commercial applications are seriously interfered by the minor but unavoidable contaminants or impurities in the raw product gas, which cause severe problems in the downstream equipment. This paper reviews the recent progress on the hot gas filtration technologies for removing particulate matters (PMs) and tars from the biomass-derived product gas, focusing on ceramic filter candles, which are widely applied in the biomass gasification systems. Developments of PM characterization, hot gas catalytic filtration, and oxidative filtration as well as the numerical simulation of computational fluid dynamics in hot gas filtration are summarized in detail. It also critically discusses the major challenges and future opportunities in hot gas filtration and concludes that the combined oxidative filtration and catalytic filtration with highly efficient catalyst at moderate temperatures (<600 °C) should be the most economical option for the widespread commercial small-scale biomass gasification systems.

A hyperdispersed Ni-based catalyst from LaNiO3 performed well in dry methane reforming reaction, which was attributed to the promotional effect of the Ni0–Ni2+ dipole.

Eucalyptus sawdust is a residue from fast-growing forest processing. Utilization of Eucalyptus sawdust as fuel by co-pelletization with natural forest sawdust could solve problems of waste disposal and material supply limitation of pellet production. This work targeted at providing a useful reference for improving pellet properties and optimizing variable combinations. Experiments were arranged using response surface methodology with a central composite design and carried out using a uniaxial piston-cylinder densification apparatus. Based on the analysis of variance of effects of variables on responses, the optimal models were all selected as quadratic and expressed in the form of regression equations. The differences between adjusted R 2 and predicted R 2 are all within 0.2 and the adequate precision is all greater than four illustrating the reliability of the established models. The optimal variable combinations were obtained according to the desired response goals and validation experiments were conducted. Errors between response predicted and actual values were calculated and applied to improve the model accuracy. After modification, final errors were reduced to less than 9% and could be accepted by pellet production. Experimental results also demonstrated that pellet properties and higher heating value were all increased by co-pelletization and optimization. This will be very beneficial for pellet application. Furthermore, these results could provide the required data for designing a suitable machine of pellet production.