Deoxy-liquefaction of switchgrass in supercritical water with calcium formate as an in-situ hydrogen donor

Adding nickel formate in alkali lignin to increase contents of alkylphenols and aromatics during fast pyrolysis

The composition of pyrolysis vapors obtained from alkali lignin pyrolysis with the additive of nickel formate was examined using the pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). Characterization of bio-chars was performed using X-ray diffraction (XRD). Results showed that the nickel formate significantly increased liquid yield, simplified the types of alkali lignin pyrolysis products and increased individual component contents. The additive of nickel formate increased contents of alkylphenols and aromatics from alkali lignin pyrolysis. With an increase in temperature, a greater amount of the relative contents can be achieved. The nickel formate was thermally decomposed to form hydrogen, resulting in hydrodeoxygenation of alkali lignin during pyrolysis. It was also found that Ni is in favor of producing alkylphenols. The analysis based on the experimental result provided evidences used to propose reaction mechanism for pyrolysis of nickel formate-assisted alkali lignin.

Synthesis of γ-Valerolactone from Carbohydrates and its Applications

γ-Valerolactone (GVL) is a valuable chemical intermediate that can be obtained by catalytic reduction of levulinic acid (LA) or alkyl levulinates (AL). There are many reports on the synthesis of GVL from LA or AL. However, the demand for the large-scale synthesis of GVL requires more environmentally friendly and cost-effective production processes. This article focuses on the recent advance in the synthesis of GVL from carbohydrates or lignocellulosic biomass. In addition, application of GVL as the reaction solvents, fuel additives, and as precursor for the synthesis of jet fuel and polymer monomers is also discussed.

Sub-supercritical liquefaction of rice stalk for the production of bio-oil: Effect of solvents

The effect of solvents (water and ethanol) on liquefaction characteristics of rice stalk (RS) was investigated in an autoclave. The highest conversion and liquid yield in water and ethanol were 84.95 wt%, 72.62 wt% and 78.93wt%, 63.84 wt%, respectively. FTIR and GC-MS of the bio-oils obtained from subcritical water (SubH2O, 300°C) and supercritical ethanol (scEtOH, 300°C) indicated that the behavior of RS liquefaction depended on solvents used. The major components of bio-oil produced in SubH2O were ketones and phenols, while esters and phenols dominated in scEtOH. ICP-OES analysis showed that the concentrations of potassium (K) and sodium (Na) in the bio-oil obtained from scEtOH were 14-15 times higher than that obtained from SubH2O. Ethanol gave rise to an improvement in the bio-oil properties including water content, density, acidity and HHV. It was concluded that the bio-oil from RS can be effectively upgraded in scEtOH.

Biofuel production by liquefaction of kenaf (Hibiscus cannabinus L.) biomass

In this study, kenaf biomass, its dried hydrolysate residue (solid residue left after removing water from hydrolysate) and non-hydrolyzed kenaf residue (solid residue left after hydrolysis process) were liquefied at various temperatures. Hydrolysis of biomass was performed in subcritical water condition. The oil+gas yield of biomass materials increased as the temperature increased from 250 to 300°C. Increasing temperature to 350°C resulted in decreases in oil+gas contents for all biomass feeds studied. On the other hand, preasphaltene+asphaltene (PA+A) and char yields significantly decreased with increasing the process temperature. The use of carbon or activated carbon supported Ru catalyst in the process significantly decreased char and PA+A formations. Oils produced from liquefaction of kenaf, dried kenaf hydrolysate and non-hydrolyzed kenaf residue consist of fuel related components such as aromatic hydrocarbons, benzene and benzene derivative compounds, indane and trans/cis-decalin.

Catalytic hydrothermal upgradation of wheat husk

Catalytic hydrothermal upgradation of wheat husk was performed at 280°C for 15 min in the presence of alkaline catalysts (KOH and K2CO3). The effect of alkaline catalysts on the yield of bio-oil products and composition of bio-oils obtained were discussed. Total bio-oil yield (31%) comprising of bio-oil1 (ether fraction) and bio-oil2 (acetone fraction) was maximum with K2CO3 solution. Powder XRD (X-ray diffraction) analysis of wheat husk as well as bio-residue samples show that the peaks due to cellulose, hemicellulose and lignin become weak in bio-residue samples which suggest that these components have undergone hydrolytic cleavage/decomposition. The FTIR spectra of bio-oils indicate that the lignin in the wheat husk samples was decomposed to low molecular weight phenolic compounds. (1)H Nuclear Magnetic Resonance (NMR) spectrum of bio-oil1 shows more than 50% of the protons resonate in the up field region from 0.5 ppm to 3.0 ppm.