Co-pyrolysis behavior of fermentation residues with woody sawdust by thermogravimetric analysis and a vacuum reactor.

This study aimed at cost-effective utilization of fermentation residues (FR) from biogas project for bio-energy via co-pyrolysis of FR and woody sawdust (WS). In this study, a vacuum reactor was used to study the pyrolysis behaviors of individual and blend samples of FR and WS. Obvious synergistic effects were observed, resulting in a lower char yield but a higher gas yield. The presence of woody sawdust promoted the devolatilization of FR, and improved the syngas (H2 and CO) content in the gaseous products. Compared to those of the char from pyrolysis of individual feedstock, co-pyrolysis of FR and WS in the vacuum reactor promoted the cracking reactions of large aromatic rings, enlarged the surface area and reduced the oxygenated groups of the resulted char.

Production of polyols via direct hydrolysis of kraft lignin: effect of process parameters.

Kraft lignin (KL) was successfully depolymerized into polyols of moderately high hydroxyl number and yield with moderately low weight-average molecular weight (Mw) via direct hydrolysis using NaOH as a catalyst, without any organic solvent/capping agent. The effects of process parameters including reaction temperature, reaction time, NaOH/lignin ratio (w/w) and substrate concentration were investigated and the polyols/depolymerized lignins (DLs) obtained were characterized with GPC-UV, FTIR-ATR, (1)H NMR, Elemental & TOC analyzer. The best operating conditions appeared to be at 250°C, 1h, and NaOH/lignin ratio ≈0.28 with 20 wt.% substrate concentration, leading to <0.5% solid residues and ∼92% yield of DL (aliphatic-hydroxyl number ≈352 mg KOH/mg and Mw≈3310 g/mole), suitable for replacement of polyols in polyurethane foam synthesis. The overall % carbon recovery under the above best conditions was ∼90%. A higher temperature favored reduced Mw of the polyols while a longer reaction time promoted dehydration/condensation reactions.

Supercritical water gasification of an aqueous by-product from biomass hydrothermal liquefaction with novel Ru modified Ni catalysts.

Supercritical water gasification (SCWG) of glucose solution (50-200 g/L), a simulated aqueous organic waste (composed of glucose, acetic acid and guaiacol) and a real aqueous organic waste stream generated from a sludge hydrothermal liquefaction process was performed in a bench-scale continuous down-flow tubular reactor with novel 0.1 RuNi/γ-Al(2)O(3) or 0.1 RuNi/activated carbon (AC) catalyst (10 wt.% Ni with a Ru-to-Ni molar ratio of 0.1). 0.1 RuNi/γ-Al(2)O(3) was very effective in catalyzing SCWG of glucose solution and the simulated aqueous organic waste, attaining an H(2) yield of 53.9 mol/kg dried feedstock at 750°C, 24 MPa and a WHSV of 6h(-1). However, the γ-Al(2)O(3)-supported catalyst was not resistant to the attack of alkali and nitrogen compounds in the real waste during the SCWG of the real aqueous organic waste, whereas the AC-based catalyst exhibited higher stability. This research provides a promising approach to the treatment and valorization of aqueous organic waste via SCWG.