Fast pyrolysis of potassium impregnated poplar wood and characterization of its influence on the formation as well as properties of pyrolytic products.

TGA results indicated that the maximum decomposition temperature of the biomass decreased from 373.9 to 359.0°C with increasing potassium concentration. For fast pyrolysis, char yield of potassium impregnated biomass doubled regardless of pyrolysis temperature compared to demineralized one. The presence of potassium also affected bio-oil properties. Water content increased from 14.4 to 19.7 wt% and viscosity decreased from 34 to 16.2 cSt, but the pH value of the bio-oil remained stable. Gas chromatography/mass spectroscopy (GC/MS) analysis revealed that potassium promoted thermochemical reactions, thus causing a decrease of levoglucosan and an increase of small molecules and lignin-derived phenols in bio-oil. Additionally, various forms of aromatic hydrocarbons, probably derived from lignins, were detected in non-condensed pyrolytic gas fractions.

Effects of various reaction parameters on solvolytical depolymerization of lignin in sub- and supercritical ethanol.

Organosolv lignin was treated with ethanol at sub/supercritical temperatures (200, 275, and 350 °C) for conversion to low molecular phenols under different reaction times (20, 40, and 60 min), solvent-to-lignin ratios (50, 100, and 150 mL g(-1)), and initial hydrogen gas pressures (2 and 3 MPa). Essential lignin-degraded products, oil (liquid), char (solid), and gas were obtained, and their yields were directly influenced by reaction conditions. In particular, concurrent reactions involving depolymerization and recondensation as well as further (secondary) decomposition were significantly accelerated with increasing temperature, leading to both lignin-derived phenols in the oil fraction and undesirable products (char and gas). As the main components in the oil fraction, oxygenated phenols, guaiacol, and syringol as well as their alkylated forms were detected. The yield of alkylated phenols showed a drastic increase at 350 °C in the presence of initial hydrogen gas due to prevailing hydrodeoxygenation and hydrogenation reactions of the vinyl/allyl/oxygenated phenols. These reactions were also demonstrated indirectly from the results of atomic H/C and O/C of the oils. The highest amount of monomeric phenols released from lignin (1.0 g) was measured as ca. 96.7 mg at 350 °C, 40 min, 100 mL g(-1), and 3 MPa of H2. In addition, GPC analysis suggested a possibility of condensation between lignin-degraded fragments during the solvolysis reaction.

Comparison of pyrolytic products produced from inorganic-rich and demineralized rice straw (Oryza sativa L.) by fluidized bed pyrolyzer for future biorefinery approach.

The objectives of this study were to investigate the effects of inorganic constituents on the fast pyrolysis of the biomass and to determine the yields as well as physicochemical properties of pyrolytic products. The pyrolytic products were obtained from raw and demineralized rice straw using a fluidized bed type pyrolyzer at different temperatures. As pyrolysis temperature increased, total biooil yield gradually decreased from 46.6 to 29.6 wt.% for the raw-straw, and from 55.4 to 35.3 wt.% for the demineralized rice straw. For demineralized rice straw, higher pyrolysis temperatures promoted gasification reactions but reduced char formations. However, char yield for the raw-straw was relatively unaffected by temperature due to an increase in carbonization reactions that were catalyzed by some inorganics. Certain inorganic constituents in the biomass were distinctively distributed in the biooil, and ICP-ES and GC/MS analysis indicated that some inorganics may be chemically bound to cell wall components.

Characterization of pyrolytic products obtained from fast pyrolysis of chromated copper arsenate (CCA)- and alkaline copper quaternary compounds (ACQ)-treated wood biomasses.

In this study, chromated copper arsenate-treated wood (CCA-W) and alkaline copper quaternary compounds-treated wood (ACQ-W) were subjected to fast pyrolysis at 500°C for ca. 2s to produce bio-oil and char. The physicochemical properties of the pyrolytic products as well as the distribution of heavy metals - arsenic, copper and chrome - during fast pyrolysis were investigated. The water content, viscosity, pH and higher heating value (HHV) of bio-oil from CCA-W were 24.8 wt%, 13.5 cSt, 2.1 and 16 MJ/kg, respectively, whereas those of bio-oil from ACQ-W were 27.9 wt%, 16 cSt, 3.0 and 14.1 MJ/kg, respectively. The yields of bio-oil from CCA-W and ACQ-W were 43.3% and 46.6%, respectively, significantly lower than that of control (61.6%). In the pyrolytic products of CCA-W, the concentrations of arsenic, copper and chromium were determined to be 36.4 wt%, 74.0 wt% and 75.4 wt% in char, respectively, 34.5 wt%, 10.3 wt% and 9.0 wt% in bio-oil, respectively, and 29.0 wt%, 15.7 wt% and 15.5 wt% in gas, respectively. In addition, most of the copper appeared in the char (98.8 wt%) and only a trace amount of copper was detected in the bio-oil (0.2 wt%) produced by ACQ-W.

Influence of pyrolysis temperature on physicochemical properties of biochar obtained from the fast pyrolysis of pitch pine (Pinus rigida).

The aim of this study was to investigate the influence of pyrolysis temperature on the physicochemical properties and structure of biochar. Biochar was produced by fast pyrolysis of pitch pine (Pinus rigida) using a fluidized bed reactor at different pyrolysis temperatures (300, 400 and 500 °C). The produced biochars were characterized by elemental analysis, Brunauer-Emmett-Teller (BET) surface area, particle size distributions, field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) spectroscopy, solid-state (13)C nuclear magnetic resonance (NMR) and X-ray diffraction (XRD). The yield of biochar decreased sharply from 60.7% to 14.4%, based on the oven-dried biomass weight, when the pyrolysis temperature rose from 300 °C to 500 °C. In addition, biochars were further carbonized with an increase in pyrolysis temperature and the char's remaining carbons were rearranged in stable form. The experimental results suggested that the biochar obtained at 400 and 500 °C was composed of a highly ordered aromatic carbon structure.