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The wide-scale production of renewable fuels from lignocellulosic feedstocks continues to be hampered by the natural recalcitrance of biomass. Therefore, there is a need to develop robust and reliable methods to characterize and quantify components that contribute to this recalcitrance. In this study, we utilized a method that incorporates pyrolysis with successive gas chromatography and mass spectrometry (Py-GC/MS) to assess lignification in cell suspension cultures. This method was compared with other standard techniques such as acid-catalyzed hydrolysis, acetyl bromide lignin determination, and nitrobenzene oxidation for quantification of cell wall bound phenolic compounds. We found that Py-GC/MS can be conducted with about 250 µg of tissue sample and provides biologically relevant data, which constitutes a substantial advantage when compared to the 50–300 mg of tissue needed for the other methods. We show that when combined with multivariate statistical analyses, Py-GC/MS can distinguish cell wall components of switchgrass (Panicum virgatum) suspension cultures before and after inducing lignification. The deposition of lignin precursors on uninduced cell walls included predominantly guaiacyl-based units, 71% ferulic acid, and 5.3% p-coumaric acid. Formation of the primary and partial secondary cell wall was supported by the respective ~15× and ~1.7× increases in syringyl-based and guaiacyl-based precursors, respectively, in the induced cells. Ferulic acid was decreased by half after induction. These results provide the proof-of-concept for quick and reliable cell wall compositional analyses using Py-GC/MS and could be targeted for either translational genomics or for fundamental studies focused on understanding the molecular and physiological mechanisms regulating plant cell wall production and biomass recalcitrance. [ABSTRACT FROM AUTHOR]

Fast pyrolysis of pine wood was carried out to yield a liquid bio-oil mixture that was separated into organic and aqueous phases. The organic phase (ORG-bio-oil) was characterized by gas chromatography–mass spectroscopy, 31P-nuclear magnetic resonance spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. It was further used as a raw material for producing a mixture of biphenolic compounds (ORG-biphenol). ORG-bio-oil, ORG-biphenol, and bisphenol-A were reacted with cyanogen bromide to yield cyanate ester monomers. Cyanate esters were characterized using FTIR spectroscopy and were thermally cross-linked to develop thermoset materials. Thermomechanical properties of cross-linked cyanate esters were assessed using dynamic mechanical analysis and compared with those of cross-linked bisphenol-A-based cyanate ester. ORG-biphenol cyanate ester was observed to have a superior glass transition temperature (350–380°C) as compared to bisphenol-A cyanate ester (190–220°C). Cyanate esters derived from bio-oil have the potential to be a sustainable alternative to the bisphenol-A-derived analog. [ABSTRACT FROM AUTHOR]

Catalytic pyrolysis may serve as an alternative production strategy to petroleum-derived fuels and chemicals. Furthermore, red mud, a toxic industrial bauxite byproduct, could serve as a sustainable catalyst and overcome the need for more robust catalysts. To test this, in situ catalytic pyrolysis was run on a semi-pilot scale reactor with various ratios of red mud and switchgrass (Panicum virgatum). Authors hypothesized that the coking process would render red mud environmentally friendly, improve soil quality, and yield for bioenergy crop production, like biochar. Therefore, this work investigated red mud's capability to enhance bio-oil quality, as well as, how the modified biochar produced from in situ pyrolysis affected switchgrass seedling vigor, and root/shoot mass. The results indicated that red mud was effective at increasing soil pH and biochar and bio-oil yields, while reducing the total acid number in bio-oil. While a high loading of reacted red mud had a negative impact on plant yield, the addition of uncatalyzed biochar to pure red mud considerably improved the seedling yield in marginal soils. These results suggest that this technology has potential for valorizing a waste stream and creating a soil amendment from red mud that closes nutrient and bioenergy production cycles while potentially reducing soil pollution. [ABSTRACT FROM AUTHOR]

Abstract: In the USA, over 21 million wood railroad ties are produced per year to replace approximately 20 million used ties that have provided primary service in railroad tracks over 40 years. Traditionally, used ties have been processed for energy recovery, typically as boiler fuel. However, recent US Environmental Protection Agency (US EPA) regulations and the low cost of natural gas is leading to preservative‐treated ties being used increasingly as landfill. This study evaluated the economic viability of a process that aims to recover the preservatives from used ties and subsequently convert the extracted wood ties to hydrocarbon fuels (gasoline and diesel blendstocks) using an integrated biorefinery concept. This techno‐economic analysis considered three plants, geographically spread across the USA to minimize transportation costs, with a capacity of 1769 dry tons per day based on a yearly available used railroad‐tie inventory estimated at 2.33 million tons. Under the baseline case scenario, the process produces 237 tons per day of recovered creosote and 69 293 and 74 922 gal per day of gasoline and diesel, respectively. The total capital investment for an nth plant is estimated at $380 million. The minimum fuel selling price (MFSP) is determined to be $2.52 per gasoline gallon equivalent (GGE) at a 10% required internal rate of return in 2016 US dollars, with a simple payback period of 9 years after tax and a market price of recovered creosote of $2.80/gal. The sensitivity analysis reveals that plant size, internal rate of return, and feedstock cost have the most impact on the MFSP. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

The vapors produced from pine wood using an intermediate auger pyrolysis process under various sweeping gas flow rates were condensed by three temperature-controlled condensers and analyzed. Increasing sweeping gas flow rate from 20 to 40 L/min did not change the yield of the pyrolysis products, however, noticeable changes were found in the bio-oil composition, such as a decrease in water content and an increase of amount of organic compounds. Increasing sweeping gas flow rate influenced the bio-oil fractionation in each temperature-controlled condenser with a reduction in bio-oil yield in the first condenser controlled between 85 and 90 °C and outgoing vapor temperature of 121 °C. There were no changes in the second condenser maintained at 45–50 °C and outgoing vapor temperature of 107 °C, and an increase in the third condenser regulated at 10–15 °C and outgoing vapor temperature of 25 °C. Higher sweeping gas flow rates also resulted in changing the bio-oil composition in the first and second condensers including a reduction in water content and an increase in viscosity and density, suggesting that refining this fraction as an intermediate source would be a more efficiency way to produce fuels and chemicals than treating the whole bio-oil. The bio-oil from the third condenser contained elevated water content, acidity and light oxygenated compounds with increasing sweeping gas flow rate, suggesting that this fraction would be more suitable as an energy source for hydrogen production via microbial electrolysis processes. In summary, the sweeping gas flow rate used for pyrolysis with an intermediate auger reactor is an important factor to change bio-oil properties in temperature-controlled multistage condensation processes. [ABSTRACT FROM AUTHOR]

Abstract A statistical response surface methodology (RSM) using a central composite design (CCD) model was applied to identify the optimum thermal desorption conditions for maximum recovery of preservative from copper naphthenate (CuNap) treated wood and subsequent production of a high quality pyrolytic vapor from the thermally treated wood. From the designed experiment, 94% of the total preservative present in the ties was desorbed at temperatures higher than 250 °C and residence times longer than 30 min. Elevating the temperature from 215 °C to 285 °C for 45 min residence time generated a weight loss of 12–36 wt%, an increase in higher heating value (HHV) from 20.1 to 21.9 MJ/kg, and a reduction of energy yield from 90.4 to 71.5% of the resulting thermally treated biomass. Pyrolysis at 450 °C of this material produced a vapor rich in sugars- and lignin-derived compounds. The predicted optimum conditions in terms of a maximum preservative recovery, minimum energy yield loss of the wood, and production of thermally treated biomass that generates a high proportion of sugars- and lignin-derived compounds during pyrolysis were found to be 265 °C and 51 min. Under these optimum conditions, the predicted maximum preservative recovery was 95% while the predicted thermally treated solid retained 77% of the original energy yield and produced high portions of levoglucosan and lignin-derived compounds during subsequent pyrolysis, similar to torrefied wood. Highlights • Used railroad wood ties were thermally treated for preservative recovery. • A response surface methodology identified optimum thermal treatment conditions. • A thermal treatment of wood ties recovered 95% preservative at 265 °C and 51 min. • Preservative-free woods contained 21.9 MJ/kg HHV and 77% energy yield. • Pyrolysis of thermally treated wood improved levoglucosan and phenolics yields. [ABSTRACT FROM AUTHOR]

Used creosote-treated wood ties were thermally treated between 250 and 350 °C to recover preservative and upgrade the wood to provide an improved quality biomass for thermochemical processes. With thermal treatments ranging from 250 to 300 °C, the amounts of creosote, mostly consisting of polycyclic aromatic hydrocarbons (PAHs), recovered were from 47 to 79% of total creosote present in the used ties. Thermal treatment at 350 °C recovered 97% of total PAH compounds. Larger amounts of PAHs with higher molecular weights (HMWs) and lower vapor pressures (LVP) were recovered at elevated temperatures. Temperature above 300 °C decomposed the wood matrix, with a mass loss ranging between 50 and 63 wt% and produced large amounts of light organics, anhydrosugars, and phenolic compounds that would contaminate the recovered creosote. Our study concluded that thermal treatment ranging between 275 and 300 °C would be preferred to recover preservative for recycling and improve the wood quality, i.e., high carbon content and caloric value, and low hazardous pollutants (creosote residues) for thermochemical processes such as pyrolysis or gasification. These findings suggest that the proposed approach could be a commercially viable and environmentally beneficial alternative to landfill for used railroad ties. [ABSTRACT FROM AUTHOR]

A two-step thermal process, an initial thermal treatment at mild temperature followed by a fast pyrolysis step, was investigated to recover wood preservatives and produce preservatives-free wood for production of high quality bio-oil from used creosote-treated railroad ties. During the initial thermal treatment at temperature of 280 °C for 10–30 min, the treated wood ties underwent a 20–25% weight loss with energy yield (77–83%). Energy yield at 280 °C was lower than that at 200 and 250 °C (92–97%) but higher than that at the 300 °C (64–74%). Recovery level of creosote at 280 °C was comparable to that at 300 °C. Fast pyrolysis at 450 °C of the 280 °C-treated wood ties produced high amount of levoglucosan and phenolic compounds with a traceable amount (1.7–1.9% of the total peak area) of creosote compounds. [ABSTRACT FROM AUTHOR]

Abstract: Surface properties of switchgrass-derived biochars produced at fast pyrolysis temperatures of 450, 600 and 800°C were characterized at different solution pHs in order to determine the structural and chemical changes of artificially-weathered biochars when incorporated into soil. As biochars were acidified from pH 7 to 3, crystalline minerals dissolved slowly releasing nutrients; however, residual minerals were still detected in biochars produced at higher pyrolysis temperatures after pH treatment. Moreover, the amount of exchangeable bases and other inorganic compounds released from the biochars increased when pH decreased. As minerals dissolved from the biochars, total surface area and pore volume were found to increase. Surface functional groups and water vapor adsorption capacity at 0.8 P/Po also increased, whereas the potential CEC of biochars decreased due to the replacement of exchangeable sites by hydrogen ion. Therefore, during the aging process, it is predicted that soil-incorporated biochars will slowly release nutrients with changes in surface functionality and porosity, which are expected to enhance water holding capacity of soil and provide a beneficial habitat for microbial colonization. [Copyright &y& Elsevier]