The steam-KOH reactivation of activated carbon fibers from liquefied wood has been studied for the first time. Using this method via altering the reactivation temperature, microporous and mesoporous ...activated carbon fibers with similar specific surface area were produced. In addition, prolonging the reactivation time from 1 to 3h made the specific surface area of the product as high as 2400m2/g. The pore volume of the ACF reached 1.530cm3/g, of which 66.8% was the contribution of the small mesopores of 2–10nm. The oxygen content of the ACF was 7.6%, of which the carboxylic functional groups accounted for the smallest part.
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•Mesoporous ACFs were prepared from liquefied wood by a novel way.•Metallic potassium vapor developed the mesoporosity in KOH reactivation.•Micro- and mesoporous ACFs with similar specific surface area were produced.
Carbon aerogels derived from biomass have low specific capacity due to the underutilized structure, limiting their application in high-performance supercapacitors. In this work, the hierarchical ...nickel sulfide/carbon aerogels from liquefied wood (LWCA-NiS) were synthesized via a simple two-step hydrothermal method. Benefitting from the unique 3D coral-like network structure of LWCA, self-assembled NiS nanowires with the dandelion-like structure showed high specific surface (389.1 m 2·g −1) and hierarchical pore structure, which increased affluent exposure of numerous active sites and structural stability, causing superior energy storage performance. As expected, LWCA-NiS displayed high specific capacity (131.5 mAh·g −1 at 1 A·g −1), good rate performance, and highly reversible and excellent cycle stability (13.1 % capacity fading after 5000 cycles) in the electrochemical test. Furthermore, a symmetrical supercapacitor using LWCA-NiS-10 as the electrode material delivered an energy density of 12.7 Wh·kg −1 at 299.85 W·kg −1. Therefore, the synthesized LWCA-NiS composite was an economical and sustainable candidate for the electrodes of high-performance supercapacitors.
► Fuel preheating required. ► Managable emissions. ► High turbine inlet temperature lower CO and THC.
The paper reports foremost the results of a successful combustion of an innovative ...lignocellulosic biofuel in a gas turbine. The fuel was processed through liquefaction of lignocellulosic materials with polyhydroxy alcohols in an acid catalyzed reaction. The liquefaction process features: high efficiency, high liquid yields and inexpensive, easily available process equipment. For the purpose of this analysis the following were developed: an experimental gas turbine with internal combustion chamber, a preheated pressurized fuel supply system with swirl-air fuel injector and a heat exchanger to obtain high primary air temperatures. The paper gives results on the emissions of CO, THC, NOx and soot. For the purpose of benchmarking the turbine was also run on diesel fuel. The paper presents analyses of the underlying phenomena with which it aims to provide guidelines for improvements in the fuel processing and in the experimental equipment. It has been shown that direct utilization of this innovative lignocellulosic biofuel gives promising results. Although the CO and THC emissions are higher compared to the benchmark diesel results it has been shown that both emissions decrease with increased turbine inlet temperature and with the increased fuel preheat temperature, due to a very high viscosity of the fuel. It is additionally shown that NOx emissions are low and comparable to those of the diesel fuel, whereas soot emissions are very low for both fuels.
Black poplar wood, diethylene glycol (DEG), and sulphuric acid as a catalyst were used as starting reactants for liquefaction. Optimal conditions for liquefaction were established: reaction ...temperature 150
°C, reaction time 95
min, ratio of wood:DEG
=
1:5 and 3% of sulphuric acid addition. The liquid mixture obtained by the liquefaction was composed of the real product of the reaction (the so called “excess solvent free liquefied wood” (ESFLW)) and of the remaining unreacted DEG. The unreacted DEG was successfully separated from the ESFLW and analysed with HPLC for levulinic acid content. Theoretical weight ratio between the wood and DEG required for the reaction was estimated. OH number investigation showed that the ESFLW in the liquid mixture contributes to maximally 60% of the free
OH groups. The crosslinking of the ESFLW without any curing agents or additives was performed for the first time, and the drying stages investigated. FT-IR investigations demonstrated that the obtained crosslinked polymer film could be an ether and/or ester network.
Purpose of Review
The development of eco-friendly panels is one of the major issues for the wood industry, particularly in terms of developing new adhesive systems for reducing harmful emissions and ...dependence from fossil fuel resources. Among the plethora of various possible solutions, liquefied wood products have demonstrated promising features to decrease the use of petroleum-based amino resins. A meta-analysis was carried out to develop a quantitative synthesis of the state of the art of the application of liquefied wood products for particleboard manufacturing, investigating their effects on the board’s properties.
Recent Findings
The results from meta-analysis revealed that the application of liquefied wood products does not significantly deteriorate the mechanical properties of particleboards. It has also been observed that there is no negative influence on the formaldehyde content of the panel, mostly when liquefied wood products are applied in mixture with commercial resin. The most interesting observation is that the performance of the boards was not affected by the type of feedstock used for liquefaction.
Summary
The option to apply liquefied wood products has the potential to significantly decrease the application of commercial formaldehyde-based resins without leading to a deterioration of the properties of the panels. It is however important to note that there is currently a limited number of studies on this topic. The meta-analysis showed a notable variability of the effect sizes in the trials. Further study is needed to determine the outcomes and the benefits for the use of liquefied wood products on an industrial level.
Different types of southern European hardwoods and softwoods were subjected to a liquefaction process with glycerol/diethylene glycol. The liquefied spruce wood was reacted in a condensation reaction ...in the hot press with different melamine–formaldehyde and melamine–urea–formaldehyde resin precursors and used as adhesives for wood particle boards. The mechanical properties of these particle boards and the determination of formaldehyde release, proved that addition of 50% of the liquefied wood to such resin precursors caused the product to meet the European standard quality demands for particle boards. Up to 40% reduction of the formaldehyde emission was achieved. The temperature of the press unit was lowered from 180
°C to 160
°C with no significant influence on the mechanical properties. On the basis of the presented results it was possible to conclude that liquefied wood can be used as substitute for synthetic resin precursors in adhesives that are used for the particle board production.
Liquefied wood (LW) prepared in a microwave process was applied as a novel; inexpensive precursor feedstock for incorporation of (
)-3-hydroxyvalerate (3HV) into polyhydroxyalkanoate (PHA) ...biopolyesters in order to improve the biopolyester's material quality;
was applied as microbial production strain. For proof of concept, pre-experiments were carried out on a shake flask scale using different mixtures of glucose and LW as carbon source. The results indicate that LW definitely acts as a 3HV precursor, but, at the same time, displays toxic effects on
at concentrations exceeding 10 g/L. Based on these findings, PHA biosynthesis under controlled conditions was performed using a fed-batch feeding regime on a bioreactor scale. As major outcome, a poly(3HB-
-0.8%-3HV) copolyester was obtained displaying a desired high molar mass of
= 5.39 × 10⁵ g/mol at low molar-mass dispersity (
of 1.53), a degree of crystallinity (
) of 62.1%, and melting temperature
(176.3 °C) slightly lower than values reported for poly(
-3-hydroxybutyrate) (PHB) homopolyester produced by
; thus, the produced biopolyester is expected to be more suitable for polymer processing purposes.
Wood liquefaction was conducted at a 2/1 phenol/wood ratio in two different reactors: (1) an atmospheric three-necked flask reactor and (2) a sealed Parr reactor. The liquefied wood mixture ...(liquefied wood, unreacted phenol, and wood residue) was further condensed with formaldehyde under acidic conditions to synthesize two novolac-type liquefied wood/phenol/formaldehyde (LWPF) resins: LWPF1 (the atmospheric reactor) and LWPF2 (the sealed reactor). The LWPF1 resin had a higher solid content and higher molecular weight than the LWPF2 resin. The cure kinetic mechanisms of the LWPF resins were investigated with dynamic and isothermal differential scanning calorimetry (DSC). The isothermal DSC data indicated that the cure reactions of both resins followed an autocatalytic mechanism. The activation energies of the liquefied wood resins were close to that of a reported lignin-phenol-formaldehyde resin but were higher than that of a typical phenol formaldehyde resin. The two liquefied wood resins followed similar cure kinetics; however, the LWPF1 resin had a higher activation energy for rate constant k₁ and a lower activation energy for rate constant k₂ than LWPF2.
Liquefied wood-based polyurethane wood coatings of an aesthetically acceptable light colour were prepared and characterised. Liquefied black poplar wood was obtained by solvolysis in a polyethylene ...glycol/glycerol mixture, and it was bleached with hydrogen peroxide. The bleaching treatment converted liquefied wood from a dark brown to a yellowish product. Polyurethane films were prepared by the curing of liquefied wood with polymeric diphenylmethane diisocyanate or trimethylolpropane toluene diisocyanate prepolymer (TMP/TDI) isocyanate-type hardeners. It was found that the selected properties of the films prepared from the bleached liquefied wood were, in general, equivalent to those prepared from unbleached liquefied wood. The mechanical properties of the films obtained with the TMP/TDI curing agent were acceptable for wood coating applications. The initial poor resistance of the films to water and ethanol was substantially improved by the addition of n-octyltriethoxysilane to the liquefied wood prior to the preparation of the polyurethane coatings; the hardness of the films also increased.
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