scholarly journals Effect of Pyrolysis Temperature and Wood Species on the Properties of Biochar Pellets

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6529
Author(s):  
Safa Arous ◽  
Ahmed Koubaa ◽  
Hassine Bouafif ◽  
Besma Bouslimi ◽  
Flavia Lega Braghiroli ◽  
...  
Keyword(s):  
Fast Pyrolysis ◽  
Treated Wood ◽  
Untreated Wood ◽  
High Heat ◽  
Treatment Temperature ◽  
Hydroxyl Groups ◽  
Thermal Treatments ◽  
Wood Pellets ◽  
Heat Treated ◽  
Wood Residues

Thermal treatments such as torrefaction and fast pyrolysis are commonly employed methods to produce biofuels with high-energetic properties. In this study, wood chips were heat-treated at different temperatures of torrefaction (315 °C) and fast pyrolysis (400 and 454 °C) to form energetic pellets. Three softwoods, jack pine (JP), balsam fir (BF), and black spruce (BS), were evaluated. Pellets are produced using 20% moisture content and 15% pyrolytic lignin as a binder. Untreated- and treated-wood residues were characterized by surface chemistry, elemental analysis, and chemical composition, whereas all pellets were characterized in terms of density, high heat value (HHV), and durability. Results showed that both thermal treatments caused significant changes in the physicochemical structure of wood residues. Using temperatures higher than 315 °C leads to the disappearance of hydroxyl groups, a decrease in oxygen and hydrogen contents, and an increase in carbon content. Regardless of the treatment temperature, pellets made from heat-treated JP had the best durability (93%). In contrast, the calorific values of wood-treated pellets reached up to 31 MJ/kg, compared to untreated-wood pellets (19 MJ/kg). Thus, the densification of the thermal-treated wood residues represents a potential approach for producing biofuels with high energetic value.

scholarly journals COLOR CHANGE — MASS LOSS CORRELATION FOR HEAT-TREATED WOOD

2014 ◽  
Vol 2 ◽  
pp. 345-352 ◽  
Author(s):  
Cristina Marinela Olarescu ◽  
Mihaela Campean
Keyword(s):  
Heat Treatment ◽  
Mass Loss ◽  
Color Change ◽  
Treated Wood ◽  
Untreated Wood ◽  
Cost Effective ◽  
Assessment Procedure ◽  
Mathematical Correlation ◽  
Heat Treated ◽  
Two Parameters

Heat treatment is renowned as the most environmentally friendly process of dimensional stabilization that can be applied to wood, in order to make it suitable for outdoor uses. It also darkens wood color and improves wood durability. The intensity of heat treatment can be appreciated by means of two parameters: the color change occured in wood due to the high temperature, and the mass loss, which is a measure of the degree of thermal degradation. In order to find a mathematical correlation between these two parameters, an experimental study was conducted with four European wood species, which were heat-treated at 180°C and 200ºC, for 1-3 hours, under atmosheric pressure.The paper presents the results concerning the color changes and mass losses recorded for the heat-treated wood samples compared to untreated wood.  For all four species, the dependency between the color change and the mass loss was found to be best described by a logarithmic regression equation with R2 of 0.93 to 0.99 for the soft species (spruce, pine and lime), and R2 of 0.77 for beech. The results of this study envisage to simplify the assessment procedure of the heat treatment efficiency, by only measuring the color – a feature that is both convenient and cost-effective. 

The Improvement of Durability of Marine Wood with Polymer and its Mechanism

2009 ◽  
Vol 79-82 ◽  
pp. 1021-1024 ◽  
Author(s):  
Yong Feng Li ◽  
Yi Xing Liu ◽  
Xiang Ming Wang ◽  
Xiu Rong Li
Keyword(s):  
Porous Structure ◽  
Dimensional Stability ◽  
Cell Walls ◽  
Treated Wood ◽  
Untreated Wood ◽  
Decay Resistance ◽  
Hydroxyl Group ◽  
Alkali Resistance ◽  
Hydroxyl Groups ◽  
Marine Corrosion

In order to improve the durability of marine wood against the long-term marine corrosion, the study explores to use two bifunctional reagents, maleic anhydride (Man) and glycidyl methacrylate(GMA), to react with wood by impregnating them into the porous structure of wood and further initiating them to polymerize with an initiator, AIBN, through a heat process. After the above modification, the durability of the marine wood treated with polymer was tested, and its mechanism was further analyzed as well. The testing results of the durability show that the acid resistance, the alkali resistance, the decay resistance against marine borers and the dimensional stability of the treated wood increases by 2.02 times, 12.39 times, 4.96 times and 3 times over untreated wood, respectively; and its Anti Swelling Efficiency (ASE) for dimensional stability reaches 53%, which almost equals the value of the wood treated by PEG-1500 under the same condition, while its leachability resistance is greatly higher than wood treated by PEG-1500. The analysis result with FTIR indicates that Man and GMA both react with wood, and Man reacts with the hydroxyl group of wood cell walls by its anhydride group, and GMA polymerizes in the porous structure of wood. The charactering result with SEM reveals that the resultant polymer fills in wood cell lumina as a solid form, which contacts tightly the wood cell walls without obvious gaps. The greatly reducing amount of hydroxyl groups after the reaction and the heavy jamming channels for water and marine borers approaching to wood cell walls both contribute to the improving durability of the modified wood.

scholarly journals Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

2020 ◽  
Author(s):  
Lijie Qu ◽  
Zhenyu Wang ◽  
Jing Qian ◽  
Zhengbin He ◽  
Songlin Yi
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Structural Changes ◽  
Aluminum Sulfate ◽  
Treated Wood ◽  
Treatment Temperature ◽  
Chinese Fir ◽  
Heat Treated ◽  
Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

scholarly journals Calorific Power Improvement of Wood by Heat Treatment and Its Relation to Chemical Composition

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5322
Author(s):  
Idalina Domingos ◽  
Umit Ayata ◽  
José Ferreira ◽  
Luisa Cruz-Lopes ◽  
Ali Sen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Chemical Composition ◽  
Lignin Content ◽  
Treated Wood ◽  
Untreated Wood ◽  
High Heating Value ◽  
Heat Treated ◽  
Positive Linear Correlation ◽  
Total Extractives ◽  
Calorific Power

Chemical composition influences the calorific power of wood, mainly due to the calorific power of structural compounds and extractives. Heat treatment changes the chemical composition of treated wood. This work studies the relationship between chemical composition and calorific power improvement by heat treatment. Samples were heat-treated by the ThermoWood process ® for 1 h and 2 h. High heating value (HHV) and chemical composition; lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol, and water were determined. The HHV of untreated wood ranged between 18.54–19.92 MJ/kg and increased with heat treatment for all the tested species. A positive linear correlation was found between HHV and Klason lignin (R2 = 0.60). A negative trend was observed for holocellulose, cellulose, and hemicelluloses content against HHV, but with low determination coefficients for linear regression. The best adjust for polysaccharides was found for hemicelluloses content. A positive correlation could be found for dichloromethane extractives (R2 = 0.04). The same was obtained in relation to ethanol extractives with R2 = 0.20. For water and total extractives, no clear positive or negative trends could be achieved. The results showed that the HHV of wood increased with heat treatment and that this increase was mainly due to the increase in lignin content.

Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 488-491 ◽  
Author(s):  
Le Xuan Phuong ◽  
Masato Takayama ◽  
Satoshi Shida ◽  
Yuji Matsumoto ◽  
Tetsuo Aoyagi
Keyword(s):  
Nmr Spectroscopy ◽  
Treated Wood ◽  
Deuterium Exchange ◽  
Fungal Resistance ◽  
Lower Amount ◽  
Hydroxyl Groups ◽  
Hydrogen Deuterium Exchange ◽  
Oh Groups ◽  
Heat Treated ◽  
Hydrogen Deuterium

Abstract A new approach based on hydrogen-deuterium exchange is proposed for measuring accessible OH groups in wood. The deuterium (D) exchanged for hydrogen in OH groups in wood was converted to D2O by combustion in oxygen gas then diluted in deionized water, and subsequently determined by 2H NMR spectroscopy. The amount of accessible OH groups in Styrax tonkinensis wood is approximately 6.8 mmol g-1. This measurement is very accurate, with an error of approximately 0.2 mmol g-1. Heat-treated wood has a lower amount of accessible OH groups than non-treated wood. This finding is in agreement with the decreased hygroscopicity of heat-treated wood and explains, at least partially, its increased fungal resistance.

Wettability of Heat-Treated Wood

Holzforschung ◽  
2003 ◽  
Vol 57 (3) ◽  
pp. 301-307 ◽  
Author(s):  
M. Pétrissans ◽  
P. Gérardin ◽  
I. El bakali ◽  
M. Serraj
Keyword(s):  
Heat Treatment ◽  
Water Drop ◽  
Chemical Change ◽  
Treated Wood ◽  
Untreated Wood ◽  
Adsorbed Water ◽  
Inert Atmosphere ◽  
Contact Angles ◽  
Heat Treated ◽  
Before And After

Summary The aim of this work was to study the wettability and chemical composition of heat-treated wood. Heat treatment was performed at 240°C under inert atmosphere on four European wood species (pine, spruce, beech and poplar). Contact angle measurements before and after treatment indicated a significant increase in wood hydrophobicity. Advancing contact angles of a water drop were in all cases systematically higher for heat-treated than for untreated wood. Chemical modifications of wood after heat treatment were investigated using FTIR and 13C NMR analysis. FTIR spectra indicated little structural change which could be attributed either to carbon-carbon double bond formation or to adsorbed water. NMR spectra also revealed little chemical change except for the degree of cellulose crystallinity which was considerably higher in heat-treated wood and could explain the higher contact angles.

Color Stability of Heat-Treated Okan Sapwood during Artificial Weathering

2011 ◽  
Vol 197-198 ◽  
pp. 13-16
Author(s):  
Qiang Shi ◽  
Jing Hui Jiang
Keyword(s):  
Treated Wood ◽  
Untreated Wood ◽  
Color Stability ◽  
Accelerated Weathering ◽  
Experimental Conditions ◽  
Color Changes ◽  
Heat Treated ◽  
Series Of Experiments ◽  
Xenon Light ◽  
Photo Stability

This study describes experiments of testing the color stability of heat-treated okan sapwood samples. Heat-treatment was done at 160°C,180°C,200°C,220°C during 4 hours, under steam. series of experiments were carried out to investigate the color stability of heat-treated okan sapwood compared to untreated wood during 100 hours xenon light irradiation. Color measurements during accelerated weathering were made at intervals throughout the test period. The results are presented in △E* and L* a* b*coordinates according to the CIE(1976)L*a*b* parameters color system. Better photo-stability in terms of color changes was recorded for heat-treated wood compared to the untreated one. The properties of heat treated wood are involved in the heat-treated wood resistanceagainst xenon light under experimental conditions.

scholarly journals Heat treatments of dormant scion wood killed the European canker pathogen in planta, while chemical treatments did not

2019 ◽  
Vol 72 ◽  
pp. 282
Author(s):  
Brent M. Fisher ◽  
Reiny W.A. Scheper
Keyword(s):  
Room Temperature ◽  
Treated Wood ◽  
Untreated Wood ◽  
Heat Treatments ◽  
Causal Agent ◽  
In Planta ◽  
Chemical Treatments ◽  
Canker Pathogen ◽  
Heat Treated ◽  
Nursery Trees

Neonectria ditissima, the causal agent of European canker, can be present in symptomless scion wood. Sanitation treatments could minimise this risk to nursery trees. In this trial, six heat treatments and five chemical treatments were tested for their effectiveness in removing this pathogen from dormant ‘Royal Gala’ wood. In July 2018, 120 symptomless inoculated shoots (three inoculations/shoot) were harvested and stored at 1oC for 3 months. Bundles of five inoculated shoots (45 cm) were placed in the centre of 24 bundles, each consisting of 25 wood pieces. Heat-treated bundles were submerged in water (45oC for 45 min or 50oC for 15 min), or wrapped in moist cloth, vacuum sealed inside plastic then submerged for 3–6 h at the same temperatures. Chemical-treated bundles were submerged for 16 h at room temperature. Treatments were compared with untreated wood. After surface sterilising, isolation of N. ditissima from inoculated wounds was attempted on apple-sap amended water agar. All wounds from the untreated wood and from the chemical-treated wood yielded the pathogen. However, N. ditissima was not isolated from wounds that had been heat treated. Therefore, heat treatments that do not affect scion wood viability may prove an effective tool to remove European canker from nursery material.

scholarly journals Coating Performance on Exterior Oil-Heat Treated Wood

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 225 ◽  
Author(s):  
Mojgan Nejad ◽  
Mahdi Dadbin ◽  
Paul Cooper
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
Color Change ◽  
Treated Wood ◽  
Untreated Wood ◽  
Average Moisture Content ◽  
Southern Pine ◽  
Coating Performance ◽  
Spruce Wood ◽  
Heat Treated

Thermal modification and the degree of improved properties from the treatment depend on wood species and treatment parameters. Southern yellow pine and spruce are two wood species commonly used for decking, fences, and siding in North America. This study evaluated coating performance when applied on oil-heat-treated Southern pine and spruce wood samples. Moisture content, color, and gloss changes of samples were analyzed before weathering and then after each month for the first three months and then every six months during 18 months of natural weathering exposure in Toronto, Canada. The results showed that coated heat-treated woods had lower moisture uptake, lower color change, and overall better appearance ranking than coated-untreated wood samples. Coated-spruce wood samples had lower checking and splitting, and in general, much better performance than coated-Southern pine treated samples. Notably, the average moisture content of treated spruce wood samples was significantly lower than that of Southern pine, which explains lower checking and improved coatings’ appearance.

Promotion effect of NP fire retardant pre-treatment on heat-treated poplar wood. Part 2: hygroscopicity, leaching resistance, and thermal stability

Holzforschung ◽  
2017 ◽  
Vol 71 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Demiao Chu ◽  
Jun Mu ◽  
Li Zhang ◽  
Yushuang Li
Keyword(s):  
Thermal Stability ◽  
Moisture Absorption ◽  
Degradation Products ◽  
Combined Treatment ◽  
Treated Wood ◽  
Fire Retardant ◽  
Crystallinity Index ◽  
Hydroxyl Groups ◽  
Heat Treated ◽  
Wood Polysaccharides

Abstract In continuation of the previous study concerning the effects of a combined treatment of wood with nitrogen-phosphorus (NP) fire retardant and heat treatment (HT), the hygroscopicity, leachability, thermal stability, Fourier transform-infrared (FT-IR) spectra, and X-ray diffraction (XRD) properties of Populus beijingensis W.Y. Hsu have been investigated. The wood samples were impregnated with 10% NP fire retardant solution and exposed to HTs at 140°C–160°C for 30 min. HT of NP treated wood reduced the moisture absorption and enhanced the leaching resistance of NP and improved the thermal stability. The HT decomposes the NP and the acidity of these degradation products has a dehydration effect on the wood polysaccharides, and the number of hydroxyl groups in wood decreased substantially. The crystallinity index of the NP-impregnated and heat-treated wood also increased. The post low-temperature HT enhanced the fixation of the NP fire retardant and hydrophobicity of the NP-treated wood.

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