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.

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. 

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.

Water absorption behavior of heat-treated and untreated red balau saw dust/LDPE composites: Its kinetics and effects on mechanical properties

2018 ◽  
Vol 32 (10) ◽  
pp. 1408-1426 ◽  
Author(s):  
Ruth A Lafia-Araga ◽  
Aziz Hassan ◽  
R Yahya ◽  
N Abd Rahman ◽  
Fauzani Md Salleh
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Water Absorption ◽  
Water Immersion ◽  
Treated Wood ◽  
Untreated Wood ◽  
Thermoplastic Composites ◽  
Wood Composites ◽  
Saw Dust ◽  
Heat Treated

The hygroscopic nature of wood limits the use of wood thermoplastic composites (WTC) in outdoor industrial and domestic applications. To reduce this tendency, red balau saw dust was heat treated at 180 and 200°C for 1 h and compounded with Low Density Poly(ethylene) (LDPE) into 20 and 37 wt% and then molded into test specimens by injection molding. Samples were immersed in distilled water at room temperature for 4 months. Heat-treated wood composites showed remarkable water resistance relative to untreated ones. Wood composites made from wood treated at 180 and 200°C exhibited almost similar water absorption pattern. Reduced water absorption of heat-treated wood composites relative to untreated ones indicates that heat treatment has resulted in a degree of modification of the wood. Most of the composites displayed the Fickian mode of water absorption with n values close to 0.5. Also, the diffusion coefficient reduced with wood content in untreated wood composites due to interaction of water with the polar groups in wood through hydrogen bonding. Untreated wood composites exhibited poorer mechanical properties with water immersion as a result of degradation due to moisture. The mechanical properties of the heat-treated wood composites were not adversely affected with water absorption. Therefore, heat treatment can reduce the proneness to water absorption in WTCs and alleviate the detrimental effects on mechanical properties.

Untersuchungen zum Einfluss der Wärmebehandlung auf die Beständigkeit von Fichtenholz gegenüber holzzerstörenden Pilzen | Examination of the influence of heat treatment on the resistance of spruce timber to wood decaying fungi

2004 ◽  
Vol 155 (12) ◽  
pp. 548-554 ◽  
Author(s):  
Fritz Bächle ◽  
Peter Niemz ◽  
Markus Heeb
Keyword(s):  
Heat Treatment ◽  
Mass Loss ◽  
Ph Value ◽  
Treated Wood ◽  
Untreated Wood ◽  
Brown Rot ◽  
Nitrogen Atmosphere ◽  
White Rot ◽  
Heat Treated ◽  
Blue Stain

Spruce wood that was heat treated in rape oil (laboratory scale) and in an autoclave with a nitrogen atmosphere (industrial scale), respectively, was tested according to EN 113 for its resistance to basidiomycetes (4 brown and 1 white rot). In addition,resistance to blue-stain fungi was tested according to EN 152 and pH-values were measured in an outdoor ageing process. Influenced by the thermal treatment a clear decrease of mass loss induced by brown rot can be seen. There is an obvious influence of the kind of fungi and the level of treatment. Inoculated with Trametes versicolor (simultaneous white rot) a higher mass loss can be seen in the heat-treated specimens than in the untreated specimens. The big differences in the results between the fungi show that the type of fungi plays a role in the degree of influence. It would therefore seem that tests using only one fungus are insufficient. Similar results were achieved by testing previously weathered samples. The tendencies are not always similar. Blue-stain was occasionally detected near the surface of heat-treated wood. The pH-value of wood treated in an autoclave is clearly lower than that of untreated wood. The colour of the heat-treated wood is not UV stable. However, the colour achieved by the oil-heat-treatment is more stable than that achieved by a treatment in an autoclave.

scholarly journals The effect of heat treatment on the moisture absorption characteristics of Cu-impregnated Masson’s pine wood

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8459-8471
Author(s):  
Lamei Li ◽  
Guijun Xie ◽  
Wanju Li ◽  
Yixin Li ◽  
Xingwei Li
Keyword(s):  
Heat Treatment ◽  
Surface Area ◽  
Water Adsorption ◽  
Moisture Absorption ◽  
Bound Water ◽  
Treated Wood ◽  
Free Water ◽  
Untreated Wood ◽  
Pine Wood ◽  
Heat Treated

The accumulation of water inside wood creates a favorable environment not only for molds, but also for wood-decaying fungi and insects. Therefore, the ability to limit water adsorption and retention is key to the longevity and performance of wood. In this study, the effect of heat-treatment and Cu nanoparticle (CuNP) impregnation on surface contact angle, specific surface area, and hygroscopicity of Masson’s pine wood was examined. Heat-treatment caused thermal degradation of hydroxyl-rich biopolymers, leading to an increase in hydrophobicity; while the resulting breakdown and blockage of the interior cell cavity network caused a decrease in effective surface area. In turn, the hygroscopicity of the heat-treated wood was considerably lower than the untreated wood. Analysis of water adsorption isotherms enabled the differentiation between bound water and free water, where the latter was a prerequisite for mold growth. The research showed that the amount of free water was reduced by both impregnation with CuNP and heat-treatment, but the previously observed antimicrobial activity was shown to rely on the presence of CuNPs as opposed to the reduced free water content. This study presented a detailed methodology for the preparation and analysis of heat-treated, CuNP-impregnated wood, and provided further insight into the mechanism of antimicrobial action of treated woods.

Comparison of the color and weight change in Paulownia tomentosa and Pinus koraiensis wood heat-treated in hot oil and hot air

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5574-5585
Author(s):  
Intan Fajar Suri ◽  
Jong Ho Kim ◽  
Byantara Darsan Purusatama ◽  
Go Un Yang ◽  
Denni Prasetia ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Color Change ◽  
Treated Wood ◽  
Pinus Koraiensis ◽  
Weight Changes ◽  
Paulownia Tomentosa ◽  
Wood Color ◽  
Color Changes ◽  
Hot Air ◽  
Heat Treated

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.

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 Heat-Treated Wood as a Substrate for Coatings, Weathering of Heat-Treated Wood, and Coating Performance on Heat-Treated Wood

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Vlatka Jirouš-Rajković ◽  
Josip Miklečić
Keyword(s):  
Heat Treatment ◽  
Wood Species ◽  
Treated Wood ◽  
Wood Properties ◽  
Treatment Method ◽  
Coating Performance ◽  
Treatment Processes ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Trade Names

Heat treatment is a method of wood modification with increasing market acceptance in Europe. The major patented European commercial heat treatment processes have trade names ThermoWood, Platowood, Retiwood, Le Bois Perdure, and Oil-Heat-Treated Wood (OHT). To what extent modification of wood affects the resistance of wood to weathering is also an important aspect for wood applications, especially where appearance is important. Unfortunately, heat-treated wood has poor resistance to weathering, and surface treatment with coatings is required for both protection and aesthetic reasons. As a substrate for coating, heat-treated wood has altered characteristics such as lower hygroscopicity and liquid water uptake and changed acidity, wettability, surface free energy, and anatomical microstructure. Various wood species, heat treatment method, treatment intensity, and treatment conditions exhibited a different extent of changes in wood properties. These altered properties could affect coating performance on heat-treated wood. The reported changes in acidity and in surface energy due to heat treatments are inconsistent with one another depending on wood species and temperature of the treatments. This paper gives an overview of the research results with regards to properties of heat-treated wood that can affect coating performance and weathering of uncoated and coated heat-treated wood.

scholarly journals Changes in Colour, Strength and Chemical Properties of Oil Heat Treated 18-Years Old Planted Acacia mangium

2017 ◽  
Vol 9 (3) ◽  
pp. 12
Author(s):  
Razak Wahab ◽  
Ros Syazmini M. Ghani ◽  
Hashim W. Samsi ◽  
Mohd Sukhairi M. Rasat
Keyword(s):  
Heat Treatment ◽  
Chemical Properties ◽  
Treated Wood ◽  
Acacia Mangium ◽  
Chemical Compositions ◽  
Bending Tests ◽  
Colour Strength ◽  
Heat Treated ◽  
The Relationship ◽  
And Chemical Properties

This study was carried to investigate changes in the oil heat treated 18-years old of planted Acacia mangium. Harvested trees segregated into bottom, middle and top portions containing heartwood and sapwood were oil heat treated in stainless tank with palm crude oil as heating medium at temperatures of 180oC, 200oC and 220oC for 30, 60 and 90 minutes respectively. The evaluation of the changes in the wood were performed by standards using a Minolta Chroma Meter, TAPPI Standard T204 om-88, TAPPI Standard T203 cm-99, TAPPI Standard T222 cm-02, and BS EN 310:1993 static bending tests. The relationship between the changes in the colour, mechanical and chemical composition, were made using correlation analysis. The result showed oil-heat treatment reduced the lightness of the wood and darkened the both parts of the wood. The strength of the wood reduced slightly after the oil-heat treatment. In the chemical compositions, the percentages of the holocellulose, α-cellulose, hemicellulose and extractive contents decrease with the increase in treatment duration and temperature. The oil heat treatment process at 200°C for duration 60 minutes is recommended for acacia mangium wood as it improved the colour of Acacia mangium and standardized the colour of sapwood and heartwood. The loss in strength at this temperature and duration is acceptable as the treated wood only loss up to 15% strength in MOR and 10.7% in MOE.

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.

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