PARAMETERS INFLUENCING DRYING BEHAVIOR OF RUBBER WOOD (<i>HEVEA BRAZILLIENSIS</i>) AS DETERMINED FROM DESORPTION EXPERIMENT

Theppaya, Thanansak; Prasertsan, S.

doi:10.1081/drt-120002554

Cited by 12 publications

(13 citation statements)

References 10 publications

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“…Similar results were found by Theppaya and Prasertsan, [21] who concluded that the drying time of H. brasiliensis wood decreases with the increase in air velocity. Moreover, this behavior corroborates with that attested by Theppaya and Prasertsan, [4] who concluded that below the FSP, air velocity plays an insignificant role in both drying rate and moisture diffusivity of wood.…”

Section: Effect Of Steaming On Initial Moisture Content and Drying Tisupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

“…The main problems regarding the use of Hevea brasiliensis (rubberwood), particularly as lumber, are due primarily to their intrinsic characteristics, such as drying defects such as warp, twist, bow, and splitting during the drying process [1][2][3][4] ; fast biodegradation and susceptibility to fungi and insects after felling [2,5] ; and high levels of growth stress. [4,6,7] Steaming wood is a technique that may alleviate the problems during the sawing and drying processes, and it is applied for a variety of other purposes, such as to reduce growth stress levels, [8][9][10] change color, improve the dimensional stability, [11][12][13][14] increase the permeability [15] and drying rate, and reduce the initial moisture content (IMC), moisture gradient, and drying defects. [1,3,13,14,[16][17][18][19] When steamed at 54°C, the H. brasiliensis logs produce boards with higher end-cracks, where 704 and 239 mm are in their respective central and peripheral boards, whereas the steamed logs at 92°C present a greater relief of growth stresses, as observed by the smaller difference between the cracks' length in the central (394 mm) and peripheral (165 mm) boards.…”

Section: Introductionmentioning

confidence: 99%

“…[20] The drying process is the best way to add value to the lumber. [3,4,19,21] Although some kinds of wood, among them Paulownia fortune, [22] Eucalyptus grandis, and Corymbia citriodora, [23] present low liquid and gas permeability, the rubberwood is a relatively fast-drying wood [24] due to its high permeability. [25] Steaming at 100°C for 5 h before conventional drying neither causes an increase in drying rate nor reduces the defects of H. brasiliensis lumber, [3] whereas the treatment at 90°C for 7 h causes a decrease of 11% in the board's end-cracks of rubberwood.…”

Section: Introductionmentioning

confidence: 99%

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Drying behavior and decay resistance of rubberwood from steamed log and presteamed lumber

et al. 2018

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The objective of this study was to evaluate the effect of log steaming and steaming prior to drying singly and both treatments together on the drying behavior and decay resistance of Hevea brasiliensis wood (rubberwood). Logs with a diameter of 34.6 � 4.4 cm were used. Half of the logs were kept in their original condition, and the other half were steamed at 90°C for 36 h. Later, the logs were cut into flat sawn boards. Half of the boards were kept in their original condition, and the other half were presteamed at 90°C for 3 h after 1 h of heating-up. These boards were dried in a drying kiln. The drying defects, drying time, drying rate, and decay resistance of wood to the Pycnoporus sanguineus fungus were determined. The results showed that the steaming is not suitable for decreases in the time and the drying rates of this kind of wood, and it neither reduces the drying defects of boards. Furthermore, these treatments adversely affected the decay resistance of rubberwood to P. sanguineus fungi.

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Section: Effect Of Steaming On Initial Moisture Content and Drying Tisupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Drying behavior and decay resistance of rubberwood from steamed log and presteamed lumber

et al. 2018

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“…Traditionally wood drying process consumes more than 60% of total energy usage, mainly in heat and electricity [ 10 ]. As the rubberwood industry is very significant for Southern Thailand and provides the primary export earnings for the local industry, there are extensive research activities carried out by Thai researchers [ 5 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Some of these researches focus on novel drying processes [ 14 , 16 , 17 , 19 , 22 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of air velocity, temperature, and relative humidity on drying kinetics of rubberwood

Chanpet

Rakmak

Matan

et al. 2020

Heliyon

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Kiln drying of rubberwood lumbers is a complex transport phenomenon for realistic modeling and simulation. To decouple this complexity, researchers usually divide their research into two parts. The first one is single-lumber drying kinetics to describe how wood lumber responds to its surface conditions. Then they combine this drying kinetics with a lumped transport model or dispersion model or computational fluid dynamics. The mathematical models are then solved numerically to predict the industrial kiln drying behaviors. This work focuses on the drying kinetics of stacked rubberwood lumbers using hot air at different air velocity (0.5, 1.5, 2.5, 3.5, 4.0 m/s), relative humidity (6–67% relative humidity (RH)) and temperature (60–100 °C). The drying kinetics followed the conventional drying theory. However, the two drying periods, namely constant and falling rate (CRP and FRP), were not distinct. As the air velocity increased, the transition from CRP to FRP is faster. The middle of the transition period (at critical moisture content, CMC) moves closer to the fiber saturation point (FSP). The overall mass transfer coefficients in the falling rate period for stacked rubberwood drying were lower than those predicted by the Ananias correlation. Hence, a modified formula was proposed, representing the overall moisture transfer coefficients as a function of air velocity, temperature, relative humidity, and lumbers thickness for the range of variables under investigation satisfactorily. In general, the drying rate and the overall moisture transfer coefficient increased with increasing air velocity, drying temperature, and decreasing RH. Relative humidity directly affects the driving force of moisture transfer rate because higher RH is associated with higher equilibrium moisture content. A lumped parameter model for kiln drying was also developed. After being integrated with the estimated mass transfer coefficient, the model can predict the moisture profiles in lab-scale kiln drying satisfactory, although the model needs more validation data. These kinetic parameters and correlation for stacked rubberwood drying can be used in more complex models and process optimization in future research.

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Evolution of internal stress during drying, cooling and conditioning of rubberwood lumber

2009

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PARAMETERS INFLUENCING DRYING BEHAVIOR OF RUBBER WOOD (HEVEA BRAZILLIENSIS) AS DETERMINED FROM DESORPTION EXPERIMENT

Cited by 12 publications

References 10 publications

Drying behavior and decay resistance of rubberwood from steamed log and presteamed lumber

Drying behavior and decay resistance of rubberwood from steamed log and presteamed lumber

Effect of air velocity, temperature, and relative humidity on drying kinetics of rubberwood

Evolution of internal stress during drying, cooling and conditioning of rubberwood lumber

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