The Hot Pressing of Dry-formed Wood-based Composites. Part II. A Simulation Model for Heat and Moisture Transfer, and Typical Results

Humphrey, Philip E.

doi:10.1515/hfsg.1989.43.3.199

Cited by 66 publications

(37 citation statements)

References 12 publications

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“…Thus, heat transfer into the core of the mat will be easier and faster which may result both in the altered rheological properties of wood particles and the board density profile Humphrey and Bolton 1989;Hata et al 1990;Thoemen and Humphrey 2001).…”

Section: Resultsmentioning

confidence: 99%

Properties of particleboard produced from post-industrial UF- and PF-bonded plywood

Laskowska

Mamiński

2017

Eur. J. Wood Prod.

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An approach based on the recycling of waste plywood as a recovered wood resource for the particleboard industry is described. It is demonstrated that post-industrial urea-(UF) and phenol-formaldehyde (PF) bonded plywood can be effectively shredded to the form of the recovered particles that can be a valuable material in particleboard manufacturing. The effects of shredding conditions and binder type on the recovered particles characteristics and the mechanical properties of the particleboards were analyzed. It is shown that the substitution of 20-100% of virgin particles with the recovered material is possible without affecting the performance of the particleboard.

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Section: Resultsmentioning

confidence: 99%

Properties of particleboard produced from post-industrial UF- and PF-bonded plywood

Laskowska

Mamiński

2017

Eur. J. Wood Prod.

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“…However, Humphrey and Bolton [23] estimated from data obtained by Ward and Skaar [24] and from their own preliminary measurements that the thermal conductivity of particleboards parallel to the main fibre direction is about 50 % higher than for the cross-sectional thermal conductivity. For fibreboards no such data are known from the literature.…”

Section: Thermal Conductivitymentioning

confidence: 99%

3D simulation of macroscopic heat and mass transfer properties from the microstructure of wood fibre networks

Thoemen

Walther

Wiegmann

2008

Composites Science and Technology

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“…Thus the driving force for diffusion through the edges is much lower than that through the surfaces. For a mat density of 650 kg m -3 (Humphrey and Bolton 1989), the combined α-pinene emission from the core and both surfaces is 2.56 g m -2 of wood, or 0.41 kg/1000 kg as calculated from the model. The data in Table 1 are for 121 cm 2 surfaces of boards weighing an average of 17.5 g, which translates to an average α-pinene emission of 0.8 g m -2 .…”

Section: Modeling the Release Of Pinene During Hot-pressingmentioning

confidence: 99%

Improving Dryer and Press Efficiencies Through Combustion of Hydrocarbon Emissions

Banerjee¹

2005

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Executive SummaryEmission control devices on dryers and presses have been legislated into the industry, and are now an integral part of the drying system. These devices consume large quantities of natural gas and electricity and down-sizing or eliminating them will provide major energy savings. The principal strategy taken here focuses on developing process changes that should minimize (and in some cases eliminate) the need for controls. A second approach is to develop lower-cost control options.It has been shown in laboratory and full-scale work that Hazardous Air Pollutants (HAPs) emerge mainly at the end of the press cycle for particleboard, and, by extension, to other products. Hence, only the air associated with this point of the cycle need be captured and treated. A model for estimating terpene emissions in the various zones of veneer dryers has been developed. This should allow the emissions to be concentrated in some zones and minimized in others, so that some of the air could be directly released without controls.Low-cost catalysts have been developed for controlling HAPs from dryers and presses. Catalysts conventionally used for regenerative catalytic oxidizers can be used at much lower temperatures for treating press emissions. Fluidized wood ash is an especially inexpensive material for efficiently reducing formaldehyde in dryer emissions.A heat transfer model for estimating pinene emissions from hot-pressing strand for the manufacture of flakeboard has been constructed from first principles and validated. The model shows that most of the emissions originate from the 1-mm layer of wood adjoining the platen surface. Hence, a simple control option is to surface a softwood mat with a layer of hardwood prior to pressing.Fines release a disproportionate large quantity of HAPs, and it has been shown both theoretically and in full-scale work that particles smaller than 400 µm are principally responsible. Georgia-Pacific is considering green-screening their furnish at several of their mills in order in order to remove these particles and reduce their treatment costs.

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The Hot Pressing of Dry-formed Wood-based Composites. Part II. A Simulation Model for Heat and Moisture Transfer, and Typical Results

Cited by 66 publications

References 12 publications

Properties of particleboard produced from post-industrial UF- and PF-bonded plywood

Properties of particleboard produced from post-industrial UF- and PF-bonded plywood

3D simulation of macroscopic heat and mass transfer properties from the microstructure of wood fibre networks

Improving Dryer and Press Efficiencies Through Combustion of Hydrocarbon Emissions

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