Modelling the Heat and Mass Transfer during Hot Pressing of Medium Density Fibreboard
-
Arun Gupta
,
Patrick Jordan
Abstract
This paper discusses the development of a one-dimensional mathematical model to describe the heat and mass transfer during the hot-compression of medium density fibreboard (MDF) composite panels. Five primary variables were considered during the model development: air content, water vapour content, bound water content, and temperature within the mat, and the extent of the cure of the adhesive system, characterized by the cure index. Different heat and mass transfer processes were identified for the transport of the heat and the moisture phases. The heat was transported by conduction and convection due to a temperature gradient, and the exothermic energy released by the curing of the urea formaldehyde resin, while the water phases were transported by bulk flow and diffusion due to total pressure and concentration gradients. The resulting differential-algebraic equation system was solved by the finite difference method. The mathematical model predicted temperature, moisture content, partial vapour pressures, and extent of adhesive cure within the mat structure under a typical hot-compression process. The model results allow a better understanding of the interacting mechanisms involved in a complex production process. The model can also assist to optimize the hot-pressing parameters for improved quality of MDF panel products, while reducing pressing time.
Acknowledgements
The authors gratefully acknowledge the financial and other support received for this research from the New Zealand government and the Department of Chemical & Process Engineering, University of Canterbury, Christchurch and later on work supported by Faculty of Chemical and Natural Resources Engineering, University Malaysia Pahang, Malaysia.
References
1. Humphrey PE. Physical aspects of wood particleboard manufacture. PhD Thesis, University of Wales, UK, 1982.Suche in Google Scholar
2. Hata T, Kawai S, Sasaki H. Computer simulation of temperature behaviour in particle mat during hot pressing and steam injection pressing. Wood Sci Technol 1990;24:65–78.Suche in Google Scholar
3. Hubert P, Dai C. An object-oriented finite element processing model for oriented strand board wood composites. Proceedings of the 13th International Conference on Composite Materials, Paris, France, 1998.Suche in Google Scholar
4. Carvalho LH, Costa C. Modelling and simulation of the hot pressing process in the production of medium density fibreboard (MDF). Chem Eng Comm 1998;170:1–21.10.1080/00986449808912732Suche in Google Scholar
5. Thomen H. Modelling the physical processes in natural fibre composites during batch and continuous pressing. PhD Dissertation, Oregon State University, Corvallis, OR, 2000.Suche in Google Scholar
6. Vonhass G. Untersuchungen zur Heibpressung von Holzwerkstoffmatten unter besonderer Berucksichtigung des Verdictungsverhaltens der permeabilities, der Tempperaturleitfahigkeit und der Sorptiongeschwinddigkeit. Dissertation, University of Hamburg, Germany, 1998:264.Suche in Google Scholar
7. Haselein CR. Numerical simulation of pressing wood-fibre composites. PhD Thesis, Oregon State University, Corvallis, OR, 1998:244.Suche in Google Scholar
8. Shao M. Thermal properties of wood fibre networks. MS Thesis, Oregon State University, Corvallis, OR, 1989:95.Suche in Google Scholar
9. Kuhlmann G. Untersuchungen der thermischen Eigenschaften von Holz und Spanplatten in Abhangigkeit von Feuchtigkeit und Temperatur im hygroskopischen Bereich. Holz als Roh-und Werkstoff 1962;20:259–70.10.1007/BF02604682Suche in Google Scholar
10. Humphrey PE, Bolton AJ. The hot pressing of dry-formed wood based composites. Part II. A simulation model for heat and moisture transfer. Holzforschung 1989;43:199–206.10.1515/hfsg.1989.43.3.199Suche in Google Scholar
11. Munson BR, Young DF, Okiishi TH. Fundamentals of fluid mechanics. New York: Wiley, 1990:843.Suche in Google Scholar
12. Fuller EN,Giddings JC, Schettler PD. A new method for prediction of binary gas-phase diffusion coefficient. J Ind Eng Chem 1966;58:19–27.10.1021/ie50677a007Suche in Google Scholar
13. Cussler EL. Diffusion: mass transfer in fluid systems. Cambridge: Cambridge University Press, 1984:525.Suche in Google Scholar
14. Kayihan F, Johnson JA. Heat and moisture movement in wood composite materials during the pressing operation-a simplified model. Numerical Methods Heat Transf 1983;2:511–31.Suche in Google Scholar
15. Simpson WT, Rosen HN. Equilibrium moisture content of wood at high temperature. Wood Fibre Sci. 1981;13:150–8.Suche in Google Scholar
16. Pang S. Some considerations in simulation of superheated steam drying of softwood lumber. Drying Technol 1997;15:651–70.10.1080/07373939708917252Suche in Google Scholar
17. Day DL, Nelson GL. Desorption isotherms for wheat. Trans Am Soc Agric Eng 1965;8:293–7.10.13031/2013.40497Suche in Google Scholar
18. USDA Forest Products Laboratory. Wood handbook. Wood as an Engineering Material. Forest Products Society, Madison, WI, 1999.10.2737/FPL-GTR-113Suche in Google Scholar
19. Ball RD, Simpson IG, Pang S. Measurement, modelling and prediction of equilibrium moisture content in Pinus radiata heartwood and sapwood. Holz als Roh-und Werkstoff 2001;59:457–62.10.1007/s001070100242Suche in Google Scholar
20. Resch H, Hoag ML, Rosen HN. Desorption of yellow-poplar in superheated steam. Forest Prod J 1988;38:13–18.Suche in Google Scholar
21. Strickler MD. High temperature moisture relations of grand fir. Forest Prod J 1968;18:69–75.Suche in Google Scholar
22. Krischer O. Die wissenschaftlichen Grundlagen der Trocknungstechnik. 2nd ed. Berlin: Springer Verlag, 1963:491.10.1007/978-3-662-26011-1Suche in Google Scholar
23. Siau JF. Transport processes in wood. New York: Syracuse University Press, 1984:245.10.1007/978-3-642-69213-0Suche in Google Scholar
24. Scott EP. Estimation of the thermal and kinetic properties associated with carbon/epoxy composites material during curing. PhD Dissertation, Michigan State University, East Lansing, MI, 1989.Suche in Google Scholar
25. Kiran E, Iyer R. Cure behaviour of paper-phenolic composite systems: kinetic modelling. J Appl Polym Sci 1994;51:353–64.10.1002/app.1994.070510218Suche in Google Scholar
26. Ahmad M. Cure characteristics of phenol formaldehyde resin. Unpublished Report. Department of Wood Science and Forest Products, VPI & SU, Blackburg, VA, 2000.Suche in Google Scholar
27. Zombori BG. Modelling the transient effects during the hot pressing of wood based composites. PhD Dissertation, Virginia Polytechnic Institute and State University, Blackburg, VA, 2001.Suche in Google Scholar
28. Denisov OB, Anisov PP, Zuban PE. Untersuchung der Permeabilitat von Spanvliesen. Holztechnologie 1975;16:10–14.Suche in Google Scholar
©2013 by Walter de Gruyter Berlin / Boston
Artikel in diesem Heft
- Masthead
- Masthead
- Ionic Liquids as Green Solvents for the Extraction of Endosulfan from Aqueous Solution: A Quantum Chemical Approach
- Neuro-Fuzzy-Based Control for Parallel Cascade Control
- Modelling the Heat and Mass Transfer during Hot Pressing of Medium Density Fibreboard
- Drying of Apple Slices in Combined Heat and Power (CHP) Dryer: Comparison of Mathematical Models and Neural Networks
- First Principle Modeling and Neural Network–Based Empirical Modeling with Experimental Validation of Binary Distillation Column
- The Correlation of Activity Coefficients of Ionic Species of Aqueous Electrolytes Using a New Model
Artikel in diesem Heft
- Masthead
- Masthead
- Ionic Liquids as Green Solvents for the Extraction of Endosulfan from Aqueous Solution: A Quantum Chemical Approach
- Neuro-Fuzzy-Based Control for Parallel Cascade Control
- Modelling the Heat and Mass Transfer during Hot Pressing of Medium Density Fibreboard
- Drying of Apple Slices in Combined Heat and Power (CHP) Dryer: Comparison of Mathematical Models and Neural Networks
- First Principle Modeling and Neural Network–Based Empirical Modeling with Experimental Validation of Binary Distillation Column
- The Correlation of Activity Coefficients of Ionic Species of Aqueous Electrolytes Using a New Model
