Thesis (Ph. D.)--Oregon State University, 1984. / Typescript (photocopy). Includes bibliographical references (leaves 139-144). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1984. / Typescript (photocopy). Includes bibliographical references (leaves 190-199). Also available on the World Wide Web.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 113-117). Also available via the Internet.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2006. / Thesis documentation sheet inserted. Appendix reprints four papers and manuscripts, two co-authored with others. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.

The commercial rotary dryers used to dry wood wafers (of approximate dimensions 0.63 mm thick, 50 mm wide and 76+ mm long) for the production of panelboard are modified versions of agricultural dryers and have not been designed for the optimal drying of wood wafers. The lack of available information on wafer drying necessitated that the first goal of this research was the characterization of wafer drying behaviour. After the important parameters of wafer drying were identified, the applicability of fluidized bed technology to wafer drying was assessed and an industrial size dryer was designed. The proposed fluidized bed wafer dryer was then compared to a commercial rotary dryer in terms of energy efficiency. Wafer drying behaviour was investigated in two factorial experiments. Three lengths of wafers (25 mm, 44 mm and 63 mm) were individually dried in a 0.15 m draft tube at temperatures of 90°C, 120°C and 150°C. The statistical analysis of the resultant drying rate curves showed that the drying behaviour of aspen wafers was influenced by the effect of wafer length on the external heat and mass transfer rates to the wafer surface, and on the length of internal pathways for bulk flow and diffusion of water. The external drying conditions had a decreasing effect on drying rate until about 10% moisture content at which time drying became limited by internal heat and mass transport. The initial assessment of fluidized bed technology for wafer drying used a 0.15 m semi-cylindrical column for the determination of wafer drying rate curves and wafer behaviour in a fluidized bed of inert particulate solids at excess superficial velocities of 0.25 to 1.0 m/s. Wafer drying times in a bed of 0.5 mm sand at 150°C were about 40% of the drying times for wafers dried by forced convection of air at the same temperature and twice the superficial velocity (~ 1 m/s). Wafer movement in the fluidized bed followed the circulation patterns of the emulsion phase and was thus dependent on the bubbling behaviour of the bed. A minimum excess superficial velocity of 0.25 m/s (depending on distributor design) was required to prevent permanent settling of the wafers to the distributor. Preliminary experimentation on a 2-compartment bed showed that wafers could be circulated through the two compartments in near plug flow. However, the application of this technique to a 4-compartment continuous fluidized bed wafer dryer was unsuccessful because of the separation of sand and wafers caused by slugging beds in two of the compartments. A preliminary design was prepared for an industrial size, 5-compartment fluidized bed wafer dryer to approximate plug flow of wafers by a series of well-mixed fluidized beds in series. The design calculations showed that this dryer was more efficient in terms of energy and plant space than a conventional triple pass rotary dryer. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Heat transfer from a flowing gas to a fixed bed of dried Dougas-fir wood chips has been studied by a transient method. Hot air at about 130°C flowed upward through 0.2 m dia x 1 m deep beds of commercially prepared wood chips which had been screened for thickness. Four different wood chip sizes were used, which varied in mean thickness from 2.44 to 7.26 mm. The thickest chips were 18.4 mm wide x 36.3 mm long. Gas temperatures were measured at a number of axial positions as the bed temperature rose from its initial temperature of about 20°C. Heat transfer coefficients were calculated by fitting the air temperature profiles to a transient mathemical model for plug flow of gas through a bed of slab-shaped particles with finite internal thermal resistance. The heat transfer model was solved analytically using an approach pioneered by Amundson (10) for fixed beds of spherical particles and based on Rosen's (6,7) function. This solution has not appeared elsewhere in the literature, and is shown to converge to that of Anzelius (1) if the Biot number for the particle approaches zero. Experiments were done at a series of air velocities with four wood-chip thicknesses and with spherical catalyst particles to provide a check on the technique. The effect on heating rate of 30% by volume steam in the incoming air was investigated. For selected experiments, solid temperatures within the wood chips were measured. A correlation of the heat transfer coefficients is presented. Pressure drop was measured as a function of air velocity for different sizes of wood chips at room temperature and the results are compared with predictions of the Ergun equation. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 145-148). Also available via the Internet.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1981. / Bibliography: leaves 181-189. / Microfiche. / xv, 189 leaves, bound ill., maps 28 cm

Thesis (Ph. D.)--University of Washington, 1993. / Vita. Includes bibliographical references (leaves [60]-61).

Thesis (M.E.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leave 107-112).