DRYING THEORY

For derivations that are more complex and a more detailed description of solid-liquid separation applications, the reader is referred to specialist texts e.g. Coulson and Richardson (1991), Purchas (1981), Purchas and Wakeman (1986), Matteson and Orr (1987), Wakeman (1990a,b), Cheremisinoff (1998), Sinnott (1999) and Svarovsky (2000). Several types of drier and associated drying theory are considered in detail in a number of texts, including Nonhebel and Moss (1971), Keey (1972, 1978, 1991), Masters (1985) and Coulson and Richardson (1991). 

Pabis S, Jayas D S and Cenkowski S (1998), Grain Drying — Theory and Practice. John Wiley and Sons, NY, USA. 

Basic elements of drying theory relevant to stress formation and related defect formation will therefore be summarised. For derivations and detailed discussions, the book by Brinker and Scherer [1] should be used. 

The relation between dr)dng process and stress formation is shown in Fig. 8.21. In accordance with drying theory in porous membrane layers a constant drying rate period (CRP) and a falling rate period (FRP) can be distinguished. The transition between them is sharper with increasing thickness. A clear explanation has not been presented but is probably related to the width of the drying zone (see Fig. 8.7) which increases with width w of the pore size distribution. 

Eortes, M., and Okos, M.R. 1980. Drying theories their bases and limitations as applied to foods and grains. In Advances in drying. Vol. 1. Ed. A.S. Mujumdar, 119-154. Washington, DC Hemisphere. 

Henderson, S.M. and Pabis, S., Grain drying theory I Temperature effect on drying coefficient, J. Agric. Eng. Res., 6,169-174,1961. 

Temperature and the duration of thermal processing are the other factors on which microbiological properties of preserved biotechnological products depend. In general, a lower process temperature enables a longer processing time. However, as follows from drying theory, under... 

---