A. Introduction

The overall fluid dynamic behavior and the local flow Structure of gas-solid fluidized beds are outlined in Section 148. Section 172 deals with fluid-to-particle (i.e., single-phase) convective heat transfer. More detailed descriptions of the basic principles and technical applications of fluidization may be found, e.g., in the books by Davidson et al. (1985) [1], Kunii and Levenspiel (1969) [2], Zabrodsky (1966) [3], and Botterill (1975) [4].

Heat exchanger elements such as plates, tubes, coils, or bundles of tubes are frequently used directly inside a flutdized-bed reactor, as shown schematically in Figure 1, or in a separate fluid bed heat exchanger Reh et al. (1983) [5] in order to remove or add the appropriate amount of thermal energy to keep the gas-solid system at a desired level of temperature.

Figure 1 Fluidized bed with heat exchanger

The problem of heat transfer to fluidized beds of solid particles was treated for the first time in Mickley and Trilling’s pioneering paper in (1949) [6]. Since then, many interesting facts about heat transfer between gas fluidized beds of solid particles and heat exchanger surfaces have been discovered through experimental work. As an example, Figure 2 shows a typical result from experiments carried out by Wunder and Mersmann (1979) [7] in a test setup similar to the one used by Mickley and Trilling about 30 years previously.