Experimental research of the influence of particle size and fluidization velocity on zeolite drying in a two-component fluidized bed

Abstract

This paper presents the results of the kinetics research into the drying of fine grained material in a two-component fluidized bed. A review of theoretical and experimental investigations of aerodynamics of the fluidized bed is given, with a special insight into two-component fluidized beds, as well as the basics of heat and material transfer through a fluidized bed. Apart from the theoretical basis of convective drying of wet materials in a stagnant fluidized bed, the paper also emphasizes different approaches to fine grained material drying kinetics. Based on the experimental investigations, where zeolits used as a representative of fine grained material and polyethylene as a representative of inert material (another component), an analysis of the influence of working parameters on drying in a two-component fluidized bed is performed. It is established that, apart from the influence of the considered parameters, such as fluidization velocity, diameter of fine grained material particles and drying agent temperature, on the drying curve, the participation of inert material can considerably increase the intensity of heat and material transfer in the fluidized bed. A comparison of the experimental drying curves of fine grained material in the two-component fluidized bed with the results from the studies by other authors shows satisfactory agreement.

The influence of the air temperature and the mass ratio of zeolite and inert material on the efficiency of the fluidized bed drying process: Experimental research

“…A bed of Group B collapses quickly when the gas flow is cut off. Group C: They are finer than Group A particles with typical dp values less than 20 μm and density differences are larger than 1 g/cm 3 . These particles are typical of flour.…”

“…Drying experiments with starch were carried out in a 0.083x0. 8where: ε g (-) gas phase hold-up ε l (-) liquid phase hold-up ε sc (-) phase hold-up of inert particles ε sf (-) phase hold-up of fine particles ρ g (kg/m 3 ) air density ρ l (kg/m 3 ) water density ρ sc (kg/m 3 ) inert particles density ρ sf (kg/m 3 ) fine particles density (kg/m 2 s 2 ) pressure drop over the length of the bed…”

“…The techniques applied for fluidizing the bed are manufactured to suit specific requirements of this experimental research, and a description of the apparatus is given below. The apparatus consists of the following components: variable speed fan (4), sections for air flow measuring with a metering station, electric heating (2), fluidized bed (1), the device for measurement, regulation and registration process (3,5). A fluidization bed has a circular cross-section with the inner diameter of 120 mm and the height of 600 mm.…”

“…The fundamental importance of the phenomenon of fluidization to the majority of chemical engineering operations and processes and hence to phase-change separations in which two phases must be brought into contact is recognized. Many operations in a fluidized bed are characterized by the processes of heat exchange between the gas and solid particles which include the mass transfer [3]. One of these processes is the material drying in a fluidized bed.…”