Draft Plates Research Articles

Circulation of particles in two-dimensional spouted beds with draft plates

Two slotted two-dimensional spouted bed units with flexible bed dimensions were used to study the average particle velocity and cycle time of shelled c

Effect of bed height on simultaneous heat and mass transfer in a two-dimensional spouted bed dryer

The drying kinetics of shelled corn was studied in a laboratory-scale two dimensional spouted bed dryer equipped with draft plates. The effect of bed height on drying rate is interpreted in terms of the heat and mass transfer mechanism with unsteady diffusion being dominant in moisture transport. The relevant apparent diffusion coefficient is evaluated from Fick's equation in spherical coordinates approaching sufficiently the geometry of a single grain, and related to the height of a bulk of grain. Page's equation is found to adequately describe the drying kinetics of the bulk of grain if parameters of this equation are related to the bed height.

BATCH DRYING OF SHELLED CORN IN TWO-DIMENSIONAL SPOUTED BEDS WITH DRAFT PLATES

ABSTRACT Geometrically similar spouted beds with draft plates were used to obtain the drying characteristics of freshly harvested shelled corn with 0.28 to 0.31 kg/kg initial moisture content at different air inlet temperatures and bed heights. Thermal equilibrium between air and grains was achieved at minimum spouting conditions. The drying kinetics of shelled corn in a drafted two-dimensional spouted bed was found to be of the thin layer type. Expressions for the model parameters in Page's equation accounting for the bed geometry, grain moisture content, and drying conditions were developed.

Spouting of two‐dimensional beds with draft plates

AbstractTwo slotted two‐dimensional spouted bed units with flexible bed dimensions were used with draft plates to study spouting pressure drop and minimum spouting superficial velocity. The data were collected while varying slant angle, spout width, separation distance, length of bed, height of bed, and size of bed (geometrical similarity) using shelled corn, soybean, and wheat. The variables which affect the spouting pressure drop and air flow through the beds are discussed. Empirical correlations are developed following the principles of dimensional analysis and similitude. The developed correlations agree closely with the collected data.

DRYING of GRAINS IN A DRAFTED TWO DIMENSIONAL SPOUTED BED

ABSTRACTA two‐dimensional spouted bed with draft plates for grain drying was tested using soybean, wheat and corn. Drying rate and material temperature were measured as functions of the dryer geometry and operating parameters. the hypothesis of intermittent drying, consisting of a heating period in draft channel and a tempering period in the downcomer was verified. the drying rate was found to be related to the measured rate of solids circulation. For mathematical description of the drying process in the configuration investigated, the Page's equation for thin layer drying of grains was used. the two parameters in this model were correlated versus the bed geometry and the operating parameters of the spouted bed.

Gas-to-particle heat transfer in two-dimensional spouted beds

The convective heat transfer coefficient to particulate material in a two dimensional spouted bed has been determined using a drying rate method. Laboratory experiments were performed at various gas velocities, particle sizes and bed height combinations for spouted bed with and without draft plates. The experimental data were correlated in the form of a dimensionless equation for Nusselt number in terms of the particle Reynolds number and relevant geometrical parameters.