Effect of Initial Static Bed Height and Liquid Superficial Velocity on the Minimum Fluidization Velocity (Umf) and Pressure Drop for the Bed of Semolina Particles in Liquid-Solid Fluidization

Abstract

The successful and economical design, scale up and operation of a fluidized bed reactor depends upon the true prediction of its bed hydrodynamics. The present research has been carried out to study the hydrodynamics behavior of bed of semolina particles in liquid solid fluidization. The prime objective of this research work is to study the effect of liquid superficial velocity and variation in static bed height on the minimum fluidization velocity and pressure drop. Liquid-solid fluidization is characterized by the uniform expansion of bed particles; therefore, it is known as particulate fluidization. In liquid, solid fluidization, there is no bubbling phase, that is the main cause of uniform bed expansion. Liquid-solid fluidization has extensive field of applications, i.e., in hydrometallurgy, waste water treatment, biochemical processing and food technology. Minimum fluidization velocity and pressure drop are important hydrodynamic parameters in the design and scale up of fluidized bed reactors. The experimental work was carried out in a column made up of acrylic having 60 mm outer diameter and 2 mm wall thickness and was 1000 mm long. Manometers were used to observe the pressure drop variations across the bed. The minimum fluidization velocity was found to be 0.404 mm/sec. It has been found that the minimum fluidization velocity is not affected by the variations in the initial static bed height. Semolina particles being sticky solids offer slightly greater pressure drop. Pressure drop becomes constant when fluidization is achieved.