ppt say

HCMC UNIVERSITY OF TECHNOLOGY AND TECHNOLOGY Facility of High Quality Training DRYING TECHNOLOGY AND DISTILLATION REPORT FLUIDIZED BED DRYING Lecturer: PhD Le Minh Nhut MEMBERS OF GROUP NAME STUDENT ID Do Quoc Huy 19147001 Le Thanh Nguyen Bao 19147042 CONTENTS Chapter I: OVERVIEW THE FLUIDIZED BED DRYER Chapter II: CALCULATION OF FLUIDIZED BED DRYER I OVERVIEW THE FLUIDIZED BED DRYER Introduction the fluidized bed dryer • Fluidized bed dryers (FBD) are used extensively for the drying of wet particulate and granular materials, and even slurries, pastes, and suspensions, that can be fluidized in beds of inert solids • They are commonly used in processing many products such as chemicals, carbohydrates, foodstuff, biomaterials, beverage products, ceramics, pharmaceuticals in powder or agglomerated form, health-care products, pesticides and agrochemicals, dyestuffs and pigments, detergents and surface-active agents, fertilizers, polymer and resins • They are also useful in manufacturing products for calcination, combustion, incineration, waste management processes, and environmental protection processes Introduction the fluidized bed dryer Figure 1: Fluidized bed dryers Principle of the fluidized bed dryer • In the fluidized-bed dryer, hot air is passed through a perforated bottom of the container containing granules to be dried The granules are suspended in the air stream and rise from the bottom This condition is called a fluidized state • Hot air surrounds each granule to dry it completely Therefore, the materials or granules are dried uniformly Figure 2: Material in drying chamber Construction of the fluidized bed dryer • The dryer is made of stainless steel • A detachable bowl is placed at the bottom of the dryer, which is used for charging and discharging • The bowl has a perforated bottom with a wire mesh support for placing materials to be dried Figure 3: A detachable bowl of FBD Construction of the fluidized bed dryer • A fan is mounted in the upper part for circulating hot air • Fresh air inlet, prefilter and heat exchanger are connected serially to heat the air to the required temperatures • The temperature of hot air and exit are monitored • Bag filters are placed above the drying bowl for recovery of fines Figure 4: Main body structure of FBD Working of the fluidized bed dryer • The main principle involved in fluidized bed dryer is "Fluidization" • In this state the granules are completely suspended in a stream of hot air which is being supplied from the bottom of the container Figure 5: Working of FBD Working of the fluidized bed dryer • Fluidization produces full agitation of solid particles and since each particle gets surrounded by hot air, heat transfer is extremely high and uniform • The product is dried fast without appreciable loss of heat Filter bags prevent particles escaping from the dryer • The material is left for some time in the dryer for reaching ambient temperature • The end product is free flowing 10 5.2 Modified Fluidized Bed Dryer 5.2.4 Vibrated fluidized bed dryers • Vibration combined with upward flow of air in an aerated bed enables particles to pseudo fluidize smoothly The problem of fine particle entrainment is also avoided • Vibrating fluidized beds are relatively shallow as the effect of vibration imparted by the vibrating grid decays with distance from the grid Figure 16: Vibrating FBD 24 5.2 Modified Fluidized Bed Dryer 5.2.5 Spouted bed dryers • Spouted bed dryers are useful for drying of large particles, which exhibit slugging under normal fluidization Figure 17: Spouted bed dryers 25