Chapter 20 - Gas-Solid Separations

Abstract

This chapter focuses on the principles and applications of gas-solid separations. The removal of solids from a gas or air stream is of great industrial importance. This is especially true in the last two or three decades with the increased requirements for effective solids removal from solid-laden streams mandated by law. The process of removal and collection of solids in a gas phase is termed as dust collection. Its objective are to control air pollution from various industrial plants; eliminate safety and health hazards from the workplace in which grinding, milling, and packaging operations take place; recover valuable products from dryers, conveyors, bagging equipment, and others for recycling back into a process; and reduce equipment maintenance on rotating equipment caused by dusts. There are four broad groups of gas-solid separation equipment, which include cyclone and inertial separators for removal of large solid particles, baghouse collectors for removal of intermediate-sized particle, wet scrubbers employing liquid sprays to entrap solid particles, and electrostatic precipitators to collect fine particles. The most commonly used equipment for the separation of dust particles from an air/gas stream is the cyclone separator. The baghouse collectors consist of a number of filter bags attached at the top of the bag to a shaker arm enclosed in a rectangular chamber. Most collectors of this type have a device to hold the bags in tension. Dust-laden air enters near the bottom of the chamber and flows inside the bag. The dust is trapped on the inside of the bag and the clean air flows through the bag and exits at the top of the chamber.