When high voltage is established between a pair of electrodes, an electric field is established. Charged particles like electrons and ions, under certain conditions, move along the field lines. Particles with a negative charge migrate in the direction of the positive electrode and particles with a positive charge in the opposite direction towards the negative electrode. Fig. 9.1 gives a [...]
In this article we will discuss about:- 1. Meaning of Electrostatic Precipitators 2. Principles of Electrical Precipitation 3. Process 4. Merits and Demerits. Meaning of Electrostatic Precipitator: Electrostatic precipitator (ESP) remove the gas borne particulate matter and the mist (liquid droplets) from the flue gas stream due to the action of electrostatic forces. When the gas stream passes through an [...]
For large throughput rates, plate type precipitators are almost exclusively used. These are of two type horizontal flow or vertical flow type-the former being preferred most even though it has a serious drawback in the amount of floor space occupied. Horizontal flow types are grouped into sections, arranged in series, so that the gas leaving one section enters the next [...]
The design and performance of precipitators are affected by a plurality of factors. These are divided into three main categories, namely – efficiency, local, high turbulence eddies scour: (i) Properties of the gas stream, (ii) Properties of the dust, and (iii) Process conditions. (i) Properties of the Gas Stream: The precipitator is designed for a particular throughput rate. Increase in [...]
In this article we will discuss about the mechanism of dust particle charging. The dust particles charging takes place by: (i) Diffusion charging, and (ii) Field charging or ion bombardment charging. Diffusion charging is the dominant mode of particle charging for particles with a diameter smaller about 0.2 µm; and field charging dominates for particles with a diameter greater than [...]