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 [...]
The following points highlight the five simplest tests for controlling pollution. The tests are: 1. Flame Photometry 2. XRF Analysis 3. Total Organic Carbon Analysis 4. Carbon-Hydrogen Analyser 5. Ion Chromatography Theory & Application. Test # 1. Flame Photometry This is a simple test to know the concentration of Alkali metals. The sodium and Potassium are more frequently determined because [...]
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 [...]
Depending upon the collection efficiency, capacity and operation mode, the dust collection devices are divided in the following three categories: 1. Internal Separators 2. Wet Collection Devices 3. Electrostatic Precipitators. 1. Internal Separators: Internal separator type dust collectors are manufactured in various shapes and sizes. Following types are most common: (a) Louver collector, (b) Fabric filters, (c) Gravity settling chamber, [...]
In this essay we will discuss about:- 1. Classification of Adsorbent 2. Characterisation of Adsorbents 3. Mechanism 4. Equipment 5. Regeneration. Essay # 1. Classification of Adsorbent: Potential adsorbent can be classified into three groups: (a) Nonpolar solids: Where the adsorption is mainly physical e.g., activated carbon. (b) Polar solids: Where the adsorption is chemical and no change in the [...]
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 [...]
Get the answer of: How to Control Rats ? Rodents include mice, squirrel, beaver, porcupine, rat, rabbit etc. Out of these rats are the main source of nuisance in the houses. Domestic rats and other rodents are the carriers of disease germs, fleas, lice, mites, intestinal parasites etc. due to their wide distribution and close association with the man. They [...]
In this article we will discuss about the diffusion theories in relation to air pollution control. The dilution of pollutants directly depends on the atmosphere turbulence and diffusion. Therefore the dilution varies with the weather conditions. As the rates of atmosphere dilution determines the levels of pollution in a given location, methods for estimating the degree of atmosphere diffusion are [...]
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 [...]