What is Wet Scrubber in Boiler

Wet Scrubbers are the pollution control devices usually installed in the path of the flue gases to extract Sulfur compounds or oxides of sulfur such as Sulfur Dioxide (SO2) and Ash particles. Wet Scrubbers are called so because of the scrubbing action of gases in contact with water to scrub off dirty particulates or gases that cause air pollution.

Why Wet Scrubber in Boiler System?

As the pollution norms are getting stringent and the government is making sure that pollution laws are being implemented, many industries are coming up with various solutions and strategies for reducing the pollution and its management. One such solution is using pollution control equipment such as Wet Scrubbers.

Sources of Pollution in Boiler?

Industries or Thermal  power plants generally have boilers or furnaces installed in their processes where combustion of fuel is taking place.

The general composition of a fuel is a mixture of Carbon (C), Hydrogen (H), Sulfur (S), Oxygen (O), Nitrogen (N)and other elements. Combustion of fuel with air generates flue gases that contain Sulfur Dioxide (SO2), Carbon Dioxide (CO2), Ash, Water vapor (H2O).

Out of these SO2 and Ash are the main pollutants that are responsible for Air pollution and therefore must be treated before the flue gases are vented out of the combustion chamber.

Working Principle of a Wet Scrubber

Wet Scrubbers are the pollutant treatment equipment in which flue gases containing Sulfur Dioxide (SO2) and Ash are allowed to bring in contact with the water by either allowing the parallel flow or counter flow. Before allowing the contact between flue gases and water, water is dosed with Calcium Carbonate (CaCO3). In water SO2 creates an acidic environment and addition of CaCO3 creates alkalinity in water which negates the acidic nature of water.

Also Read: Air Pollution Control Equipment

Because of the acidic nature of SO2 in water, a tower is generally constructed in an SS material to avoid the corrosion of tower and to increase its operating life. The tower is filled with the random packing that allows the effective area of contact between the flue gases and water thereby increasing the residence time.

Increase in residence time helps in increasing the transfer of SO2 and ash from flue gases to water until they get in equilibrium before they cross each other.

Pros of Wet Scrubbers in Boiler System:-

• Reduces pollution and follow the compliance of the Pollution Control Board.

• Easy operation so trained operator is not required.