Process industries release a substantial emission that leads to ever-increasing air pollution, water pollution, and causes harm to the climate. It is imperative to monitor the pollutants with the aid of pollution control equipment. Industrial pollution is a serious concern faced worldwide that affects the environment and health of people living nearby to process plants. It has been found that those living near the source of pollution are at 20% more risk of death from lung cancer. Disposing of industrial waste in water causes the death of around 1 million seabirds and 100,000 sea mammals every year. Bag filter is one of the pollution control equipment that helps in controlling the wastes from industries.
What are Bag Filters?
Bag Filters are pollution control equipment, primarily used with steam boiler facilities to control the hazardous pollutants released during process operations such as sulfur dioxide and various others. Bag filters are effective and efficient for the filtration of flue gases by separating the particles and collecting them at their bottom. The flue gas is passed through the outlet while the hazardous particulates are disposed of. The bag filters are ideal for resisting high temperatures with a range of gas flow rates.
Types of Bag Filters:
There are three types of bag filters commonly found in process industries:
Pulse Jet Type:
Pulse jets are the most preferred bag filters in process industries, designed to ensure low-pressure drop and ease of installation and maintenance with components like cages, tube sheets, and venturies. It assures complete gas tightness across the tube sheet that prevents polluted gases ingression into clean air. It is designed with an optimal air-to-cloth ratio as per its process requirements. Pulse jet type bag filters are primarily used in process industries such as cement, power, steel, etc.
Reverse Air Bag:
The Reverse Air Bag is ideal for handling high-temperature gases in large volumes. It can facilitate the emission level of 20 to 50 mg/ nm3. The PLC control panel ensures its cleaning operations, optimum pressure drop, and longer lifespan of the baghouse. The hook assembly and springs at the top help in the suspension of filter bags and appropriate tensioning. The complete gas tightness is ensured by casing, hopper, and tube sheet that prevents ingression of polluted gases to clean airside. The design of the reverse airbag includes balanced gas distribution of the inlet and outlet plenums that ensures uniform distribution of gases.
Mechanical Shakers:
The mechanical shaker bag filters are designed by attaching tubular filter bags on a cell plate at the bottom and suspending it from the horizontal beams at the top. The polluted gases enter from the bottom and pass through the filter. On the other hand, the pollutants get collected on the internal surface of the bags. Mechanical shaker filter bags have high space requirements due to relatively low air-to-cloth ratio. It is widely used in mineral processing industries.
Design of the Bag Filter:
Filter bags are made of filter cloth and are cylindrical or round in shape. The filter bag fabric must be as per the requirements of the process operations of the industries and the dust and chemical characteristics.
The design of the bag filter consists of the upper part and the lower part. The lower part can be opened or closed as required, while the upper part is open with elements for fixing, such as metal fastening rings, springs, and various others. The seam connecting both ends needs considerable attention to ensure that the bag filter handles the load.
The primary component of the bag filter is the filtering sleeves that must be of quality material to withstand the chemical properties of the pollutants released from the process operations of steam boilers. Filtering sleeves often wear out and require regular replacement.
Cleaning the Bag Filter:
As the bag filters aid the processing industries with the emission released from steam boilers, they must be cleaned and maintained regularly. Bag filters are cleaned in the following ways:
Reverse Push of Air: The method utilizes continuous low-pressure air flows to remove the solids collected in the cell
Pulse Regeneration: The pulse regeneration method removes the solid particles through a compressed stream of air at high pressure
Mechanical shaking or vibration for the removal of the dust particles
Advantages of Bag Filter:
- Highly tolerant with a wide range of temperature
- Filtration of various sized particles
- High dirt holding capacity
- Hassle-free process operations
- Easy to install and maintain
- Long life cycle
Rakhoh Boilers, being one of the leading steam boiler manufacturers, deliver highly efficient and reliable steam boilers and boiler services to their extensive clientele. We manufacture boiler accessories and pollution control equipment of world-class quality to enhance productivity and efficiency in the process industries.
Know more about us at www.rakhoh.com