Dust need not be a problem when you choose the right equipment

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Dust need not be a problem when you choose the right equipment

Air pollution affects health, well-being, daily life and the environment. Some pollution is visible or perceptible, but many hazardous pollutants are colorless and odorless. We therefore need to understand each pollutant's hazards and harmful levels so that treatment objectives can be clearly defined, including the required treatment efficiency or permitted emissions.

This article discusses particulate air pollution arising in industrial operations.

Dust is not a gas: it consists of solids or liquids suspended in air. Important properties include size, concentration, shape, density, electrical conductivity, corrosiveness, moisture absorption, reactivity and toxicity. Typical suspended particles range in size from 0.001 to 100 microns ( 0.1 mm), divided into 3 size ranges:

• 0.001 to 1 microns (smaller than 1 microns)
• 1 to 10 microns (inhalable dust)
• 10 to 100 microns (soil and mineral dust)

This article presents one type of equipment that can help remove dust:   is   Bag-type dust filtration equipment

Dust filters are normally filter bags made from woven fabric ( woven) Today, however, filter bag materials can also be fiber sheets, such as polypropylene plastic, bonded by heat, mechanical forces or chemicals without weaving ( non-woven) Dust is filtered by passing contaminated air through the bag from the outside. Air entering the inside is clean. After operation for some time, substantial dust accumulates on the bag surface, restricting airflow and raising the pressure drop. The bags then need cleaning to restore normal operation. Key aspects of a bag filter are the fabric characteristics and cleaning method. Bags normally have a diameter of approximately 20-30 centimeters but may be several meters long. A bag chamber can contain tens or more than a hundred bags to provide a large filtration area and collect substantial dust before clogging. Filter materials include cotton, which withstands temperatures no higher than approximately 100 degrees Celsius; polypropylene, which has better acid, corrosion and bending resistance; or Nomex which withstands temperatures of approximately 200 degrees Celsius   If the gas temperature exceeds the fabric's operating temperature, the gas must first be cooled.

 

Filter bags were traditionally cleaned by reverse air flow ( Reverse air-jet) but the method now commonly used is Pulse-jet which uses a short burst of high-pressure air (approximately 100 psig) for a short period. This saves cleaning time and quickly returns the same bags to service, avoiding the need for spare bags while dirty ones are being cleaned.