dustladen-exhaust-gas

- Main components: Various types of particulate matter, including dust (such as cement dust and coal dust), smoke, fog droplets, etc. 
- Sources: Mining, building materials production, boiler combustion, metal smelting, and other processes.

Dust-laden exhaust gas treatment equipment is primarily used to separate solid particulate matter from exhaust gas. Common equipment includes the following:

Gravity Settling Chamber
- Principle: Utilizes gravity to naturally settle dust. After dust-laden exhaust gas enters the settling chamber, the flow rate decreases, and large dust particles gradually fall to the bottom of the chamber under the action of gravity, achieving separation.
- Application: Suitable for treating dust with large particle size (generally greater than 50μm) and high density, such as coarse dust generated in ore crushing and casting. It has a simple structure and low cost, but low purification efficiency, and is generally used as pre-treatment equipment.

Cyclone Dust Collector
- Principle: After entering the dust collector, dust-laden exhaust gas rotates along the cylinder wall, generating centrifugal force that throws dust toward the cylinder wall. Dust then falls into the hopper under the action of gravity, and the purified gas is discharged through the central tube.
- Application: Suitable for treating non-fibrous, non-sticky dust with a particle size of 5-20μm, such as boiler flue gas and dust from cement production. Compact in structure, low energy consumption, and moderate purification efficiency (generally 70%-90%), it is often used as intermediate or pre-treatment equipment.

Bag Dust Collector
- Principle: Utilizing the filtering action of filter bags (such as needle felt or canvas), dust is trapped on the bag surface as dust-laden exhaust gas passes through the bag, and the purified gas is discharged. Dust is regularly removed from the bag using cleaning devices (such as pulse jets or mechanical vibration).
- Applications: Highly efficient (up to 99% or more) for fine dust (particle size 0.1-10μm), it is suitable for various industrial dust removal processes, such as those in the metallurgical, chemical, and power industries. However, filter bags are susceptible to high temperatures, high humidity, or corrosive gases, so the appropriate filter media must be selected based on the nature of the exhaust gas.

Electrostatic Precipitator
- Principle: Under the action of a high-voltage electric field, the gas is ionized. The charged dust particles migrate toward the oppositely charged electrodes and deposit, thereby separating from the gas. - Applications: Suitable for flue gas treatment in industries such as thermal power generation and steel smelting, with high air volumes, high temperatures (up to 350°C), and high dust concentrations. They offer high purification efficiency (over 99%) and low resistance, but require large equipment investment and floor space, and are sensitive to dust resistivity.

Wet Dust Collectors (such as spray towers and Venturi dust collectors)
- Principle: By spraying a liquid (such as water) into dust-laden exhaust gas, dust particles collide with the liquid droplets, causing them to condense and form droplets or a slurry that is then discharged with the liquid.
- Applications: Suitable for treating exhaust gases with high humidity, high temperatures, or those containing sticky dust. They can also absorb some harmful gases (such as sulfur dioxide). Examples include dust treatment in the chemical and paint spraying industries. However, they generate wastewater, requiring associated wastewater treatment equipment, and are less effective for treating hydrophobic dust.

In actual applications, a single device or a combination of devices (such as cyclone dust collector + bag dust collector) is often selected based on the particle size, concentration, properties (such as viscosity, corrosiveness) and exhaust volume of the dust to improve purification efficiency and reduce costs.