Flue gas treatment is a process that removes pollutants from exhaust gases produced by industrial processes, power plants, and other sources before they are emitted into the atmosphere. Specific flue gas treatment processes can vary based on the type of contaminants and regulatory requirements. 

The following is an overview of typical flue gas treatment processes:

1. Flue Gas Collection: The first step is to collect flue gas emissions at their source, such as a boiler, furnace or industrial process.

2. Particle Removal: Many flue gas treatment processes begin with the removal of particulate matter, such as dust, ash, and soot. This is usually done using equipment such as electrostatic precipitators, baghouses or cyclones.

3. Desulfurization (SO2 Removal): If the flue gas contains sulfur dioxide (SO2), a desulfurization process is used to reduce or eliminate it. Common desulfurization methods include wet flue gas desulfurization (WFGD) using limestone or lime slurry, dry sorbent injection, or using renewable processes such as activated carbon.

4. Nitrogen oxide removal (NOx reduction): Nitrogen oxides (NOx) are another group of harmful pollutants found in smoke. Selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) systems reduce nitrogen oxide emissions by reacting with ammonia or urea in the presence of a catalyst.

5. Particle Filtration: After the initial removal of particles, a further stage of filtration can be employed to capture any remaining fine particulate matter not removed in the first stage.

6. Mercury Removal: If the flue gas contains mercury, it can be removed using activated carbon injection or other specialized processes designed to capture mercury compounds.

7. Emission Monitoring: Continuous monitoring of emissions is critical to ensure treatment systems are operating efficiently and within regulatory limits.

8. Waste Disposal: By-products and waste generated during processing, such as captured particulate matter or waste in scrubbers, must be properly managed and disposed of in accordance with environmental regulations.

9. Flue gas outlet: After treatment, the purified flue gas is discharged into the atmosphere, and the pollutant content is significantly reduced.

The specific flue gas treatment process used in a given application depends on the types and concentrations of contaminants present, as well as the regulatory requirements that must be met. Various combinations of technologies and equipment can be used to achieve effective flue gas treatment and meet environmental standards.

The role of wet scrubbers in flue gas treatment processes

The role of the wet scrubber (Wet Scrubber) in the flue gas treatment process is mainly to remove particulate matter and gaseous pollutants in the flue gas to improve air quality and comply with environmental regulations. The following are the main functions of wet scrubbers in flue gas treatment:

• Particulate matter removal: Wet scrubbers effectively remove particulate matter from flue gases by bringing the flue gases into contact with a liquid, usually water or other scrubbing fluids. These particles include dust, smoke, particulate matter and other suspended matter. They settle in the scrubbing liquid, purifying the flue gas and making it cleaner.

• Gaseous pollutant removal: Wet scrubbers are also capable of removing gaseous pollutants, especially acidic gases such as sulfur dioxide (SO2), hydrogen chloride (HCl) and ammonia (NH3). These gases can be dissolved in the scrubbing liquid or chemically react with the scrubbing liquid, thereby reducing their concentration in the flue gas.

• Flue gas cooling: In a wet scrubber, when the liquid is sprayed or circulated, it absorbs the heat in the flue gas, thus reducing the temperature of the discharged flue gas. This is beneficial for lowering the temperature of the exhaust flue gases, especially where exhaust temperature limits need to be met.

• Chemical Neutralization: Some wet scrubbers use chemicals, such as alkaline solutions, to neutralize acid gases, thereby reducing environmental harm. These chemical reactions help convert harmful substances into harmless ones.

• Emission Control: Wet scrubbers help industrial facilities comply with environmental regulations, reduce the concentration of pollutants emitted, and ensure emissions are within legal limits. This helps reduce environmental and health risks.

In general, the role of wet scrubbers in the flue gas treatment process is to improve the quality of flue gas emissions, reduce the impact on the environment, and ensure compliance with regulatory requirements. Wet scrubber is a common and effective flue gas treatment equipment, especially suitable for removing particulate matter and gaseous pollutants to improve air quality.