Activated Carbon for Desulfurization and Denitrification
Desulfurization and denitrification activated carbon is a functional material used for flue gas purification. Through its unique microporous structure and surface chemical properties, combined with catalysis and adsorption, it can effectively remove sulfur dioxide (SO2) and nitrogen oxides (NOx) in flue gas. This activated carbon is widely used in industrial flue gas treatment such as thermal power plants, steel plants, cement plants, and chemical plants, and is one of the core materials for achieving ultra-low emissions.
Principles of desulfurization and denitrification activated carbon
1. Desulfurization principle
- Physical adsorption: The micropores and mesopores on the surface of activated carbon can adsorb SO2 molecules and fix them in the pores.
- Chemical adsorption: SO2 reacts chemically with alkaline functional groups (such as alkali metal oxides) on activated carbon to generate sulfates or bisulfates, completing the desulfurization process.
2. Denitrification principle
- Selective catalytic reduction (SCR): The catalyst in the activated carbon (such as vanadium, titanium or iron compounds) promotes the reaction of the reducing agent (such as ammonia or urea) with NOx to generate harmless nitrogen (N2) and water.
- Adsorption oxidation: Some activated carbon can oxidize NOx into easily adsorbed NO₂, and generate nitrates through further reactions.
Performance characteristics of activated carbon for desulfurization and denitrification
1. High specific surface area
The specific surface area of activated carbon usually reaches 1000-1500 m²/g, providing sufficient active sites for gas adsorption and reaction.
2. Porous structure
- Micropores: adsorb small molecules SO₂ and NOx.
- Mesopores/macroporos: provide gas diffusion channels to increase reaction rate.
3. Catalyst carrier performance
Activated carbon is an excellent catalyst carrier that can load metal oxides (such as V₂O₅, TiO₂) to enhance SCR reaction efficiency.
4. High mechanical strength and heat resistance
- Able to withstand high temperature flue gas (usually in the range of 150-400°C), not easy to pulverize or deactivate.
- High strength is suitable for long-term operation of fixed bed or moving bed process.
5. Toxicity resistance and regeneration
- Strong anti-poisoning ability to impurities in flue gas (such as dust, acidic gas) and long service life.
- Adsorption and catalytic ability can be restored through thermal regeneration or chemical regeneration to reduce operating costs.
Desulfurization and denitrification process
1. Fixed bed process
The flue gas passes through a fixed bed filled with activated carbon, and SO₂ and NOx are adsorbed and catalytically decomposed, which is suitable for small and medium-sized flue gas treatment.
2. Moving bed process
The activated carbon slowly descends in the moving bed, and the flue gas flows in reverse and fully contacts with the activated carbon, which is suitable for large industrial facilities.
3. Injection adsorption process
Powdered activated carbon is injected into the flue gas duct to adsorb SO₂ and NOx, and then captured by a bag filter.
4. Combined process
Desulfurization and denitrification activated carbon is combined with other technologies (such as dry desulfurization, SCR) to synergistically treat multiple pollutants and improve purification efficiency.
Application areas
1. Thermal power plants
- SO₂ and NOx in flue gas are the main pollutants. Activated carbon can achieve efficient desulfurization and denitrification to meet ultra-low emission requirements.
2. Iron and steel smelters
- Remove SO₂ and NOx in sintering flue gas purification to reduce the emission of acid rain formers.
3. Cement plants
- Treat acid gases and nitrogen oxides in high-temperature flue gas during cement production to reduce air pollution.
4. Waste incineration plants
- Synergistically remove various pollutants such as SO₂, NOx and dioxins in incineration flue gas.
5. Chemical plants and refineries
- Purify acid gases and nitrogen oxides generated during the process to reduce environmental hazards.
Selection and use recommendations
1. Select according to the type of pollutant
- If the SO₂ content is high, choose alkaline modified activated carbon.
- If the NOx content is high, choose activated carbon loaded with catalyst.
2. Adaptation of process conditions
- Control the flue gas temperature in the range of 150-400°C to avoid deactivation of activated carbon.
- Configure appropriate deacidification equipment to extend the service life of activated carbon.
3. Regular replacement or regeneration
- When the adsorption capacity is close to saturation, its adsorption performance can be restored by thermal regeneration or chemical regeneration.
4. Comprehensive treatment
- It can be used in conjunction with SCR denitrification, wet or semi-dry desulfurization to achieve integrated treatment of multiple pollutants.
Summary
Desulfurization and denitrification activated carbon is an indispensable core material in industrial flue gas treatment. Its high efficiency, environmental protection and multi-functional characteristics are suitable for flue gas purification needs in thermal power, cement, steel, waste incineration and other fields. When selecting and using, the specific process conditions and emission standards should be combined to reasonably configure equipment and materials to ensure the treatment effect and economy.
If you need to customize desulfurization and denitrification activated carbon or design a detailed treatment plan, please feel free to contact us!
