The efficiency of ozone denitration technology in treating low-temperature flue gas can exceed 95%. A steel plant in northern China reduced its NOx emissions by 70%, while an cement factory in Zhejiang cut its exhaust gas treatment costs by 3 million yuan.

In recent years, as environmental regulations have become increasingly stringent, nitrogen oxide (NOx) emissions have become a headache for industries such as steel, cement, and chemicals. Traditional denitrification technologies (e.g., SCR and SNCR) face issues like insufficient efficiency and high operating costs in specific scenarios, while ozone denitrification technology, with its unique advantages, is emerging as a “new favorite” in industrial flue gas treatment.

 

1. Ozone Denitration Principle: Denitrification of NOx

 

Ozone (O₃) is a potent oxidant that can initiate a chain reaction with NO in flue gas (accounting for over 90% of NOx), converting it into water-soluble NO₂ and N₂O₅, which are then completely removed through an alkaline absorption tower.

Technical Advantages:
Adapt to low-temperature flue gas (80~200°C) and compensate for the shortcomings of SCR technology (300~400°C)
No catalyst poisoning risk, especially suitable for exhaust gases with high sulfur and dust content
The denitrification efficiency reaches over 95%, and it can synergistically oxidize pollutants such as VOCs and dioxins

 

2. Application Scenario: High-Pollution-Risk Enterprises

 

Ozone denitrification technology has been successfully applied in multiple industries with high NOx emissions:
(1)The steel industry
Sintering machine flue gas: Traditional SCR fails due to dust blockage, while ozone denitration can operate stably
Case: After the renovation of a sintering machine at a steel plant in northern China, NOx emissions decreased from 300mg/m³ to below 50mg/m³
(2) Cement Industry
Tail gas from the kiln: replaces SNCR (severe ammonia slip), reducing comprehensive operating costs by 30%
Case: A cement plant in Jiangsu adopted a combined process of “ozone + wet scrubbing,” saving 2 million yuan in ammonia water costs annually
(3) Glass Melting Furnace
High-temperature flue gas (500°C+): Cooling is required before ozone injection, but no additional heat exchanger is needed like in SCR
Case: A glass factory in Guangdong passed the environmental protection acceptance for its ozone denitrification project, with stable NOx emissions below 100mg/m³

 

3. Practical Case: A Chemical Plant’s Annual Cost Savings of 4 Million Through Renovation

Corporate Pain Point: Fluctuating NOx concentration in nitric acid production line tail gas (800~2000mg/m³), frequent catalyst poisoning in the original SCR system, with annual replacement costs exceeding 1.5 million yuan
Solution:
In 2023, the combined process of ozone oxidation and alkali scrubbing was adopted:
Ozone Generator: 20kg/h production capacity, automatically adjusts dosage based on NOx concentration
High-efficiency absorption tower: NaOH solution is circulated and sprayed, with NOx ultimately recovered in the form of NaNO₃
Running effect:
NOx emissions < 50 mg/m³ (ultra-clean emission standard)
The cost of catalyst replacement is reduced to zero, resulting in an annual comprehensive savings of 4.06 million yuan
The byproduct NaNO₃ can be reused as raw material, achieving “waste-to-waste” treatment

 

4. Challenges and Future Prospects of Ozone Denitrification

Despite its prominent advantages, this technology still needs to overcome challenges
The energy consumption for ozone generation is high: approximately 10~15 kWh of electricity is required to produce 1 kg of ozone, necessitating optimization of the generator’s efficiency
(2) NO₂ Escape Risk: Precise control of the O₃/NOx molar ratio (typically 1.0~1.5) is required
With the development of new technologies such as photovoltaic/wind power coupled ozone production, future operating costs are expected to decrease by another 30%. Under the “dual carbon” goals, ozone denitrification may become a standard technology for industrial flue gas treatment.