NOx Gas Treatment Solutions

Ever-power’s advanced NOx gas treatment solutions utilize highly efficient SCR technology. Our systems achieve NOx reduction rates of up to 95%, ensuring compliance with the world’s most stringent environmental standards. Our solutions can be customized to meet the needs of various industries, including power plants and manufacturing, and can be seamlessly integrated into existing operations, enabling cleaner emissions in a cost-effective manner.

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Nitric Oxide (NO)

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Nitrogen Dioxide (NO₂)

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N₂O, N₂O₃

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Other Nitrogen Oxides

Efficient NOₓ Reduction for Cleaner Air

Nitrogen oxides (NOₓ) are major air pollutants that contribute to smog, acid rain, and respiratory illnesses—posing serious risks to both the environment and public health. As global emissions regulations tighten—from China’s GB standards to the EU’s Industrial Emissions Directive and U.S. EPA requirements—industries face growing pressure to implement effective NOₓ control.

Ever-power’s NOx Gas Treatment Solution delivers unmatched value by combining high destruction efficiency (99%) with economic viability, priced at 35% of Western competitors like Dürr or Eisenmann, while offering superior performance in NOx reduction through advanced rotary RTO design. This system not only meets stringent regulations (e.g., US EPA 40 CFR Part 60, China GB 16297-1996) but also reduces operating costs by 70% via 95% heat recovery, making it ideal for high-VOC industries. Clients benefit from custom engineering, ensuring seamless integration with existing exhaust systems, and long-term reliability with minimal downtime (less than 1% annually).

What is NOx?

NOₓ (nitrogen oxides) is a collective term primarily referring to **nitric oxide **(NO) and **nitrogen dioxide **(NO₂)—two harmful gases formed during high-temperature combustion. Trace amounts of other nitrogen oxides (e.g., N₂O, N₂O₃) may also be present.

Sources

High-temperature combustion processes: power plant boilers, industrial furnaces, internal combustion engines
Chemical manufacturing: nitric acid production, explosives synthesis

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Environmental Impact

NOₓ is a key precursor to **ground-level ozone **(smog) and **fine particulate matter **(PM2.5), both major contributors to urban air pollution. It also reacts with moisture in the atmosphere to form nitric acid, a primary component of acid rain that damages forests, soils, and aquatic ecosystems.

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Health Risks

Exposure to NOₓ can cause immediate irritation of the eyes, nose, and throat. Long-term exposure is linked to reduced lung function, aggravated asthma, bronchitis, and other chronic respiratory diseases—especially in children and the elderly.

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Regulatory Pressure

Governments worldwide enforce strict NOₓ limits:

China: GB 13223 (Emission Standard for Air Pollutants from Thermal Power Plants)
EU: Industrial Emissions Directive (IED) requiring Best Available Techniques (BAT)
USA: EPA regulations under the Clean Air Act, including NSPS and NESHAP

Non-compliance risks fines, operational restrictions, or shutdowns

Major Sources of NOₓ Emissions

Source Category	Specific Examples	Key Characteristics
Combustion Processes	– Coal/oil/gas-fired power plants – Industrial boilers & furnaces – Cement kilns – Metal smelting	High-temperature combustion (>1,300°C) causes thermal NOₓ formation from atmospheric N₂ and O₂
Transportation	– Gasoline & diesel vehicles – Ships & aircraft engines	Mobile source; major contributor in urban areas; emits both NO and NO₂
Chemical Industry	– Nitric acid production – Explosives manufacturing – Adipic acid plants	Fuel-bound nitrogen in feedstocks leads to “fuel NOₓ”; often high-concentration streams
Waste Incineration	– Municipal solid waste incinerators – Hazardous waste combustors	Combustion of nitrogen-containing waste (e.g., proteins, plastics) generates significant NOₓ
Other Industrial	– Glass manufacturing – Refineries – Pulp & paper mills	Process-specific high-temp operations with air-fuel mixing

Note: Over 90% of anthropogenic NOₓ emissions come from high-temperature combustion, where nitrogen and oxygen in the air react to form thermal NOₓ. In processes involving nitrogen-rich fuels or feedstocks, fuel NOₓ also contributes significantly.

Gas-fired power plant

Metal smelting

Explosives manufacturing

Waste incineration

Glass manufacturing plant

Our Core Technologies for NOx Treatment (DeNOx)

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Selective Catalytic Reduction (SCR)

By utilizing a catalyst (such as a vanadium-titanium system) within a temperature window of 300–400°C, NOₓ reacts with a reducing agent (ammonia or urea) to efficiently convert it into harmless nitrogen (N₂) and water (H₂O).
Advantages: Denitrification efficiency up to 80–95%, stable operation, suitable for high-requirement scenarios such as power plants, chemical plants, and waste incineration.

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Selective Non-Catalytic Reduction (SNCR)

Ammonia or urea solution is directly injected into the high-temperature zone of the furnace (850–1100°C) to achieve the thermal decomposition and reduction of NOₓ without a catalyst.
Advantages: Low investment cost, simple system, suitable for small and medium-sized boilers or as a supplement to SCR.

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Sodium Hypochlorite Denitrification (DeNOx)

A strong oxidizing sodium hypochlorite (NaClO) solution is used to oxidize NO to NO₂ or higher oxidation states of nitrogen oxides in a scrubbing tower, which are then removed by alkaline absorption.
Advantages: Suitable for low-temperature flue gas and small to medium air volume applications; can be integrated with desulfurization and dust removal systems.

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Ozone Oxidation Denitrification (O₃ DeNOx)

Ozone (O₃) is used to rapidly oxidize water-insoluble NO into easily soluble NO₂, N₂O₅, etc., which are then completely removed by wet scrubbing (such as with alkaline solutions).
Advantages: Fast reaction speed, no secondary pollution, seamless integration with existing wet desulfurization systems, especially suitable for low-concentration, high-volume flue gas.

Comparison of Four DeNOx Technologie

Parameter	SNCR (Selective Non-Catalytic Reduction)	SCR (Selective Catalytic Reduction)	Sodium Hypochlorite DeNOx	Ozone DeNOx (O₃)
Working Principle	Inject ammonia/urea into flue gas at 850–1100°C to reduce NOₓ without a catalyst	Reduce NOₓ to N₂ and H₂O over a catalyst at 300–400°C	Oxidize NO to NO₂ using sodium hypochlorite (NaClO), then absorb with alkaline solution	Oxidize NO to NO₂/N₂O₅ using ozone (O₃), followed by wet scrubbing
NOₓ Removal Efficiency	30% – 70%	80% – 95%+	50% – 80%	60% – 90%
Optimal Temperature Range	850 – 1100°C	300 – 400°C	Ambient – 80°C	Ambient – 150°C
Catalyst Required?	❌ No	✅ Yes	❌ No	❌ No
By-products / Secondary Waste	Minor ammonia slip	Very low ammonia slip (controllable)	Saline wastewater (requires treatment)	No harmful by-products
Space Requirement	Low (only injection system needed)	Medium–High (reactor + catalyst modules)	Low–Medium (scrubber + chemical tanks)	Medium (O₃ generator + scrubber)
Operating Cost	Low (no catalyst replacement)	Medium (catalyst life: 2–5 years)	Medium (continuous NaClO consumption)	High (significant electricity for O₃ generation)
Capital Cost	Lowest	Highest	Low–Medium	Medium
Best For	Small/medium boilers, limited budget, moderate emission limits	Power plants, chemical facilities, waste incinerators with strict compliance needs	Low-temperature, small-to-medium flow, high-humidity streams	Low-concentration NOₓ, retrofit projects, integration with existing wet FGD
Key Advantages	Low CAPEX, simple installation, ideal for retrofits	High efficiency, stable performance, predictable long-term OPEX	No high temperature required, easy operation	Fast reaction, no catalyst, tolerant to complex gas compositions
Limitations	Narrow temperature window, variable efficiency	Catalyst susceptible to poisoning (e.g., As, P, Ca); larger footprint	Corrosive chemicals; generates wastewater	High energy cost; requires strict O₃ safety management

Need ultra-low emissions (<50 mg/m³)? → Choose SCR
Already have a boiler but no space for a catalyst reactor? → Consider SNCR
Treating low-temperature, high-humidity, or small-flow exhaust? → O₃ or Sodium Hypochlorite are better suited
Require rapid deployment without high-temperature modifications? → Ozone DeNOx is an ideal solution

All technologies can be combined (e.g., SNCR + O₃ as a cost-effective alternative to SCR). we engineers will design the optimal, customized solution for your specific application.

Our Customized Solutions for NOx Treatment

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Analyze Gas Composition & Pollutant Profile

The composition of exhaust gases varies significantly across different industries, directly impacting technology selection:

Chemical/Pharmaceutical: Nitrogen-containing organic compounds (amines, nitro compounds) → Easily generate fuel-type NOₓ after incineration → SCR is essential;
Waste Incineration: Contains chlorine, sulfur, and heavy metals → Requires pre-treatment with acid removal and dust removal before introducing an anti-poisoning SCR catalyst;
Food Processing Plants: High humidity, ammonia content, low NOₓ concentration → O₃ oxidation or sodium hypochlorite scrubbing should be prioritized to prevent catalyst deactivation.

✅ Our Approach: We provide free flue gas composition testing advice to accurately identify NOₓ types (thermal/fuel/rapid).

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Match Operating Conditions

Temperature, airflow, and fluctuations determine system stability:

Industry	Typical Operating Conditions	Recommended Technology
Power Plant Boilers	High temperature (300–400°C), stable	Conventional SCR
RTO Outlet	High temperature but intermittent operation	RTO + Heat Recovery + SCR (with electric backup heater)
Biomass Boilers	Low temperature (<250°C), high dust	SNCR or Low-Temperature SCR (with specialized catalyst)

This format is clear, professional, and suitable for technical documentation, websites, or client proposals. Let me know if you’d like to add more industries or include efficiency/compliance notes!

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Integrate with Existing Infrastructure

Avoid starting from scratch and reduce customer investment costs:

Add a compact SCR module to the back end of the existing RTO system;
Install an SNCR injection grille in the space behind the boiler economizer;
Integrate the O₃ DeNOx system with the existing wet desulfurization tower to save space.

✅ Our approach: Provide 3D plant layout scanning to achieve a “zero-conflict” installation design.

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Align with Local Emission Standards

Significant regional regulatory differences exist:

Key regions in China (e.g., Beijing-Tianjin-Hebei): NOₓ ≤ 50 mg/m³ → SCR is mandatory;
EU IED: Requires BAT technology + Continuous Emission Monitoring System (CEMS) → SCR + online ammonia slip analyzer is recommended;
Emerging markets in Southeast Asia: Limited budgets → Offers economical solutions with SNCR + ozone-assisted emission control.

✅ Our approach: Built-in global emissions standards database, automatically matching compliance pathways.

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Balance CAPEX vs. OPEX for Long-Term Value

For plants with high operating hours (such as continuous chemical production) → choose SCRs with high initial investment and low energy consumption;
For small plants with intermittent operation (such as seasonal food processing) → recommend low-maintenance O₃ or sodium hypochlorite systems;
For regions with high energy costs → prioritize RTO waste heat driven SCRs to reduce natural gas consumption.

✅ Our approach: Provide a 5-year life cycle cost analysis report (LCC) to help clients calculate their “total costs”.

Our Customization Workflow

Needs Diagnosis: Industry Type + Exhaust Gas Parameters + Emission Standards + Budget Range
Technology Comparison: 3 Option Options (High-Efficiency / Economical / Integrated)
Simulation Verification: CFD Flow Field + Reaction Efficiency Simulation
Modular Delivery: Factory Pre-assembly, Rapid On-Site Integration
Intelligent Operation and Maintenance: Remote Monitoring + Early Warning Maintenance, Ensuring Long-Term Compliance

Case Study: Customized SCR DeNOx System for a 300 MW Coal-Fired Power Plant in Indonesia

Client: PT Jaya Energi
Location: East Java, Indonesia
Industry: Power Generation

Background

PT Jaya Energi operates a 300 MW coal-fired power plant that supplies electricity to over 500,000 households. In 2023, Indonesia’s Ministry of Environment and Forestry (KLHK) tightened air emission standards under Regulation No. PM-14/2023, requiring all coal plants to reduce NOₓ emissions to ≤100 mg/Nm³ (from the previous 400 mg/Nm³). The plant’s existing combustion controls could only achieve ~250 mg/Nm³—far from compliance.

Facing potential fines and operational restrictions, the plant began searching for a reliable DeNOx solution. After reviewing international suppliers, they discovered Ever-power through an industry webinar on “High-Efficiency SCR Systems for Southeast Asian Coal Plants” and were impressed by Ever-power’s reference projects in Vietnam and the Philippines.

Key Challenges

High Ash & Alkali Content: Indonesian coal has high calcium and potassium levels, which can poison conventional vanadium-based catalysts.
Limited Space: The boiler rear flue area was congested with existing ESP and ID fan—no room for large reactors.
High Humidity Flue Gas: Monsoon climate leads to frequent condensation, risking ammonium bisulfate (ABS) deposition below 300°C.
Local Support Needs: Required on-site commissioning and training for local operators unfamiliar with SCR systems.

Ever-power’s Customized Solution

To meet these challenges while ensuring long-term compliance, Ever-power designed a high-efficiency, compact SCR system based on the fundamental principles of Selective Catalytic Reduction (SCR)—a technology proven effective in thousands of global installations.

How SCR Works: Chemistry Meets Engineering

The core of the SCR process lies in the selective oxidation of nitrogen oxides (NOₓ) using ammonia (NH₃) as a reducing agent. Under controlled conditions, NH₃ reacts preferentially with NOₓ rather than oxygen in the flue gas, producing harmless nitrogen (N₂) and water (H₂O)—with no secondary pollutants or harmful by-products.

The key chemical reactions are:

(1) 4NO + 4NH₃ + O₂ → 4N₂ + 6H₂O
(2) 2NO₂ + 4NH₃ + O₂ → 3N₂ + 6H₂O

These reactions occur efficiently only within a narrow temperature window—approximately 980°C without a catalyst. However, when a catalyst is introduced, the reaction becomes viable at much lower temperatures: 300–400°C, which aligns perfectly with the flue gas temperature between the economizer and air preheater in coal-fired boilers. This makes SCR ideal for retrofitting into existing plants without major thermal modifications.

Moreover, since NOₓ concentrations in flue gas are relatively low, the heat released during the reaction is negligible—meaning no additional heating is required, and the system remains thermally stable under normal operation.

This scientific foundation enabled Ever-power to design a solution that not only meets performance targets but also integrates seamlessly into the plant’s operating environment.

SCR Selective Catalytic Reduction

Engineered for Real-World Conditions

Based on this chemistry-driven approach, Ever-power implemented the following tailored solutions:

✅ 1. High-Resistance Catalyst Design

Selected V₂O₅-WO₃/TiO₂ catalyst with enhanced resistance to alkali poisoning (Ca, K), common in Indonesian coal
Optimized pore structure and cell pitch (6.5 mm) to minimize ash accumulation and pressure drop

✅ 2. Compact Vertical Reactor Layout

Installed downflow SCR reactor directly between boiler and ESP to save space
Designed with modular construction for easy transport and installation during outage

✅ 3. Temperature & Ammonia Control Strategy

Maintained flue gas temperature at 320–350°C—above ABS dew point—to prevent ammonium sulfate formation
Used 3-zone ammonia injection grid (AIG) with real-time feedback control to ensure optimal NH₃/NOₓ ratio and minimize slip

✅ 4. Localized Operation & Support

Provided bilingual HMI interface (English/Indonesian) for intuitive operation
Conducted comprehensive training for plant engineers
Established regional spare parts depot in Surabaya for rapid response

The entire system was delivered in prefabricated modules, installed within 8 weeks, and commissioned successfully during a scheduled maintenance shutdown.

Results & Performance

NOₓ Removal Efficiency: 92% (inlet: 280 mg/Nm³ → outlet: 22 mg/Nm³)
Ammonia Slip: <2 ppm (well below 3 ppm limit)
Pressure Drop: <800 Pa — no impact on boiler draft
Compliance: Successfully passed KLHK inspection in Q1 2024
Operational Simplicity: Fully automated control; local team now operates independently

“Ever-power didn’t just sell us a reactor—they delivered a compliance guarantee. Their understanding of Southeast Asian coal made all the difference.”
— Mr. Budi Santoso, Plant Manager, PT Jaya Energi

Editor: Miya