Flue Gas Recirculation System for Low NOx Chemical Boiler
The flue gas recirculation system for low NOx chemical boiler is engineered to meet the stringent emission standards of modern petro‑chemical and specialty‑chemical plants. By returning a calibrated portion of cooled flue gas to the furnace inlet, the system lowers peak flame temperature, suppresses nitrogen‑oxide formation, and improves overall combustion stability. Designed for continuous‑duty operation, it integrates seamlessly with existing boiler control loops and can be customized for capacities ranging from 5 MW to 200 MW.
How It Works
The recirculation loop consists of a high‑temperature‑resistant duct, a variable‑speed fan, and a precision‑controlled mixing valve. Exhaust gases are first passed through a rapid‑cooler that reduces temperature to a safe range (typically 150‑200 °C) while preserving moisture content. The cooled stream is then metered back into the combustion chamber, diluting the oxygen concentration and flattening the temperature profile. This process cuts NOx emissions by up to 70 % without sacrificing thermal efficiency.
Control is achieved via a PLC‑based algorithm that continuously monitors O₂, CO, and flame scanner data, adjusting recirculation rate in real time. The system can be retrofitted to existing boiler stacks or installed as part of a new plant design, and it complies with EPA 40 CFR Part 60, EU Directive 2010/75, and Chinese GB 18484 standards.
Technical Specifications
| Parameter | Typical Range | Unit |
|---|---|---|
| Design Boiler Capacity | 5 – 200 | MW |
| Recirculation Ratio | 5 – 25 | % of total flue flow |
| Maximum Operating Temperature (post‑cooler) | 150 – 200 | °C |
| Fan Power Consumption | 0.5 – 3 | % of boiler output |
| Control Interface | Modbus/TCP, Profibus, OPC-UA | – |
| Material Construction | Inconel 625, Stainless‑Steel 316L | – |
*All parameters are customizable per order to match specific plant conditions and regulatory requirements.*
Competitive Advantages
- Proven Emission Reduction: Field‑tested NOx cut rates of 60‑70 % without auxiliary burners.
- Energy‑Neutral Operation: Optimized fan speed and heat‑exchange design keep auxiliary power under 2 % of boiler output.
- Robust Materials: High‑temperature alloys resist corrosion from sulfur‑rich flue streams common in chemical boilers.
- Scalable Architecture: Modular duct sections and valve assemblies allow quick expansion from 5 MW to 200 MW.
- Full OEM Support: Engineering, factory‑acceptance testing, and on‑site commissioning are included in the standard package.
FAQ
What is the minimum order quantity (MOQ) for a custom system?
Our engineering team can design a system for a single 5 MW unit, but standard production runs start at 3 units to achieve optimal pricing and lead‑time efficiency.
Can the flue gas recirculation system be integrated with existing PLCs?
Yes. The control module supports Modbus/TCP, Profibus, and OPC‑UA, allowing direct connection to most legacy and modern PLC platforms.
What is the typical lead time from order to delivery?
Standard configurations ship within 15‑30 days after order confirmation. Fully customized solutions require 30‑45 days, depending on material specifications and testing scope.
What warranty and after‑sales support are provided?
All units carry a 24‑month comprehensive warranty covering parts, labor, and software updates. Our technical service team offers 24/7 remote assistance and optional on‑site maintenance contracts.
Ready to achieve low‑NOx compliance while maintaining peak efficiency?
Contact Our Engineering Team Today