Low NOx Combustion Retrofit for Ligang Unit 4 Power Plant in Jiangsu, China
Project Overview
The power plant is currently owned by China CITIC Group with a stake of 65.05%.
|
Project Type |
Thermal |
|---|---|
| Total Capacity (MW) | 3900 |
| Active Capacity (MW) | 3900 |
| Pipeline Capacity (MW) | 2000 |
| Project Status | Active |
| Project Location | Jiangsu, China |
| Unit name | Status | Fuel(s) | Capacity (MW) | Technology | Start year | Retired year |
|---|---|---|---|---|---|---|
| Phase I Unit 1 | operating | coal - bituminous | 350 | subcritical | 1993 | – |
| Phase I Unit 2 | operating | coal - bituminous | 350 | subcritical | 1993 | – |
| Phase II Unit 1 | operating | coal - bituminous | 370 | subcritical | 1998 | – |
| Phase II Unit 2 | operating | coal - bituminous | 370 | subcritical | 1998 | – |
| Phase III Unit 1 | operating | coal - bituminous | 650 | supercritical | 2006 | – |
| Phase III Unit 2 | operating | coal - bituminous | 650 | supercritical | 2006 | – |
| Phase IV Unit 3 | operating | coal - bituminous | 620 | supercritical | 2007 | – |
| Phase IV Unit 4 | operating | coal - bituminous | 620 | supercritical | 2008 | – |
| Phase V Unit 1 | permitted | coal - bituminous | 1000 | ultra-supercritical | 2025 | – |
| Phase V Unit 2 | permitted | coal - bituminous | 1000 | ultra-supercritical | 2025 | – |
Project Name:
- Ligang Unit 4 Low NOx Combustion Retrofit
Location:
- Jiangsu Province, China
Boiler Model:
- BEL Design, WGZ1246/18.15-1
Fired Fuel:
- Bituminous Coal
Combustion System:
- Front wall firing with 4 elevations of a total of 24 burners.
Pulverize System:
- Mid-speed ball mill
Pre-Retrofit Challenges
High NOx Emissions:
- Normal range: 600-700 mg/Nm³
- Maximum recorded: 838 mg/Nm³
Design Issues:
- The spray speed of the burners was excessively high.
Retrofit Solution: LNB + OFA
Low-NOx Burners (LNB):
- Modification or replacement of existing burners with Low-NOx Burners designed to reduce NOx formation during combustion.
Over-Fire Air (OFA) System:
- Implementation of an OFA system to optimize combustion, further aiding in NOx reduction.
Post-Retrofit Performance
Boiler Performance:
- No significant changes in boiler performance, ensuring compatibility with existing systems.
NOx Emissions:
- Reduced to ≤380 mg/Nm³ at 50%-100% ECR (Economic Capacity Ratio) with any mills configuration.
Boiler Operational Parameters:
- No changes in boiler steam flow, steam temperature of the superheater and reheater, or habit-control.
- Maintained stable flame, with no issues of high-temperature corrosion or severe slagging on tubes.
Efficiency and Byproducts:
- Boiler efficiency remained unchanged.
- Fly ash Loss on Ignition (LOI) reduced by 15%, indicating more complete combustion and reduced unburnt carbon in the ash.