Improving Gas-Fired Boiler Efficiency: Causes and Solutions for Incomplete Combustion

In recent years, with rapid economic growth, environmental pollution has become a pressing concern. Energy-saving and emission reduction efforts are receiving increased attention from relevant authorities. As a clean energy source, natural gas has gradually replaced kerosene as the primary fuel for boilers, finding widespread use in industrial production. However, during boiler operations, the issue of incomplete gas combustion remains a challenge, impacting energy efficiency, environmental protection, and, to a significant extent, the safe operation of boilers.

Causes of Incomplete Combustion in Gas-Fired Boilers

Incomplete combustion in gas boilers not only reduces thermal efficiency but also introduces various hazards. The primary causes are as follows:

1. Mismatch Between Gas and Air Volumes:

During boiler operation, the blower pressurizes air and mixes it with gas in the furnace for combustion. If the combustion adjustment is not properly managed, the gas and air volumes may not match, leading to incomplete combustion and reduced operational efficiency.

2. Decrease in Flame Temperature:

To ensure stable combustion and a complete flame, the flame must be maintained at a standard temperature. Incomplete combustion occurs if the flame’s temperature drops due to contact with cold objects.

3. Insufficient Smoke Extraction:

Efficient removal of flue gas is crucial for maintaining combustion efficiency. Poorly controlled flue gas discharge can lead to flue gas retention in the furnace, resulting in insufficient air supply and incomplete combustion.

4. Ineffective Mixing of Gas and Air:

Inadequate mixing of gas and air within the furnace can easily cause incomplete combustion.

Hazards of Incomplete Combustion in Gas-Fired Boilers

1. Reduced Thermal Efficiency:

Incomplete combustion creates a reducing environment within the boiler furnace, leading to the accumulation of carbon deposits on heat transfer surfaces. This increases thermal resistance, decreases heat transfer rates, raises exhaust gas temperatures, and results in significant heat loss during exhaust, all of which negatively impact boiler efficiency.

2. Generation of CO:

Incomplete combustion produces large amounts of CO, posing significant health risks to operators and increasing the likelihood of boiler explosion accidents.

3. Increased Gas Consumption:

Incomplete combustion means some gas in the furnace does not participate fully in the combustion process, leading to higher gas consumption and reduced boiler economy.

4. Production of Carbon Black:

During gas boiler operation, carbon particles form as a result of incomplete combustion. These particles are not fully burned and are carried away by combustion products, leading to soot formation and environmental pollution.

Technical Improvement Measures for Incomplete Combustion

Given the serious consequences of incomplete combustion in gas-fired boilers, the following improvement measures should be implemented:

1. Enhanced Air Volume Control:

To ensure a stable relationship between air and gas volumes, operators should adjust the blower’s moving blades and regulate air supply according to combustion rate and gas volume. An intelligent adjustment system can help control air supply, with quick response mechanisms ensuring stable oxygen content in the furnace.

2. Improved Induced Air Volume Control:

Maintaining stable negative pressure within the boiler furnace is essential for safe operation. Operators should keep the furnace pressure around -200 Pa, using feedback systems to adjust induced air volume effectively.

3. Optimized Oxygen Control in Flue Gas:

Adding a closed-loop control circuit for flue gas oxygen content helps ensure complete combustion by adjusting the gas-to-air ratio based on real-time monitoring.

4. Increased Boiler Hot Air Temperature:

Raising the temperature of the air entering the furnace aids in rapid combustion and stabilizes furnace temperature. Adjusting the hot air recirculation valve and air distribution ensures optimal combustion and improved furnace temperature.

5. Strengthened Energy Conservation Management:

Enhancing energy-saving management involves regular equipment maintenance, improved energy-saving protocols, and training for managers and operators. Monitoring energy consumption and conducting regular combustion tests ensure the boiler operates efficiently.

Conclusion

The incomplete combustion of gas-fired boilers not only reduces thermal efficiency but also causes severe environmental pollution. It also leads to increased gas consumption and poses significant safety risks due to CO production. By addressing the causes of incomplete combustion and implementing technical improvements, FangKuai boilers can achieve full combustion, improving energy efficiency, environmental protection, safety, and economy in boiler operations.