The Influence of Gas Pressure Fluctuations on Burners

The Influence of Gas Pressure Fluctuations on Burners

The Influence of Gas Pressure Fluctuations on Burners
As the gas pressure increases or decreases, the jet flow rate of gas passing through the nozzle will also correspondingly increase or decrease. Due to the inability of the burner to detect this change, the combustion air of the blower remains unchanged, and the air-fuel ratio will inevitably fluctuate.1、 The impact of gas pressure fluctuations on various aspects of the burner1. The impact of gas pressure fluctuations on the thermal load of the burner.The main function of a burner is to convert the chemical energy in the gas into thermal energy. The thermal load is a visual representation of the heat release rate and is also the most important parameter of the burner. Its size directly affects the working efficiency of the burner. The thermal load of the burner under pressure drop is too small, and the heating process takes a long time, which affects the combustion effect; Under high pressure, excessive heat load on the burner can cause excessive carbon monoxide in the flue gas, high smoke temperature, and decreased thermal efficiency, which can easily burn out the burner and reduce its service life.2. The impact of gas pressure fluctuations on the combustion characteristics of the burner.The thermal load of the burner also determines the size of the burner structure. When the gas pressure exceeds the standard, causing the injection flow rate of gas through the nozzle to exceed the standard, it will result in insufficient supply of primary air (pre mixed air) and secondary air (peripheral supplementary air) required for combustion, incomplete combustion, yellow flames, black smoke, and a significant increase in carbon monoxide content in the flue gas. Black smoke is an important factor leading to an increase in PM2.5, and when the combustion condition continues to deteriorate, it leads to a sharp increase in environmental pollution. When the gas supply pressure continues to increase or the damper is not adjusted correctly, the flow rate of gas in the combustion hole will be greater than the combustion speed, causing the flame to leave the edge of the fire hole, which is called flame separation and then developing into misfire.3. The impact of gas pressure fluctuations on the thermal efficiency of the burner.From the change in exhaust gas temperature, it can be seen that the higher the exhaust gas temperature, the lower the thermal energy utilization rate, and the lower the thermal efficiency of the burner.2、 The consequences of air fuel ratio imbalance caused by gas pressure fluctuations.1. Underoxygenation combustion: That is, if the amount of combustion gas is greater than the required amount of air, the combustion is incomplete, and the carbon monoxide content in the flue gas increases significantly, resulting in a corresponding increase in chemical incomplete combustion losses. Ordinary mechanical blast burners do not have the ability to self detect under oxygen combustion.2. Deignition: If the gas supply pressure continues to increase and the airflow velocity of the gas inside the burner exceeds the combustion speed, causing the flame to leave the edge of the flame hole, it is called de ignition, and then it develops into de ignition. This can lead to stalling or unstable combustion, and even safety hazards. Ordinary mechanical blast burners have their own high-pressure control function, which will automatically shut down for protection when the air pressure exceeds the limit.3. Excessive air combustion: That is, the amount of gas is less than the required amount of air, resulting in an excessive amount of air, causing excess cold air to enter the furnace for heating. Therefore, as heat loss increases, general mechanical blast burners do not have the ability to self detect under oxygen combustion.4. Flashback: If the air pressure continues to decrease or the air door adjustment cannot keep up, the airflow velocity in the burner gas nozzle is lower than the combustion velocity, causing flame flashback and affecting the safe operation of the burner. Generally, mechanical blast burners have a low-pressure control function, and when the air pressure exceeds the limit value, they will automatically shut down for protection.When the fluctuation of gas pressure exceeds the pressure range required for normal operation of the burner, the flame shape will change. Excessive gas pressure elongates the flame and increases its length, causing incomplete combustion of combustible gases to come into contact with the furnace wall. Due to the low thickness of the furnace wall, it is generally lower than the ignition point of combustible gases. This partially unburned gas will be unable to burn due to the low temperature, resulting in energy waste.