What is the purpose of combustion flue gas analysis?
Plant operators have used combustion flue gas analysis for decades as a method of optimizing boiler combustion fuel/air ratios. By measuring the amount of excess oxygen and/or carbon monoxide (CO) in the flue gases, the plant can be tuned to operate at the best heat rate and lowest nitrogen oxide (NOx) levels.
What should flue gas Analyser readings be?
Generally when this level is below 0.004 the boiler is considered to be running efficiently. When between 0.004 and 0.008 this indicates a potential problem and investigation and retesting must take place. When above 0.008 the appliance must be fully investigated, cleaned and retested.
What is the ideal CO2 content of flue gas?
approximately 10%
Carbon dioxide – CO2 – is a combustion product and the content of CO2 in a flue gas is an important indication of the combustion efficiency. Optimal content of carbon dioxide CO2 after combustion is approximately 10% for natural gas and approximately 13% for lighter oils.
What percentage of CO is acceptable in a sample of the flue gas?
The Need to Measure CO Ideally, CO measurements should be less than 100 ppm and stable during the run cycle for vented gas-fired HVAC equipment. The ANSI Z-21 maximum CO level is 400 ppm air-free. When equipment operates above this range, it exceeds the certified safety range.
What causes high CO in a boiler?
High Carbon monoxide readings tend to point to what I like to call “unbalanced combustion”. You see, it could be due to lack of combustion air, too much gas, or too much excess air. No matter how you slice it, the combustion process is out of balance.
What should the CO CO2 ratio be?
The calculations suggest that, to avoid occasional exceedence of the room CO limit, the CO/CO2 ratio should in many cases be lower than 0.02, and in some cases lower than 0.01.
What is the acceptable CO When looking at the combustion analyzer?
But to be safe you would not want to see any more than 150 ppm. A reading above 150 ppm would be a red flag to double-check the combustion. High levels of carbon monoxide suggest that there is not enough oxygen for the amount of fuel being burned.
What is good combustion?
Perfect combustion is simply a mixture of fuel and oxygen, with both being completely consumed in the burning process. The ideal situation would be to provide just enough air in the combustion chamber to insure complete burning of the fuel.
What percent of oxygen is required for combustion?
16 percent
Oxygen. Air contains about 21 percent oxygen, and most fires require at least 16 percent oxygen content to burn. Oxygen supports the chemical processes that occur during fire. When fuel burns, it reacts with oxygen from the surrounding air, releasing heat and generating combustion products (gases, smoke, embers, etc.).
What is normal CO ppm?
Average levels in homes without gas stoves vary from 0.5 to 5 parts per million (ppm). Levels near properly adjusted gas stoves are often 5 to 15 ppm and those near poorly adjusted stoves may be 30 ppm or higher.
How do you calculate CO in a gas flue?
Total amount of dry flue gas per 1 kg wood = 4.872 m3. Therefore % CO2 = 0.97/4.872 = 19.91 assuming stoichiometric combustion (0 % O2). For 20 % excess air = 16.6 % CO2 For 40 % excess air = 14.2 % CO2 For 50 % excess air = 13.27. A Conversion Chart is given below.