What is the temperature of flue gas?
What is the temperature of flue gas?
The typical furnace outlet temperature of flue gases is usually around 1200 °C which will decreases gradually along the pathway of heat transfer, while the temperature of the flue gases going to stack is around 150 °C.
What should boiler stack temperature be?
around 350 to 450 degrees Fahrenheit
Normally, you should expect stack temperatures around 350 to 450 degrees Fahrenheit. Every 100 degrees above that equates to a 2.5% efficiency loss. Most buildings schedule boiler cleanings at regular intervals throughout the year, but if you notice those numbers jump above that range, it’s time for a cleaning.
At what temperature does boiler flue gas condensate?
around 135°F.
Flue gas will form and condense on a heat exchanger and in the boiler stack when it falls below its dew point, and this occurs when the return water temps of the system are around 135°F.
How do excess air and the flue gas exit temperature affect the thermal efficiency of the boiler?
The dry gas loss is dependent on the flue-gas exit temperature from the boiler and the amount of excess air. Insufficient excess air will increase the amount of unburned carbon. Less excess air will improve efficiency, while the resulting higher amount of unburned carbon will reduce efficiency.
How is flue temperature measured?
A probe meter is the only way to measure flue gas temps. As to what temps are proper well, below 400 you’ll be making creosote too fast since you need the flue gas to be hot enough at the top of the chimney to have not condensed the liquid out of it yet.
What is boiler flue gas?
Flue gas refers to a chemical byproduct substance that is generated as a result of a combustion reaction that has escaped through long pipes such as those in boilers, furnaces or steam generators. Flue gas may also be referred to as exhaust gas and may act as a reactor agent for atmospheric corrosion.
What causes high flue temperature?
The boiler water is being pushed through the fairly small coil at a flow rate high enough to accommodate the boiler flow rates and the tank loss. The tank can’t absorb all of the BTUs the boiler is pushing out. The remaining BTUs exit through the flue, causing the rise in temperature.
How is the net flue gas temperature determined?
The “net stack temperature” is the difference between the flue gas inside the chimney and the room temperature outside the burner. Net stack temperatures above 700oF (370oC) are in general to high. Typical values are between 330 – 500oF (160 – 260oC).
How do you stop flue condensation?
Up the Chimney In order to stop the vapor from condensing, conditions must be adjusted so that it does not cool before leaving the chimney.
What should flue gas Analyser readings be?
Flue gas analysers usually display a CO/CO2 ratio. This shows the ratio of carbon monoxide and carbon dioxide in the exit flue (chimney) of the appliance. Generally when this level is below 0.004 the boiler is considered to be running efficiently. For oil or coal fired appliances the CO should not be above 200ppm.
How does flue gas affect the efficiency of a boiler?
The flue gas loss depends on the final flue gas temperature and the amount of flue gases. Thus the higher the air ratio, the higher the flue gas losses. The flue gases should leave the boiler at a temperature as low as possible to minimize the flue gas losses.
How many BTU does it take to heat flue gas?
The fuel is considered to be Standard Natural Gas (1040 Btu/std. ft3 ), the fuel consumption is 100,000 Btu/hr (HHV Basis), and the heat delivered to the home is 80,000 Btu/hour. The percent excess air for this combustion system is 10 %.
How is the efficiency of a boiler determined?
Boiler efficiency includes the calculation of sensible heat losses (in boiler flue gases and ash), which are dependent on coal composition, excess air levels and temperatures at boiler inlet and airheater outlet. From: The Coal Handbook: Towards Cleaner Production: Coal Utilisation, 2013
How is the combustion efficiency of natural gas determined?
Using a Flue Gas Analyzer or any meter designed to measure oxygen or carbon-monoxide, and taking the flue gas temperature and the temperature of the combustion air, the following Table can be used to determine combustion efficiency when operating on natural gas.
