BOILER BURNER FUEL
Burners work by mixing together air and fuel to create an efficient flame inside of the boiler. The style of burner and fuel availability will determine which fuel you use, but it is commonly one of the following:
Natural Gas
Propane
Biogas
#2 Fuel Oil
Heavy Oil
Solid Fuels (wood or coal for example)
Tallow
THE IMPORTANCE OF AIR AND YOUR BURNER
In order to burn this fuel efficiently, burners must have the correct amount of air available. This is why the air to fuel ratio is a key indicator to ensure efficient burner function. When ratios of fuel and air get out of whack, unburned fuel can get deposited as soot in boiler tubes. This directly impacts the ability of the heat to transfer from the tubes to the surrounding water and will reduce steam output.
When pulling outside air in to feed a burner, you must also consider the temperature of that air. When there are large swings in the temperature of the supply air for the burner, it can cause combustion problems. We commonly start seeing combustion issued after a 15 to 20 degrees temperature change.
Combustion tuning is one way you can ensure this is not occurring in your system. This should generally be done seasonally if you are bringing in outside air. This is due to the temperature variance that effects burner combustion.
BOILER BURNER BYPRODUCTS
Once you get the correct fuel to air ratio achieved, the burner must ignite the mixture and prove the flame. The result of this combustion is the production of CO, CO2, NOx, particulate matter and other byproducts. Environmental regulations at the federal, state and local level have focused on setting limits on the productions of these byproducts. You can meet these regulations through both pre-combustion and post combustion methods.
Depending on which byproduct you are trying to reduce, there are many different methods for addressing them. By increasing efficiency of the boiler for example, you can reduce the load on the system. This will in turn reduce the CO2 output. Some low NOx burners, on the other hand are able to lower NOx production to levels below 10ppm. This is typically achieved by lowering the flame temperature.