Basically the boiler works on combustion of fuel in the presence of air – oxygen to heat the water which turns into steam. Fundamentally if we do not maintain the right mix of fuel and air mixing we would end up losing optimum efficiency of the boiler. This would mean operating a boiler at lower efficiency and hence more fuel would be consumed to produce required steam.
More air flow means the heat would get lost from the chimney to the environment – not utilising the heat transfer area within the boiler. And short supply would mean less air to fuel ratio and hence compromised boiler efficiency.
As energy efficiency and reducing carbon footprint become increasingly popular, boiler operators and plant managers look for ways to improve boiler efficiency. A boiler that is more efficient will reduce fuel consumption, thus reducing CO2 emissions from the boiler and reducing emission compliance issues. One way to increase boiler efficiency is to use oxygen trimming, or O2 Trim, at the stack.
A typical burner will operate from 3 to 4% O2 at 50% boiler load and higher. Excess air is necessary for burner operation to ensure complete combustion of fuel, and this stack concentration of O2 corresponds to the amount of excess air at the burner. In natural gas firing, 3% O2 corresponds to 15% excess air. Burner service engineers set the fuel / air ratio for optimum combustion over the burner’s firing range at commissioning. In addition, service engineers should be aware that ambient conditions (mainly changes in air temperature) can affect air density, which ultimately affects burner fan airflow. On cold days the fan will flow more air due to a higher air density, and on hotter days the flow will be less. The operation of a burner can be adversely affected by varying air flow conditions.
If not readjusted, the boiler pile can differ by at the very least 2% O2 (i.e., if regular procedure is 3% O2, it can enhance to 5% O2 on a cool day). Including an O2 Trim system would certainly set you back a portion of that quantity (thinking a 150,000 lb/hr vapour boiler or smaller sized), offering a fast as well as rewarding ROI. What specifically is an O2 Trim System?
Along with enhanced boiler effectiveness, making use of O2 Trim will certainly make sure secure and also secure O2 degrees. On warm days with lowered follower air circulation, the pile O2 degree can go down to hazardously reduced degrees and also boiler exhausts can head out of conformity. With O2 surveillance, alarm systems can be developed to notify the boiler driver to either lower gas circulation or rise air circulation, to go back to secure operating problems.
O2 Trim isn’t perfect for every boiler. For systems with quick boiler tons adjustments, the O2 Trim system normally can not maintain up conveniently as well as it is commonly “searching” for the maximum air circulation.
Some components of air trimming systems include: Oxygen analyser to sense oxygen% on a real time basis, sensors for measuring pressure and temperature that indicates where heat is getting consumed, air dampers to regulate air flow and that are actuated through control signals and other fully automatic systems that regulate air flow and allow boilers to run at optimum efficiency levels.
As clarified over, the air circulation can differ based on ambient problems triggering the pile O2 to differ; this can be addressed by including O2 Trim to the control system. O2 Trim is an air circulation cutting system where pile O2 is determined (utilising an O2 probe) as well as the air circulation is changed (cut) based on the analysis.
If you are interested in learning more about whether an O2 Trim System will benefit your operations, reach out to one of our qualified parts specialists at: +91-7207215602 or email us at: [email protected] Check out other articles on Shanti Boilers Blog for more tips and tricks for improved boiler efficiency, routine maintenance, and more!