We apply first principles in a coordinated approach to methodically and properly balance the system from bottom to top.
Pulverized coal (PC) fired boilers are the most common in utility service. Although we can step into the process to help our clients at any stage in combustion improvement, our complete First Principles Program includes the following for pulverized coal-fired boilers:
- Obtain a full range of expected fuel analyses as well as necessary drawings, dimensions and data on the boiler, burners, classifiers, coal conduits, mills, feeders and fans.
- Perform boiler performance tests. Include boiler exit gas grid sampling and analysis.
- Properly test the mills, or obtain proper mill test data.
- Certain mill modifications and repeat testing may be recommended at this time to improve fineness and fuel balance. We have redesigned reject valves, throat rings, classifier vanes, and other internal components.
- Perform mill dribble tests to determine minimum throat velocity.
- Perform mill response tests to evaluate proper balance of mill primary air/fuel ratio at high load.
- Calculate minimum primary air (PA) flow based upon plant elevation & coal conduit I.D.
- Correct mill PA/Fuel Flow curve if necessary based upon minimum PA flow and mill response tests.
- Correct throat ring size, if necessary to reject pyrites and minimize dribble.
- Calculate burner nozzle velocity.
- Evaluate excess O2 curve and adjust if necessary. This involves consideration of slagging, fouling, steam temperatures and sprays.
- Determine total air flow.
- Evaluate FD and ID fan sizes, if necessary.
- Calculate burner secondary air velocities (inner and outer).
- Redesign burner and air register sizes if necessary.
- Reconfigure and/or tune controls as necessary to accommodate new settings.