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These 13 Essentials have expanded from the 10 pre-requisites for optimum combustion, first promoted in the 1980’s. The point is, they are simple, have been around a long time, and they make a great “punch list” for resolving slagging, LOI, and NOX issues in large P.C.-fired utility boilers.
Nine of these essentials are directly related to pulverizer performance and are coded in BLUE for your reference. |
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| Thirteen Essentials of Optimum Combustion for Low NOXBurners |
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Furnace exit must be oxidizing preferably, 3%. |
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Fuel lines balanced to each burner by “Clean Air” test ±2% or better. |
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Fuel lines balanced by “Dirty Air” test, using a Dirty Air Velocity Probe, to ±5% or better. |
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Fuel lines balanced in fuel flow to ±10% or better. |
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Fuel line fineness shall be 75% or more passing a 200 mesh screen. 50 mesh particles shall be less than 0.1%. |
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Primary airflow shall be accurately measured & controlled to ±3% accuracy. |
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Overfire air shall be accurately measured & controlled to ±3% accuracy. |
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Primary air/fuel ratio shall be accurately controlled when above minimum. |
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Fuel line minimum velocities shall be 3,300 fpm. |
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Mechanical tolerances of burners and dampers shall be ±1/4” or better. |
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Secondary air distribution to burners should be within ±5% to ±10%. |
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Fuel feed to the pulverizers should be smooth during load changes and measured and controlled
as accurately as possible. Load cell equipped gravimetric feeders are preferred. |
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Fuel feed quality and size should be consistent. |
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| Thirteen Essential for Optimum Combustion of Low NOX Burners |
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Achieving Optimum
Combustion by Applying
the Fundamentals |
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