Conversion of fuel to natural gas brings the following challenges to operating the furnace air-gas system.
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Increase in supply of combustion air needed for natural gas combustion. Facilities may need to alter FD fan capacity or use PA fans for supplemental air.
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The rapid response of natural gas combustion:
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More sensitive to changes in fuel flow due to faster kinetics
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An MFT leads to a transient furnace pressure excursion that is 3-5X more severe than that of coal-firing excursions
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TRAX suggests several mitigating strategies:
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Tuning of draft controls including kicker circuits
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Adjustment of valve and fan actuator speeds
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Fine-tuning of equipment trip set-points
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