TANGENTIAL FIRING

• Tangential firing create turbulent zone in the center of the furnace by directing a horizontal coal firing from each corner of furnace.
• It form an imaginary circle in which the flame path is tangent.
• This is done at each elevation for tangential firing.
• As each elevation creates a circle then combination of them creates a fire cylinders.
• The tangential coal & air nozzles firing the mixture of coal and air. Mixture of coal & secondary air is takes place at outside of the burners.
• There is an alternate layers of coal & air burners with oil fires nozzles.
• For maintaining stable flame a differential pressure between furnace & wind box air is maintained.
• This burner arrangement is with tilting mechanism which helps to shift the complete fire cylinder in upward or downward. This helps to control the main steam temperature & reheat steam temperature.
• When burner tilt is lower then more area of furnace expose to heat and heat absorption is greater. So the flue gas exit temperature is lower.
• When burner tilt is upper then less area of furnace expose to heat & heat absorption is lower hence the flue gas exit temperature is higher.

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