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SADC

The document summarizes the operation of a tangential firing boiler. It describes that the boiler uses primary and secondary air flows for combustion. The secondary air flow is controlled by the SADC and depends on the type of fuel used. The SADC controls dampers in the four corners and 23 elevations/compartments of the boiler to control air flow at different heights depending on the firing rate and load. It also describes the control and operation of fuel air dampers and auxiliary air dampers.

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VIJAYPOR
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1K views7 pages

SADC

The document summarizes the operation of a tangential firing boiler. It describes that the boiler uses primary and secondary air flows for combustion. The secondary air flow is controlled by the SADC and depends on the type of fuel used. The SADC controls dampers in the four corners and 23 elevations/compartments of the boiler to control air flow at different heights depending on the firing rate and load. It also describes the control and operation of fuel air dampers and auxiliary air dampers.

Uploaded by

VIJAYPOR
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPT, PDF, TXT or read online on Scribd
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SADC

TANGENTIAL FIRE BOILER FIREBALL AT CENTRE RESULTING IN SWIRLING ACTION OF FUEL AND AIR LEADS TO GOOD MIXING AND COMBUSTION. The total combustion air flow supplied in the boiler consists of two parts, one, the primary air, which is used for drying and transporting the coal from the pulveriser through the coal piping into the furnace and is supplied by the primary air fans and two, the secondary air sent through the four corners of the wind box and is supplied by the FD fans.

SECONDARY AIR FLOW DEPENDS ON FUEL. AEROFOIL TO MEASURE AIRFLOW. DIFFERNCE OPERATE INLET GUIDEVANE OF FD FAN. INDEPENDENT OF SADC POSITON. SADC CONTROLS THE AIR FLOW IN DIFFERENT ELEVATIONS DEPENDING UPON FIRNG RATE,NO OF ELEVATIONS AND TYPE OF FUEL BURNT.

FOUR CORNERS 23 ELEVATIONS/COMPARTMENTS COMPARTMENTS HAVE DAMPERS. 10 COAL 5 OIL 2 OVER FIRE 2 END AIR 4 AUX AIR

CONTROL DAMPERS ARE OPERATED WITH ELECTRO PNEUMATIC POSITIONERS. SAME COMMAND TO ONE ELEVATION /FOUR CORNERS. FEEDBACK FROM ONLY CORNER ONE. LOCAL INDICATORS AND REMOTE POSITION FEEDBACKS. INSTRUMENT AIR PRESSUR 7 KSC. COPPER TUBE WITH AIR FILTER REGULATOR.

FUEL AIR DAMPERS AUXILIARY AIR DAMPERS BOTH HAVE DIFFERENT CONTROLS.

CONTROL PHILOSOPHY
FUEL AIR DAMPER OPERATES WITH FIRING RATE. AUX AIR DAMPERS OPERATE TO MAINTAIN THE WINDBOX TO FURNACE DP DPENDING UPON THE COAL QUALITY. LOFA DAMPER START OPENING AT 50% LOAD AND OPEN TO 100 %AT 75% LOAD . UOFA DAMPERS START OPENING AT 75% AND OPEN AT 100% AT 100% LOAD.

OPERATION
All elevations of the aux. air dampers will be automatically switched to Manual control and then commanded to open 100%, if Both FD fans are off. Both ID fans are off. Master fuel trip occurs. Loss of unit critical power (+24V DC

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