When undertaking 3T boiler tuning projects, it has been observed that some boilers do not get tuned properly after several attempts.
The main reason that can be attributed to this, is the fan performance does not match the design specifications.
Fans have issues with impellers or tongue clearance or bearings or leakages in ducts where in the fan delivery pressure does not suffice to furnace operations.
Why the fan design pressure is important ?
The fan pressures are a function derived by furnace dimensions, bed height & bed weight. For PF the flame length, curvature, flame spread etc..
For the same furnace dimension if there is a drop in fan design pressure, it gets compensated to volume & increases load on ID fans & the user ends up in losing Boiler Efficiency in the Direct Method.
In the test block these fans do not conform to the pressure volume curve, as provided by OEM.
There are two primary problems with the fans
1) Pressure compensating to volume means the air delivery pressure reduces, increases volume delivery
2) Volume compensates to pressure means the air delivery volume reduces
Both the above problematic fans give distinct combustion problems & many times the client will never know that there is an issue with the fans, they keep suspecting the fuel or any other mechanical part in the boiler.
These boilers have functionally lower efficiency in the Direct Method & 3T conditions cannot be implemented.
The FD fan had an issue of low delivery pressure from commissioning & went undetected for 2 decades at one client. There are several examples where this type of problem go undetected.
For the fan testing there are many codes like BS 848 / AMCA 210 / ISO 5801 / ASME PTC 11 etc.
Whether the boiler is Stoker / FBC / AFBC / CFBC / PF, the test block has to be conducted on all fans to conform all parameters of design, which should be checked every time during annual shutdown.
What should be done if the pressure, volume curve by design & actual installation does not match ?
Check the original drawing & verify what is not matching, repair & reconduct the test block.
Even after all the repairs do not produce matching curves, replace the fan after thorough verification at the time of installation.
Check the following regularly during shutdowns for a consistent & smooth operation, long life of boilers, with excellent combustion characteristics :
1) Test block of fans & take necessary action
2) Test block all air & flue gas ducts, to check pressure drop across all points to conform to design parameters
Advantages of Fans correction ::
Improves fan performance, air delivery by pressure & volume, sets off many combustion issues, faced in operations.
The boiler becomes fully tunable to 3T exercise, where in highest efficiency by Direct Method can be realized.
This issue of fans conforming to design pressure & volume is of very high importance & criticality, as these very parameters define inter relationships with others.
PA pressure is critical to coal density & volume of flow, furnace dimensions.
FD pressure is critical for combustion, C + O2 reaction stability, controls turbulence & time functions in 3T, flame height or length, curvature, bed resistance, flue gas velocity, furnace dimensions etc.
A correct fan profile will relieve the user of many tensions in the combustion front,
If you have any questions, please mail me at sap@chargewave.in
The main reason that can be attributed to this, is the fan performance does not match the design specifications.
Fans have issues with impellers or tongue clearance or bearings or leakages in ducts where in the fan delivery pressure does not suffice to furnace operations.
Why the fan design pressure is important ?
The fan pressures are a function derived by furnace dimensions, bed height & bed weight. For PF the flame length, curvature, flame spread etc..
For the same furnace dimension if there is a drop in fan design pressure, it gets compensated to volume & increases load on ID fans & the user ends up in losing Boiler Efficiency in the Direct Method.
In the test block these fans do not conform to the pressure volume curve, as provided by OEM.
There are two primary problems with the fans
1) Pressure compensating to volume means the air delivery pressure reduces, increases volume delivery
2) Volume compensates to pressure means the air delivery volume reduces
Both the above problematic fans give distinct combustion problems & many times the client will never know that there is an issue with the fans, they keep suspecting the fuel or any other mechanical part in the boiler.
These boilers have functionally lower efficiency in the Direct Method & 3T conditions cannot be implemented.
The FD fan had an issue of low delivery pressure from commissioning & went undetected for 2 decades at one client. There are several examples where this type of problem go undetected.
For the fan testing there are many codes like BS 848 / AMCA 210 / ISO 5801 / ASME PTC 11 etc.
Whether the boiler is Stoker / FBC / AFBC / CFBC / PF, the test block has to be conducted on all fans to conform all parameters of design, which should be checked every time during annual shutdown.
What should be done if the pressure, volume curve by design & actual installation does not match ?
Check the original drawing & verify what is not matching, repair & reconduct the test block.
Even after all the repairs do not produce matching curves, replace the fan after thorough verification at the time of installation.
Check the following regularly during shutdowns for a consistent & smooth operation, long life of boilers, with excellent combustion characteristics :
1) Test block of fans & take necessary action
2) Test block all air & flue gas ducts, to check pressure drop across all points to conform to design parameters
Advantages of Fans correction ::
Improves fan performance, air delivery by pressure & volume, sets off many combustion issues, faced in operations.
The boiler becomes fully tunable to 3T exercise, where in highest efficiency by Direct Method can be realized.
This issue of fans conforming to design pressure & volume is of very high importance & criticality, as these very parameters define inter relationships with others.
PA pressure is critical to coal density & volume of flow, furnace dimensions.
FD pressure is critical for combustion, C + O2 reaction stability, controls turbulence & time functions in 3T, flame height or length, curvature, bed resistance, flue gas velocity, furnace dimensions etc.
A correct fan profile will relieve the user of many tensions in the combustion front,
If you have any questions, please mail me at sap@chargewave.in
