FGR
Setting
Flue gas
FGR
FGR characteristics
The FGR characteristics is used to define the progression
of the flue gas recirculation section. Depending on the
progression selected, the FGR section is determined
based on the position of the ash screw using switch points
“
Temp 1
” and “
Temp 2
”.
Temp 1
Depending on the FGR characteristic selected, the FGR
section is modified from this temperature value.
Temp 2
Depending on the FGR characteristic selected, the FGR
section is modified from this temperature value.
FGR
characteristic
progression 0:
FGR
characteristic
progression 1:
FGR
characteristic
progression 2:
FGR
characteristic
progression 3:
FGR
characteristic
progression 4:
FGR flap position at partial load
At “
Heating
“ and “
Empty stoker
“ status, the FGR flap
regulates between the setting values of the “
FGR flap
position at partial load
“ and “
FGR flap
position at nominal load
“ depending on the flue
gas temperature.
FGR flap position at nominal load
At “
Heating
“ and “
Empty stoker
“ status, the FGR flap
regulates between the setting values of the “
FGR flap
position at partial load
“ and “
FGR flap
position at nominal load
“ depending on the flue
gas temperature.
Reduce underpressure at 100% FGR by
A certain value is deducted from the underpressure
setpoint depending on the FGR flap position.
Startup criteria for FGR - Flue gas temperature
The FGR flap is regulated from this flue gas temperature;
the flap closes below the set value.
ID fan control for FGR cleaning
Desired control of ID fan during boiler status “
FGR
cleaning
“.
Release FGR flue gas temperature
Flue gas temperature at or above which the flue gas
recirculation control system is activated. If the flue gas
temperature falls to a level 3 °C below this value, then the
FGR will be deactivated.
Release FGR combustion chamber temperature
Specifies the value in percent of the combustion chamber
signal at or above which the flue gas recirculation is
activated. If the combustion chamber temperature falls so
low that the CCT signal falls below this value again, the
flue gas recirculation will be deactivated again.
FGR power influence
Specifies as a percentage the influence that the current
infeed level has on the FGR primary air. If this parameter
is set to 100%, then the FGR primary air will adjust
downwards proportionally to the feed level. If this
parameter is set to 0%, then the FGR primary air is
adjusted according to the combustion chamber signal and
the calculated curve, and ignores the infeed level. At
minimum output, this may result in the primary air being
adjusted up to the maximum value. If the power influence
is set to a negative value, this function is inverted. For
negative values the FGR primary air is increased in
proportion to the infeed rate.
Max. reduction of primary air in FGR mode
Specifies the amount by which the primary air (fresh air)
can be reduced at maximum FGR primary air. Please note
that the reduction is dependent on the infeed level and that
the maximum reduction will not necessarily have been
achieved at the point when the parameter "CCT signal for
primary FGR stop" is reached. At full FGR primary air (=
Maximum FGR Primary) and maximum feed level, the
maximum reduction to the primary air will also be active.
4
Parameters overview
System
94
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