Honeywell BCU 460 Technical Information page 37

Low NOx mode (flameless operation)
Flame mode
In order to heat up the furnace, the burner operates in
Flame mode.
The ignitable gas/air mixture is ignited using an electri-
cal ignition spark and combusts inside and outside of
the ceramic burner tube. The presence of the flame is
monitored in compliance with EN 746-2.
Flameless mode
As soon as the combustion chamber temperature is ≥
850°C, the burner control unit BCU..D2 can switch to
flameless operation.
Gas and air are supplied via the same connections as in
Flame mode. No ignition takes place in the burner tube.
BCU 460, BCU 465 · Edition 11.19
The combustion process is relocated to the combustion
chamber. The oxidation reactions take place without a vis-
ible flame. Compared to traditional Flame mode, the reac-
tion zone is considerably larger and the reaction density
considerably lower. This prevents the occurrence of peak
temperatures which are responsible for high NO
Emissions of NO are drastically reduced.
x
400
Natural gas, air preheating to 450°C
300
200
100
0
850 900 950
In Flameless mode, the NO
below 150 mg/m³ (reference value of 5% O
a furnace temperature of 1200°C and hot air at 450°C
without expensive additional piping. The high output
pulse frequency and rotary impulse control ensure tem-
perature uniformity which is of great advantage.
For further information on burner BIC..M,
see www.docuthek.com
x
1000 1050 1100 1150 1200
Furnace temperature [°C]
values can be reduced to
x
) even at
2
values.
1250
37