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BCU 460, BCU 465 · Edition 11.19
15
Application
1 .1 .8 Flameless mode to reduce NO
x
formation
VAD
BIC..M
IC 40 + BVH
M
VAS..L
VMV
DG
BCU 465..D2
PZL
Process Control (PCC)
AKT
STM
The burner control unit BCU 465 switches the burner
BIC..M ON/OFF in cycles. Burner BIC..M is controlled
without pneumatic air/gas ratio control system. The gas
supply pressure is controlled by the gas pressure regu-
lator VAD; the required burner capacity is set using the
fine-adjusting valve VMV. The capacity is controlled by
actuator IC 40 and butterfly valve BVH. An air pressure
switch upstream of the burner monitors the functioning
of the butterfly valve. In addition, air/gas ratio monitor-
ing for the zone or the furnace is required.
As soon as the safety temperature monitor STM signals
a furnace temperature of ≥ 850°C (1562°F), the burner
can be switched to flameless combustion (Low NO
x
mode) to significantly reduce NO
x
emissions.
Switching to Low NO
x
mode eliminates the counter-
pressure by the flame in the ceramic tube TSC. At a
constant gas supply pressure, the gas volume increases
by approximately 15%. In Low NO
x
mode, the butterfly
valve moves to a smaller open position tailored to the
pressure conditions.