Integration Of 4-Draught Steam Boiler - Bosch CHP CE 240 NE Technical Manual

Engineering information and sizing
3.2.4

Integration of 4-draught steam boiler

The integration of a 4-draught steam boiler is effected
via the flue of the CHP module. Here, 2 versions have to
be distinguished.
4-draught steam boiler with bypass
By installing a bypass, an operation independently of the
CHP module is possible. Instead of shutting down the
CHP module in case of a boiler fault or after achieving
the boiler target pressure, the bypass mode is activated,
thus current and LT heat continue to be produced.
Also during maintenance on the steam boiler, the CHP
module can be operated in bypass mode, but is has to
be observed that all inspection apertures on the flue gas
side are closed during operation of the CHP module to
prevent reverse flow of fuel.
Fig. 10 4-draught steam boiler with bypass
Changing from normal to bypass operation is effected
via pneumatically controlled flaps in the flue gas line of
the CHP module. Here one of the bypass flaps is opened
and subsequently the flue gas line leading to the fourth
draught of the boiler is closed. The flue flows unused
directly to the chimney, and passes the boiler and
possibly existing economisers. It has to be observed that
always one flue gas path is open and that both flue gas
paths are never closed at the same time. The flap control
is monitored with regard to safety, so that at eventual
faults, the system is securely shut down.
20
The bypass operation should only be used
for a limited time.
Otherwise all heat contained in the flue is
lost, because no flue gas heat exchanger is
connected to the bypass. In consequence,
the efficiency of the total plant is
considerably reduced.
Systemlösung – 6 720 885 509 (2018/03)
6 720 819 535-06.1T