Working Principle - Danfoss Ammonia IPS 8 User Manual

User Guide | Intelligent Purging System (IPS 8) Ammonia

Working principle

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The Danfoss IPS 8 is factory-tested and ready to
use in ammonia plants with a condenser pressure
of more than 6,5 bar (94 psi). The purger is
charged with 900 gram (31.7 oz) of R452A.
Only 1 mechanical connection is needed for the
purger (see fig. 1). The flow of ammonia/NC gases
from the main plant is done through the flange
for ammonia (see 13 in Fig. 1 below), while the
NC gas purge is done through the blow-off pipe
after the purge restrictor (18).
Through the flange for ammonia (13), a mixture
of ammonia gas and NC gases enters the heat
exchanger (12) part of the purger.
The ammonia gas/NC gas mix is cooled down
below the condensing temperature of the
ammonia by the R452A circuit. At this point,
ammonia gas condenses and returns by gravity
to the ammonia plant whereas the NC gases
accumulate in the heat exchanger (12) for
subsequent purging.
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4
3
2
1a
1
Fig. 1 - Purger R452A lay-out
Compressor (900 gram (31.7 oz) R452A) controlled via Digital
1
Output, DO1
1a Compressor Cranck case heater
2
Thermostat for crankcase heater control
3
Discharge temp sensor R452A via Analog Input AI3, Pt 1000
Suction temperature sensor R452A via Analog Input AI4, Pt
3a
1000
4
Pressure safety switch
5 Condenser
6 Extraction fan
7
Pressure switch for Condenser Fan
8
Receiver
9
Filter
10 Sight glass
By condensing the ammonia gas, a new
ammonia/NC gases mix is naturally pulled
through. This new mix is separated through a
continuous process.
As the NC gas concentration in the heat
exchanger (12) increases, the R452A heat
exchanger pressure and temperature will
simultaneously decrease.
The controller continuously monitors the R452A
heat exchanger pressure as well as ammonia
pressure and temperature. When the R452A
pressure reaches a predefined pressure difference
when compared with the ammonia pressure
(temperature) it prepares to purge the NC gases
through the solenoid valve (16). The blow-off
is activated by the solenoid (16) and through
appropriate piping/hosing, should be led into
a water bath. This process is recommended
to retain small amounts of ammonia (see
Installation section).
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9
8
3a
14
12
11 Expansion valve, R452A
12 Heat exchanger Ammonia/R452A
13 Welding Flange
Pressure transmitter R452A. Measured via via Analog Input
14
AI1, Pressure transmitter, AKS 32R
Pressure transmitter R717. Measured via Analog Input, AI2,
15
Pressure transmitter, AKS 2050
16 Main Purge Valve controlled via Digital Output, DO2
NC temperature sensor R717. Measured via Analog Input,
17
AI5, Pt1000
18 Restrictor, purge line
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10
11
15
16
13
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