Marine Installation Manual
2022-03
4-97
4 Ancillary Systems
4.9 Leakage collection system and washing devices
X62DF-S2.0
Figure 4
-
57 The iCER drainage system for installations with only gas mode operation
Arrangement of the iCER drainage system for installations which include iCER
diesel Tier III mode operation
During diesel Tier III mode operation, soot can be found in the EGC circulation
water. This must be removed by a water treatment unit. The design of this water
treatment unit may vary depending on the supplier. In addition, as the ultra-low
sulphur MGO with a maximum content of 0.10% m/m sulphur is not sul
-
phur-free, neutralisation of the resulting acids is required. For this purpose, a
dosing unit for caustic soda (NaOH) is required for the EGC circulation water.
The dosage amount is controlled by the water analyser which measures the
acidity of the EGC circulation water in a bypass stream. The caustic soda dosing
system is designed for an aqueous solution consisting of a maximum concentra
-
tion of 50% m/m NaOH. Alternatively, the design can also be made for solutions
with lower concentrations, typically for 25% or 30% m/m NaOH.
If the oil-in-water content of the bleed-off water and the SAC drain water (during
iCER operation) exceed 15 ppm, then the water is stored in the EGC drain tank.
During iCER diesel Tier III mode operation, the SAC drain water must be di
-
rected through a pH-neutralisation dosing unit before being drained to the EGC
drain tank. This ensures that the water in the EGC drain tank maintains a proper
pH value (e.g. above pH 6).
SM-0624
EGC
Water
treatment
unit
(with coagulant dosing,
if required)
pH
o/w
1 EGC circulation water cooler
2 EGC circulation water pumps
(frequency controlled)
3 Oil-in-water (o/w) monitoring sensor
(UV-type)
4 pH sensor
5 Level transmitter
6 High-level switch
1
2
Overboard
EGC circulation water system
Bleed-off system
Bleed-off handling system
pH-neutralisation dosing unit
Venting pipes
SAC drain
EGC
drain
tank
3
3
pH-neutra-
lisation
dosing
unit
4
o/w
EGC
circulation
water tank
Fresh water
refill
from SAC drain during
iCER operation
with manual
override
LT
LSH
6
5
NOTE
According to resolution MEPC 307(73), a water treatment system for
iCER operation in gas mode is required, if the oil-in-water content is
above 15 ppm.
