Lyngso Marine
PARAMETER CHANGES MAY ONLY BE DONE BY AUTHORISED PERSONNEL
2.4 Sea Water Systems
2.4.3 Engine Room Ballast System
The aft peak can be used as a ballast tank. It is used in conjunction with the main ballast system to trim the vessel. It can also be used during certain loaded conditions to provide optimum trim for efficient operation of the main engine.
The aft peak tank is serviced by the bilge, ballast and fire pump with the main fire pump available, if required.
The aft peak tank has a filling/suction valve, which is normally used during ballast operations. This stops the level in the aft peak tank falling below the propeller shaft. This level is maintained to provide an element of cooling to the stern tube. Another suction valve, which is normally blanked, is provided to empty the tank completely for maintenance and inspection.
Procedure for Ballasting/Deballasting the Aft Peak Tank Ballasting
a) Ensure that the transmitters for the remote reading gauges are in operation.
b) Set up the valves as shown below.
All valves are in the closed position including fire main valves Bilge, Ballast and Fire Pump
Position Description Valve
Open Aft Peak Ballast Tank Suction /Filling Valve QD40 Open Bilge, Ballast and Fire Pump Sea Suction Valve QD27 Closed Bilge, Ballast and Fire Pump Discharge Valve QD34
Open Discharge Valve to Aft Peak Tank QD42
Start the Bilge, Ballast and Fire Pump.
c) Open the discharge valve QD34 slowly until the discharge piping is pressurised.
d) Fill the tank to the required level.
e) Shut the pump discharge valve and stop the pump.
f) Close all valves.
No.1 Bilge, Fire and G.S. Pump
Position Description Valve
Open Aft Peak Ballast Tank Suction /Filling Valve QD40
Open Main Fire Pump Sea Suction Valve QD28
Closed Main Fire Pump Discharge Valve QD30
Open Discharge Valve to Aft Peak Tank QD29
Start the Main Fire Pump.
a) Open the discharge valve QD34 slowly until discharge piping is pressurised.
b) Fill the tank to the required level.
c) Shut the pump discharge valve and stop the pump.
d) Close all valves.
Deballasting
a) Ensure that the transmitters for the remote reading gauges are in operation.
b) Set up the valves as shown below.
All valves are in the closed position including fire main valves Bilge, Ballast and Fire Pump
Position Description Valve
Open Aft Peak Ballast Tank Suction Valve QD40 Closed Bilge, Ballast and Fire Pump Sea
Suction /Filling Valve QD27
Closed Bilge, Ballast and Fire Pump Discharge Valve QD34 Open Bilge, Ballast and Fire Pump
Ballast Suction Valve QD35
Open Bilge, Ballast and Fire Pump
Discharge to Overboard QD33
Open Overboard Discharge QD45
Start the Bilge, Ballast and Fire Pump
c) Open the discharge valve QD34 slowly until the discharge piping is pressurised.
d) Empty the selected tanks, taking care that the pump is not run dry.
e) Shut the pump discharge valve and stop the pump.
f) Close all valves.
No.2 Bilge, Fire and G.S. Pump
Position Description Valve
Open Aft Peak Ballast Tank Suction /Filling Valve QD40
Closed Main Fire Pump Sea Suction Valve QD28
Closed Main Fire Pump Discharge Valve QD30
Open Main Fire Pump Ballast Suction Valve QD31 Open Main Fire Pump Discharge to Overboard QD32
Open Overboard Discharge QD45
Start Main Fire Pump Pump
a) Open the discharge valve QD30 slowly until the discharge piping is pressurised.
b) Empty the selected tanks, taking care that the pump is not run dry.
c) Shut the pump discharge valve and stop the pump.
d) Close all valves.
e) Line up the pump for fire main duty.
If the tank is to be completely emptied, for tank inspections etc., swing spectacle piece QD98 and open valve QD41.
Aft Peak Tank
Stern Tube Cooling Water
Tank
Fresh Water Generator
PI
Chemical Solution Tank
Key
Fresh Water
H.T. Cooling Water
Sea Water
P P T
V
QT
To Bilge Holding Tank
TG15
Illustration 2.4.4a Evaporator
TI
FQ
Flowmeter Including Regulating
Valve
From Fresh Water System In Engine Room
TG13 TG11
TG12
TG14 Ejector Pump
Distillate Pump
From Main Sea Water Pipeline P
T
T
P From Fresh
Water Filling Line on Deck
To/From Fresh Water H.T. Cooling
System Fresh Water
Tank (Port)
Fresh Water Tank (Starboard)
Distilled Water Tank
TG9
TG23
TG7 TG4
TG2
TG3
TG20 TG21
TG27
TG26
TG25
From Service System In Engine Room
TG24 TG22
Reharding Filter Steriliser
2.4.4 Evaporator
Maker: Alfa Laval
Type: JWP-26-C100
Capacity; 25 m3/24h
One evaporator is installed which utilises the heat from the main engine jacket cooling water system.
The combined brine/air ejector, driven by the ejector pump, creates a vacuum in the system in order to lower the evaporation temperature of the feedwater.
The ejector pump takes suction from the main seawater suction line. The feedwater is introduced into the evaporator section through an orifice and is distributed into every second plate channel (evaporation channels).
The hot water is distributed into the remaining channels, thus transferring its heat to the feedwater in the evaporation channels.
Having reached boiling temperature - which is lower than at atmospheric pressure - the feed water undergoes a partial evaporation. The mixture of generated vapour and brine then enters the separator vessel, where the brine is separated from the vapour and extracted by the combined brine/air ejector.
After passing through a demister the vapour enters every second plate channel in the condenser section.
The sea water, supplied by the combined cooling/ejector water pump, distributes itself into the remaining channels, thus absorbing the heat being transferred from the condensing vapour.
The fresh water produced is extracted by the freshwater pump and led to the freshwater tanks.
Freshwater Quality
To continuously check the quality of the produced freshwater, a salinometer is provided together with an electrode unit fitted on the freshwater pump delivery side.
If the salinity of the fresh water produced exceeds the chosen maximum value, the dump valve and alarm are activated to automatically dump the fresh water to the bilge.
Main Components
The freshwater generator consists of the following components:
Evaporator
The evaporator consists of a plate heat exchanger and is enclosed in the separator vessel.
Separator vessel
The separator separates the brine from the vapour.
Condenser
The condenser section, like the evaporator section, consists of a plate heat exchanger enclosed in the separator vessel.
Combined brine/air ejector
The ejector extracts brine and incondensable gases from the separator vessel.
Ejector pump
The ejector pump is a single-stage centrifugal pump which supplies the condenser with sea water and the brine/air ejector with jet water, it also supplies feed water for evaporation.
Freshwater pump
The freshwater pump is a single-stage centrifugal pump which extracts the produced fresh water from the condenser, and pumps the water to the freshwater tanks.
Salinometer
The salinometer continuously checks the salinity of the produced water. The alarm set point is adjustable.
Control panel
The control panel contains motor starters, running lights, salinometer and contacts for remote alarms.
Operating Procedures
WARNING
Do not operate the plant in polluted water. Fresh water must not be produced from polluted water, as the produced water will be unsuitable for human consumption.
Starting
a) Open valves on the suction (TG15) and discharge side (TG13) of the ejector/cooling water pump.
b) Open the overboard valve (TG15) for the combined brine/air ejector.
c) Close air screw (vacuum release valve) on the separator.
d) Start ejector pump to create a 90% minimum vacuum.
Pressure at the combined brine/air ejector inlet should be a minimum of 3.0 kg/cm2. Back pressure at the combined brine/air ejector outlet should be no more than 0. 6 kg/cm2.
Evaporation
When there is a minimum of 90 % vacuum (after a maximum 10 minutes):
e) Open the valve for feedwater treatment. Ensure chemical dosing tank is full.
f) Open the jacket water inlet (TG11) and outlet (TG12) valves.
g) Start the hot water supply to the distiller by adjusting the jacket water bypass valve to increase the temperature in steps of 10°C, until the desired jacket water temperature is reached.
The boiling temperature will now rise, whilst the obtained vacuum drops to approximately 85%.
This indicates that evaporation has started.
Condensation
After approximately 5 minutes the boiling temperature will drop again and a normal vacuum is re-established.
h) Open the valve to the freshwater tank.
i) Switch on the salinometer.
j) Start the freshwater pump.
(Note ! The freshwater pump discharge pressure must be between 1.2 - 1.6 kg/cm2.) Adjustment of Jacket Water Flow
In order to obtain the specified flow of hot water, it is necessary to adjust the bypass valve until desired flow is achieved. For maximum output the outlet temperature of the heating water should be about 68.5ºC
Adjustment of Sea Water Flow
The sea water flow is correct when the inlet pressure at the inlet to the brine/air ejector is between 3.0 - 4.0 kg/cm2.
Stopping the Plant
a) Stop the distillate pump.
b) Switch off the salinometer.
c) Stop the ejector pump.
d) Close the valve for feedwater treatment.
e) Open the air screw (vacuum release valve).
f) Close the inlet and outlet valves for the ejector pump.
g) Close the overboard valve for the combined brine/air ejector.
h) Close the valve to the water tank being filled.
! CAUTION
All valves must be shut, while the generator is out of operation, except the air screw release valve.
Aft Peak Tank
Stern Tube Cooling Water
Tank
Fresh Water Generator
PI
Chemical Solution
Tank
Key
Fresh Water
H.T. Cooling Water
Sea Water
P P T
V
QT
To Bilge Holding Tank
TG15
Illustration 2.4.5a Distilled W ater and Distribution Transfer System
TI
FQ
Flowmeter Including Regulating
Valve
From Fresh Water System In Engine Room
TG13 TG11
TG12
TG14 Ejector Pump
Distillate Pump
From Main Sea Water Pipeline P
T
T
P From Fresh
Water Filling Line on Deck
To/From Fresh Water H.T. Cooling
System Fresh Water
Tank (Port)
Fresh Water Tank (Starboard)
Distilled Water Tank
TG9
TG23
TG7 TG4
TG2
TG3
TG20 TG21
TG27
TG26 QG51
QG24
TG25
From Service System In Engine Room
TG24 TG22
Reharding Filter Steriliser
Boiler Hot Well