There are three kinds of semi-automatically operated sequences in the IAS:
z Stripping pump start sequence
z Cargo unloading sequence
z Ballasting/Deballasting sequence 4.3.4.1 Stripping pump start sequence
The stripping pump start sequence is prepared in the IAS for each cargo tank respectively and is used for cargo tank/line cool down or supplying LNG to LNG/forcing vaporizer for gas generation.
The sequence start is done from the IAS group display G046, G047, G048 and G049.
The stripping pump start sequence controls and monitors the following equipment.
z Stripping pump discharge valves
z Stripping pump return valves (Strip/spray header pressure control valve)
z Stripping pumps.
z Stripping pump load controller’s initial set value
z Stripping/spray header pressure controller’s initial set value Operation of stripping pump start sequence is as follows;
z Check the strip and cool down line-up status at the IAS graphic display.
z Manually preset desired initial value before start sequence at the IAS graphic display C59:
¾ Discharge valve initial opening percent
¾ Pump load controller’s initial load percent
¾ Strip header pressure controller’s initial setting
z Start the sequence from the IAS group display G046, G047, G048 and G049 by changing PV status from
“STOP” to “START” for each cargo tank respectively.
z Sequence will automatically control related equipment.
z After start sequence, manually adjust set point of the strip header pressure controller and pump load controller.
START
PRE-SET POSITION DISCHARGE VALVE
END SEQ START/STOP
SWITCH = START
N
ABNORMAL STOP CONDITION STRIP PUMP START SEQUENCE
STRIP RETURN V/V SP 100 %
RUN STRIP PUMP
WAIT 5 SECS
SET PRESET VALUE OF PUMP LOAD TO STRIP PUMP LOAD
CONTROLLER
SET PRESET VALUE OF STRIP HDR PRESS TO STRIP HDR
PRESS CONTROLLER
START CONTROL*1
ACTIVATE CHIME(10 SECS)
SEQ START/STOP SWITCH="STOP"
*1 DISCHARGE V/V POSITION CONTROLLER MODE : CAS STRIP PUMP LOAD CONTROLLER MODE : AUTO STRIP RETURN V/V POSITION CONTROLLER MODE : CAS STRIP HDR PRESS CONTROLLER MODE : AUTO
- ESDS
- No.1~4 TK PROTECTION - CARGO TK LEVEL <= LOWLOW - CARGO TK LEVEL >=HIGH - CTS ABNORMAL
- SEQUENCE STOP REQUEST - DISCHARGE VALVE FAIL LIST - DISCHARGE VALVE DEV ALARM - STRIP PUMP RETURN V/V FAIL LIST - STRIP RETURN VALVE FAIL LIST - STRIP RETURN VALVE DEV ALARM - STRIP PUMP AMMETTER BAD PV - STRIP HEADER PRESS BAD PV - DISCHARGE V POSITON BAD PV - STRIP RETURN V POSITION BAD PV
- SAME AS THE *A1 MARK - PUMP STOP
*A1 Y
4.3.4.2 Unloading sequence
Unloading sequence is prepared from the IAS for each cargo tank respectively and is used for automatic starting of the cargo pump and discharge LNG to shore.
This sequence will be activated when the sequence start software point is changed from off to on. The sequence start software point is arranged in the IAS group display.
The IAS sequence has two kinds of discharging steps, 4 step and 8 step.
The discharging step is selected from the guidance schematic display C31 during the preparation of LNG discharging. The 8 step/4 step selection cannot be done during running of any sequence.
The unloading sequence controls and monitors the following equipment.
z Cargo pump discharge valves control
z Cargo tank filling valve control
z Cargo tank liquid isolating valve control
z Cargo pumps control
z Cargo pump load controller’s initial set value
z Cargo tank level low monitoring
Operation of the cargo pump start sequence is as follows:
z Check the guidance items, start from the guidance display C36
¾ On the operation plan display C31, select PORT/STBD side and manifold line to discharge LNG to shore.
¾ Select sequence step (8step or 4step)
z Manually preset desired initial values before starting sequence on the IAS graphic display C31.
¾ Discharge valve initial opening percent
¾ Pump load controller’s initial load percent
¾ Pump stop level
z Check valve fail status on C34.
z Check Line-up status on C42, C43 and C44.
¾ Check the line status around tanks, liquid manifold line and vapor header line.
z Sequence will automatically control related equipment.
*A1 START
SEQ START/STOP SWITCH = "START"
N
ABNORMAL STOP CONDITION UNLOADING SEQUENCE
OPERATION MODE IS SELECTED
N
SEQ START/STOP SWITCH STOP
RUN PUMP ANOTHER CARGO PUMP START FUNCTION IN SAME
TK IS RUNNING
ANOTHER CARGO PUMP IS SAME TK IS RUNNING
Y
Y
Y N
N Y
Y
N
·ESDS
·NO.1~4 TK PROTECTION(OR) ·SEQUENCE STOP REQUEST ·CARGO PUMP AMMETER BAD PV
·CARGO PUMP DISCH VALVE POSITION BAD PV ·CARGO PUMP DISCH VALVE POSITION DEV ALARM ·CARGO PUMP DISCH VALVE V FAIL LIST
· CARGO TK FILL V POSITION BAD PV
· CARGO TK FILL V POSITION DEV ALARM
· CARGO TK FILL V POSITION V FAIL LIST
OWN CARGO PUMP IS RUNNING
SET PRE-SET VALUE OF CARGO PUMP DISCHARGE VALVE
POSITION TO CONTROLLER
FULL OPEN FILLING VALVE
*A2 5
2 Y
1
(MODE:P-AUTO)
· SAME AS *A1 MARK · SAME AS *A2 MARK · CARGO TK LEVEL <= LOW
z After starting the sequence, adjust set point of the cargo pump load controller
ABNORMAL STOP CONDITION UNLOADING SEQUENCE
<UNLOADING SEQUENCE(2/5)>
DISCHARGE VALVE POSITION CONTROLLER MODE:CAS
SEQ START/STOP SWITCH STOP
N
·SAME AS *A1 MARK ·SAME AS *A2 MARK ·PUMP STOP 1
5
3 WAIT (5SEC)
PER-SET VALUE OF PUMP LOAD TO PUMP LOAD CONTROLLER
LOAD CONTROLLER MODE:AUTO
CARGO PUMP START FUNCTION IS COMPLETED
N ACTIVATE CHIME (10SEC)
8 STEP OR 4 STEP
8STEP
4STEP
*A4 DISCHARGE START
CONDITION CHECK FILLING V POSITION>=95%
AND
LIQ ISO V POSITION<=2%
ABNORMAL STOP CONDITION UNLOADING SEQUENCE
<UNLOADING SEQUENCE(3/5)>
ACTIVATE CHIME(10SEC)
·FIL V <95% OR ISO.V>2%
AND
FIL V >2% OR ISO.V<50%
· SAME AS *A1 MARK · SAME AS *A2 MARK · SAME AS *A3 MARK 2
4
3 8STEP OR 4STEP
*1 DISCHARGE OPERATION START FULL
OPEN
FULL
CLOSE TIME
(SEC) LIQ ISO
VALVE
FULL OPEN
FULL
CLOSE TIME
(SEC) FILL
VALVE
A B
C 5sec 35sec
60sec 3
NOT COMPLETED NO
CONPLETED Y
8 STEP 4 STEP
·SAME AS *A1 MARK ·SAME AS *A2 MARK ·PUMP STOP
·CARGO TK LIQ ISO V POSITION BAD PV ·CARGO TK LIQ ISO V DEV ALARM ·CARGO TK LIQ ISO V FAIL LIST
*A3
*1 THE SET-POINT OF POSITION CONTROLLER IS SET ACCORDING TO THIS DIAGRAM (MODE:P-AUTO)
DISCHARGE START OPE. FINISH CHECK FILLING V POSITION<=2%
AND
LIQ ISO V POSITION>=50%
N
ABNORMAL STOP CONDITION UNLOADING SEQUENCE
ANOTHER CARGO PUMP IN SAME TK IS RUNNING
<UNLOADING SEQUENCE(4/5)>
SEQUENCE ABNORMAL STOP PROCESSING
Y
8STEP OR 4STEP 4
3
8STEP OR 4STEP N
8 STEP
8 STEP 4 STEP
4 STEP
·SAME AS *A1 MARK ·SAME AS *A2 MARK ·PUMP STOP
Y
N
ABNORMAL STOP CONDITION UNLOADING SEQUENCE
STOP LEVEL>=L0 *2
<UNLOADING SEQUENCE(5/5)>
ACTIVATE CHIME(10SEC)
Y TK LEVEL<=L0 *2 + α1 *4
3
5
TK LEVEL<=
STOP LEVEL + α2 *5
N
STOP *3 STRIPPING
USE *3
·SAME AS *A1 MARK ·PUMP STOP ·CTS ABNORMAL
Y
N N
LOAD CONTROLLER MODE:MAN
REDUCE POSITON DISCHARGE VALVE
WAIT(60SEC)
STOP PUMP
FULL CLOSE DISCHARGE VALVE
PUMP STOP
SEQ START/STOP SWITCH STOP Y
Y
*2 L0:STRIPPING START LEVEL
*3 PUMP STOP LEVEL DECIDES WHETHER A PUMP IS "STOP PUMP" OR "STRIPPING PUMP"
*4 α1 :STRIPPING LEVEL BIAS
*5 α2 :STOP LEVEL BIAS
·SAME AS *A1 MARK ·PUMP STOP
·SAME AS *A1 MARK
4.3.4.3 Ballast/Deballast sequence
The ballasting/deballasting sequences consist of ballast tank fill/suction valve controls and ballast pump control.
The filling/suction valve sequences are composed of the following four parts.
z Forward part (fore peak ballast tank, forward deep ballast tanks )
z Middle forward part (ballast tanks no 1 and 2)
z Middle after part (ballast tanks no 3 and 4)
z After part (engine room ballast tanks and aft peak ballast tank)
The ballasting/deballasting sequence controls and monitors the following equipment:
z Each ballast tank’s filling/suction valves (the operator must adjust manually according to the ballast tank level.)
z Ballast tank level and volume will be displayed on the IAS graphic display.
z Ballast pumps
z Ballast pump discharge valves
z Ballast pump suction valves from sea chest or ballast main line
z Valve from ballast pump to ballast tank
Operation of ballasting/deballasting sequence is as follows:
z Set desired values at pages C32 or C33 according to the ballasting or deballasting plan.
z Check valve fail status on C34.
z Check line-up status on C85 or C86.
z The sequence is started from the IAS group display G076, G077, G078 and G079 by changing the PV from
“STOP” to “START” (use the ‘arrow up’ key) for each part of filling/suction valve group. Filling /suction valve open sequence will be activated.
z Turn on start flag from the IAS group display G081 and G082 in order to start ballast pump.
z Sequence will automatically control the following equipment:
¾ Each ballast tank’s filling/suction valve
¾ Ballast pump
¾ Ballast pump suction valve
¾ Ballast pump discharge valve
¾ Valve from ballast pump to ballast tank.
z Manually adjust each position of the ballast tank’s filling/suction valve.
z Manually adjust ballast pump’s discharge valve in order to control pump’s load.
When the automatic sequence detects an abnormal condition, the sequence will stop and audible alarm will be given.
After recovery, the operator may restart the sequence.
4.3.4.3.1 Ballast tank suction valve sequence
After the sequence has been started from G076, G077, G078 or G079, the filling/suction valve will automatically open to the position set at initial stage.
When the ballast tank’s level reaches the high or low setting level, the filling/suction valve will automatically close to the throttling position with high or low level alarm sounding.
When the ballast tank’s level reaches the high-high or low-low setting level, the filling/suction valve will be fully closed by the sequence with high-high or low-low level alarm sounding.
Abbreviation...5 Part 1 Cargo and Ballast System ... 1 - 1 1.1 Cargo Piping System... 1 - 2 1.1.1 Liquid, Vapour, Spray Pipes... 1 - 2 1.1.2 Gas Line (One Tank Operation) ... 1 - 4 1.1.3 Fuel Gas and Vent Pipes... 1 - 4 1.1.4 Inerting/Aeration Pipes ... 1 - 4 1.2 Cargo Pumps... 1 - 6 1.2.1 Main Cargo Pumps ... 1 - 8 1.2.2 Stripping/Spray Pumps ... 1 - 10 1.2.3 Emergency Cargo Pump ... 1 - 12 1.3 Cargo Compressors... 1 - 14 1.3.1 HD Compressors... 1 - 14 1.8 Custody Transfer System... 1 - 30 1.8.1 Radar-Based Level Gauge ... 1 - 30 1.8.2 System Readout and Control ... 1 - 32 1.8.3 Float Level Gauge... 1 - 40 1.8.4 Trim-List Indicator ... 1 - 42 1.9 Nitrogen Production System ... 1 - 44 1.10 Inert Gas and Dry Air System... 1 - 46 1.11 Gas Detection System ... 1 - 48 1.12 Cargo and Ballast Valve Control ... 1 - 50 1.12.1 Cargo and Ballast Control System... 1 - 50 1.12.2 Emergency Shutdown System ... 1 - 54 1.12.3 Ship Shore Link ... 1 - 56 1.12.4 Mooring Load Monitoring System ... 1 - 60 1.13 Relief Systems ... 1 - 62 1.13.1 Cargo Tank Relief Valves... 1 - 62 1.13.2 Insulation Space Relief Valves ... 1 - 62 1.13.3 Pipe Relief Valves ... 1 - 62 1.14 Ballast Level and Draft Indicating System ... 1 - 64 1.15 Fuel Oil Bunkering and Transfer Systems ... 1 - 66
2.2 Insulation Space Nitrogen Control System ... 2 - 4 2.3 Cofferdam Glycol Heating System ... 2 - 6 2.3.1 Hull Ventilation ... 2 - 10 2.4 Fire Fighting System... 2 - 12 2.4.1 Fire Protection and Wash Deck... 2 - 12 2.4.2 Water Spray System... 2 - 14 2.4.3 Dry Powder System ... 2 - 16 2.4.4 CO2 System ... 2 - 18 2.4.5 Fire Detection System... 2 - 20 2.5 Auxiliary FW Cooling System... 2 - 22 2.6 Steam Condensate System ... 2 - 23 2.7 Bilge and Scupper System ... 2 - 26 2.8 Instrument Air System ... 2 - 27 2.9 Emergency Air System ... 2 - 28 Part 3 Cargo Operations... 3 - 1 3.1 Insulation Space Tests... 3 - 1 3.2 Post Dry Dock Operation ... 3 - 3 3.2.1 Insulation Space Inerting ... 3 - 3 3.2.2 Drying Cargo Tanks... 3 - 7 3.2.3 Inerting Cargo Tanks ... 3 - 9 3.2.4 Gassing-up Cargo Tanks... 3 - 11 3.2.5 Cooling Down Cargo Tanks ... 3 - 15 3.3 Ballast Passage... 3 - 17 3.3.1 Cooling Down Tanks Prior to Arrival... 3 - 19 3.3.2 Spraying During Ballast Voyage ... 3 - 21 3.4 Loading ... 3 - 23 3.4.1 Preparations for Loading... 3 - 23 3.4.2 Cargo Lines Cool Down ... 3 - 23 3.4.3 To Load Cargo with Vapour Return to Shore ... 3 - 27 3.4.4 Nitrogen Set-up During Loading ... 3 - 31 3.4.5 De-Ballasting ... 3 - 33 3.5 Loaded Voyage with Boil-Off Gas Burning ... 3 - 35 3.5.1 Normal Boil-Off Gas Burning ... 3 - 35 3.5.2 Forced Boil-Off Gas Burning ... 3 - 37 3.6 Discharging with Gas Return from Shore ... 3 - 39 3.6.1 Preparations for Unloading ... 3 - 39 3.6.2 Liquid Line and Arm Cooldown before Discharging ... 3 - 42 3.6.3 Discharging... 3 - 44 3.6.4 Ballasting ... 3 - 47
3.7.2 Tank Warm Up... 3 - 51 3.7.3 Inerting ... 3 - 53 3.7.4 Aeration... 3 - 55 Part 4 Integrated Automation System (IAS)... 4 - 1 4.1 General ... 4 - 3 4.2 Hardware ... 4 - 6 4.3 Operation... 4 - 7 Part 5 Emergency Procedures... 5 - 1 5.1 Vapour Leakage ... 5 - 2 5.2 Liquid Leakage... 5 - 4 5.3 Water Leakage to Barrier Space... 5 - 7 5.4 Fire and Emergency Breakaway... 5 - 7 5.5 Emergency Cargo Pump Installation... 5 - 9 5.6 One Tank Operation ... 5 - 11 6.1 Principal Particulars ... 6 - 1 6.2 Rules and Regulations... 6 - 7 6.3 Design Concept of the Cargo System... 6 - 9 6.3.1 Cargo Containment System Principle ... 6 - 9 6.3.2 Membrane Cargo Containment ... 6 - 10 6.3.3 Deterioration or Failure... 6 - 15 6.4 Hazardous Areas and Gas Dangerous Zone ... 6 - 17 Part 7 Properties of LNG... 7 - 1 7.1 Physical Properties, Composition and Characteristics of LNG... 7 - 1 7.2 Characteristics of LNG... 7 - 4 7.2.1 Flammability of Gases ... 7 - 4 7.2.2 Supplementary Characteristics... 7 - 5 7.2.3 Avoidance of Cold Shock to Metal ... 7 - 6 7.3 Health Hazards ... 7 - 7