lchs 4000 lng description of system eng

8/9/2019 LCHS 4000 LNG Description of System Eng

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© Transas Ltd. November, 2005

LCHS 4000LCHS 4000LCHS 4000LCHS 4000

LNG TANKERLNG TANKERLNG TANKERLNG TANKER

DESCRIPTION OF SYSTEMS


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© 2005, D.Kazunin PhD, associated prof., LCHS product manager, Transas Ltd.

© Transas Ltd. 2005

All rights reserved. The information contained herein is proprietary to Transas Ltd.

and shall not be duplicated in whole or in part.

The technical details contained in this manual are the best that are available at the date of issue

but are subject to change without notice. Transas Ltd. pursues the policy of continuous development.

This may lead to the product described in this manual being different from the product delivered after its publication.

Microsoft and Windows are registered trademarks of Microsoft Corporation.

The names of actual companies and products mentioned herein may be the trademarks of their respective owners.


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LCHS 4000. LNG TANKER. Description of Systems. 1

This document contains:

Introduction ................................................................................................................3

Purpose ................................................................................................................3

Printing House Conventions.................................................................................4

Tanks Overview Layout.............................................................................................5

Purpose ................................................................................................................5

System Description ..............................................................................................5

Controls ................................................................................................................5

Indicators, Monitored Parameters ........................................................................5

Alarms ..................................................................................................................6

Protection .............................................................................................................6

Principal Faults.....................................................................................................6

Exercise Limits and Termination ..........................................................................7

Ballast System ...........................................................................................................8

Purpose ................................................................................................................8

System Components ............................................................................................8

Controls ................................................................................................................8

Indicators..............................................................................................................9

Alarms ..................................................................................................................9

Protection .............................................................................................................9

Principal Faults.....................................................................................................9

Exercise Limits and Termination ..........................................................................9

Cargo Handling System (Medium-Liquid) .............................................................11

Purpose ..............................................................................................................11

System Components ..........................................................................................11

Controls ..............................................................................................................11

Indicators............................................................................................................12

Alarms ................................................................................................................12

Protection ...........................................................................................................13

Principal Faults...................................................................................................13

Exercise Limits and Termination........................................................................13

Spray System ...........................................................................................................16

Purpose ..............................................................................................................16


Controls ..............................................................................................................16

Indicators............................................................................................................16

Alarms ................................................................................................................17

Protection ...........................................................................................................17



Cargo Handling System (Gas Medium) .................................................................18

Purpose ..............................................................................................................18


Controls ..............................................................................................................19

Indicators............................................................................................................19

Alarms ................................................................................................................19

Protection ...........................................................................................................20




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LCHS 4000. LNG TANKER. Description of Systems.2

Fuel Gas Supply System ........................................................................................ 21

Purpose.............................................................................................................. 21

System Components ......................................................................................... 21

Controls.............................................................................................................. 21

Indicators ........................................................................................................... 21

Alarms................................................................................................................ 22 Protection........................................................................................................... 22

Principal Faults .................................................................................................. 22

Exercise Limits and Termination ....................................................................... 22

Inert Gas Generation System ................................................................................. 23

Purpose.............................................................................................................. 23


Controls.............................................................................................................. 24

Monitored Parameters ....................................................................................... 24

Alarms................................................................................................................ 25

Protection........................................................................................................... 25

Principal Possible Faults.................................................................................... 25 Exercise Limits and Termination ....................................................................... 26

Nitrogen Generation System.................................................................................. 27

Purpose.............................................................................................................. 27


Controls.............................................................................................................. 27


Alarms................................................................................................................ 28

Protection........................................................................................................... 28

Principal Faults .................................................................................................. 28


Inert Gas Distribution System................................................................................ 30 Purpose.............................................................................................................. 30


Controls.............................................................................................................. 31


Alarms................................................................................................................ 31

Protection........................................................................................................... 31

Principal Fault .................................................................................................... 31



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Introduction


INTRODUCTION

Purpose

The Liquid Cargo Handling Simulator (Liquid Natural Gas Tanker) is intendedfor the training and practising of tanker personnel in the cargo handling and auxiliary

operations control functions in compliance with he requirements of the STCW-95,

MARPOL 73/78 and other international regulations and conventions.

The general description of systems provided in this document is the basis for

familiarizing with the simulator structure and serves for studying the tanker systems

within the framework of standard IMO courses: IMO 2.06 “Cargo and Ballast

Handling Simulator” and IMO 1.01 “Tanker Familiarization”, 1.06 “Specialized

Training for Liquefied Gas Tankers”.

LCHS 4000 LNG simulator models two different types of LNG tankers operating

under the supervision of a single Instructor Console. The first one is a spherical LNG

with Moss type cargo tanks (LNG-s), and the second one is membrane LNG withNo96 type of cargo tanks (LNG-m).

For a prototype, an LNG-s was selected tanker with deadweight 67900 tones, length

overall 290 m, breadth 48 m and depth 27 m. The tanker has been built in

compliance with all the up-to-date requirements. Cargo spaces consist of four self-

supporting independent spherically shaped tanks of B type. Cargo column are

located in the central part of the tank. The cargo is pumped from the bottom by using

submerge electric driven pumps.

For a prototype, an LNG-m was selected tanker with deadweight 62700 tones,

length overall 275 m, breadth 43 m and depth 27 m. The tanker has been built in

compliance with all the up-to-date requirements. Cargo spaces consist of four

non-self-supported membrane tanks Cargo column are located in the afterpeak partof the tank. The cargo is pumped from the bottom by using submerge electric driven

pumps through pipe lines or by portable pump through emergency column.

Ballast tanks are exclusively for receiving clean ballast.

Tonnage and dimensions:

• Deadweight 67.900 t

• Length overall 290.0 m

• Length b.p. 275.0 m

• Breadth moulded 48.1 m

• Depth moulded 27.00 m

• Summer load line draft 11.77 m

Cargo capacities and facilities:

• Cargo 135.000m3

• Water ballast 63.000 m3


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Introduction


Tonnage and dimensions:

• Deadweight 62.700 t

• Length overall 275.0 m

• Length b.p. 260.0 m

• Breadth moulded 43.4 m

•

Depth moulded 26.00 m• Summer load line draft 11.95 m

Cargo capacities and facilities:

• Cargo 130.000m3

• Water ballast 46.000 m3

Operations connected with a transfer of the cargo vapours are performed by

centrifugal compressors installed in a special room on the main deck. During the

transfers, the cargo vapours are supplied to the main boiler where they are burnt,

and if surplus, are released into the atmosphere.

To generate an inert environment in the cargo tanks, auxiliary spaces and pipelines,

inert gas generators are installed. For an inert gas either nitrogen or carbon dioxide

can be used.

All the tanker systems except ballast system are implemented as a linear structure.

Tanker systems are considered below.

Printing House Conventions

Sample of notation Usage comments

“Open Sea” To highlight names of windows, pages, buttons, etc.


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Tanks Overview Layout


TANKS OVERVIEW LAYOUT

Purpose

General information on the location of tanks on board the ship and in-tank

parameters. There are indicators of main parameters: metal temperatures in 5vertical points and gas pressure, levels in cargo the tanks and level in ballast tanks.

System Description

The essential system equipment is shown in the drawing (see Fig 1, 2).

The system shows information about:

• General tank location on bard the ship: ballast and cargo tanks and auxiliary

Engine Room tanks;

• General in-tanks information;

• For LNG-s: annular/hold space information;

• For LNG-m: primary/secondary barrier void space information.

Controls

There are no controls on the screen.

Indicators, Monitored Parameters

• Tanks location on board the ship:

– for LNG-s:

22 Ballast tanks: BS1P, BD2P, BS4P, BD5P, BS7P, BD8P, BS10P,

BD11P – portside tanks; BS1S, BD2S, BS4S, BD5S, BS7S, BD8S,

BS10S, BD11S – starboard tanks; BC3, BC6, BC9-three central tanks;

BFP, BFT – two forepeak tanks; BAP – afterpeak tank;

4 Cargo tanks: C1, C2, C3, C4.

– for LNG-m:

10 Ballast tanks: B1P, B2P, B3P, B4P – portside tanks; B1S, B2S, B3S,

B4S – starboard tanks; BFP, BD – two forepeak tanks;

4 Cargo tanks: C1, C2, C3, C4.

• Level on all tanks;

• Gas pressure and temperature in 5 levels for cargo tanks;

• Gas pressure for annular space (LNG-s) or primary barrier void space (LNG-m);

• Gas and temperature in hold space (LNG-s) or secondary barrier void space

(LNG-m);

• In pop-up window there are: tanks general information: capacity, current level,

cargo density, cargo weight, inlet or out flow rate, average temperature, gas

pressure, concentration (mix indicator).

On the top line (for all screens) there are:

• Brief tanker information: deadweight, displacement, cargo and ballast quantity

in LNG tanks;

• LNG forepeak, middle and afterpeak drafts and list;

•“Open Sea” or “Terminal connection” indicator.


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Alarms

There are tow alarms in ballast tanks:

• High level;

• Low level.

There are three alarms in cargo tanks:

• Very high (99,5%), high-high (98%), high (95%) level;

• Low (10%) and low-low (5%), very low (3%) level.

Protection

There is no protection of the system.

Principal Faults

There are no faults of the system.


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Exercise Limits and Termination

There is no exercise termination.

Fig. 1 LNG-s overview screen

Fig. 2 LNG-m overview screen


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Ballast System


BALLAST SYSTEM

Purpose

The system is used for ballasting operations on the ship. The main purpose of the

system is to ensure the ship trim and stability in order to maintain its seaworthinessand admissible stresses on the hull.

System Components

The system consists of:

• LNG-s ballast tanks including:

– eight portside tanks: BS1P – 2055 m3, BD2P – 3594 m

3, BS4P – 2379 m

3,

BD5P – 4238 m3, BS7P – 2706 m

3, BD8P – 4262 m

3, BS10P – 2462 m

3,

BD11P – 2108 m3;

– eight starboard tanks: BS1S – 2055 m3, BD2S – 3594 m

3, BS4S – 2379 m

3,

BD5S – 4238 m3, BS7S – 2706 m

3, BD8S – 4262 m

3, BS10S – 2462 m

3,

BD11S – 2108 m3;

– three central tanks: BC3 – 1500 m3, BC6 – 1500 m

3, BC9 – 1500 m

3;

– two forepeak tanks: BFP – 7782 m3, BFT – 1500 m

3 (void space);

– afterpeak tank: BAP – 3110 m3.

• LNG-m ballast tanks including:

– four portside tanks: B1P – 4751 m3, B2P – 6182 m

3, B3P – 6233 m

3,

B4P – 5518 m3;

– four starboard tanks: B1S – 4751 m3, B2S – 6182 m

3, B3S – 6233 m

3,

B4S – 5518 m3;

– two forepeak tanks: BD – 1167 m3, BFT – 1780 m3 (void space).

• Ballast tanks communicate with ballast lines via throttling valves:

– throttling valves for filling tanks: Bv…P, Bv…S and Bv…C, Bv6, Bv9, Bv22,

Bv23, Bv24.

• Centrifugal pumps BP…. The pumps have identical characteristics and provide

charging pressure of ~2,8 bar at a flow of ~2.800 m3/h);

• Two sea chests Bch1, Bch2 with strainers;

• Throttling valves on the charging line of each pump: Bv1...Bv3;

• Cut-off valves: BV4… BV19;

• Non-return valve Bv20.

Controls

• ON/OFF pump control buttons;

• Control of cut-off valves;

• Control of variable valves;

• Control of the non-return valve.


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Ballast System


Indicators

• Level indicator (in each tank);

• Animation of pumps BP… operation;

• ON/OFF pump status indicator (for each pump);

• Pressure indicators on the suction and charging lines (for each pump);

• Position indicator for each variable valve;

• Status indicator for each cut-off and non-return valve.

Alarms

• Liquid levels in ballast tanks:

– volume of more than 95 per cent;

– volume of less than 5 per cent.

• Tanker heel of more than 2 degrees (information is output in the LCS program);

• Bending moment and shearing forces exceeding marine limitations (information

is output in the LCS program).

Protection

No protection is provided.

Principal Faults

Faults are set by the instructor. The following types of faults are implemented for the

system components:

• Faults in pumps (Pump switching ON/OFF failure, spontaneous stop);

• Fault in valves (Valve failure to respond: jamming, remote control system failure).


For the training purposes, an exercise is terminated if:

• The tank is overfilled;

• Admissible heel and draft values have been attained.


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Ballast System


Fig. 3 LNG-s Ballast System

Fig. 4 LNG-m Ballast System


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Cargo Handling System (Medium-Liquid)


CARGO HANDLING SYSTEM (MEDIUM-LIQUID)

Purpose

The cargo handling system (liquid lines) is designed for the loading and discharging

of a single cargo grade into/from the four tanks. The system is used for the processof stripping, cooling down, filling of tanks and pipelines with cargo vapours or inert gas.

System Components

The cargo handling system is implemented as a linear structure. The system includes:

• For LNG-s there are four tanks C1, C2, C3, C4, each of them has a volume

of 33750 m3. Tanks are independent, self-supporting, spherically shaped

(“В” type). In an emergency, tanks withstand an excessive pressure of P = 2 bar;

• For LNG-m there are four tanks C1 – 19750 m3, C2 – 37686 m

3, C3 – 38795 m

3,

C4 – 34126 m3. Tanks are membrane, non-self-supported, prismatic form.

In emergency condition tanks discharging by portable cargo pump.

Tanks are fitted out with P/V venting valves which maintain the surplus pressure

of 100-200 mbar under normal conditions. In the emergency conditions,

the safety relief valve pressure setting can be changed.

• Eight main electrically driven centrifugal submerge pumps (Cp11, Cp12),

(Cp21, Cp22), (Cp31, Cp32), (Cp41, Cp42) installed in tanks С1...С4 in pairs.

Each pump’s discharge is ~1350 m³/ hour at P=~ 15 bar;

• Cut-off valves for the communication of (liquid) manifolds (Cv1pL…Cv4pL

on the portside) and (Cv1sL…Cv4sL on the starboard) with shore pipelines;

• Additional cut-off valves for the communication of (liquid) manifolds

(Cv12pL, Cv21pL, Cv34pL, Cv43pL on the portside) and (Cv12sL, Cv21sL,

Cv34sL, Cv43sL on the starboard) with the ship cargo line;

• Throttling valves on the drop line (Cv13, Cv23, Cv33, Cv43);

• Throttling valves on the charging line of pumps (Cv11, Cv12), (Cv21, Cv22),

(Cv31, Cv32), (Cv41, Cv42);

• Pipelines for the distribution of cargo among the tanks;

• Cut-off valves CvL1, CvL2 for the communication of cargo lines with auxiliary

pipelines;

• Spool-pieces Gls1 and CGvLM for connection liquid and gas lines of Cargo

system;

• Spool piece for connection liquid and IGG line.

Controls

System controls are shown on the mnemonic diagram:

• Cut-off valves on drop line (Cv13, Cv23, Cv33, Cv43);

• Throttling valves on the charging line of pumps (Cv11, Cv12), (Cv21, Cv22),

(Cv31, Cv32), (Cv41, Cv42);

• Start/Stop of cargo pumps (Cp11, Cp12), (Cp21, Cp22), (Cp31, Cp32),

(Cp41, Cp42);

• Button for the emergency stop of the gas carrier cargo handling operation;

• Cut-off valves CvL1, CvL2;


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• Cargo distribution cut-off pumps Cv…pL, Cv…sL;

• Spool-pieces Gls1 and CGvLM.

Indicators

• Animation of the pumps operation (Cp11, Cp12), (Cp21, Cp22), (Cp31, Cp32),

(Cp41, Cp42);

• ON/OFF pumps status indicator;

• Cargo pump charging pressure;

• Current in the windings of the cargo pump drive’s electric motor;

• Indicators of the throttling valves’ open position;

• Cargo level, type and density in the tanks;

• Cargo temperature in the tanks: at four two tank height levels;

• Rate of cargo delivery into the tanks;

• Gas pressure and temperature in the tanks;

• Gas medium composition in the tanks;

• Pressure in the cargo line Cg1L, Cg3L.

Alarms

• High level of cargo in the tanks:

– (High) generated at 95 per cent filling of the tank capacity, a warning is provided;

– (High High) generated at 98 per cent filling of the tank capacity, an alarm is

provided;

– (Very High) generated at 99 per cent filling of the tank capacity, an alarm isprovided.

• Low level of cargo in the tanks:

– (Low) low cargo level in the tank (5%);

– (Low Low) very low cargo level in the tank (2%);

– (Very Low) the lowest cargo level in the tank (1%).

• Cargo temperature in the tanks:

– Limit lowest value;

– Limit top value.

• High current in the electric motor windings;

• Low current in the electric motor windings (to prevent the shaft bearings

from operating in the conditions of no lubrication);

• High pressure in the cargo lines.


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Protection

Cargo pumps are stopped automatically in the following cases:

• Low pressure in the tanks;

• High current in the electric motor windings;

• Low current in the electric motor windings (to prevent the sliding bearings

from operating in the conditions of no lubrication);

• Automatic stop of pumps in case of overload.

All the pumps can be stopped simultaneously from the cargo post in the area of the

cargo manifold connection.

Principal Faults


system units:

• Faults in pumps (switching ON/OFF failure, spontaneous stop, cargo pump

break-down);

• Faults in cut-off and throttling valves (valve failure to respond: jamming, remote

control system failure);

• Imperfection of cargo composition characteristics as a result of its mixing and

spoiling.



• Overfilling of a cargo tank, as this causes its destruction;

• Pressure in the cargo lines is 1.5 times the rated value (message about damageconstruction is appear);

• Thermal stress which is a result of the inadmissible change rate of the tank wall

temperature. Admissible values are within 0 – 10 degrees/h interval (message

about damage construction is appear).


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Fig.5 LNG-s Cargo Handling System (afterpeack par)

Fig. 6 LNG-s Cargo Handling System (forpeack part)


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Fig. 7 LNG-m Cargo Handling System (afterpeack part)

Fig. 8 LNG-m Cargo Handling System (forpeack part)


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Spray System


SPRAY SYSTEM

Purpose

The system serves for lowering the temperature of medium in tanks (by atomizing

liquid cargo), cargo pipelines (by filling), and pumping out of cargo residue to the

shore and for other auxiliary operations.

System Components

The system includes:

• Cargo tanks C1….C4;

• Cargo handling system lines with valves;

• 4 centrifugal pumps Cps1….Cps4. Each pump has a discharge of 50 m3/h at

a head of ~ 13.5 bar;

• 4 cut-off valves Cv1….Cv4 which connect deck cargo lines with the charging line

of pumps Cps1….Cps4;• Throttling valves (Cv14, Cv24, Cv34, Cv44) on the pumps’ charging line and on

the drop line (Cv15, Cv25, Cv35, Cv45);

• For LNG-s: Three loop pipelines which are located in the top half of the tank.

Liquid is fed through valves (Cv…6, Cv…7, Cv…8) into these pipelines and is

then atomized through the nozzles into the tank;

• For LNG-m: Two loop pipelines which are located in the top part of the tank.

Liquid is fed through valves (Cv…7, Cv…8) into these pipelines and is then

atomized through the nozzles into the tank.

As a result, there is a drop of the tank medium temperature. Liquid cargo can be

supplied to the loop pipelines both, from pumps Cps1….Cps4, and from the

main cargo pumps.

• Pumps (Cps1,Cps2) and (Cps3,Cps4) can be connected to the main deck small

diameter line via valves CvL12, CvL34. This line communicates with evaporator

Forcing V. via valve CvF, with cargo line via valves CvL3 and CvL…p, CvL…s.,

and also with the Evaporator via valves CvL3, CvV.

Controls

Main units of the control system are shown on the drawings of the cargo handling system:

• Cut-off valves CvL…;

• Throttling valves (Cv14, Cv24, Cv34, Cv44), (Cv15, Cv25, Cv35, Cv45);

• Start/Stop of pumps Cps1…Cps4.

Indicators

• Animation of pumps Cps1…Cps4. operation;

• ON/OFF pump status indicator;

• Charging pressure of pumps Cps1…Cps4;

• Current in the drive electric motor windings;

• Position of cut-off valves CvL…;

• Position of throttling valves (Cv14, Cv24, Cv34, Cv44), (Cv15, Cv25, Cv35, Cv45);

• Cargo levels in tanks C1…C4.


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Spray System


Alarms

No alarms are provided.

Protection

No protection is provided.

Principal Faults


system components:

• Faults in pumps Cps1…Cps4 (Pump switching ON/OFF failure, spontaneous

stop, pump break-down);

• Faults in cut-off and throttling valves CvL…, (Cv14, Cv24, Cv34, Cv44),

(Cv15, Cv25, Cv35, Cv45). (Valve failure to respond: jamming, remote control

system failure).

Exercise Limits and TerminationEmergency termination of an exercise is not provided.


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Cargo Handling System (Gas Medium)


CARGO HANDLING SYSTEM (GAS MEDIUM)

Purpose

The cargo handling system (gas lines) is designed for the gas exchange in the

process of the cargo handling operations performed with the liquid. The system isused for pumping the gas over to the shore and reception of gas from the shore for

filling in the space over the cargo level in the tanks.

In addition, the system is used for the pipeline purging after the end of loading/

discharging, as well as for the process of tank inerting and cooling down of the pipes

and tanks.

System Components

The system is implemented as a linear structure. It includes:

• Four tanks C1, C2, C3, C4;

•

Valves (GCv11,GCv12) (GCv21,GCv22) (GCv31,GCv32) (GCv41,GCv42),which enable the tanks to communicate with the gas line;

• Ship gas line has valves GvL and (Gv1pL, Gv2pL), (Gv1sL Gv2sL) which allow

communication with shore pipeline both, on the portside and starboard;

• Venting devices CGmr1…CGmr4 which are fitted out with safety release valves

which control pressure in the tanks. In the normal conditions, the surplus

pressure of 250 mbar is maintained (valve popping pressure). The valve

actuation pressure is +250 mbar/-40 mbar);

• Two gas centrifugal compressors CHD1, CHD2. The discharge of each

compressor is ~25.500 m³/hour at P=~ 0.96 bar and temperature of –106°C,

(suction pressure of P=~ 0.03 bar, T=-140°С);

• Heat exchanger HD Heater which is used for increasing the gas temperature in

the range of -106°C (Pin=1.96 bar) to +70°C (Pout=1.8 bar). Gases at high

temperature are used for the Warming-up operation;

• Throttling and cut-off valves Gv… for the control of the system;

• Valves Gv1, Gv3 enable the system’s communication with the ship gas main;

• Valves Gv5, Gv7 enable the system’s communication with the gas manifold

which is connected to the shore lines;

• Valves Gv16, Gv11, Gv6 enable the system’s communication with the auxiliary

system which supplies cargo vapours for burning in the engine room boiler;

• Liquid cargo Evaporator which is used for the change of the cargo aggregate

state as a result of throttling and heat influx. Heating is by the water steam fed

from the Engine Room under a pressure of 8 bar and at a temperature of +175

degrees. The evaporator is used for obtaining cargo vapours during the filling of

cargo tanks with gas, during the discharging, emergency cargo transfer, i.e. in

all the cases when it is impossible to receive gaseous cargo from the shore. The

evaporator is used for the generation of nitrogen vapours where liquid nitrogen

is supplied from the terminal. In the discharging mode without return of cargo

vapours to the shore, the output is 11 000 kg/hour (at Pin =2 bar, Tin=-163°C,

Pout=0.3 bar, Tout= -60°C). In the tank gassing-up mode, output is 6716

kg/hour (at Pin =2 bar, Tin=-163°C, Pout=0.3 bar, Tout= +20°C). In an

emergence, the device is used for building up surplus gas pressure of 2 bar in

the tanks (liquid pressure of Pin =5 bar, gas pressure of Pout=2 bar);

• Valves СvV, СvV1, СvV2 enable the supply of liquid cargo to the Evaporator;


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• Spool–pieces Gls2, Gls4 and CGvGM, CGvp0 for connection gas lines

of cargo system;

• Spool piece for connection gas and IGG line.

Controls


• Cut-off valves (Gv1, Gv2, Gv5, Gv6, Gv9, Gv10, Gv11,Gv19, Gv21, Gv23,

Gv26, Cv29, CvV);

• Throttling valves (Gv3, Gv4, Gv7, Gv8, Gv13, Gv12, Gv15, Gv14, Gv18,

Gv27, Gv28);

• Start/Stop of compressors (CHD1, CHD2);

• Auto/Manual operating mode switch; in the automatic mode, gas temperature at the

heat exchanger outlet is analyzed, and control of the bypassing is exercised);

• Valves Gv6, Gv11, Gv16;

• Valves V1, V3 for the supply of steam into the evaporator and cargo heater;

• Spool–pieces Gls2, Gls4 and CGvGM, CGvp0 for connection gas lines

of cargo system;

• P/V spring adjusting.

Indicators

• Animation of compressors operation (CHD1, CHD2);

• Animation of heat exchangers operation (Evaporator, HD Heater);

• Indicator of the automatic control over heat exchangers;

• Compressors charging and suction pressure;

• Indicators of throttling valves open position;

• Gas pressure in the tanks;

• Pressure in the cargo line Cg2G;

• In-tank gas medium monitoring system – carbohydrates, oxygen, carbon dioxide

content and dew point;

• Spool–pieces position;

• P/V spring set parameters.

Alarms• High pressure in the tanks:

– alarm is generated at +220 mbar.

• Low pressure in the tanks:

– alarm is generated at +20 mbar.

• High pressure in the gas line.


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Protection

Compressors are stopped automatically in the following cases:

• Low gas pressure in the tanks;

• High current in the electric motor windings.

Principal Faults


system components:

• Faults in compressors (compressor switching ON/OFF failure, spontaneous stop);

• Faults in valves (valve failure to respond: jamming, remote control system failure).


For the training purposes, an exercise is terminated and message about damage

construction is appear if:

• pressure in the gas lines is more than 1.5 times the rated value;

• low pressure in the tank, as this causes the tank destruction;

• high pressure in the tank, as this causes the tank destruction;

• temperature drop in the tank at a high humidity of the gas medium,

as this causes ice to form and damage to the pump.

For the training purposes, units will be damaged if:

• there are explosive concentrations in the tanks;

• compressor operates with closed valves for a long time.

Fig. 9 Auxiliary systems


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Fuel Gas Supply System


FUEL GAS SUPPLY SYSTEM

Purpose

The system is used for supplying engine room boilers with natural gas and,

simultaneously, for maintaining surplus pressure in the gas tanks within theadmissible limits during the sea passage.

System Components

The system includes the following units:

• Valves (Gv16, Gv11, Gv6) which enable the system’s communication with the

cargo gas lines;

• Mist separator;

• Two gas centrifugal compressors (CLD1, CLD2). The discharge of each

compressor is ~8.500 m³/hour at P=~ 0.96 bar and temperature of –103°C,

(suction pressure of P=~ 0.03 bar, T=-140°С

);• Heat exchanger LD Heater which used for increasing gas temperature in the

range of -103°C (Pin=1.96 bar) to +40°C (Pout=1.8 bar);

• Throttling and cut-off valves Gv… for the system control;

• Valve Gv30 which provides gas supply to the engine room;

• Evaporator Forcing V. which generates additional gas is case of pressure drop

before the compressors. The liquid cargo evaporator changes the cargo’s

aggregate state as a result of heat exchange with the water steam. The

evaporator output is 7000 kg/hour (at Pin =3 bar, Tin=-163°C, Pout=0.2 bar,

Tout= -40°C);

•

Valves СvF, СvF1, СvF2 which provide the liquid cargo supply to evaporatorForcing V.

Controls


• Cut-off valves (Gv11, Gv21, Gv23, Gv9, Gv26, CvF);

• Throttling valves (Gv6, Gv16, Gv20, Gv22, Gv17, Gv16, Gv24, Gv25, Gv30,

CvF2, CvF1);

• Start/Stop of compressors (CLD1, CLD2);

• Auto/Manual operating mode switch;

• Valves V2 and V4 for the supply of heating steam into the evaporator and cargo

heater;

• Automatic valve is controlled via the controller which analyses gas temperature

at the heater outlet.

Indicators

• Animation of compressors operation (CLD1, CLD2);

• Animation of heat exchangers operation (Forcing V., LD Heater);

• Indicator of the automatic control over heat exchangers;

• Compressors charging and suction pressure;

• Indicators of throttling valves open position.


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Fuel Gas Supply System


Alarms

High pressure in the gas line.

Protection

No protection.

Principal Faults


system components:


• Faults in valves (valve failure to respond: jamming, remote control system failure).


For the training purposes, an exercise is not terminated.

For the training purposes, units will be damaged if:

• compressor operates with closed valves for a long time;

• pressure in the gas lines is more than 1.5 times the rated value.

Fig.10 Auxiliary systems


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Inert Gas Generation System


INERT GAS GENERATION SYSTEM

Purpose

The inert gas generation system produces cooled down inert gas. For the inert gas,

carbon dioxideСО2

produced by burning diesel oil, is used.

The system enable performance of auxiliary operations connected with the filling of

cargo lines, tanks and hold spaces with the inert gas, which rules out formation of

explosive gas concentrations in these spaces. In addition, the system is used for

feeding damp or dry air into the tanks, hold space and pipelines.

System Components

The system includes the following units:

• Gear type pumps Ipf1 and Ipf2. The fuel pressure is controlled by recycle valve Iv7.

Pumps taken out of operation are cut off with valves Iv19, Iv21 and Iv20, Iv22;

•

Burner/scrubber;• Air blowers Ib1, Ib2. Air is sucked in from the atmosphere and is fed to the

furnace through cut-off valves Iv18, Iv17. Each air blower has an output of

11000 m3/h at a pressure of P=350 mbar (3500 mmWC);

• Controls of the burner/scrubber furnace device – Burning Control. The unit

controls automatically throttling valves Iv4, Iv7. Throttling valve Iv4 sets the gas

flow through the burner/scrubber;

• Centrifugal pumps Ips1, Ips2 supply water through throttling valve Iv5 to the

burner/scrubber cooling system, and for the spraying used for the cooling of hot

furnace gases. Pumps taken out of operation are cut off with valves Iv14, Iv12

and Iv15, Iv13;

• One automatic refrigerator module Iref which cools down the inert gas.

The cooling is performed for the primary lowering of the inert gases dew point

(to ~+5°C). For the cooling agent, freon R22 is used. The running time is about

7 – 12 minutes;

• Idemister;

• Drying module which consists if two units: Idryer1, Idryer2 containing 4800 kg of

alumina each. For the alumina regeneration, the module includes air blower Ib3

and heater Ih1. The air blower provides an output of 4400 m3/h at 20 mbar

(200 mmWC). The air is supplied from the atmosphere through valve Iv40.

Heater Ih1 ensures the rise of air temperature up to +150 С. A complete

regeneration process takes about 8 hours. (Partial adsorbent regeneration which

occurs after 4 hours of processing is permissible). To cool down aluminiumoxide to the operating temperature range (+3°С – +5°С), gases to air blower Ib3

are supplied through valve Iv41;

• Drying module control valves Iv40…Iv50. Automatic regeneration cycle mode is

provided;

• Non-return valve Iv1 which protects the plant from the gas backflow. Gad is fed

to the cargo gas or liquid line via valve Iv1;

• Automatic valves Iv3 and Iv2 which are controlled at a signal from Ig1 (analyzer

of oxygen content and dew point, temperature and pressure sensors);

• Cut-off valve Iv26 which maintains permanent water level in the burner/scrubber;


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• Unit for the automatic control ( Аuto/Мanual) of inert gas supply to the deck line

through valve Iv2 or gas discharge into the atmosphere via valve Iv3:

– in “ Аuto” mode, the unit receives information and automatically controls

throttling valves Iv2 and Iv3;

– in “Мanual” mode, control of throttling valves Iv2 and Iv3 is exercised

arbitrarily.

Controls

• Burning control:

– selection of the burner start mode;

– operating mode selection: manual/automatic; the automatic start performs the

~ 15 min long plant running program;

– control of the burner/scrubber capacity is exercised by manipulating the valves:

Iv7 – valve for the control of fuel supply in the burner/scrubber;

Iv4 – valve for the control of gas flow through the burner/ scrubber.

– emergency stop.

• Ipf1, Ipf2 fuel pumps start and stop buttons;

• Cut-off valves of fuel pumps Iv19, Iv21 and Iv20, Iv22;

• Air blowers start and stop buttons;

• Refrigerator module start/stop;

• Drying module control valves Iv40…Iv50;

• Spool pieces for the connection with deck lines.

Monitored Parameters

Generated gas flow in the burner/scrubber (BURNING CONTROL panel):

• Gas colour – Smoke (BURNING CONTROL panel);

• Fuel and air flow (BURNING CONTROL panel);

• Water temperature, pressure Ig5 at the burner/scrubber inlet;

• Oxygen temperature and cubic contents in gas at the outlet from burner/

scrubber Ig3;

• Water temperature in burner/scrubber Ig4;

• Gas temperature at the outlet from refrigerator module Ig7;

• Gas temperature at the inlet to regeneration plant Ig6;

• Gas temperature and pressure at the outlet from regeneration plant Ig8;

• Gas temperature at the outlet from drying module Ig9;

• Temperature, pressure, cubic content of oxygen and dew point of the gas at the

plant outlet.


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Alarms

• High temperature of gases Ig3 at the outlet from the burner/scrubber;

• High cubic content of oxygen at the outlet from the burner/scrubber;

• High/low gas pressure Ig1;

• High oxygen and moisture content in the generated gas Ig1;

• High temperature of gases at the plant outlet Ig1;

• Low water pressure that the inlet to burner/scrubber Ig5;

• High water level in burner/scrubber Ig4;

• Alarm is generated in case of an emergency stop of the burning process in the

burner/scrubber.

Protection

• In case of high temperature Ig3 of gases at the outlet from the burner/scrubber,

fuel pumps Ipf1, Ipf2 are stopped;

• In case of high water level Ig4 in the burner/scrubber, fuel pumps Ipf1, Ipf2 are

stopped;

• In case of high oxygen (О2) and humidity content, gas pressure Ig1, valve Iv2 is

closed and valve Iv3 opens up;

• In case of low pressure (BURNING CONTROL) of fuel and cooling water Ig5,

fuel pumps Ipf1, Ipf2 are stopped;

• The heater is turned off in case of high temperature in the drying module;

• The heater is turned off if air blower Ib3 does not operate for 5 minutes.

Principal Possible FaultsFaults are set by the instructor. The following types of faults have been implemented

for the system units:

• break-down and unsteady operation of the burner/scrubber air blowers;

• stop of burning in the burner/scrubber in case low-quality burning of fuel, high

temperature of exhaust gases and high О2 percentage in them;

• break-down and unsteady operation of fuel pumps;

• breakdown and unsteady operation of the burner/scrubber cooling pumps;

• breakdown of the regenerator air blower;

• faulty valves.


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• inert gas (СО2) is fed into the tanks where the temperature is below minus 45°С,

as this causes crystallization of carbon dioxide in these tanks;

• inert gas with inadmissible parameters is fed into the tanks.

Fig. 11 Inert gas generation system


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Nitrogen Generation System


NITROGEN GENERATION SYSTEM

Purpose

The system is intended for the generation of nitrogen which is used as an inert gas

for the purging of cargo lines; drying of tank insulation and surface, cargo pumps,compressors, heaters. The system maintains surplus pressure in the annular space,

gas seals. The use of nitrogen rules out formation of explosive gas concentrations in

these spaces.

System Components

The nitrogen generation system includes:

• Two screw air compressors cooled with water. Each compressor has a

discharge of 285 Nm3/h of gas at P=10 bar. At the compressors outlet, the air

passes through the special filter and air refrigerator cooled with water. This

results in the primary separation of moisture and oil vapours. The temperature of

air at the outlet should not be more than 45°С;

• Two electric heater. In the heater, the air is heated to 50°С, where after is it fed

to the diffusive generators;

• Two diffusive type generators. The heated air is supplied to the generator where

oxygen and moisture are separated. The separated components are discharged

to the atmosphere, and the nitrogen is fed to the gas analyzers. Each generator

has an output of 60 Nm3/h of gas which contains 97 per cent of nitrogen and has

a dew point of –70°C. The simulator uses the diaphragm type generator where

nitrogen is passed through the diaphragm. Oxygen stays before the diaphragm

and is discharged into the atmosphere;

• Throttling valves (Iv78, Iv77) (Iv76, Iv75) which determine oxygen/nitrogen ratio at

the plant outlet. These valves maintain the compressor pressure at about 9.5 bar;• Four control valves (Iv82, Iv81) (Iv80, Iv79) which maintain the nitrogen

concentration of more than 97 per cent in the mixture. Otherwise gas is

discharged into the atmosphere through Iv83;

• Buffer tank. In the 10 m3 tank, pressure of 5 – 8 bars is maintained. With the

pressure drop to less than 3 bars, the compressor have to be started; it will be

turned off at a pressure of 7 bars;

• Cut-off control valves;

• System of pipelines;

• Nitrogen supply to High Duty compressor seals.

With two compressors and two generators operating, the output of 120 Nm3/h is

provided.

Controls

The nitrogen generator consists of two single type modules controlled separately.

The main module controls are:

• Turning ON/OFF of water supply to the compressor and air refrigerators;

• Turning ON/OFF of the air compressor;

• Compressor operation mode switch. In the automatic mode, the pressure

in the buffer tank is maintained within the range of 3 to 7 bars;


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• Throttling valves for maintaining the nitrogen concentration in the range of 97

to 100 per cent and counter pressure of 9.5 bars;

• Throttling valves which keep the nitrogen medium parameters under control:

when within the standard range, gases are directed to the buffer tank; if they are

out of the standard range, discharge into the atmosphere is opened;

• Control of the throttling and cut-off valves;

• Control of spool pieces for the connection with deck lines;

• Nitrogen supply valve GvHD to High Duty compressor seals.


• Pressure, temperature, flow, dew point and oxygen content at the system outlet;

• Pressure in the buffer tank;

• Pressure before the constant counter-pressure valves (Iv78, Iv77);

• Temperature after compressors coolers;

• Pressure after compressors coolers.

Alarms

• Low pressure in the buffer tank: 2.5 bars;

• High pressure in the buffer tank: 9 bars;

• Very high pressure in the buffer tank: 9.5 bars;

• High counter-pressure at the plant outlet: 10 bars;

• High moisture content at the nitrogen generator outlet (dew point of > -70

degrees at the atmospheric pressure);

• High oxygen content at the nitrogen generator outlet: > 4 per cent;

• Very high oxygen content at separator outlet: > 5 per cent;

• High air temperature at the compressor outlet;

• High pressure at the compressor outlet.

Protection

Emergency safety relief valve on the buffer tank opens up at a pressure of more

than 10 bars.

Principal FaultsFaults are set by the instructor. The following main types of faults have been

implemented for the system units:


• Faults in valves (valve failure to respond: jamming, remote control system failure);

• Faulty generator.


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For the training purposes, exercise units are damaged if:

• Compressor operation without flow for 10 minutes;

• High gas temperature before the diaphragms.

Fig. 12 Nitrogen generator


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Inert Gas Distribution System


INERT GAS DISTRIBUTION SYSTEM

Purpose

The system is intended for maintaining positive pressure in cargo tank annular

spaces for LNG-s and in primary/secondary barrier for LNG-m, monitoring of gasmedium in the cargo tank space and ventilation of the cargo tank insulation. These

prevent formation of explosive gas concentrations and frosting of the tank surface.

System Components

The LNG-s system consists of:

• Four hold spaces H1….H4 which surround cargo tanks;

• Inert gas feeding line whereto the gas is supplied from the IG generator located

in the ship superstructure;

• Throttling valves Hv1…Hv4 which enable the supply of inert gas into hold

spaces H1….H4 respectively;• Tanks orifice stations are equipped by flowmeter and Av…2, Av…3 valves;

• Throttling valves (Hv11…Hv41) and automatic valves (Hv12…Hv42) which

maintain the pressure in the hold space within the admissible range;

• Nitrogen feeding line where to the gas is supplied from the nitrogen generator

which is located in the ship superstructure;

• Throttling bypass valves Av1…Av4 which enable the supply of nitrogen to the

automatic supply units;

• Nitrogen automatic supply units At 15, 25, 35, 45 on tanks which enable the

supply of nitrogen to the annular space or bypass it in hold space;

• Throttling valves Av11…Av41 which maintain nitrogen pressure in the annularspace. The discharge of nitrogen is from the annular space to the hold space;

• Pipeline system.

The LNG-m system consists of:

• Four primary barrier void space At1….At4 which surround cargo tanks;

• Four secondary barrier void space H1….H4 which surround cargo tanks;

• Four cofferdams which segregate cargo tanks holds;

• Cofferdams are equipped by heating coils with inlet Hivt1…Hivt4 and outlet

Hiv11…Hivt44 valves. Heat agent is supplying to the coils from Engine room

through Hiv1 and returns back through Hiv2 valve. Hiv3 is used as bypass valve;

• Nitrogen gas feeding line where the gas is supplied from the generator located

in the ship superstructure;

• Nitrogen gas feeding line where gas is from Manifold (shore) through AAvM valve;

• Supply pressure control station which include AA1, AA2, AA3 pressure auto

controllers;

• Throttling valves Hv1…Hv4 which enable the supply of nitrogen into secondary

barrier void space H1….H4 respectively;

• P/v valves Hv1…Hv4, which maintain nitrogen pressure in the secondary barrier

void space. The discharge of nitrogen is from the space to atmosphere;


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• Throttling bypass valves Av1…Av4 which enable the supply of nitrogen to the

primary barrier void space At1….At4 respectively;

• Throttling valves AvAt1… AvAt4 and p/v valves AAt1…Aat4, which maintain

nitrogen pressure in the primary barrier void space. The discharge of nitrogen is

from the space to nitrogen vent riser;

• Deck pressure control station which include AA4, AA5, AA6 pressure auto controllers;

• Vacuum compressors Icom1, Icom2, which is connected with nitrogen vent riser;

• Pipeline system.

Controls

• Control of the throttling and cut-off valves;

• P/V spring adjusting;

• Control of the system configuration through the connection/disconnection

of spool pieces;

• Compressor start/stop buttons.


• Pressure, temperature and oxygen/CHx content in the gas atmosphere of cargo

tanks;

• Pressure, temperature and oxygen/CHx content in the spaces;

• Pressure in pipe lines;

• Valve positions.

Alarms

• Excessive hydrocarbons content in the hold space atmosphere;

• “High” – high pressure in the hold space;

• “Very-Low” – very low pressure in the hold space;

• “Low-Low” – low pressure in the hold space;

• “Low” – low pressure in the hold space;

• “High” – large pressure drop between the tank and hold space;

• “High-High” – large pressure drop between the tank and hold space.

ProtectionThe safety release valve is opened automatically if the pressure or vacuum limit is

exceeded in the space.

Destroy of AAvM in case of liquid flow.

Principal Fault

Faults are set by the instructor. Some faults in valves have been implemented

for the system units.


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For the training purposes, the exercise is terminated when:

• pressure in the gas lines is more than 1.5 times the rated value;

• explosive concentrations are attained in the hold space.

Fig. 13 LNG-s Inert gas and nitrogen distribution system

Fig. 14 LNG-m nitrogen distribution and cofferdam heating system

lchs 4000 lng description of system eng

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