Custody transfer systemfor LNG carriers

2

Reliable tank gaugingfor LNG carriers

Thousands of tons of liquefied natural gas rush through the pipes

into the tanks of your LNG carrier. Raising your eyes, you look

beyond the dazzling lights of the tank terminal into the dark sand

dunes behind.

Concentrating on the levels, temperatures and pressures in the tanks,

you feel confident that the Saab TankRadar system is giving you

instant, accurate, reliable information about your cargo.

This brochure tells you how your LNG carrier operation can become

more efficient and profitable with the Saab TankRadar custody

transfer system.

3The Saab TankRadar custody transfer system can be installed on LNG carriers with

either spherical or membrane type tanks.

4All values from the Saab TankRadar system are available on the Work Stations. The Work Stations are

based on PCs with a fast real time operating system. The system is operated using a light pen.

5

In control of your cargo

The feeling of being in control and of

being able to rely on your equipment is

important to all professionals in tanker

operations. But, when your job is to

handle liquefied natural gas in a safe,

efficient way, this becomes significantly

important.

With the Saab TankRadar custody trans-

fer system for LNG carriers, you have

reliable information so that you can safely

control your cargo operation.

No downtime due to repairsinside the tanks

With Saab TankRadar we introduce a

whole new way of measuring the cargo

in LNG carriers. With the tank gauges on

top of the tanks, there are no parts inside

the tanks that can break down or degrade.

Knowing how much unscheduled down-

time costs, your Saab TankRadar system

will soon pay off with its reliable opera-

tion.

Accurate and reliable radarmeasurement

We have put a lot of effort into making a

tank gauge that measures with high

accuracy even under the most demand-

ing circumstances. You receive accurate,

reliable figures during all stages of

loading, transporting or discharging.

The temperature and pressure sensors

are connected to the radar tank gauges,

so that the Saab TankRadar system always

gives you the complete picture of the

cargo in your LNG tanks.

6

Certified custodytransfer system

The costs of transporting gas and the cost

of the cargo places a lot of importance on

the custody transfer system on any LNG

carrier. The custody transfer system must

generate detailed and indisputable cargo

reports, based on accurate measurements

and calculations.

Saab TankRadar is a completecustody transfer system for

LNG carriers.

The Saab TankRadar gauge measures

ullage, temperature and pressure. From

these values the Work Station calculates

for example, levels, vapor and liquid

average temperatures and cargo volumes

at average liquid temperature. It uses

certified tank tables and corrects for

parameters, such as thermal expansion of

the tank and the still pipe, the propaga-

tion speed of the radar waves in the

vapor space, trim and heel.

Accuracy certified by NKKK

NKKK, the Japanese sworn surveyor, has

certified the Saab TankRadar system for

custody transfer. Saab TankRadar ’s

accuracy of ± 5 mm meets the requirement

of LNG exporters and importers. And all

the major classification societies have type

approved the Saab TankRadar system.

Verification at any time

Whenever company procedures or mea-

surement standards require verification,

the crew can easily verify the performance

of any of the Saab TankRadar gauges.

They just set it to measure the distance to

a verification pin inside the still pipe. This

pin is “invisible” to the tank gauge in nor-

mal operation.

Furthermore, the performance of the Saab

TankRadar gauges can be checked against

verifiers set to correspond to 20% and 80%

of the tank’s level.

7Detailed and indisputable cargo reports are generated by the Saab TankRadar custody transfer system.

8

Radar is the natural choicefor LNG carriers

Because the temperature sensors are

placed in a thermowell, they can easily be

replaced from outside the tank. Spare

temperature sensors are stored onboard

in the spare parts set.

The still pipe guidesthe radar waves

The electronic box generates and trans-

mits radar waves into the cone antenna.

It provides a smooth transition for the

waves into the still pipe. Because the still

pipe guides the radar waves, very little

signal energy is lost, which results in a

strong echo from the liquid surface.

Saab TankRadar meansno maintenance

No maintenance is required on the Saab

TankRadar system. This means years of

trouble free operation, with highly accu-

rate and reliable results calculated and

presented on the Work Stations.

In a tank that is -160 °C, and may not be

opened for years, you really do not want

to have electrical cabling or moving

mechanical parts. Any failure on such

equipment inside the tank might result in

having to warm the tank, inert it, gasfree

it, enter into it to repair the failed equip-

ment, inert, purge and cool down the tank.

No LNG carrier operator wants to do

these time-consuming tasks.

This is where radar tank gauging, with

only the still pipe and the cone antenna

inside the tank, comes into the picture. No

equipment inside the tank can break

down or degrade in operation. The safety

risk involved when gasfreeing is elimi-

nated and no harmful gases have to be

released to the environment.

The electronic box of the Saab TankRadar

gauge is placed outside the tank. In the

unlikely event of a failure, the crew can

easily replace it with a certified spare. The

tank gauge can be serviced, tested and

back in operation in less than an hour.

9The Saab TankRadar gauges are installed on top of your tanks.

No equipment inside the tank can break down or degrade in operation.

10

Pressure seal

Ball valve

Antenna cone

Still pipe

Electronic box

Pressure sensor

Protective hose

Thermowell

Temperature sensor

11The Saab TankRadar gauge is installed on top of a still pipe. The temperature sensors are installed in a thermowell.This means that you can easily replace the electronic box and the temperature sensors, with the tank in operation.

12

Convenient installation

Because the only parts inside the tank

are the still pipe, cone antenna and

thermowell, the installation of the Saab

TankRadar system is very convenient. It

can be installed on newbuildings or be

retrofitted on existing LNG carriers.

Reduced testing at shipyard

We put each Saab TankRadar system and

each tank gauge, including the still pipe,

through a factory acceptance test, that is

also supervised by a sworn surveyor,

before delivery. This minimizes testing at

the shipyard and ensures the best possible

measurement conditions.

We deliver the still pipe in typically six-

meter-long, numbered sections, ready to

be installed into the tank’s pipe tower or

tripod.

The temperature sensors are installed into

a thermowell manufactured by the ship-

yard. After the sensors have been installed

and connected, the thermowell is inerted.

Both the still pipe and the thermowell can

share the same penetration through the

tank dome.

Technical support from designto commissioning

Saab Marine Electronics supports the

shipyard with documentation and tech-

nical support from the design stages to the

commissioning of the system. Together

with each Saab TankRadar system, we also

provide comprehensive and dedicated

documentation that includes all appli-

cable certificates. One of our certified

service engineers assists during the com-

missioning of the system.

13

Electronic box

Antenna cone

Still pipe

Pressure equalization

hole

Verification pin

Protective hose for cables

Tank dome penetration

Thermowell

Temperature sensors

Pipe for inerting the thermowell

The Saab TankRadar system can be installed on newbuildings or retrofitted on existing LNG carriers.Both the still pipe and the thermowell can normally share the same tank penetration.

14

Window Overview Setup Grou p Trend Alarm

Alarm

Saab TankRadarWed Aug 24 20:05:30 1994

Hi.Hi CT 6 Ullage 1,837 (2,000) mAccept BuzzerStop

2...more

Help Exit all

ExitBackCargo System Fore

P

LC8LC7

26 bar

P

LC6LC5

24 bar

P

LC4LC3

20 bar

P

LC2LC1

23 bar

T.avg18.8 C

T=18.6

T=18.7

T=19.1

0.00 m/h

Ullag e1.956 m

CT4

T.avg18.8 C

T=18.6

T=18.7

T=19.1

0.00 m/h

Ullage5.630 m

CT3

T.avg18.8 C

T=18.6

T=18.7

T=19.1

0.00 m/h

Ullage8.502 m

CT2

T.avg18.8 C

T=18.6

T=18.7

T=19.1

0.00 m/h

Ullag e1.559 m

CT1

Window Overview Setup Grou p Trend Alarm

Alarm

Saab TankRadarWed Aug 24 20:05:30 1994

Hi.Hi CT 6 Ullage 1,837 (2,000) mAccept BuzzerStop

2...more

Help Exit all

ExitBackCargo S ystem Fore

P

LC8LC7

26 bar

P

LC6LC5

24 bar

P

LC4LC3

20 bar

P

LC2LC1

23 bar

T.avg18.8 C

T=18.6

T=18.7

T=19.1

0.00 m/h

Ullage1.956 m

CT4

T.avg18.8 C

T=18.6

T=18.7

T=19.1

0.00 m/h

Ullage5.630 m

CT3

T.avg18.8 C

T=18.6

T=18.7

T=19.1

0.00 m/h

Ullage8.502 m

CT2

T.avg18.8 C

T=18.6

T=18.7

T=19.1

0.00 m/h

Ullag e1.559 m

CT1

7 8 9 0

4 5 6

1 2 3

ALARM SYSTEM

MENU SERV

ENTER CLEAR

OK i

1 2 3

LCP LCM LCS LCM LCS LCI

Technical details

Technical specifications for Saab TankRadar

The main parts of the Saab TankRadar

system are:

• The tank gauges that measure ullage,

vapor pressure as well as liquid and

vapor temperature.

• The Level Unit that contains much of

the calculation power for the signal pro-

cessing and the circuits for ensuring the

intrinsic safety. The tank gauges are

connected to the Level Unit. The signal

processors and memory circuits are

doubled for internal redundancy in the

Level Unit.

• The Work Stations that calculate the

cargo volume from tank parameters and

measured values. They also supervise

and warn of any alarms that may occur.

A Work Station consists of a PC that

is type approved for operating in

the marine environment. A printer is

included for printing custody transfer

reports and various logs.

• The Redundancy Box that automatically

switches master Work Station, if the ac-

tive master fails.

Accuracy: ±5 mm

Measurement range: 0-45 m

Gauge operating temperature: -40 to +80 °C (in-tank temperatures can be down to -165 °C)

Max. operating pressure: 8 barabs

Intrinsic safety of gauge: EEx ia IIC T4

Temperature measurement range: -165 to +55 °C

Temperature measurement accuracy (includingsensor): ±0.2 °C for cargo temperatures -165 to-145 °C, ±1.5 °C for cargo temperatures -145 to+50 °C

Number of temperature sensors: Typically 5active sensors per tank

Pressure measurement range: 0.8 to 1.4 barabs

Pressure measurement accuracy: ±1% of full scale

Still pipe (Saab or yard supply): 114.3 x 3.65 mm instainless steel or aluminum

Thermowell (yard supply): Max. outer Ø 32 mm

Tank penetration (yard supply): Still pipe only:Min. inner Ø 154 mm, recommended 250 mmPipe and thermowell: Min. inner Ø 300 mm

Work Station Work Station Level Unit

RadarTank

Gauge

Still pipeand

thermowell

RedundancyBox I/O Box

Interface to othercomputers

Printer

15

Saab Marine Electronics –Pioneers in radar tank gauging

Tank gauging with radar is not a new

technology for Saab Marine Electronics.

We have developed, produced and mar-

keted radar tank gauging systems for

tankers since 1975. We have released three

generations of Saab TankRadar systems

for tankers – each new generation bring-

ing new customer benefits. Today, more

than 1 100 tankers are sailing with Saab

TankRadar systems.

In the early 1980s Saab Marine Electron-

ics released Saab TankRadar for onshore

tanks. Many of the same features that

brought success on the tanker market,

appealed to the instrument engineers at

refineries, tank terminals, chemical plants

and other industries. More than 500 LPG

onshore tanks are equipped with Saab

TankRadar and it has been successfully

installed on LNG storage tanks in Japan.

More than 35 000 Saab TankRadar gauges

have been installed on both tankers and

onshore tanks.

Certified quality andenvironmental systems

In 1992, Saab Marine Electronics was the

first supplier of tank gauging equipment

to be certified according to ISO 9001. In

1997 we were again first to be certified

according to ISO 14001 for our environ-

mental management system.

LNG/C Khannur with Saab TankRadar onboard.

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