Hamworthy Gas Systems AS - Digital Ship

Hamworthy Gas Systems AS 

LNG Shipping Operations 27th Sept. 2006 

Reliquefaction & Regasification Systems 

on LNG carriers

Agenda 

LNG Shipping Operations Sept. 27, 2006 

• Organization & references 

• Why LNG reliquefaction systems ? 

• LNG onshore pilot plant and other recent references 

• LNG RS recent orders 

• Equipement 

• Contol principles 

• Next generations 

• LNG regasification


�Owned by Hamworthy PLC with HQ in UK 

�Gas division located in Norway, approx 200 employees 

�International operations 

�UK, Norway, Denmark, Singapore, Germany, Korea, China, 

USA, India, Netherlands, Spain 

�Products mainly for production and transportation of oil & gas 

�Gas Division supplies high technology products for: 

�Cargo handling on gas carriers & FSO/FPSO’s 

�Reliquefaction systems for LPG, LEG & LNG 

�Inertgas- og Nitrogen-generators 

�Recovery of VOC from crude on shuttletankers/terminals 

�Condensation of VOC with 100% emission reduction 

�Regasification directly from LNG-carriers/FSRU 

�Test plant under construction in co-operation with ship owner 

�Onshore LNG production 

�Small scale plants e.g “Snurrevarden” (30 ton/day �) 

�Mini LNG-plants (Sintef) (8 – 40 ton/day)

Hamworthy plc 

Structure, products and sales 

Gas 

Gas Systems Inert Gas Systems 

40 years of gas system delivery references 

of liquid gas handling systems 

Process and systems design 

Pump Systems 

General arrangement, fabrication and assembly 

Ships integration 

Installation, commissioning and start-up 

Average sales last 3 years 

Wastewater 

Management Systems 

Typical customers: 

Bergesen, Daewoo, 

Statoil, Exmar, 

ExxonMobil, Gasnor, 

Geogas, Hyundai, IHI, 

Kawasaki, Mitsui, 

Navion/Teekay, OSG, 

Pronav, Samsung, 

Solvang, Ugland, AP 

Møller, Sonatrac, 

Chevron, Leif Høegh.

LNG -Markets 

International gas trade by LNG tankers (1985) 

Alaska 1.4 

Exporting countries 

Existing LNG market 

50.9 bcm transported of which 73% to Japan 

0.7 

13.6 

Abu-Dhabi 3.1 

Brunei 6.9 

Indonesia 20 

Malaysia 5.9 

� LNG is a 40 years old industry dominated by few players and projects 

� Deregulation has opened up for new players and increased competition 

� New technology and players significant cost cuts in the LNG value chain

LNG -Markets 

International gas trade by LNG tankers (2004) 

Alaska 1.7 

Spot 

Exporting countries 

Existing LNG market 

Future LNG market 

177.5 bcm transported of which 43% to Japan 

13.9 

Brasil 

26.4 

12.6 

40.5 

India 

China 

70.7 

11.8

Hamworthy Gas Systems 

LNG Global Demand - Projections 

400 

350 

300 

250 

200 

150 

100 

50 

0 

North America 

Europe 

Asia Pacific 

2000 2005 2010 2015 

Source: WoodMackenzie 

LNG trade 

projected to grow 

at an average of 

7% to 363,5 

mtpa by 2015 

Key contributing 

factors; 

• Demand for 

energy 

• Demand for 

cleaner fuel 

• Security of supply

Hamworthy Gas Systems 

LNG Fleet Growth 1999 - 2010 

350 

300 

250 

200 

150 

100 

50 

7 

108 

12 

115 

1 

127 

10 

128 

14 

138 

24 

152 

18 

176 

19 

9 

194 

33 

222 

54 

255 

36 

309 

0 

1999 2001 2003 2005 2007 2009 

Basis no scrapping 

Based on orders as at 30 April 2006 Source: Drewry & Clarkson 

3 

345 

Orderbook 

Deliveries 

Fleet start

The LNG value chain 

LNG: a mean for concentrating & transporting energy (1/600 th of volume in gaseous state) 

Small scale Liquefaction plants 

Transportation: reliquefaction 

Floating regasification systems 

18-24% 32-36% 29-32% 14-15%


Forward Orderbook: LNG systems as off August 2006 

Client Type Site/Shipowner Delivery 

DSME 4 LNG Reliquefaction Plants (QG II ) Pronav 2006 

Hyundai 2 LNG Reliquefaction Plants (QG II) OSG 2006 

Samsung 2 LNG Reliquefaction Plants (QG II) OSG 2006 

Samsung 4 LNG Reliquefaction Plants (Rasgas III) Teekay 2006/07 

GASNOR 1 LNG Plant 240 t LNG/day Gasnor, Kollsnes 2007 

Hyundai 3 LNG Reliquefaction Plants (Rasgas III) J5 NYK) 2006/07 

DSME 5 LNG Reliquefaction Plants (Rasgas III) J5 (MOL,KL) 2007 

Hoegh LNG 1 LNG Regasification plant prototype 2006 

Samsung 6 Regasification skids to 2 SRV’s Hoegh LNG/MOL 2008 

HHI 3 LNG Reliquefaction Plants (QGIII) QGTC 2008/09

Agenda 



• Why LNG reliquefaction systems? 







LNG carriers’ traditional propulsion system 

Why change ? 

Low efficiency of turbines 

high fuel consumption/cost 

Valuable cargo used as fuel 

Lack of crew to operate 

steam turbines 

Power required by large 

LNG carriers at boundary of 

existing turbine design 

Limited redundancy 

2 suppliers 

• Boil-Of-Gas (BOG) is a result of the LNG warming up during transportation. 

• All BOG now used as fuel in steam turbine propulsion systems. 

• Reliability in existing system considered to be very high. 

• Proven system with low lubrication and maintenance cost

Alternative to to-days practice 

BOG reliquefaction 

system in combination 

with 2 stroke diesel 

engine(s) 

The Moss RS reliquefies 

BOG and send LNG 

back to the cargo tanks 

Results in 

economical and 

technical advantages 

Hamworthy has 

worldwide rights to the 

patented Moss RS TM

LNG Reliquefaction system 

Two principle different solutions available for LNG carrier propulsion: 

1. Use BOG & LNG as fuel e.g steam turbines, dual-fuel diesel electric, gas engines 

2. Use efficient slow speed diesel engines and BOG reliquefaction, sell all LNG loaded onboard 

LNG level 

in tanks 

Maximum 

Minimum 

Ballast 

Pattern for ship’s using BOG & LNG as fuel for propulsion 

Minimum heel required for cool down of tanks 

Laden Ballast 

Fuel used during roundtrip 

(Natural BOG & forced) 

Additional LNG delivered 

with Slow Speed diesel and 

BOG Reliquefaction System 

27.08.03


LNG & HFO prices 

$/mBTU 

7,00 

6,00 

5,00 

4,00 

3,00 

2,00 

1,00 

0,00 

1997 1998 1999 2000 2001 2002 2003 2004 2005 

Future price 

difference ?? 

Japan CIF 

EU CIF 

US Henry Hub 

HFO price 

HFO always been competitive compared with natural gas prices in Europe, USA and Japan. 

Gas price in Europe and USA in average (1994-2001) 110% higher than HFO prices 

Japanese gas prices have been 160 % of HFO prices 

The gas prices have increased considerably compared with HFO the last years 

27.08.03

Propulsion alternatives & energy consumptions 

Source: Man B&W 

50 

40 

30 

Propulsion type Relative energy cons. 

Main + aux system (%) 

Slow Speed diesel 66 

Diesel electric 72 

Gas turbines 84 

Conventional steam turbine 100 

Best efficiency, 

Lowest total fuel consumption, 

Lowest value fuel (HFO) 

Improved efficiency, 

High value fuel (LNG or MDO) 

Improved efficiency, 

High value fuel (LNG) 

Lowest efficiency, 

Highest total fuel consumption, 

High value fuel (LNG) + HFO 

Example made by 

ship owner


Slow speed diesel and reliquefaction system (RS) compared with alternatives: 

Lowest total operating cost (efficient propulsion using HFO, maintenance and lube oil) 

Additional sale of LNG 

4,00 % 

3,50 % 

3,00 % 

2,50 % 

2,00 % 

1,50 % 

1,00 % 

0,50 % 

0,00 % 

Relative increase annual LNG deliveries 

LNG sales price 3.5 $/Mbtu 

3.4 M$ 

4.3 M$ 

Steam turbine Diesel 

5.5 M$ 

Avg. BOR 0,08%/day Avg. BOR 0,10%/day Avg. BOR 0,12%/day 

Slow speed diesel and RS competitive, in particular for large LNG Carriers 

Traditional size vessels, reason to believe steam still lowest

Agenda 




• LNG onshore pilot plant and other recent 

references 






Snurrevarden LNG plant - Norway 

Hamworthy delivered a free 

standing mini LNG plant in 

March 2003 based on the 

same principles as the 

re-liquefaction system. 

The mini LNG plant uses 

same type of equipment 

as for re-liquefaction 

systems. 

Control functions are also 

much similar. 

The plant is designed for 

unmanned operation


Snurrevarden LNG plant has resulted in awards of – 23 LNG RS for LNG Carriers ! 

Onshore 

Main equipment 

plant vs 

same 

installation 

as for 

on 

the 

LNG 

ships; 

carrier; 

LNG 

Same 

production 

make of 3 

capacity 

stage centrifugal 

60 ton/day 

compressor 

(2500kg/hr) 

with expander for the refrigeration 

cycle 

Pre-treatment of feed gas, removal of CO2 & water (not on LNG carriers) 

Same cold box type (plate fin heat exchanger) 

Feed gas pressure to be reduced – no need for low duty compressors Storage tank 

Same control system principles 

Gas engine 

Cooling cycle 

compressor 

Instrument air & 

Nitrogen 

LPG separator & 

Gas condensation (LNG) 

H2O removal 

CO2 removal


Approval in principle from DNV, Lloyds, BV, ABS


Proven or unproven! 

� The system only use proven components - first class, high quality with extensive 

reference 

Process/system 

System 

status 

Risk 

area 

� Low duty compressors used on all LNG carriers 

Comfort factors 

Risk mitigation 

� Cold box (plate fin heat exchanger) widely used in onshore cryogenic installations. 

� Refrigeration & cargo cycle have been proven in operation 

� Analysis concludes 99.98 % availability 

� Approval in principle by several class societies 

� Independant HAZOP/HAZID with owners & class 

� Hamworthy has supplied a small scale LNG plant based on same principles. 

Operational experience since Mar 2003.

Agenda 










LNG Re-liquefaction 

- Refrigeration system 

- Redundancy considerations 

- Capacity control 

- Separation of N 2–rich vent gas 

- Functional diagrams 

- N 2 compander 

- Cryogenic heat exchangers 

- BOG compressor 

- LNG pump skid 

- N 2 booster skid 

Equipment and control system 

is defined and selected in order 

to ensure the best possible 

operation of the re-liquefaction 

system in accordance with 

class regulations


Redundancy considerations 

IACS Rules for Redundancy for RS 

� Spare capacity of RS unit, or 

� Auxiliary boiler(s) for BOG, or 

� Gas oxidiser (GCU) for the BOG, or 

� Controlled venting 

Different configurations/alternatives 

• 2x100% capacity with 1 cold box 

• 1x100% capacity with gas oxidizer (GCU) 

• QGII ; 

2x100% capacity with GCU 

• Different configurations studied for new 

projects resulting in operational flexibility 

BOG FEED 

COOLING 

WATER 

+100 

0 

-100 

-200 

+100 

-100 

-200 

SUCTION THROTTLE 

0 

MAX 

MIN 

+100 

-100 

-200 

2 3 

1 E 

0 

NITROGEN 

RESERVOIR 

+100 

0 

-100 

-200 

RECYCLING 

BY-PASS 

+100 

0 

-100 

-200 

+100 

0 

-100 

-200 

+100 

0 

-100 

-200 

MAX 

MIN 

+100 

0 

-100 

-200 

VENT 

+100 

0 

-100 

-200 

TO TANKS

LNG Re-liquefaction 

The Re-liquefaction system is based on the N 2-Brayton cycle 

This system has proven to be advantageous for several 

reasons: 

- simplicity (single component, single phase refrigerant) 

- short response time for capacity adjustments 

- dynamic type (centrifugal) machinery can be employed 

The Hamworthy 

supplied 

Moss TM RS is a 

patent protected 

system.

Process Description – Cargo Cycle 

� BOG from the cargo 

tanks (1.06-1.15 bar a) 

by conventional LD 

compressors. 

� To enable stable 

temp at inlet cold 

box, BOG is 

pre-cooled upstream 

compressors 

� Discharge pressure from BOG compressor is 

4,5 bar and the BOG is cooled and condensed to 

LNG at this pressure in a 3-stream plate-fin 

cryogenic heat exchanger (cold box). 

Vent or GCU 

�Non-condensibles, 

mainly N 2 , are removed 

in a separator ( 4,5 bar) 

and exited to a flare 

(GCU) or vent mast. 

Partial reliq (if N 2 

>12%) results in ; 

-reduced power req. 

-tank pressure control 

� From the separator, 

the LNG flows back to 

the cargo tanks

Process Description – Nitrogen Cycle 

The RS system needs to have sufficient capacity to cater for heat ingress to the cargo tanks, 

vapour header and LBOG piping, in adition to heat introduced by BOG compressors 

� N 2 at 13.5 bar 

compressed to 57 bar 

in 3-stage centrifugal 

compressor with water 

cooling. 

�The gas is led to the “warm” part of the cryogenic 

H/E where it is pre-cooled (–110°C) and send to the 

expander 

�The gas expanded to 

a pressure of 14.5 bar 

and temp of –163°C. 

Gas then introduced 

into the “cold” part of 

the cryogenic H/E 

where it cools and 

reliquefies the boil-off 

gas to LNG.


LNG Reliquefaction systems 

23 reliquefaction units contracted 

with Hamworthy so far…


LNG Reliquefaction systems

Normal Cargo Handling Operations 

� Operations with the Re-Liquefaction plant 

in use; 

� Laden voyage – normal boil off rate 

� Laden voyage + extra BOG 

� Ballast voyage 

� Cooling down during ballast voyage 

before loading 

� One tank operations at sea and Re-Liq 

on remaining tanks 

� Warming up 

� Gas freeing 

� Aerating 

� Drying 

� Inerting 

� Gassing up 

� Cooling down 

� Gas freeing/warm gas through BOG 

compressors to GCU

Dynamic simulation model of RS 

Pre-qualification of Hamworthy as 

a supplier to Qatar Gas involved ; 

- extensive process discussions 

- qualifications of our sub-suppliers 

and 

- development of a Dynamic model. 

Typical dynamic simulation cases; 

1. Start-up from warm condition 

2. Normal operation 

3. Stand-by operation 

4. Ballast (40% capacity, 

warm BOG (-40degC)) 

5. Normal shut down 

6. Emergency shut down 

7. Varying N2 content in BOG

LNG RS simulator 

Overview screen

Agenda 











LNG Reliquefaction project 

Awarded new contract 9 Sep 05 

New add. capacity 84000 tons/year 

Ready for operation Feb 2007


New concepts with 

15-20 % reduction in 

power consumption 

developed

Improvements on power consumption 

What distinguishes double expander from current Qflex design, 

Mark I? 

Three major changes: 

1. New compander design 

1. New cold box geometry 

1. New precooling 

concept 

RESULT: 

Typically 15-20% decrease in 

specific liquefaction energy (kWh/kg LBOG) 

Patent pending

Further improvements – ambient BOG comp 

What about Mark III ? 

Proposed changes: 

1. BOG compressor (3 stages) 

works under ambient 

temperatures 

2. BOG compressor inter- & 

after- coolers 

3. Removes heat with cooling 

water from high temp BOG 

4. Can down size Compander 

5. Reduce exergy losses in 

cold box 

Patent pending

Power consumption example Qmax 

1 expander versus 2 expander solution verses Mark III 

Power cons. 

1 exp solution 

N2 compander 

BOG compressor 

Sum 

Power cons. 


6356 

462 

6818 

Power cons. 


kw 

5406 

447 

5853 

7000 

6000 

5000 

4000 

3000 

2000 

1000 

0 

Power cons. 

Mark III 

Power consumption 

- 14% 

4441 

1014 

5454 

- 20% 

1 Exp 2 Exp Amb. BOG

Power consumption example Qflex 

1 expander Mark I versus Mark III 

Power consumption 

N2 compander 

BOG compressor 

Sum 

Power cons. 

1 exp solution Mark I 

4859 

332 

5191 

5200 

5000 

4800 

4600 

4400 

4200 

4000 

Power cons. 

Mark III 

Power Consumption 

- 14% 

3623 

784 

4407 

-15% 

Mark I Mark III


Kollsnes II 

New refrigerant cycle with double expander 

will be commissioned and put in operation 

February 2007. 

Retrofit installation on existing LNG production site


Summary 

• Slow speed diesel engines in combination with 

reliquefaction system, results in improved 

economy 

• LNG business is conservative and typical attitude 

has for a long time been; 

“We do not want to be the first, but first to follow” 

This is now possible ! 

• Expect several alternative propulsion systems to 

be used in the future. 

Selection dependant on trade, size of vessels, 

charterer’s and owners’ preference, etc 

• Hamworthy continues improving the system; 

- Reduced power consumption 

- Improved redundancy configurations 

- Improved project execution models

Agenda 

LNG Shipping Summit 2006 



• Snurrevarden LNG and other recent references 

• LNG Reliquefaction Systems 



• Next generation Mark III 


LNG regasification system 

• Increased import & 

spot/short term 

LNG trading 

in the future 

• Capacity in existing 

import terminals 

booked/limited 

• Permission to build 

new land terminals 

in US/Europe 

difficult 

• Vaporization plant 

onboard LNG 

carriers or Floating 

Storage Units will 

not need “terminals” 

Not in my back yard !!

LNG regasification system 

Regasification units 

on; 

Process/system 

• Floating Storage 

Regasification Unit 

(FSRU) permanently 

anchored receiving 

LNG from LNG 

carriers 

or 

• Shuttle Regasification 

Vessels overlapping 

at unloading site in 

order to ensure 

continuous send-out 

3 alternative Hamworthy Regass systems: unit 

- Steam based (closed loops) 

- Cascade type using seawater and propane 

with or without phase change of propane 

- Pure seawater based

Hamworthy LNG regasification system 

What is a shuttle regasifcation vessel ?

LNG Regasification Unit 

Steam/glycol system 

Heat to the regas process is taken 

from the onboard steam boilers 

Pressure & capacity ranges; 

40-130 bar 

50-1100 t/hr 

LNG booster pumps 

Printed circuit 

heat exchanger 

(steam against 

water-glycol mix) 

Shell & tube 


(water-glycol mix 

against LNG) 

Water glycol mix 

circulation pump

LNG Regasification Unit 

Cascade (propane/seawater) system 

Propane in closed loop heat LNG 

Heat to the regas process from ambient seawater 

Reduced regas fuel consumptions 

Same pressure & capacity ranges 

LNG/seawater 


Gas out 

Propane / 

Seawater HX 

(plate type in titanium) 

Seawater In 

Seawater out 

Propane pump 

LNG/propane 


(PCHE) 

Gas in 

LNG booster 

pump


Neptune project outside Boston, US (Hoegh LNG for Suez)


Neptune project outside Boston, US (Hoegh LNG for Suez)


RE-GASIFICATION TEST PLANT 

• Propane 2-phase solution 

• Water/Glycol solution 

• Placed at Kollsnes, Bergen Norway 

• Capacity: abt 200 kg/h (scale abt 1:1000) 

• Currently under final commissioning 

• Estimated official test run mid September

Hamworthy 

Thank you for 

your patience !

Hamworthy Gas Systems AS - Digital Ship

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