evaluation of process system for floating lng
TRANSCRIPT
8/13/2019 Evaluation of Process System for Floating LNG
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Presentation overview
Who we are
Why Floating LNG (FLNG)
FLNG Concepts
FLNG Process selection
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Aragon
Kanfa Aragon AS is a limitedcompany in the Sevan MarineGroup.
Located in Bergen, Norway.
Kanfa Group topside references:
Process packages 5 FPSO topsides
2 FPSO topsides this year
Developed FLNG technology andinvolved in a number of FLNGstudies for FPSO ship owners and
LNG shipping companies
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What is LNG
Liquefied Natural Gas, LNG = natural gas in its liquid form
Cooled to typically -155 to -165 deg Celsius
The specific power consumption (kWh/kg LNG) is a common way to
specify the efficiency of the liquefaction system
NATURAL GAS
1,000,000 Sm3
100 x 100 x 100 m
LNG
1,000,000
Sm3
12 x 12 x 12m
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Why FLNG?
Exploration of stranded gas fields can meet the worldsenergy demand
Recovery of oil-associated gas
The energy demand and gas prices are increasing
Source: Ingvar Tjostheim Source: Poten and Partners
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Stranded gas fields - a large potential for FLNG
Note: 0.25 TCF = 250 BFC = 5.2 million ton LNGCorresponds to 8 years production with LNG given production capacityof 1 million ton LNG p.a and a normal production profile
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Oil-associated gas
Annually a tremendous amount of oil-associated gas isflared or vented due to the distance from the fields to themarkets
Annual gas flaring exceeding 150 Billion m3 pr year
More than 350 million tonnes CO2 emissions per year
West Africa, South America and Asia topping oil-associated gas
flaring statistics
Political trends and increased energy demand willchange the existing flaring philosophy
Oil-associated gas liquefied to LNG clearly canrepresent a new energy supply source
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Solutions for FLNG production
With well stream reception and separation system, or
Gas from new or existing oil FPSO (separate hull)
Converted ship, new hull or barge
Mid-size, 0.3 – 3.6 mtpa LNG
For small and medium stranded gas fields
For associated gas fields
LNG storage & offloading
Up to 14 Mill Sm3 /day
1 – 4 LNG trains
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Gas processing sequence and requirements
ACID GAS
REMOVAL
Hg
REMOVAL
WATER
REMOVAL
LIQUEFACTION
SOLVENTREGENEN.
FEEDGAS
50 ppmCO2
DRYERREGENEN.
HHC
CO2, H2S
SEPARATION/
FEED TREATM.
LNG
WATER
>1 ppmH2O
>0.01 µg/Nm3Hg
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Offshore liquefaction technology selection criteria
Compact and low weight
Simple operation and start-up
High inherent process safety Robust to vessel motions/ marine enviroment
Robust to changes in process conditions
High availability
High efficiency
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Cascade Cycle
Chosen technology for the first LNG base load plant
1 mtpa of LNG production
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Cascade Cycle
Separate refrigerant cycles withpropane, ethylene and methane
High efficiency (~0.3 kWh/kg LNG)
Optimised technologies are evolvedand proposed
Large equipment count
Requires large plot area forrefrigerant storage and management
Increased risk due to flammable liquid
inventory Not recommended for offshore
environmentsSource: Natural Gas Processing Principles and Technology part II
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Mixed Refrigerant (MR) Cycle
Dominant baseload plant technology
Source: Foster Wheeler Energy Limited
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Mixed Refrigerant (MR) Cycle
Uses a single multi-component refrigerantcomprising typically nitrogen, methane,ethylene, propane and butane
The MR evaporates over a wide range oftemperatures and thereby follows the naturalgas condensing curve closely
High efficiency (~0.3 kWh/kg LNG)
Up to 50% less equipment items than thecascade process
Several modifications are developed andproposed
Sensitive to change in feed composition Requires extensive plot space for
refrigeration generation, storage andmanagement
Flammable refrigerants
Source: Cryoplants Ltd.
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Expander Cycle
Based on the classic Reverse Brayton / Claude Cycle
Several options:
Single expander cycle
Double expander cycle
Open expander loop (methane as refrigerant)
Closed expander loop (nitrogen as refrigerant)
Efficiencies down to 0.4 kWh/kg LNG
A pure refrigerant (typically nitrogen) is deep-cooled by expansion tocondense the natural gas to LNG in the cold box
LNGPRETREATED
FEED GAS
TURBO
EXPANDER
BOOSTER
COMPRESSORCYCLE
COMPRESSOR
HEATEXCHANGER
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Proposed FLNG Processes
Multifluid Cascade Process (MFCP) by Linde
Standard single and dual nitrogen expander cycle
NicheLNGSM
by CB&I Lummus LNG SmartR Liquefaction Technologies (open and
closed loops) by Mustang Engineering
Optimised Expander Cycle by Kanfa Aragon
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Operation
The Expander cycle is easier to operate than the MR Cycle
No sophisticated level control, phase or composition exchange in therefrigerant loops are giving operation upsets
No complex control system coupled to the process gas composition High turndown
The N2 Expander Cycle has additional advantages
The expander refrigerant loop contains nitrogen which gives the highestavailability for rotating equipment
Seal leakages are non hazardous and easily compensated by nitrogenfrom the refrigerant loop.
Turndown down to approx. 25% for one single train is obtained byreducing the nitrogen containment in the loop. Rotating equipment ismaintained at fixed speed during turndown.
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Safety
The N2 Expander cycle has a significantly higher inherent safetylevel than MR cycles, Cascade cycle and Open Expander cycle
Nitrogen is a non-flammable refrigerant
Half of the plant does not contain hydrocarbons and can be
regarded as safer than most FPSO topsides.
There are minor volumes of LNG in the plant, since the producedLNG are led directly to cargo thanks
Proven equipment offshore (compressor,gas turbines, heat exchangers)
Safe area
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Change in feed gas composition
The Nitrogen Expander Cycle is by it’s nature much lesssensitive to feed gas changes than MR Cycles
MR Cycles have higher efficiency since the refrigerant
evaporation curve are ideally following the LNG condensation,minimizing the exergy loss
Change in the feed gas composition requires changes in the
refrigerant or acceptance of lower efficiency At off-spec operation, the nitrogen expander cycles can
have higher efficiency than a MR Cycle
The Aragon Optimised Expander cycle optimises thesplit between NGL and LNG products
This increases the efficiency and increases the acceptable
window for the feed composition
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Offshore enviroment
MFLEX LNG producer
Incl. Kanfa Aragon’s Optimised expander cycle
Floating production units are subject to motion
The Expander cycle is robust for the offshoreenvironment as no liquid phase refrigerant is present
Avoids high focus on equal distribution of two phase/liquid flow
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Complexity and cost
Expander Cycles are superior to Cascade and MR Cycles when itcomes to simplicity
Can be built compact and light
Example for 2.7 mtpa:Cost estimate pr production capacity
[MMUSD/mtpa LNG]*
Topside weight estimate
[ton]
>1000**up to 35,000**MR Cycle
450 - 70010,000Aragon expander cycle
*Including vessel, gas pre-treatment, liquefaction and offloading (excluding field spesific items and cost of financing etc. )** Source: SBM Offshore and CB&I Lummus
N 2 Expander Cycle
2.7 mtpa
O i i d D l N2 E d C l
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Optimised Dual N2 Expander Cycle
Kanfa Aragon has developed new liquefactiontechnology (patent filed)
Based on the well-proven Dual Nitrogen Expander Cycleand optimised for offshore liquefaction application
Maximised LNG production for given driver
Minimal or no condensate bi-production if preferred
Integrated LPG / NGL recovery if preferred
Very high efficiency
Integrated and optimised power generation LNG specifications adjusted acc. to Client requirements
A li f ti t h l
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CASCADE,
PRECOOLED MRC,DUAL / CASCADE MRC
<0.3 – 0.4 kWh / kg
SINGLE MIXEDREFRIGERANT
~0.40 kWh / kg
PRECOOLEDDOUBLE EXPANDER
N2 CYCLE
~ 0.45 kWh / kg
Aragon liquefaction technology
SINGLE EXPANDERN2 CYCLE
~ 0.8 kWh / kg
PLANT COMPLEXITY(QUALITATIVE)
S
P E C I F I C P O W E R
@ T
R O P I C A L C
O N D I T I O N S
( k
W h / k g L N G )
DOUBLE EXPANDER
N2 CYCLE
0.55 – 0.65 kWh / kg
* PATENT PENDING TECHNOLOGY
SUITABLE FOR MEDIUM/ LARGE SCALE FLNG
SUITABLE FOR MEDIUM/ LARGE SCALE FLNG
HIGHLY COMPLEX AND LOW INHERENT SAFETY
HIGHLY COMPLEX – SUITABLE FOR SOMELARGE SCALE FLNG PLANTS ONLY
KANFA ARAGON OPTIMISED EXPANDER
CYCLE*
0.40 – 0.55 kWh / kg
L t t d i l
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Lat out design example
LIQUIFACTION MODULE
COMPRESSOR MODULE
PRE-TREATMENT MODULE
Includes all required topsides utilities ans auxilliary systems
Li f ti iti
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Liquefaction capacities
1 LNG TRAIN UP TO 0.9 MTPA
SINGLE PRE-TREATMENT TRAIN FOR ALL SIZES
UP TO 125 MMSCFDUP TO 3.5 MSm3 /d
PARALLEL LNG TRAINS LNG PRODUCT FEED GAS
2 LNG TRAINS UP TO 1.8 MTPAUP TO 250 MMSCFDUP TO 7 MSm3 /d
3 LNG TRAINS UP TO 2.7 MTPA UP TO 375 MMSCFDUP TO 10.5 MSm3 /d
4 LNG TRAINS UP TO 3.6 MTPAUP TO 500 MMSCFDUP TO 14 MSm3 /d
Expander Cycles for LNG liquefaction
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Expander Cycles for LNG liquefaction
Nitrogen Gas Expander Cycles are better suitedfor offshore liquefaction than more traditional
systems because of their compactness, weight,
ease of operation, safety and cost.
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THANK YOU!
Tekna Conference 18-19th June 2008 – Floating Production in Challenging Environment