evaluation of process system for floating lng

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



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



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



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



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



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



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



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



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



Cascade Cycle

Chosen technology for the first LNG base load plant

1 mtpa of LNG production



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



Mixed Refrigerant (MR) Cycle

Dominant baseload plant technology

Source: Foster Wheeler Energy Limited



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.



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



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



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.



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



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



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



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



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



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



Lat out design example

LIQUIFACTION MODULE

COMPRESSOR MODULE

PRE-TREATMENT MODULE

Includes all required topsides utilities ans auxilliary systems

Li f ti iti



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



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.



THANK YOU!

Tekna Conference 18-19th June 2008 – Floating Production in Challenging Environment

evaluation of process system for floating lng

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