Owned and presented by

Host IGU Member

Supporting Association

VERSATILE CRYOGENIC NITROGEN REJECTION

Heinz C. Bauer – Linde EngineeringMarcus Lang – Linde Engineering

Why is nitrogen rejected?Nitrogen is rejected only, if this cannot be avoided.

Nitrogen recovery is not the objective, the added value lies in more attractive properties of the treated feed stock like

• increased Wobbe Index of the processed natural gas• reduced risk of LNG stratification in a flat bottom tank

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NRU flash process• high k-value (>20) of N2/CH4 at

low pressure requires few stages• example:

boil-off gas reliquefaction (BOGR) based on a double flash process

• load balancing between BOG and MR compressor by recycle

• N2 rich fuel for gas turbines

BOG

MR

BOG

LNGFuel

6% N2

1% N2

30% N2

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NRU flash process• Customer: Malaysia

LNG• Location: Bintulu,

Malaysia• Capacity: 130,000

Nm³/h• N2 in feed: 6 mol%• Start-up: 2015

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NRU single column processNG

MP N2

CH4

• fit for low-to-medium N2 content

• example:heat pumped single column

• side condenser for best efficiency

• CO2 tolerant due to partitioned column

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NRU single column process• Customer: Gazprom• Location: Svobodny,

Russia• Capacity: 6x 815,000

Nm³/h• N2 in feed: 4-7 mol%• Start-up: 2021

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NGL+NRU

NRU double column process

NG

LNG

LP N2

• fit for medium-to-high N2 content

• example:refrigerated double column

• liquid HC (LNG) product• no need for HC product

compression

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NRU double column process

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• Customer: Snøhvit Group

• Location: Hammerfest, Norway

• Capacity: 71,400 Nm³/h• N2 in feed: 34 mol%• Start-up: 2007

Further selected references (1/3)

• Customer: Helison Production S.p.A.

• Location: Skikda, Algeria• Capacity: 47,000 Nm³/h• N2 in feed: 47 mol%• Start-up: 2005• Process: Single column

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Further selected references (2/3)

• Customer: Xinjiang Jimunai Guanghui

• Location: Jimunai, PR China

• Capacity: 62,500 Nm³/h• N2 in feed: 4 mol%• Start-up: 2011• Process: Single column

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Further selected references (3/3)

• Customer: Pluto LNG • Location: Karratha, WA

Australia• Capacity: 78,000 Nm³/h• N2 in feed: 47-54 mol%• Start-up: 2012• Process: Double column

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ConclusionLinde Engineering has a proven and comprehensive expertise in customizing nitrogen rejection units (NRU) to a wide range of applications. This expertise is an excellent platform for future challenges in nitrogen rejection such as

• Nitrogen based enhanced oil recovery (EOR) projects• Unlocking large nitrogen rich natural gas reservoirs (e.g.

Natuna)• Tie-back of nitrogen rich reservoirs into existing LNG plants

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