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<Title of Presentation> By: <Author Name>, <Organization>

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17th INTERNATIONAL CONFERENCE & EXHIBITION

ON LIQUEFIED NATURAL GAS (LNG 17)

Lean LNG Plants – Heavy Ends Removal

and Optimum Recovery of Liquid

Hydrocarbons for Refrigerant Make-up By: Laurent Brussol & Dominique Gadelle, Technip France

April 17, 2013

17th INTERNATIONAL CONFERENCE & EXHIBITION ON

LIQUEFIED NATURAL GAS (LNG 17)

1

LNG 17 – Lean Gas Liquefaction Processes – Laurent Brussol & Dominique Gadelle 2

Summary

1. The trends towards liquefaction of lean gas

2. Scrub column or turbo-expander based NGL recovery

3. Technico-economic comparison

4. Conclusions

Lean gas feed – high methane content.

3

The trends towards liquefaction of lean gas

LNG 17 – Lean Gas Liquefaction Processes – Laurent Brussol & Dominique Gadelle

New LNG provinces – pipeline gas

New LNG provinces – lean gas reserves

3

4

C3/MR Liquefaction process requires continuous make-up

Nitrogen

From utility generation

Methane

From feed gas

Ethane

Extracted from feed gas

Propane

Extracted from feed gas

Extraction of C2 and C3 is desirable and is a challenge for

lean gas

Refrigerant make-up requirements

NG


5

Pipeline gas liquefaction

High cost feed stock

No revenue from condensate or LPG

Lean gas from “non associated gas” fields

Challenging separation of traces of heavy HC

No revenue from condensate or LPG

Penalized economics need to be compensated by best

efficiency through high pressure liquefaction

Economics of Lean gas liquefaction


6

Scrub column or turbo-expander based NGL recovery

6 LNG 17 – Lean Gas Liquefaction Processes – Laurent Brussol & Dominique Gadelle

7

Scrub Column

The most commonly used method with long history

Scrub column operation at liquefaction pressure

Reflux generated by the main refrigeration cycles

Works well with rich gas

More difficult with lean gas

• Low NGL extraction rates

• Low density difference between L&V

• Uncertain heavy ends removal


NG

8

NGL Recovery : Single or Dual Reflux

Used in several recent LNG plants and FLNG

T1 operates at low pressure

No integration with refrig. Cycles

No risk of C5+ / Benzene carry-over

High NGL extraction rates

Opportunity to use a d/s booster

compressor & High pressure liquefaction


Dual reflux selected for comparison study

Single Reflux Dual Reflux

T1

M

NG

To Fractionation

Unit

Treated

Gas

Ethane

T1

M

NG

To Fractionation

Unit

Treated

Gas

Ethane

9

Technico-economic Comparison

9

• Main assumptions

• Equipment count

• Production / Efficiency

• CapEx

• Operability


10

Main assumptions

Representative of many lean gas liquefaction plants

Lean Feed Gas Composition

C3/MR Liquefaction Process

Fixed 4.8 MTPA LNG Production

Heavy Duty Gas Turbines + Helpers

No LPG production

Air-cooling

Component Mol. %

CO2 50 ppm

Nitrogen 0.30

Methane 97.27

Ethane 1.60

Propane 0.35

i-Butane 0.20

n-Butane 0.20

i-Pentane 0.02

n-Pentane 0.02

C6+ incl. Benzene 0.04


NG

11

More equipment in an NGL Recovery unit compared to a the Scrub Column…

Yet the return on investment is improved


M

NG

12

....compensated by OPEX savings

NGL Recovery means lower auto-consumption

Higher liquefaction pressure requires less energy consumption

for a given quantity of LNG

NGL Recovery

vs

Scrub column

Refrigeration Power (C3+MR Compressors) -16%

Liquefaction pressure +30 bar

Total power (C3+MR+Booster Compressors) -4%

Specific power (C3+MR Compressors) -16%

Specific power (C3+MR+Booster Compressors) -4%

Fuel Gas consumption -4%


13

... without increasing overall CapEx …

Liquefaction CapEx is reduced when an NGL Recovery Unit is used

Cost Comparison /

Method

NGL recovery

vs

Scrub Column

Remark

NGL Extraction Unit +300% Additional equipment

Liquefaction Unit

(including refrigeration) -10% Smaller equipment

Fractionation Unit Similar

Overall Installed Cost Similar

Liquefaction > 90% of

investment cost in both

cases


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… and with improved operability

The NGL recovery unit is a happy combination of operating

flexibility and reduced energy consumption

Criteria Scrub Column NGL recovery

Sensitivity to feed gas

composition variations

Cannot handle

> 97% methane

Robust reflux

Refrigerant make-up

production when

liquefaction shutdown

Relies on main

refrigeration

Independent of

liquefaction

Availability Simplicity With JT mode

and sparing


Summary of main advantages and disadvantages

Scrub column NGL recovery

CapEx = = Robustness to composition

variation - + + Refrigeration drivers duty - + + Refrigerant make-up

production - + + Efficiency - + + Availability + -

NGL Recovery is more attractive overall

LNG 17 – Lean Gas Liquefaction Processes – Laurent Brussol & Dominique Gadelle 15

16

Main conclusions

Turbo-expander based NGL Recovery should always be

considered for plants liquefying lean gas

Consider savings in the liquefaction unit when selecting the NGL

Recovery method

Overall efficiency is better when a NGL Recovery is considered

NGL Recovery offers better operability and flexibility as it is

decoupled from refrigeration cycles

Overall layout is similar for both options

For a given installed refrigeration power the LNG production can be increased by installing an upfront NGL Recovery unit


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Thank you

17

Visit us at Technip booth #545

lean lng plants heavy ends removal and optimum … · thank you 17 visit us at technip booth #545 ....

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