LNG Custody Transfer: LNG Energy determination calculations Warsaw.pdf · ISO 6578 NBS TN 1030 NBS...

LNG Custody Transfer: LNG Energy determinationHans Buytaert - SGS Belgium

Warsaw: 29/01/2019

2

SGS IS THE WORLD’S LEADING INSPECTION, VERIFICATION, TESTING AND CERTIFICATION COMPANY

Version: April 2018

3

SGS ORGANISATIONAL

GROWTH

HISTORY

SGS GLOBAL EXPANSION

1913Leader in grain

inspection

(21 million tons)

1913Pan-Europe

1878Rouen,

France

1878Agriculture and Food

1915Headquarters moved

from Paris to Geneva

1919Company

named SGS

1955Africa

Asia

1939South

America

1981Listed on the Swiss

Stock Exchange

1878

ESTABLISHED

ONE BRAND SERVING

THE VALUE CHAIN

GLOBALLY AND

ACROSS INDUSTRIESTODAY

1955

1990Consumer Testing

1980Life Sciences

Automotive

Certification

SGS INDUSTRY EXPANSION

1981Expands to

ex-USSR

1970Environmental

1960Oil and Gas

Chemical

Public Sector

1955Industrial Manufacturing

1939Mining

2001SGS rebranded

1946Inspection

of European

imports

2017

CHF 6.3 BILLIONtotal revenue

2 400 offices and laboratories

95 000 employees

1985

CHF 1.5 BILLIONtotal revenue

1981

CHF 780 MILLIONtotal revenue

180 offices and laboratories

10 675 employees

1913

45 offices and laboratories

192821 further

global countries

4

Nº1WORLD LEADER

95 000EMPLOYEES

2 400OFFICES AND LABORATORIES

11GLOBAL INDUSTRIES

GLOBAL SERVICELOCAL EXPERTISE

AT A GLANCE

5

INSPECTIONVERIFICATIONTESTINGCERTIFICATIONCONSULTANCY

TRAININGOUTSOURCING

GLOBAL SERVICES TAILORED

TO INDIVIDUAL INDUSTRIES

6

LNG Value Chain

7

LNG MSA Table of content (discharge)

1. DEFINITIONS AND INTERPRETATION

2. SALE AND PURCHASE

3. TERM

4. QUANTITY AND DELIVERY WINDOW

5. QUALITY

6. DELIVERY LIABILITIES

7. GAS SUPPLY, FACILITIES,

TRANSPORTATION AND ALTERNATE

LOCATIONS

8. CONTRACT PRICE

9. TRANSFER OF TITLE AND RISK

10. TAXES, DUTIES AND CHARGES

11. INVOICING AND PAYMENT

12. FORCE MAJEURE

13. EVENTS OF DEFAULT AND REMEDIES

14. GOVERNING LAW AND JURISDICTION

15. DISPUTE RESOLUTION

16. INDEMNITY AND LIMITATION OF

LIABILITY

17. GENERAL

SCHEDULE A FORM OF CONFIRMATION

MEMORANDUM

SCHEDULE B BUYER’S FACILITIES, LNG

SHIPS AND DISCHARGE PORT

SCHEDULE C DETAILS OF ADDRESSES

SCHEDULE D MEASUREMENT, SAMPLING

AND TESTING

SCHEDULE E FORM OF BUYER’S LC

SCHEDULE F FORM OF PERFORMANCE

SECURITY

SCHEDULE G INTEGRITY PACT

8

LNG SPA Table of content

9

LNG CONTRACTS

Avoiding disputes

Loading vs unloading

Responsibility

International Standards

Terminal regulations vs Contractual regulations

10

LNG Custody Transfer

11


Ship: Quantity

• Temperatures

• Pressure

• Level

• Trim/List

• BOG Consumption

Volume Composition

Shore: Quality

• Sampling

• analysis

Energy Determination

12


Ship: Quantity

• Temperatures

• Pressure

• Level

• Trim/List

• BOG Consumption

Volume Composition

Shore: Quality

• Sampling

• analysis


DES: Seller

13


Ship: Quantity

• Temperatures

• Pressure

• Level

• Trim/List

• BOG Consumption

Volume Composition

Shore: Quality

• Sampling

• analysis


DES: Buyer

14

Inaccuracy Gauging Devices: ISO 10976

15

Sensitivity analysis: Vapour Temperature

* For a 150000 m³ vessel

16

Sensitivity analysis: Vapour Temperature

Sensitivity Analysis Tvap

0

500

1.000

1.500

2.000

2.500

3.000

-130 -135 -140 -145 -150 -155

Temperature Vapour [°C]

En

erg

y [

MM

BT

U]


17

Sensitivity analysis: Liquid Temperature

Sensitivity Analysis Tliq

3.498.000

3.500.000

3.502.000

3.504.000

3.506.000

3.508.000

3.510.000

-160,2 -160,1 -160,0 -159,9 -159,8 -159,7 -159,6

Temperature LNG [°C]

Net

En

erg

y [

MM

BT

U]


18

Sensitivity analysis: Liquid Temperature

Sensitivity Analysis Tliq

0

2.000

4.000

6.000

8.000

-160,2 -160,1 -160,0 -159,9 -159,8 -159,7 -159,6

Temperature LNG [°C]

En

erg

y [

MM

BT

U]


19

Sensitivity analysis: Vapour Pressure

Sensitivity Analysis Pvap

3.500.000

3.502.000

3.504.000

3.506.000

3.508.000

1025 1050 1100 1150 1200

Vapour Pressure [mbar]

Net

En

erg

y [

MM

BT

U]


20

Sensitivity analysis: Vapour Pressure

Sensitivity Analysis Pvap

0

500

1.000

1.500

2.000

2.500

1025 1050 1100 1150 1200

Vapour Pressure [mbar]

En

erg

y [

MM

BT

U]


21

Lng sampling: challenges

LNG: mixture Hydrocarbons & Nitrogen

Difference in Boiling Point*• N2: -195.8 °C

• C1: -161.5 °C

• C2: -88.7 °C

• C3: -42.1 °C

• iC4: -11.2 °C

• nC4: -0.4 °C

• iC5: 30.1 °C

• nC5: 36.1 °C

• nC6: 68.8 °C

* NIST Chemistry WebBook

22

LNG sampling: challenges

Composition Vapour Phase

• Methane

• Nitrogen

Composition LNG

• Hydrocarbons C1 – C6

• Nitrogen

Fractionation effect

C1, N2

C1-C6, N2

23

LNG Sampling and analysis

IC

E

24


GENERAL

26

LNG CUSTODY TRANSFER

GIIGNL

27

ENERGY BALANCE: DISCHARGE OPERATION

Shore Tank (FSRU)Vessel Tank

Liquid line

vapour line

AFTER Discharge

BEFORE Discharge

Shore Tank (FSRU)Vessel Tank

Liquid line

vapour line

BOG

BOG

28

ENERGY BALANCE: LOADING OPERATION

Shore TankVessel Tank

Liquid line

vapour line

AFTER Load

BEFORE Load

Shore TankVessel Tank

Liquid line

vapour line

BOG

BOG

29

ENERGY BALANCE

Liquid phase (Gross Energy)

Vapour phase (Vapour Displaced)

Boil Off Gas (BOG) consumed

30

ENERGY BALANCE




Gas Up / Cool Down (loading only)

Other: ref terminal rules (flaring, venting, etc)

31

ENERGY BALANCE

Liquid (Gross)

Vapour Displaced

BOG consumed

Liquid (Gross)

Vapour Displaced

BOG consumed

Gassing Up (if any)

Cool down (if any)

+

-

-

+

-

+

+

+

Discharge Loading

32

ENERGY BALANCE: LNG CONTRACTS

Energy Balance Discharge

▪ Liquid – Vapour Displaced – BOG

▪ Liquid – Vapour Displaced

Energy Balance Loading

▪ Liquid – Vapour Displaced + BOG

▪ Liquid

▪ Liquid + BOG

▪ Liquid – Vapour Displaced

▪ Gas up + Cool Down + Liquid – Vapour Displaced +

BOG

GROSS ENERGY

34

ENERGY BALANCE: GROSS ENERGY


▪ Volume

▪ Volume x Density Mass

▪ Mass x Gross Heating Value Mass based Energy



35



▪ Volume (m³)

▪ Volume (m³) x Density (kg/m³) Mass (kg)

▪ Mass (kg) x Gross Heating Value Mass based (MJ/kg,

MMBTU/kg, kWh/kg, etc.) Energy



36


Volume

▪ As per Ships CTMS

Density

▪ Composition (from lab)

▪ Temperature (from Ship CTMS)

▪ Calculation method (as per contract)

Gross Heating Value Mass based

▪ Composition (from lab)

▪ Calculation method (as per contract)

37

DIFFERENT STANDARDS: GHV - DENSITY

Density (Vi, k1,k2)

▪ ISO 6578

▪ NBS TN 1030

▪ NBS IR 77-867

▪ etc.

GHV Mass based

▪ GPA 2145/2172

▪ ISO 6976

▪ ISO 6578

▪ IP 251/76

▪ etc.

38

DIFFERENT STANDARDS: REVISION STANDARDS

ISO 6976

▪ 1995 edition

▪ 2016 edition

ISO 6578

▪ 1991 edition

▪ 2017 edition

GPA 2145

▪ 2003 edition

▪ 2009 edition

▪ 2016 edition

DENSITY

40

GROSS ENERGY: DENSITY CALCULATION

There are two ways of determining density:

Measuring the average value directly in the LNG tank by

means of densitometers

▪ Not used for custody transfer

▪ Used for monitoring inventory (ref rollover)

▪ Kongsberg (ref below)

Calculation on the basis of composition and temperature

of the LNG

▪ LNG contracts: Revised Klosek McKinley method

▪ Other methods (ref below)

41

DENSITY: REVISED KLOSEK MCKINLEY

Easy to apply and only requires the

▪ LNG temperature

▪ Composition

▪ (Pressure: ref below Enhanced KMK)

Limitations*

▪ Molar mass LNG < 20 kg/kmol

▪ < 5 mol% Nitrogen

▪ < 5 mol% Butanes

▪ < 1 mol% Pentanes

▪ -167.15 °C < LNG temperature < -155.15 °C

ISO 6578 (2017)

42


This method is based on an empirical evaluation of the

molar volume of the mixture in the thermodynamic state

of the LNG considered.

GIIGNL

43


- Vi is the molar volume of each component at LNG temperature

- Vc is the reduction in volume on mixing components;

- k1 is the correction factor, in cubic meters per kilomole, due to the

presence of hydrocarbons and based on the average molar mass and

temperature of the mixture

- k2 is the correction factor, in cubic meters per kilomole, due to the

presence of nitrogen and

- x1: molar fraction of Methane in LNG

- x2: molar fraction of Nitrogen in LNGISO 6578 (2017)

44

DENSITY: DIFFERENT STANDARDS

Xi, Xn, Xm determined by analysis in laboratory

▪ Xi: Molar fraction of the ith component

▪ Xn: Molar fraction of Nitrogen

▪ Xm: Molar fraction of Methane

Mi by standard

▪ Molecular mass of the ith component

Vi by standard and dependent on LNG temperature

▪ Molecular volume of the ith component

K1, k2 by standard and dependent on LNG temp. and molar mass

▪ Volume correction factors for Nitrogen and Methane

45

DENSITY: DIFFERENT STANDARDS

Volume

[m³]

GHV mass

[MJ/kg]

Density

[kg/m³]

Gross Energy

[MMBTU]

Difference with

Minimum [MMBTU]

ISO 6578 (1991) 155.000 54,925 439,42 3.545.710 726

ISO 6578 (2017) 155.000 54,925 439,33 3.544.983 0

NBS TN 1030 155.000 54,925 439,36 3.545.225 242

NBS IR 77-867 155.000 54,925 439,44 3.545.871 888

Volume

[m³]

GHV mass

[MJ/kg]

Density

[kg/m³]

Gross Energy

[MMBTU]

Difference with

Minimum [MMBTU]

ISO 6578 (1991) 155.000 55,434 421,64 3.433.817 0

ISO 6578 (2017) 155.000 55,434 421,66 3.433.980 163

NBS TN 1030 155.000 55,434 421,69 3.434.224 407

NBS IR 77-867 155.000 55,434 421,69 3.434.224 407

Volume

[m³]

GHV mass

[MJ/kg]

Density

[kg/m³]

Gross Energy

[MMBTU]

Difference with

Minimum [MMBTU]

ISO 6578 (1991) 155.000 54,208 465,65 3.708.303 0

ISO 6578 (2017) 155.000 54,208 465,70 3.708.701 398

NBS TN 1030 155.000 54,208 465,73 3.708.940 637

NBS IR 77-867 155.000 54,208 465,67 3.708.462 159

Lean LNG

Middle LNG

Rich LNG

GHV MASS

47

GROSS ENERGY: GHV MASS CALCULATION

Gross Heating Value = amount of heat that would be

released by the complete combustion with oxygen of a

specified quantity of gas (i.e. 1 kg), in such a way that the

pressure, p1, at which the reaction takes place remains

constant, and all the products of combustion are returned to

the same specified temperature, t1, as that of the reactants,

all of these products being in the gaseous state except for

water, which is condensed to the liquid state at t1

Gross Heating Value = Higher Heating Value = Superior

Heating Value = Poder Calorific Superior (PCS)

GHV = HHV = SHV

As per ISO 6976 (2017)

48


As per ISO 6976 (2017)

49


GHVMass based calculation

= molar fraction of component i (mol/mol)

= mass based Gross Heating Value of

component i (MJ/kg)

= molecular mass of component i

(kg/kmol)

GHVmol based calculation

= molar fraction of component i (mol/mol)

= mol based Gross Heating Value of

component i (MJ/kmol)

= molecular mass of component i

(kg/kmol)

𝑮𝑯𝑽𝒎𝒂𝒔𝒔 =σ𝑿𝒊 ∙ 𝑴𝒊 ∙ 𝑮𝑯𝑽𝒊,𝒎𝒂𝒔𝒔

σ𝑿𝒊 ∙ 𝑴𝒊

𝑋𝑖

𝐺𝐻𝑉𝑖,𝑚𝑎𝑠𝑠

𝑀𝑖

𝑮𝑯𝑽𝒎𝒂𝒔𝒔 =σ𝑿𝒊 ∙ 𝑮𝑯𝑽𝒊,𝒎𝒐𝒍


𝑋𝑖

𝐺𝐻𝑉𝑖,𝑚𝑜𝑙

𝑀𝑖

50


= molar fraction of component i, determined by analysis in

laboratory

= mass based Gross Heating Value of component i (MJ/kg)

by standard

= molecular mass of component i (kg/kmol) by standard

𝑮𝑯𝑽𝒎𝒂𝒔𝒔 =σ𝑿𝒊 ∙ 𝑴𝒊 ∙ 𝑮𝑯𝑽𝒊,𝒎𝒂𝒔𝒔


𝑋𝑖

𝐺𝐻𝑉𝑖,𝑚𝑎𝑠𝑠

𝑀𝑖

51

GHV MASS: DIFFERENT STANDARDS SUMMARY

Lean LNG

Middle LNG

Rich LNG

GHV – DENSITY COMBO

53

GHV – DENSITY: LEAN LNG

Volume (m³)Gross Energy

(MMBTU)

155 000 421.64 55.439 3 434 103

155 000 421.66 55.439 3 434 266

155 000 421.69 55.439 3 434 511

155 000 421.69 55.439 3 434 511

155 000 421.64 55.438 3 434 042

155 000 421.66 55.438 3 434 204

155 000 421.69 55.438 3 434 449

155 000 421.69 55.438 3 434 449

155 000 421.64 55.438 3 434 042

155 000 421.66 55.438 3 434 204

155 000 421.69 55.438 3 434 449

155 000 421.69 55.438 3 434 449

155 000 421.64 55.421 3 432 989

155 000 421.66 55.421 3 433 151

155 000 421.69 55.421 3 433 396

155 000 421.69 55.421 3 433 396

155 000 421.64 55.437 3 433 980

155 000 421.66 55.437 3 434 142

155 000 421.69 55.437 3 434 387

155 000 421.69 55.437 3 434 387

155 000 421.64 55.435 3 433 856

155 000 421.66 55.435 3 434 019

155 000 421.69 55.435 3 434 263

155 000 421.69 55.435 3 434 263

min 3 432 989 MMBTU

max 3 434 511 MMBTU Difference 1 522 MMBTU

Density

(kg/m³)

GHV

mass

54

GHV – DENSITY: MIDDLE LNG


(MMBTU)

155 000 439.42 54.926 3 545 798

155 000 439.33 54.926 3 545 072

155 000 439.36 54.926 3 545 314

155 000 439.44 54.926 3 545 959

155 000 439.42 54.925 3 545 733

155 000 439.33 54.925 3 545 007

155 000 439.36 54.925 3 545 249

155 000 439.44 54.925 3 545 895

155 000 439.42 54.925 3 545 733

155 000 439.33 54.925 3 545 007

155 000 439.36 54.925 3 545 249

155 000 439.44 54.925 3 545 895

155 000 439.42 54.908 3 544 636

155 000 439.33 54.908 3 543 910

155 000 439.36 54.908 3 544 152

155 000 439.44 54.908 3 544 797

155 000 439.42 54.924 3 545 669

155 000 439.33 54.924 3 544 943

155 000 439.36 54.924 3 545 185

155 000 439.44 54.924 3 545 830

155 000 439.42 54.922 3 545 540

155 000 439.33 54.922 3 544 813

155 000 439.36 54.922 3 545 056

155 000 439.44 54.922 3 545 701

min 3 543 910 MMBTU


Density

(kg/m³)

GHV

mass

55

GHV – DENSITY: RICH LNG


(MMBTU)

155 000 465.65 54.211 3 708 542

155 000 465.70 54.211 3 708 940

155 000 465.73 54.211 3 709 179

155 000 465.67 54.211 3 708 701

155 000 465.65 54.210 3 708 474

155 000 465.70 54.210 3 708 872

155 000 465.73 54.210 3 709 111

155 000 465.67 54.210 3 708 633

155 000 465.65 54.210 3 708 474

155 000 465.70 54.210 3 708 872

155 000 465.73 54.210 3 709 111

155 000 465.67 54.210 3 708 633

155 000 465.65 54.195 3 707 448

155 000 465.70 54.195 3 707 846

155 000 465.73 54.195 3 708 084

155 000 465.67 54.195 3 707 607

155 000 465.65 54.209 3 708 405

155 000 465.70 54.209 3 708 803

155 000 465.73 54.209 3 709 042

155 000 465.67 54.209 3 708 565

155 000 465.65 54.208 3 708 337

155 000 465.70 54.208 3 708 735

155 000 465.73 54.208 3 708 974

155 000 465.67 54.208 3 708 496

min 3 707 448 MMBTU


GHV

mass

Density

(kg/m³)

REFERENCE CONDITIONS

57

INFLUENCE REFERENCE CONDITIONS

LNG industry: different reference temperature for

combustion

0 °C (ISO 6976)

15 °C (ISO 6976, ISO 6578, GPA 2145)

60 °F (ISO 6976, GPA 2145)*

20 °C (ISO 6976)

25 °C (ISO 6976)

Depending standard 60 °F can be defined as 15.56 °C or 15.55 °C

58


59


Gross Energy delivered

Gross EnergyDifference with

minimum

Tref 0 °C 3.549.624 9.183 [MMBTU]

Tref 15 °C 3.544.090 3.649 [MMBTU]

Tref 15.55 °C 3.543.893 3.452 [MMBTU]

Tref 20 °C 3.542.284 1.843 [MMBTU]

Tref 25 °C 3.540.441 0 [MMBTU]

60


61


VAPOUR DISPLACED

63

VAPOUR DISPLACED

Vapour displaced vs. vapour return

Energy of the vapour phase

▪ Before loading

▪ After Discharge

▪ “Vapour heel”

64

VAPOUR DISPLACED: CALCULATIONS

volume of Gas Displaced = volume of LNG loaded/discharged

Temperature correction: actual vapour temperature (before

loading/after unloading to reference temperature (in Kelvin)

Pressure correction: actual vapour pressure (before loading/after

unloading) to reference pressure

GHV volume based of the vapour:

- based upon analysis of the vapour

- fixed values (e.g. 100% methane)

- ref below

𝑽𝒂𝒑𝒐𝒖𝒓 𝑫𝒊𝒔𝒑𝒍𝒂𝒄𝒆𝒅 = 𝑽 ∙𝑻𝑹𝒆𝒇

𝑻𝒗𝒂𝒑∙𝑷𝑽𝒂𝒑

𝑷𝑹𝒆𝒇∙ 𝑮𝑯𝑽𝑽𝒂𝒑𝒐𝒖𝒓

𝑷𝑽𝒂𝒑

𝑷𝑹𝒆𝒇

𝑮𝑯𝑽𝑽𝒂𝒑𝒐𝒖𝒓

𝑻𝑹𝒆𝒇

𝑻𝒗𝒂𝒑

𝑽

65

VAPOUR DISPLACED: GHV VAPOUR

GHV Vapour determination can be done by either of the

following:

Analysis vapour return

▪ Several terminal in Europe: France, Spain, Greece, Italy

Analysis onboard composition

▪ Not common

▪ only for dewpoint or Oxygen

Assumed a fixed composition

▪ Most common in contract

▪ Assumed composition (at reference conditions

applicable)

• 100% Methane

• Mixture Methane, Nitrogen

BOG CONSUMPTION

67

BOG CONSUMPTION

EU directive

Contract shipper friendly

Gas to Engine vs Gas to GCU

Determination quantity

▪ counters

▪ fixed

▪ percentage

68

Venting

Gas Combustion

unit (GCU)

Engine

ReliquefactionLNG

BOG

BOG CONSUMPTION

69

BOG COUNTERS: STEAM SHIP

70

GHV VS. NHV

Calculated as per ISO 6976 (2016)

GHV NHV

55,011 49,547 MJ/kg @ 0 °C

54,925 49,538 MJ/kg @ 15 °C

54,922 49,538 MJ/kg @ 15.55 °C

54,897 49,536 MJ/kg @ 20 °C

54,869 49,532 MJ/kg @ 25 °C

Heating Values

71

GHV VS. NHV

Calculated as per ISO 6976 (2016) for volume of 155 000 m³ @ -159,5 °C, grade middle LNG

Hans Buytaert - SGS Belgium

LNG Business Development manager

[email protected]

mailto:[email protected]

LNG Custody Transfer: LNG Energy determination calculations Warsaw.pdf · ISO 6578 NBS TN 1030 NBS...

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Transcript of LNG Custody Transfer: LNG Energy determination calculations Warsaw.pdf · ISO 6578 NBS TN 1030 NBS...