LNG

1. LNG TRAINING COURSE
Mostafa Elsayed

2. 1. QUANTITY CALCULATION
ROUTINE
(VOLUME / MASS)

3. 3
MEASUREMENTS
 Static measurement
 Tank containment measurement
• Static conditions
• Equilibrium conditions P/T
• Closed systems
• Line system content

4. 4
MEASUREMENTS
 Static measurement
 observed level
 level corrections
 corrected level
 observed volume
 ship/landtank calibration
 actual volume
 mass

5. 5
MEASUREMENTS
 Dynamic measurement
 Dynamic measurement = metering
• controled conditions
• Repeatable metering results
• cavitation

6. 6
MEASUREMENTS
 Dynamic measurement
 observed volume
• meter calibration
• meter factor
 actual volume
 mass

7. 2. QUANTITY CALCULATION
ROUTINE
(ENERGY)

8. 8
QUANTITY CALCULATION
 Liquid Quantity?
expressed in liquid mass:
Actual liquid volume x actual liquid density (KMK)

9. 9
QUANTITY CALCULATION
 Liquid Quantity?
Expressed in Energy terms:
Liquid mass x GCV liquid (mass)
GCV: Gross Calorific Value
units? Kg x MJ/kg = MJ
MJ  BTU  MMBTU

10. 10
HEATING VALUES
 Heating values?
 Vapour
 Liquid

11. 11
HEATING VALUES
 Heating values?
 GHV (Gross heating value)
 HHV (Higher heating value)
 GCV (Gross calorific value)

12. 12
MEASUREMENTS
 Temperature of LNG liquid and vapour phase
 Level
 Corrections on level measurement
• Trim
• List
• Temperature
 Determine volume from gauge tables
 Pressure

13. 13
QUALITY AND QUANTITY
 Volume before/after loading
 Laboratory analysis
 Density of LNG
 GCV of gas displaced
 GCV of LNG
E = (VLNG * DLNG * GCVLNG) – Egas displaced

14. 14
COMPOSITION CALCULATION
 Xi molar fraction: ratio of the number of moles of the component to
the total number of moles in a mixture
 Gas chromatograph
 Mi (kg/kmol) molecular weight
 norm
 Xi*Mi (kg/kmol) molar mass
 Vi (m³/kmol) molecular volume
 norm
 Interpolation for T
 Vi*Xi (m³/kmol) molar volume
 Hmi (MJ/kg) molecular GHV: quantity of heat produced by
complete combusion in air of a unit of volume or mass of the gas, at a
constant absolute pressure of 1.01325 bar and at a temperature T
 Norm
 Xi*Hmi*Mi (MJ/kg) molar GHV

15. 15
TABLES VI (NORM: NBSI REPORT 77-867)
Temperature -170 -166 -162 -160 -158 -154 -150
Methane 0,036890 0,037375 0,037884 0,038148 0,038419 0,038983 0,039579
Ethane 0,047116 0,047442 0,047774 0,047942 0,048111 0,048455 0,048805
Propane 0,061602 0,061957 0,062316 0,062497 0,062678 0,063045 0,063417
Iso Butane 0,077356 0,077751 0,078151 0,078352 0,078554 0,078962 0,079374
N-Butane 0,075926 0,076303 0,076684 0,076876 0,077068 0,077456 0,077847
Iso Pentane 0,090641 0,091071 0,091504 0,091721 0,091939 0,092377 0,092817
N-Pentane 0,090535 0,090953 0,091373 0,091583 0,091794 0,092217 0,092643
N-Hexane 0,103800 0,104236 0,104677 0,104899 0,105122 0,105570 0,106020
Nitrogen 0,041779 0,043543 0,045702 0,046995 0,048488 0,051921 0,055877
Oxygen 0,029800 0,030450 0,031150 0,031510 0,031910 0,032750 0,033670
Carbon Dioxide 0,026400 0,026700 0,027000 0,027200 0,027300 0,027650 0,027950

16. 16
DETERMINATION VI AT TLIQ = -162.39°C
Component Vi at -166°C Vi at -162°C Vi at -162.39°C
Methane 0.037375 0.037884 0.037834
Ethane 0.047442 0.047774 0.047742
Propane 0.061957 0.062316 0.062281
Iso Butane 0.077751 0.078151 0.078112
N-Butane 0.076303 0.076684 0.076647
Iso-Pentane 0.091071 0.091504 0.091462
N-Pentane 0.090953 0.091373 0.091332
N-Hexane 0.104236 0.104677 0.104634
Nitrogen 0.043543 0.045702 0.045491
Oxygen 0.030450 0.031150 0.031082
Carbon dioxide 0.027600 0.027000 0.026971
)
(
*
))
/(
)
(( 1
1
2
1
2
1 T
T
T
T
V
V
V
V T
T
T
T 




037834
.
0
))
166
(
39
.
162
(
*
))
166
(
162
(
)
037375
.
0
037884
.
0
(
037375
.
0 















17. 17
COMPOSITION CALCULATION
components Xi Mi
kg/kmol
Xi*Mi
kg/kmol
Vi
m³/kmol
Vi*Xi
m³/kmol
Hmi
MJ/kg
Xi*Mi*Hmi
MJ/kg
Methane 0.8789 16.043 14.100 0.037834 0.033252 55.560 783.4067
Ethane 0.0812 30.070 2.442 0.047742 0.003877 51.926 126.7869
Propane 0.0206 44.097 0.908 0.062281 0.001283 50.393 45.7769
Iso Butane 0.0031 58.124 0.180 0.078112 0.000242 49.402 8.9015
N-Butane 0.0042 58.124 0.244 0.076647 0.000322 49.544 12.0947
Iso-Pentane 0.0000 72.151 0.000 0.091462 0.000000 48.944 0.0000
N-Pentane 0.0000 72.151 0.000 0.091332 0.000000 49.053 0.0000
N-Hexane 0.0000 86.178 0.000 0.104634 0.000000 48.719 0.0000
Nitrogen 0.0120 28.013 0.336 0.045491 0.000564 0.000 0.0000
Oxygen 0.0000 31.999 0.000 0.031082 0.000000 0.000 0.0000
Carbon
Dioxide
0.0000 44.010 0.000 0.026971 0.000000 0.000 0.0000
TOTALS: 1.0000 18.210 0.039522 976.9667
GC norm Multiply 2 previous columns
Norm + interpolation
Multiply 1st and 4th column norm
Multiply 1st, 2nd, 6th column

18. 18
DENSITY CALCULATION
 Revised Klosek McKinley density calculation
0.0425
Density =
Σ ( Xi * Mi )
Σ ( Xi * Vi ) – [(k1 + (k2 – k1)*Xn) * Xm]
 k1 and k2 correction factors depending on molar mass and the T of the
LNG
 Xm molar fraction of methane
 Xn molar fraction of nitrogen
Application limits:
 min 60 % CH4
 max 4 % C4
 max 4 % N2
 T < 115 K

19. 19
TABLES K1 (NORM: NBSI REPORT 77-867)
-170 -166 -162 -160 -158 -154 -150
16,0 -0,000007 -0,000007 -0,000008 -0,000009 -0,000009 -0,000010 -0,000012
16,5 0,000078 0,000086 0,000094 0,000100 0,000106 0,000118 0,000135
17,0 0,000163 0,000179 0,000197 0,000209 0,000221 0,000245 0,000282
17,2 0,000195 0,000214 0,000235 0,000248 0,000261 0,000293 0,000337
17,4 0,000228 0,000250 0,000274 0,000287 0,000301 0,000342 0,000392
17,6 0,000260 0,000286 0,000312 0,000327 0,000342 0,000390 0,000447
17,8 0,000293 0,000321 0,000351 0,000366 0,000382 0,000438 0,000502
18,0 0,000325 0,000357 0,000389 0,000405 0,000422 0,000486 0,000557
18,2 0,000349 0,000385 0,000423 0,000441 0,000460 0,000526 0,000597
18,4 0,000373 0,000412 0,000456 0,000477 0,000499 0,000566 0,000637
18,6 0,000397 0,000440 0,000489 0,000513 0,000537 0,000605 0,000677
18,8 0,000421 0,000467 0,000523 0,000548 0,000575 0,000645 0,000717
19,0 0,000445 0,000494 0,000556 0,000584 0,000613 0,000685 0,000757
19,2 0,000474 0,000526 0,000589 0,000619 0,000649 0,000724 0,000800
19,4 0,000503 0,000558 0,000622 0,000653 0,000685 0,000763 0,000844
19,6 0,000532 0,000590 0,000655 0,000688 0,000721 0,000803 0,000888
19,8 0,000561 0,000622 0,000688 0,000722 0,000757 0,000842 0,000932
20,0 0,000590 0,000654 0,000721 0,000757 0,000793 0,000881 0,000976
25,0 0,001116 0,001220 0,001339 0,001407 0,001475 0,001619 0,001782
30,0 0,001435 0,001567 0,001714 0,001790 0,001867 0,002043 0,002238

20. 20
DETERMINATION OF K1 AT TLIQ = -162.39°C
Tliq
Σ(Xi*Mi)
-166°C -162°C
18.2 g/mol 0.000385 0.000423
18.4 g/mol 0.000412 0.000456
)
(
*
))
/(
)
(( 1
1
2
1
2
1 T
T
T
T
k
k
k
k T
T
T
T 




000419
.
0
))
166
(
39
.
162
(
*
))
166
(
162
(
)
000385
.
0
000423
.
0
(
000385
.
0 














Interpolation for temperature for both molar masses:
000452
.
0
))
166
(
39
.
162
(
*
))
166
(
162
(
)
000412
.
0
000456
.
0
(
000412
.
0 














Σ(Xi*Mi) = 18.2 g/mol
Σ(Xi*Mi) = 18.4 g/mol

21. 21
DETERMINATION OF K1 AT TLIQ = -162.39°C AND
Σ(XI*MI) = 18.210 G/MOL
Interpolation for molar mass (MM) at Tliq = -162.39°C
Tliq
Σ(Xi*Mi)
-166°C -162°C -162.39°C
18.2 g/mol 0.000385 0.000423 0.000419
18.4 g/mol 0.000412 0.000456 0.000452
)
(
*
))
/(
)
(( 1
1
2
1
2
1 


 








MM
MM
MM
MM
k
k
k
k MM
MM
MM
MM
000421
.
0
)
2
.
18
210
.
18
(
*
)
2
.
18
4
.
18
(
)
000419
.
0
000452
.
0
(
000419
.
0
1 











k

22. 22
TABLES K2 (NORM: NBSI REPORT 77-867)
-170 -166 -162 -160 -158 -154 -150
16,0 -0,000009 -0,000012 -0,000017 -0,000021 -0,000024 -0,000031 -0,000039
16,5 0,000101 0,000131 0,000162 0,000178 0,000196 0,000269 0,000315
17,0 0,000210 0,000274 0,000341 0,000377 0,000416 0,000568 0,000669
17,2 0,000246 0,000318 0,000397 0,000436 0,000478 0,000630 0,000745
17,4 0,000282 0,000362 0,000452 0,000495 0,000540 0,000692 0,000821
17,6 0,000318 0,000406 0,000508 0,000554 0,000602 0,000754 0,000897
17,8 0,000354 0,000449 0,000564 0,000613 0,000664 0,000816 0,000973
18,0 0,000390 0,000493 0,000620 0,000672 0,000726 0,000878 0,001049
18,2 0,000425 0,000530 0,000658 0,000714 0,000772 0,000939 0,001116
18,4 0,000460 0,000567 0,000696 0,000756 0,000819 0,001000 0,001184
18,6 0,000496 0,000605 0,000735 0,000799 0,000865 0,001061 0,001252
18,8 0,000531 0,000642 0,000773 0,000841 0,000912 0,001121 0,001320
19,0 0,000566 0,000679 0,000811 0,000883 0,000958 0,001182 0,001388
19,2 0,000594 0,000708 0,000844 0,000920 0,000998 0,001222 0,001434
19,4 0,000623 0,000737 0,000876 0,000956 0,001038 0,001262 0,001480
19,6 0,000652 0,000765 0,000908 0,000992 0,001078 0,001302 0,001526
19,8 0,000681 0,000794 0,000941 0,001029 0,001118 0,001342 0,001573
20,0 0,000709 0,000823 0,000973 0,001065 0,001158 0,001382 0,001619
25,0 0,001383 0,001562 0,001777 0,001893 0,002014 0,002374 0,002734
30,0 0,001934 0,002172 0,002459 0,002631 0,002806 0,003230 0,003723

23. 23
Tliq
Σ(Xi*Mi) -166°C -162°C
18.2 g/mol 0.000530 0.000658
18.4 g/mol 0.000567 0.000696
DETERMINATION OF K2 AT TLIQ = -162.39°C
AND Σ(XI*MI) = 18.210 G/MOL
Interpolation for temperature and Σ(Xi*Mi)
Same as for k1
k2 = 0.00674

24. 24
DENSITY CALCULATION
0.0425
Density =
Σ ( Xi * Mi )
Σ ( Xi * Vi ) – [(k1 + (k2 – k1)*Xn) * Xm]
Σ (Xi * Mi) = 18.210
Σ (Xi * Vi) = 0.039522
k1 = 0.000421
k2 = 0.000647
Xn = 0.0120
Xm = 0.8789
 Density = 465.78 kg/m³
constant

25. 25
HIGHER HEATING VALUES



)
*
(
)
*
*
(
Mi
Xi
Mi
Hmi
Xi
Hm
kg
MJ
Hm /
53.6500
210
.
18
9667
.
976



26. 26
CONSUMED ENERGY
 Energy of gas consumed
 E gas consumed =
V gas.metered x GCV gas
(GCV gas => MMBTU/m3) – (ISO 6976)

27. 27
BTU QUANTITY DELIVERED
MMBTU
V
D
H
Q LNG
m
total 904749
12
.
1055
400
.
38201
*
78
.
465
*
6500
.
53
12
.
1055
*
*



MMBTU
P
T
V
Q
vap
LNG
r 3663
12
.
1055
7
.
37
*
25
.
1013
*
15
.
273
15
.
288
* 


MMBTU
Q
Q
Q r
total
net 901086
3663
904749 




Conversion factor MJ  MMBTU
GCV of 100% CH4 at 1013.25mbar and 15°C
Standard temperature
Standard pressure

28. 28
CALCULATION WITH DIFFERENT STANDARDS
 Density
 GHV (15°C)
 GHV (0°C)
ISO 6578 NBS TN 1030
NBS IR 77 -
867
434.7074 kg/m³ 434.7078 kg/m³ 434.7506 kg/m³
GPA 2145 ISO 6976 ISO 6578
55.2686 MJ/kg 55.2667 MJ/kg 55.2506 MJ/kg
ISO 6976
55.3533 MJ/kg

29. 3. Q + Q SPECIFICS:
- ROB
- WOBBE INDEX
- DISPLACED VAPOUR

30. 30
WOBBE INDEX
 Interchangeable?
substitute gas yields same results in the combustion process as the original gas
 Determining interchangeability?
Wobbe index: measure of the energy flow through a nozzle
Qv = flow rate
P = static pressure
DP = differential pressure
SG = specific gravity
T = temperature
C = constant based on geometry
5
,
0
)
*
/
*
(
* T
SG
DP
P
C
Qv 

31. 31
WOBBE INDEX
 Energy flow would be:
HV = Heating Value
 For constant pressure and T:
 for the same pressure at the burner, gases of equal Wobbe Index will
generate heat at equal rates per unit of burner port area.
5
,
0
)
*
/
*
(
*
*
* T
SG
DP
P
C
HV
HV
Q
E v 

index
Wobbe
SG
HV
E ~ 5
,
0


32. 32
WOBBE INDEX (NORM: ISO 6976:1995)
density
gas
relative
H
index
wobbe
gas
v

mix
vi
Z
H
Xi


)
*
(
H gas
v
2
)
)
*
(
(
1 

 i
mix b
Xi
Z
Hvi = ideal calorific value on a volumetric basis of component i
Z = compression factor
Root bi = summation factor
mix
air
air
i
i
r
Z
Z
M
M
X
D


*
*
(
)

33. 33
Components
Xi Mi Root(Bi) Xi*Root(Bi) MJ/m³ Hvi
MJ/m³
Xi*Hvi
Mi/Mair Xi*Mi/Mair
Methane 87,8900 16,0430 0,04900 0,0431 39,77700 34,96000 0,5539 0,4868
Ethane 8,1240 30,0700 0,10000 0,0081 69,69000 5,66160 1,0382 0,0843
Propane 2,0560 44,0962 0,14530 0,0030 99,09000 2,03730 1,5225 0,0313
Iso Butane 0,3140 58,1230 0,20490 0,0006 128,07000 0,40210 2,0068 0,0063
N- Butane 0,4180 58,1230 0,20690 0,0009 128,48000 0,53700 2,0068 0,0084
Iso-Pentane 0,0000 72,1498 0,25100 0,0000 157,57000 0,00000 2,4911 0,0000
N-Pentane 0,0000 72,1498 0,28640 0,0000 157,87000 0,00000 2,4911 0,0000
N-Hexane 0,0000 86,1760 0,32860 0,0000 187,30000 0,00000 2,9754 0,0000
Nitrogen 1,1980 28,0140 0,02240 0,0003 0,00000 0,00000 0,9672 0,0116
Oxygen 0,0000 0,0000 0,03160 0,0000 0,00000 0,00000 0,0000 0,0000
Carbon
Dioxide
0,0000 0,0000 0,08190 0,0000 0,00000 0,00000 0,0000 0,0000
TOTALS: 100,0000 Z= 0,996864 0,00000 43,59800 0,6287
Mair=28.9626
norm
GC
(1)*(3) (1)*(5) (1)*(7)
(2)/28.9626

34. 34
WOBBE INDEX
3
gas
v /
74
.
43
996864
.
0
59800
.
43
)
*
(
H m
MJ
Z
H
Xi
mix
vi




6303
.
0
996864
.
0
99941
.
0
*
6287
.
0
*
*
(
D
)
r 



mix
air
air
i
i
Z
Z
M
M
X
³
/
09
.
55
6306
.
0
74
.
43
density
gas
relative
H
index
wobbe
gas
v
m
MJ




35. 35
EXERCISE
 Tliq = -159.5°C
 Tvap = - 112.8
 P = 1195 mbar
 V = 126589 m³
Composition:
component Molar fraction
Methane 0.9320
Ethane 0.0416
Propane 0.0191
Iso butane 0.0029
N-Butane 0.0032
Iso-Pentane 0.0004
N-Pentane 0.0000
N-Hexane 0.0000
Nitrogen 0.0008
Oxygen 0.0000
Carbon dioxide 0.0000

36. 36
EXERCISE
 Calculate with previous methods
 Density
 Hm
 Qtotal
 Qr
 Qnet

37. 37
EXERCISE
1. Density
a) Σ (Xi*Mi)
component Xi Mi Xi*Mi
Methane 0.9320 16.043 14.952
Ethane 0.0416 30.070 1.251
Propane 0.0191 44.097 0.842
Iso butane 0.0029 58.124 0.169
N-Butane 0.0032 58.124 0.186
Iso-Pentane 0.0004 72.151 0.029
N-Pentane 0.0000 72.151 0.000
N-Hexane 0.0000 86.178 0.000
Nitrogen 0.0008 28.013 0.022
Oxygen 0.0000 31.999 0.000
Carbon dioxide 0.0000 44.010 0.000
TOTALS 1.0000 17.451

38. 38
EXERCISE
Temperature -160 -158 -159.5
Methane 0,038148 0,038419 0.038216
Ethane 0,047942 0,048111 0.047984
Propane 0,062497 0,062678 0.062542
Iso Butane 0,078352 0,078554 0.078403
N-Butane 0,076876 0,077068 0.076924
Iso Pentane 0,091721 0,091939 0.091776
N-Pentane 0,091583 0,091794 0.091636
N-Hexane 0,104899 0,105122 0.104955
Nitrogen 0,046995 0,048488 0.047368
Oxygen 0,031510 0,031910 0.031610
Carbon Dioxide 0,027200 0,027300 0.027225
1. Density
b) Interpolation for Vi and calculation Σ (Xi * Vi)

39. 39
EXERCISE
component Xi Vi Xi*Vi
Methane 0.9320 0.038216 0.035617
Ethane 0.0416 0.047984 0.001996
Propane 0.0191 0.062542 0.001195
Iso butane 0.0029 0.078403 0.000227
N-Butane 0.0032 0.076924 0.000246
Iso-Pentane 0.0004 0.091776 0.000037
N-Pentane 0.0000 0.091636 0.000000
N-Hexane 0.0000 0.104955 0.000000
Nitrogen 0.0008 0.047368 0.000038
Oxygen 0.0000 0.031610 0.000000
Carbon dioxide 0.0000 0.027225 0.000000
TOTALS 0.039356

40. 40
EXERCISE
-160 -158 -159.5
17,4 0,000287 0,000301 0.000291
17,6 0,000327 0,000342 0.000331
1. Density
c) Interpolation for k1 and k2
k1 = 0.000301
-160 -158 -159.5
17,4 0,000495 0,000540 0.000506
17,6 0,000554 0,000602 0.000566
k2 = 0.000521

41. 41
EXERCISE
1. Density
d) Calculation of density
0.0425
Density =
Σ ( Xi * Mi )
Σ ( Xi * Vi ) – [(k1 + (k2 – k1)*Xn) * Xm]
³
/
64
.
446
9320
.
0
*
0425
.
0
0008
.
0
*
)
000301
.
0
000521
.
0
(
000301
.
0
039356
.
0
451
.
17
m
kg
density 





 




42. 42
EXERCISE
2. Calculation Hm
component Hmi Xi*Hmi*Mi
Methane 55.560 830.7373
Ethane 51.926 64.9549
Propane 50.393 42.4436
Iso Butane 49.402 8.3272
N-Butane 49.544 9.2150
Iso-Pentane 48.944 1.4125
N-Pentane 49.053 0.0000
N-hexane 48.719 0.0000
Nitrogen 0.000 0.0000
Oxygen 0.000 0.0000
Carbon Dioxide 0.000 0.0000
TOTALS 957.0905

43. 43
EXERCISE
kg
MJ
Mi
Xi
Mi
Hmi
Xi
Hm /
8445
.
54
451
.
17
0905
.
957
)
*
(
)
*
*
(






44. 44
EXERCISE
MMBTU
V
D
H
Q LNG
m
total 2939109
12
.
1055
126598
*
64
.
446
*
8445
.
54
12
.
1055
*
*



MMBTU
P
T
V
Q
vap
LNG
r
9586
12
.
1055
7
.
37
*
25
.
1013
1195
*
8
.
112
15
.
273
15
.
288
12
.
1055
7
.
37
*
25
.
1013
*
15
.
273
15
.
288
* 




3. Calculation Qtotaal, Qr, Qnet
MMBTU
Q
Q
Q r
total
net 2929523
9586
2939109 





45. 45
Thank you