Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
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Chapter 13 : PRODUCT BLENDING
Introduction
• The major refinery products produced by blending are:
- Gasoline
- Jet fuels
- Diesel fuel
- Furnace oils.
- Residual fuels.
- Heating oils.
- Lubricating oils.
More restrictions on product specs
• Refinery sources of gasoline (blending components)
- Straight-run gasoline (CDU naphtha).
- Coker gasoline
- FCC/TCC gasoline
- Hydrocracker gasoline (hydrocrackate)
- Reforming (reformate)
- Alkylation (alkylate)
- Polymerization (polymerate)
- Isomerization (isomerate)
- ARDS/isomax gasoline
- H-oil gasoline
- Thermal cracker gasoline.
- Aromatic concentrate
- C4+ Gases
Figure 13-1: Refinery gasoline blending
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-2
• These gasoline blending-stocks have different molecular contents and performance
qualities (RON, MON, RVP, API, BP range, etc.) as shown in Table 13-1.
• They must be blended into various grades that meet market demands.
• Blending components must meet all desired specifications like boiling point, specific
gravity, RVP, RON and MON.
• The product is designated ‘off spec’ if it does not meet one or more of the required
specifications which could make it either unsalable or salable for a lower price.
Exceeding one or more of the required product specifications is termed ‘giveaway’,
which is also a loss since it means selling a higher quality product for a lower price.
• Basic intermediate streams are usually blended to produce a variety of on-spec
finished products. For example, naphtha can be blended into either gasoline or jet
fuel, depending upon the product demand. Likewise, middle distillates can be blended
into the kerosene or diesel pool.
• The objective of product blending is to allocate the available blending components in
such a way as to meet product demands and specifications at the lowest possible cost
and to yield products which maximize overall profit.
• For example, if a refiner sells about one billion gallons of gasoline per year (about
65,000 BPCD), a saving of one-hundredth (1/100) of a cent per gallon results in an
additional profit of $100,000 per year.
Figure 13-2: Refinery tank farm blending & shipping farcicalities
Figure 13-3: Refinery blending facilities
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-3
Table 13-1: Blending Component Values for Gasoline Blending Streams.
No Component RVP (psi) BMON BRON °API
1. i-C4 71.0 92.0 93.0
2. n-C4 52.0 92.0 93.0
3. i-C5 19.4 90.8 93.2
4. n-C5 14.7 72.4 71.5
5. i-C6 6.4 78.4 79.2
6. LSR gasoline (C5-180°F) 11.1 61.6 66.4 78.6
7. LSR gasoline Isomerized, once-through 13.5 81.1 83.0 80.4
8. HSR gasoline 1.0 58.7 62.3 48.2
9. Lt hydrocrackate 12.9 82.4 82.8 79.0
10. Hydrocrackate, C5-C6 15.5 85.5 89.2 86.4
11. Hydrocrackate, C6-l90 °F 3.9 73.7 75.5 85.0
12. Hydrocrackate, 190-250 °F 1.7 75.6 79.0 55.5
13. Hvy hydrocrackate 1.1 67.3 67.6 49.0
14. Coker gasoline 3.6 60.2 67.2 57.2
15. Lt thermal gasoline. 9.9 73.2 80.3 74.0
16. C6+ lt thermal gasoline. 1.1 68.1 76.8 55.1
17. FCC gasoline, 200-300 °F 1.4 77.1 92.1 49.5
18. FCC C5+ gasoline 4.4 76.8 92.3 57.2
19. Hydrog lt FCC gasoline, C5+ 13.9 80.9 83.2 51.5
20. Hydrog C5-200 °F FCC gasoline 14.1 81.7 91.2 58.1
21. Hydrog lt FCC gasoline, C6+ 5.0 74.0 86.3 49.3
22. Hydrog C5+ FCC gasoline 13.1 80.7 91.0 54.8
23. Hydrog 300-400 °F FCC gasoline 0.5 81.3 90.2 48.5
24. Reformate, 94 RON 2.8 84.4 94.0 45.8
25. Reformate, 98 RON 2.2 86.5 98.0 43.1
26. Reformate, 100 RON 3.2 88.2 100.0 41.2
27. Aromatic concentrate 1.1 94.0 107.0
28. Alkylate, C3= 5.7 87.3 90.8
29. Alkylate, C4= 4.6 95.9 97.3 70.3
30. Alkylate, C3=, C4= 5.0 93.0 94.5
31. Alkylate, C5= 1.0 88.8 89.7
32. Polymer 8.7 84.0 96.9 59.5
33. C5+ TCC gasoline 4.0 76.6 85.5
34. C6+ TCC gasoline 2.6 75.8 84.3
BMON = Blending motor octane number, BRON = Blending research octane number.
These values are provided for illustration and cannot be generalized.
Table 13-2: Blending values of octane improvers (boosters/additives)
Compound Formula MW API Tb (ºF) RVP (psi) Flash (ºF) RON MON
Methanol
Ethanol
TBA
MTBE
ETBE
TAME
TEL
CH4O
C2H6O
C4H10O
C5H12O
C6H14O
C6H14O
C8H20Pb
32
46.1
74.1
88.1
102.2
102.2
323.4
46.2
46.1
47.4
58.0
56.7
53.7
3.143
148.5
173
180.4
131.4
159.8
185
239
40
11
6
9
4
1.5
0
53.6
53.6
39.2
-18.4
-2.2
12.2
199.4
135
132
106
118
118
111
10,000
105
106
89
101
102
98
13,000
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
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Blending for API gravity
• API Gravities are not linear and therefore cannot be averaged.
• Specific gravity can be volume averaged.
Example 13-1: Blending for API
Calculate the API of a blend from
1,000 bbls oil 70 ºAPI
2,000 bbls oil 5 ºAPI
Solution:
𝑆𝐺 =141.5
𝐴𝑃𝐼 + 131.5=
141.5
70 + 131.5= 0.7026
𝑆𝐺 =141.5
𝐴𝑃𝐼 + 131.5=
141.5
5 + 131.5= 1.0374
Ave. sp. gr. = 0.3333(0.7026) + 0.6666(1.0374) = 0.9258
API = (141.5/ 0.9258)-131.5 = 21.34 √
If you average the API then the answer is = 0.3333 x 70 + 0.6666 x 5 = 26.67 X
Blending for Initial & Final BP
• The initial boiling point of the blend equals the lowest of the blending stocks and the
final boiling point equals the highest.
Example 13-2: Blending for Boiling Point
Calculate the initial and final boiling points of the blend from the following blending stocks,
LSR gasoline (C5 – 180 ºF)
HSR gasoline (200 – 380 ºF)
FCC gasoline (200 – 300 ºF)
Blend (C5 – 380 ºF)
Blending for Reid Vapor Pressure (RVP)
• The theoretical method for blending to the desired RVP requires knowledge of the
average molecular weight of each of the streams.
A more convenient way developed by Chevron Research Company is to use ‘Vapor
Pressure Indices’ (VPI) compiled as a function of the RVP of the blending streams as
shown in Table 13-3.
• The RVP of the blend is closely approximated by the sum of all the products of the
volume fraction (Xv) times the VPI for each blending component i.
(VPI)blend = ∑ Xvi (VPI)i 13-1
• RVP of a gasoline is controlled by adding n-butane to (C5 – 380°F) naphtha.
• If the volume of the n-butane to be blended for a given RVP is given by,
V0 (VPI)0 + V1 (VPI)1 + …...… = (V0 +V1 + …) (VPI)m 13-2
where
V0 = Volume (bbl) of n-butane.
V1 = Volume (bbl) of blending stock 1,
1, 2, 3 = blending stocks 1, 2, 3, etc.
(VPBI)m = VPBI of the mixture.
𝑅𝑉𝑃𝑚 =(∑ (𝑉𝑖 𝑅𝑉𝑃𝑖
1.25)𝑛
𝑖=0)
0.8
𝑉𝑚 13-3
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
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Table 13-3: RVP Index for Gasoline and Turbine Fuels.
Vapor
Pressure,
psi
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
0.00
1.00
2.37
3.94
5.65
7.47
9.39
11.4
13.4
15.6
17.8
20.0
22.3
24.7
27.1
29.5
32.0
34.5
37.1
39.7
42.3
45.0
47.6
50.4
53.1
55.9
58.7
61.5
64.4
67.3
0.05
1.12
2.52
4.11
5.83
7.66
9.58
11.6
13.7
15.8
18.0
20.3
22.6
24.9
27.3
29.8
32.2
34.8
37.3
39.9
42.6
45.2
47.9
50.6
53.4
56.2
59.0
61.8
64.7
67.6
0.13
1.25
2.67
4.28
6.01
7.85
9.78
11.8
13.9
16.0
18.2
20.5
22.8
25.2
27.6
30.0
32.5
35.0
37.6
40.2
42.8
45.5
48.2
50.9
53.7
56.5
59.3
62.1I
65.0
67.9
0.22
1.38
2.83
44.4
6.19
8.04
9.98
12.0
14.1
16.2
18.4
20.7
23.0
25.4
27.8
30.2
32.8
35.3
37.8
40.4
43.1
45.8
48.4
51.2
54.0
56.7
59.6
62.4
65.3
68.2
0.31
1.52
2.98
4.61
6.37
8.23
10.2
12.2
14.3
16.4
18.7
20.9
23.3
25.6
28.0
30.5
33.0
35.5
38.1
40.7
43.4
46.0
48.7
51.5
54.2
57.0
59.8
62.7
65.6
68.4
0.42
1.66
3.14
4.78
6.55
8.42
10.4
12.4
14.5
16.7
18.9
21.2
23.5
25.9
28.3
30.8
33.2
35.8
38.4
41.0
43.6
46.3
49.0
51.7
54.5
57.3
60.1
63.0
65.8
68.8
0.52
1.79
3.30
4.95
6.73
8.61
10.6
12.6
14.7
16.9
19.1
21.4
23.7
26.1
28.5
31.0
33.5
36.0
38.6
41.2
43.9
46.6
49.3
52.0
54.8
57.5
60.4
63.3
66.1
69.0
0.64
1.94
3.46
5.13
6.92
8.80
10.8
12.8
14.9
17.1
19.4
21.6
24.0
26.4
28.8
31.2
33.8
36.3
38.9
41.5
44.2
46.8
49.5
52.3
55.1
57.9
60.7
63.5
66.4
69.3
0.75
2.08
3.62
5.30
7.10
9.00
11.0
13.0
15.2
17.3
19.6
21.9
24.2
26.6
29.0
31.5
34.0
36.6
39.1
41.8
44.4
47.1
49.8
52.6
55.3
58.1
61.0
63.8
66.7
69.6
0.87
2.23
3.78
5.48
7.29
9.19
11.2
13.2
15.4
17.6
19.8
22.1
24.4
26.8
29.3
31.8
34.3
36.8
39.4
42.0
44.7
47.4
50.1
52.8
55.6
58.4
61.3
64.1
67.0
69.9
30
40
70.2
101
Example:
Calculate the vapor-pressure of a gasoline blend as follows
(nC4) 51.6
(iC4) 72.2
(C3) 190.0
138
210
705
Component
Volume
Fraction
Vapor
Pressure
psi
Vapor
Pressure
Index No.
Volume
Fraction
x
VPI
Equation:
VPI = VP1.25
n-Butane
Light Straight Run
Heavy Refined
Total
0.050
0.450
0.500
1.000
51.6
6.75
1.00
7.45
138
10.9
1.00
12.3
6.90
4.90
0.50
12.3
From the brochure, “31.0°API Iranian Heavy Crude Oil,” by arrangement with Chevron
Research Company. Copyright © 1971 by Chevron Oil Trading Company.
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
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Blending for Octane Number
• Octane numbers are blended on a volumetric basis.
• True octane numbers do not blend linearly therefore blending octane numbers are used.
• Those are numbers which, when added on a volumetric average basis, will give the true
octane of the blend.
• Blending octane numbers are based on experience.
• The formula used for calculations is:
Vblend (ON)blend = ∑ Vi (ON)i 13-4
where,
Vblend = Total volume of gasoline blended (bbl).
Vi = Volume of blending component i (bbl).
(ON)blend = Desired true octane of blend.
(ON)i = Octane number of component i.
• If n-butane alone is not sufficient to increase the Pool octane number of the gasoline,
different ways are used to improve the octane number;
1. Increase severity of reforming to produce a 98.8 or 100 RONC reformate.1
2. Use oxygenates such as MTBE or ETBE (Table 13-2) to improve the pool octane.
Example 13-3: Blending for RVP and Octane Number:
From the following stocks; 1,250 bbls HSR gasoline,
750 bbls LSR gasoline,
620 bbls C5+ FCC gasoline,
a. Calculate the amount of n-butane required to produce a gasoline with an RVP of 9 psi.
b. Calculate the RON and MON for the blend.
c. Calculate the posted octane number (PON) if 10 V% MTBE is added (keeping RVP = 9).
Solution
a. Amount of n-butane
RVP values are obtained from Table 13-1
VPBI values are obtained from Table 13-2
COMPONENT # (BPDi) (RVPi)
Table 13-1
(VPIi)
Table 13-3
(BPDi)(VPIi)
n-butane 2 W 51.6 138 138W
HSR gasoline 8 1250 1.0 1.0 1250.00
LSR gasoline 6 750 11.1 20.3 15225.00
C5+ FCC gasoline 18 620 4.4 6.37 3949.40
Total for blend 2620 + W 138W + 20424.4
∑(BPDi) ∑ (BPDi)(VPIi)
For the blend at 9.0 RVP, (VPI)m = 15.6, from Table 13-3 into the equation
(VPI)blend = ∑ Xvi (VPI)i 13-1
(VPI)m ∑(BPDi) = ∑(BPDi)(VPIi)
15.6 (2620 + W) = 20424.4 + 138 W
W = 165 BPD of n-butane
1 (This is not attractive because it is costly, and the aromatics content of the gasoline would increase
and the volume would decrease).
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-7
b. RON and MON of the blend Component # BPD Vol.
Frac.
MON
Table 13-1
RON
Table 13-1
MON x
Vol. frac.
RON x
Vol. frac.
n-butane 2 165 0.0592 92.0 93.0 4.85 5.51
HSR gasoline 8 1250 0.4488 58.7 62.3 26.34 27.96
LSR gasoline 6 750 0.2693 61.6 66.4 16.59 17.88
C5+ FCC gasoline 18 620 0.2226 76.8 92.3 17.10 20.55
Total for blend 2785 64.9 71.9
MON of the blend = ∑MON x vol. frac. = 64.9
RON of the blend = ∑RON x vol. frac. = 71.9
c. RON and MON of the blend after adding 10 V% MTBE
10 % MTBE is equal to 0.1(2785 BPD) = 278.5 BPD
MTBE octane number is from Table 13-2.
Component BPD Vol.
Frac.
MON RON MON x Vol.
frac.
RON x
Vol. frac.
n-butane 165 0.054 92.0 93.0 4.97 5.022
HSR gasoline 1250 0.408 58.7 62.3 23.95 25.42
LSR gasoline 750 0.245 61.6 66.4 15.1 16.27
C5 FCC gasoline 620 0.202 76.8 92.3 15.51 18.64
MTBE 278.5 .091 101 118 9.19 10.74
Total 3063.5 68.72 76.1
PON of the blend = (vol. frac. x RON) (vol.frac. x MON)
2
=
76.1 68.72
2
= 72.4
BLENDING FOR OTHER PROPERTIES
• Several methods exist for estimating the physical properties of a blend from those of
the blending stocks.
• One of the most convenient methods of estimating properties, that do not blend
linearly, is to substitute for the true value to be blended another value (called blending
factor or index) which has the property of blending approximately linear.
• The Chevron Research Company has compiled factors or index numbers for several
other properties such as viscosity, flash point, aniline, and pour point.
Blending for Viscosity
• Viscosity blending is more complicated than blending for the other properties.
• It is not an additive property and it is necessary to use special techniques to estimate
the viscosity of a blend from the viscosities of its blending stocks.
• The method most commonly accepted is the use of ASTM charts.
• The viscosity factor of the blend can be calculated using the equation:
(VF) blend = ∑ Xvi (VF)i 13-5
where, Xvi = Volume fraction.
(VF)i = Viscosity factor for component i (Table 13-6, Table 13-7, Table 13-8).
(VF)blend = Viscosity factor for the blend.
• Blending of kinematic viscosities (centistokes, cSt = mm2/s) the viscosities of all
components of the blend in cSt must be at the same temperature. Table 13-6
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-8
• Blending of viscosities in Saybolt universal seconds (SUS) may also be done at any
temperature and interchangeably with kinematic viscosities at the same temperature
using Table 13-7.
• Viscosity factors also are given in Table 13-8 for viscosities expressed in Saybolt
Furol Seconds (SFS).
• SFS viscosities are blended only at 122°F. If SFS viscosities are at any other
temperature, they must be converted to centistokes or SUS before blending.
• Viscosity factors for SFS at 122 °F may be used interchangeably with viscosity
factors for SUS at 130 °F and with centistokes at 130°F.
• Table 13-6, Table 13-7, and Table 13-8 may be used to convert viscosities in SFS at
122 °F to either kinematic or Saybolt Universal viscosities at 130 °F.
• Other viscosity units include
- Redwood sec
- Redwood Admiralty Seconds
- Redwood No.1 Seconds
• The viscosity of a blend can also be estimated by API Procedure 11A4.3 in the API
Technical Data Book on Petroleum Refining.
Blending for Flash Point
• The flash point index of a blend is given by
(FPI) blend = ∑ Xvi (FPI)i 13-6
where
Xvi = Volume fraction.
(FPI) blend = Flash point blending index of the blend.
(FPI)i = Flash point index of component i from Table 13-9
Blending for Aniline Point
• The aniline point index of a blend is given by
(API) blend = ∑ Xvi (API)i 13-7
where
Xvi = Volume fraction.
(API) blend = Aniline point blending index of the blend.
(API)i = Aniline point index of component i from Table 13-10
Blending for Pour Point
• The pour point index of a blend is given by
(PP) blend = ∑ Xvi (PPI)i 13-8
where
Xvi = Volume fraction.
(PP) blend = Pour point of the blend.
(PPI)i = Pour point index of component i, from Table 13-11
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-9
Example 13-4
Calculate the viscosity, flash point, aniline point, and pour point of the blend from the following
blending stocks.
Stock bbls ASTM 50%
temp (ºF)
Viscosity Flash point
(ºF)
Aniline
point (ºF)
Pour point
(ºF)
A
B
C
5,000
3,000
2,000
575
425
500
430 SFS at 122 ºF
82.5 SUS at 130 ºF
2.15 cSt at 130 ºF
100
90
130
70
160
40 (mixed)
10
50
65
Blend 10,000 ? ? ? ?
Solution:
a. Viscosity
Stock vol. frac.
of blend
Viscosity Factor
(Table 13-6)
vol. frac. x
Factor
A
B
C
0.5
0.3
0.2
430 SFS at 120 ºF
82.5 SUS at 130 ºF
2.15 cSt at 130 ºF
0.700
0.500
0.300
0.350
0.150
0.060
Total 1 0.560
For a blend with a factor of 0.56 Table 13-6, Table 13-7 and Table 13-8 give the following viscosities
39.5 cSt at 130 ºF, 183 SUS at 130 ºF, and 25.7 SFS at 122 ºF
b. Flash point
Stock vol. frac. of blend Flash point (ºF) Blending Index (Table 13-9) vol. frac. x index
A
B
C
0.5
0.3
0.2
100
90
130
753
1,170
224
376.5
351
44.8
Total 1 772
The Table 13-9 gives a flash point for the blend of 99.5 ºF for a blending index of 772.
c. Aniline Point
Stock vol. frac.
of blend
Aniline point (ºF) Blending Index
(Table 13-10)
vol. frac. x index
A
B
C
0.5
0.3
0.2
70
160
40 (mixed)
347
855
-425
173.5
256.5
-85
Total 1 345
Table 13-10 gives for a blending index of 345 an aniline point for the blend of 69.5 ºF or a mixed
aniline point of 115.3 ºF.
d. Pour Point
Stock vol. frac.
of blend
ASTM 50%
temp (ºF)
Pour Point (ºF) Blending Index
(Table 13-11)
vol. frac. x
index
A
B
C
0.5
0.3
0.2
575
425
500
10
50
65
8
61
98
4
18.3
19.6
Total 1 41.9
The pour point of the blend is 41.9 ºF or 42 ºF.
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-10
Notice that for the Octane number and the pour point the property (not the index) is
calculated, therefore, there is no need to go back to the Table to get the desired property.
Blending for Freezing point
• The freezing point index of a blend is given by
(FPI) blend = ∑ Xvi (FPI)i 13-9
where
Xvi = Volume fraction.
(FPI) blend = Freezing point blending index of the blend.
(FPI)i = Freezing point blending index of component i from Table 13-4 or13-5.
Table 13-4. Freezing point index in Fahrenheit
Freeze Point (°F) Index Freeze Point (°F) Index Freeze Point (°F) Freeze Point (°F)
-250 0.0064 -105 1.2286 40 235.03
-245 0.0077 -100 1.4727 45 281.71
-240 0.0092 -95 1.7651 50 337.66
-235 0.0111 -90 2.1157 55 404.72
-230 0.0133 -85 2.5359 60 485.11
-225 0.0159 -80 3.0396 65 581.46
-220 0.0190 -75 3.6433 70 696.94
-215 0.0228 -70 4.3669 75 835.37
-210 0.0274 -65 5.2343 80 1001.3
-205 0.0328 -60 6.2739 85 1200.2
-200 0.0393 -55 7.5199 90 1438.5
-195 0.0471 -50 9.0135 95 1724.2
-190 0.0565 -45 10.804 100 2066.7
-185 0.0677 -40 12.949 105 2477.2
-180 0.0811 -35 15.521 110 2969.2
-175 0.0973 -30 18.604 115 3558.9
-170 0.1166 -25 22.299 120 4265.7
-165 0.1397 -20 26.728 125 5112.9
-160 0.1675 -15 32.037 130 6128.4
-155 0.2007 -10 38.400 135 7345.6
-150 0.2406 -5 46.026 140 8804.6
-145 0.2884 0 55.168 145 10553.3
-140 0.3457 5 66.125 150 12649.3
-135 0.4143 10 79.258 155 15161.6
-130 0.4966 15 95.000 160 18173.0
-125 0.5953 20 113.87 165 21782.4
-120 0.7135 25 136.48 170 26108.7
-115 0.8552 30 163.59 175 31294.2
-110 1.0250 35 196.08 Courtesy Albahri 2016
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-11
Table 13-5 Freezing point index in Kelvin
Freeze Point (K) Index Freeze Point (K) Index Freeze Point (K) Index
116 0.0061 196 1.139 276 210.1
118 0.0070 198 1.297 278 238.8
120 0.0080 200 1.473 280 272.4
122 0.0091 202 1.683 282 310.8
124 0.0104 204 1.919 284 353.8
126 0.0119 206 2.183 286 402.0
128 0.0135 208 2.486 288 459.4
130 0.0154 210 2.838 290 523.6
132 0.0175 212 3.233 292 595.3
134 0.0200 214 3.672 294 678.5
136 0.0227 216 4.193 296 774.5
138 0.0259 218 4.783 298 881.8
140 0.0295 220 5.442 300 1001.3
142 0.0336 222 6.191 302 1144.5
144 0.0383 224 7.071 304 1305.0
146 0.0437 226 8.058 306 1484.2
148 0.0497 228 9.157 308 1689.9
150 0.0565 230 10.45 310 1929.7
152 0.0646 232 11.92 312 2198.0
154 0.0736 234 13.57 314 2496.8
156 0.0837 236 15.42 316 2851.1
158 0.0953 238 17.62 318 3252.2
160 0.1088 240 20.08 320 3700.2
162 0.1240 242 22.83 322 4209.2
164 0.1408 244 26.02 324 4807.9
166 0.1608 246 29.70 326 5478.5
168 0.1834 248 33.82 328 6225.8
170 0.2087 250 38.40 330 7102.2
172 0.2374 252 43.89 332 8104.3
174 0.2712 254 50.05 334 9224.3
176 0.3090 256 56.92 336 10483
178 0.3512 258 64.81 338 11979
180 0.4006 260 74.01 340 13654
182 0.4571 262 84.30 342 15523
184 0.5203 264 95.75 344 17691
186 0.5913 266 109.3 346 20194
188 0.6756 268 124.7 348 22994
190 0.7702 270 141.9 350 26109
192 0.8756 272 161.4 352 29842
194 0.9979 274 184.4 354 33576
Courtesy Albahri 2016
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-12
Blending for Smoke point
• The smoke point of a blend is given by
(SP) blend = ∑ Xvi (SP)i 13-10
where
Xvi = Volume fraction.
(SP) blend = Smoke point blending index of the blend.
(SP)i = Smoke point of component i
Example 13-5
Calculate the smoke point and the freezing point of the blend from the following kerosene
blending stocks.
Stock bbls Freezing point
(ºF)
Smoke Point
(mm)
A
B
C
5,000
3,000
2,000
-55
-50
-51
25
22
21
Blend 10,000 ? ?
Solution:
Smoke point Stock vol. frac.
of blend
Smoke Point
(mm)
Smoke Point x
vol. frac.
A
B
C
0.5
0.3
0.2
25
22
21
12.5
6.6
4.2
Blend 1 23.3
The smoke point of the blend is 23.3 mm
Freezing Point (ºF) using Table 13-4
Stock vol. frac.
of blend
Freezing point (ºF) Freezing Point
blending index
vol. frac. x index
A
B
C
0.5
0.3
0.2
-55
-50
-51
7.5199
9.0135
8.6928
3.7600
2.7041
1.7386
Total 1 8.2027
The table gives a freezing point of -52.7 ºF for a blend with a factor of 8.2027
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-13
Viscosity conversion using tabular method
Viscosity Conversions
(Older SUS or SSU to current cSt. or mm2/s)
Assumes that viscosities are at the same temperature and the Viscosity Index is 95.
35 SSU ~ 2.5 cSt 550 SSU ~ 119 cSt
40 SSU ~ 4.2 cSt 600 SSU ~ 129 cSt
45 SSU ~ 5.8 cSt 650 SSU ~ 140 cSt
50 SSU ~ 7.4 cSt 700 SSU ~ 151 cSt
55 SSU ~ 8.8 cSt 750 SSU ~ 162 cSt
60 SSU ~ 10.4 cSt 800 SSU ~ 173 cSt
65 SSU ~ 11.8 cSt 850 SSU ~ 183 cSt
70 SSU ~ 13.1 cSt 900 SSU ~ 195 cSt
75 SSU ~ 14.4 cSt 1,000 SSU ~ 216 cSt
80 SSU ~ 15.6 cSt 1,100 SSU ~ 237 cSt
85 SSU ~ 17.0 cSt 1,200 SSU ~ 259 cSt
90 SSU ~ 18.3 cSt 1,300 SSU ~ 280 cSt
95 SSU ~ 19.4 cSt 1,400 SSU ~ 302 cSt
100 SSU ~ 20.6 cSt 1,500 SSU ~ 324 cSt
110 SSU ~ 22.9 cSt 1,600 SSU ~ 345 cSt
120 SSU ~ 25.2 cSt 1,700 SSU ~ 368 cSt
130 SSU ~ 27.5 cSt 1,800 SSU ~ 389 cSt
140 SSU ~ 29.7 cSt 1,900 SSU ~ 411 cSt
150 SSU ~ 31.9 cSt 2,000 SSU ~ 432 cSt
160 SSU ~ 34.2 cSt 2,100 SSU ~ 453 cSt
170 SSU ~ 36.5 cSt 2,200 SSU ~ 475 cSt
180 SSU ~ 38.6 cSt 2,300 SSU ~ 496 cSt
190 SSU ~ 40.8 cSt 2,400 SSU ~ 518 cSt
200 SSU ~ 43.0 cSt 2,500 SSU ~ 539 cSt
225 SSU ~ 48.5 cSt 2,600 SSU ~ 562 cSt
250 SSU ~ 53.8 cSt 2,700 SSU ~ 584 cSt
275 SSU ~ 59.2 cSt 2,800 SSU ~ 605 cSt
300 SSU ~ 64.8 cSt 2,900 SSU ~ 627 cSt
325 SSU ~ 70.1 cSt 3,000 SSU ~ 648 cSt
350 SSU ~ 75.6 cSt 3,500 SSU ~ 756 cSt
375 SSU ~ 81.1 cSt 4,000 SSU ~ 864 cSt
400 SSU ~ 86.5 cSt 5,000 SSU ~ 1,080 cSt
425 SSU ~ 92.0 cSt 6,000 SSU ~ 1,296 cSt
450 SSU ~ 97.4 cSt 7,000 SSU ~ 1,509 cSt
475 SSU ~ 102.7 cSt 8,000 SSU ~ 1,726 cSt
500 SSU ~ 108.0 cSt 9,000 SSU ~ 1,943 cSt
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-14
Numerical Method for blending freezing point
In British units
FPIFi = 55.168 (1.0369)FPFi i = 1, 2, 3, … 13-11
FPIm = ∑ Xvi (FPIF)i 13-12
FPFm = -111.1628+27.682 ln (FPIm) 13-13
where
FPFi = freezing point of component i in °F
FPFm = freezing point of the blend in °F
FPIi = freezing point index for component i
FPIm = freezing point index for the blend
Xvi = volume fraction of component i
Freezing Point (ºF) using numerical method
Stock vol. frac.
of blend
Freezing point (ºF) Freezing Point
blending index
vol. frac. x index
A
B
C
0.5
0.3
0.2
-55
-50
-51
7.5199
9.0135
8.6928
3.7600
2.7040
1.7386 Total 1 8.2026
Equation gives a freezing point of -52.9 ºF for a blend with a factor of 8.2026
In SI units
FPIKi = (3.2312E-6)(1.06735)FPKi i = 1, 2, 3, … 13-14
FPIm = ∑ Xvi (FPIK)i 13-15
FPFm = 193.7984+15.3789 ln (FPIm) 13-16
where
FPKi = freezing point of component i in K
FPKm = freezing point of the blend in K
FPIi = freezing point index for component i
FPIm = freezing point index for the blend
Xvi = volume fraction of component i
Example 13-6
Freezing Point (K) using table
Stock vol. frac.
of blend
Freezing point (K) Freezing Point
blending index
vol. frac. x index
A
B
C
0.5
0.3
0.2
225
227.8
227.2
7.5199
9.0278
8.7028
3.7600
2.7083
1.7406
Total 1 8.2089
Table gives a freezing point of 226.3 K (-52.7 ºF) for a blend with a factor of 8.2026
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-15
Freezing Point (K) using numerical method
Stock vol. frac.
of blend
Freezing point (K) Freezing Point
blending index
vol. frac. x index
A
B
C
0.5
0.3
0.2
-225
227.8
227.2
7.5580
9.0712
8.7233
3.7790
2.7214
1.7447
Total 1 8.2450
Equation gives a freezing point of 226.2 K (-52.8 ºF) for a blend with a factor of 8.2026
Numerical Method for blending viscosity
Table 13-6, Table 13-7, and Table 13-8 are correlated to obtain the following equations,
For blend no. 1
X1 = log10 (visc.1) 13-17
for viscosity in centistokes (use the following equations)
𝑉𝐹1 =0.17+0.5238 𝑋1
1+0.5124 𝑋1−0.01233 𝑋12 13-18
or more accurately
α = (X1 + 0.3103)/10 13-19
𝛽 = 0.2917 (𝛼)−0.164 13-20
𝑉𝐹1 = 1.056 (𝛼)𝛽 13-21
for the viscosity in SUS (use one of the following equations)
𝑉𝐹1 = 0.6068 + 0.04797𝑋1 − 0.80755
𝑋12 13-22
or
𝑉𝐹1 =−97993438+103852082 𝑋1
1+118310078 𝑋1−3052999 𝑋12 13-23
or more accurately
VF1 = 0.5909 (X1 -1.4414)0.2537 13-24
for viscosity in SFS
VF1 = 0.5008 X10.345 13-25
For blend no. 2, use the above equations 17 through 25.
For example, Equations 17 and 18 would become,
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-16
X2 = log10 (visc.2) 13-26
𝑉𝐹2 =0.17+0.5238 𝑋2
1+0.5124 𝑋2−0.0123 𝑋22 13-27
The viscosity factor for the blend
1 1 2 2
1 2
V VF V VF ...
V V ...blendVF
13-28
To calculate the viscosity of the blend in cSt
𝑙𝑜𝑔 (𝑣𝑖𝑠𝑐.𝑏𝑙𝑒𝑛𝑑 ) =−0.3148+1.796 (𝑉𝐹𝑏𝑙𝑒𝑛𝑑)
1−1.26376 (𝑉𝐹𝑏𝑙𝑒𝑛𝑑)+0.4498 (𝑉𝐹𝑏𝑙𝑒𝑛𝑑)2 13-29
To calculate the viscosity of the blend in SUS use either of the following equations
𝑙𝑜𝑔 (𝑣𝑖𝑠𝑐.𝑏𝑙𝑒𝑛𝑑 ) =5.2602+34.83 (𝑉𝐹𝑏𝑙𝑒𝑛𝑑)3.9746
3.7246+(𝑉𝐹𝑏𝑙𝑒𝑛𝑑)3.9746 13-30
log(visc.blend) = 21.0553 -19.6471 exp[-0.4467(VFblend)3.9315] 13-31
𝑙𝑜𝑔 (𝑣𝑖𝑠𝑐.𝑏𝑙𝑒𝑛𝑑 ) = 1.4123 +33.4177 (𝑉𝐹𝑏𝑙𝑒𝑛𝑑)3.9746
3.7246+(𝑉𝐹𝑏𝑙𝑒𝑛𝑑)3.9746 13-32
Equations 31 and 32 are more accurate than 30
To calculate the viscosity of the blend in SFS
log(visc.blend) = 13.0784 -12.6188 exp [-0.7749(VFblend)3.9578] 13-33
Example 13-7: Blending for viscosity using above (Albahri Viscosity Blending equations)
visc.i VFi Vi vol frac x factor
500 0.691 0.3333 0.230
300 0.669 0.3333 0.223
200 0.651 0.3334 0.217
Total 0.670
Log (viscblend) = 2.503 → Visc = 318 cSt
Using tabular method
Stock vol. frac. of blend Viscosity Factor (Table 13-6) vol. frac. x Factor
A
B
C
0.3333
0.3333
0.3334
500 cSt at 130 ºF
300 cSt at 130 ºF
200 cSt at 130 ºF
0.689
0.663
0.648
0.230
0.221
0.216
Total 1 0.667
Table 13-6 gives 300 cSt at 130 ºF for a blend with a factor of 0.667
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-17
Example 13-8: Blending for viscosity using above (Albahri Viscosity Blending equations)
visc.i VFi Vi vol frac x factor
500 0.691 0.3333 0.230
300 0.669 0.3333 0.223
200 0.651 0.3334 0.217
Total 0.670
Log (viscblend) = 2.503 → Visc = 318 cSt
Using tabular method
Stock vol. frac.
of blend
Viscosity Factor (Table
13-6)
vol. frac. x
Factor
A
B
C
0.3333
0.3333
0.3334
500 cSt at 130 ºF
300 cSt at 130 ºF
200 cSt at 130 ºF
0.689
0.663
0.648
0.230
0.221
0.216
Total 1 0.667
Table 13-6 gives 300 cSt at 130 ºF for a blend with a factor of 0.667
Example 13-9: viscosity conversion (Numerical Method)
Convert the viscosity of an oil sample having 100 cSt to SUS and SFS
Solution: From Table 13-6 the viscosity factor for 100 cSt is 0.613. This factor corresponds
to 460 SUS and 62 SFS at 122 °F.
Numerical Method
From equation (17 and 19 – 21) get the viscosity factor
X1 = log (vcSt) = log (100) = 2
α = (X1 + 0.3103)/10 = 0.23103
𝛽 = 0.2917 (α)−0.164 = 0.3709
𝑉𝐹1 = 1.0559 (𝛼)𝛽 = 0.6132
Then use equation (31) to get the viscosity in SUS
log(visc.blend) = 21.0553 -19.6471 exp[-0.4467(VFblend)3.9315]
log(visc.blend) = 21.0553 -19.6471 exp[-0.4467(0.6132)3.9315] = 2.65
visc = 446.8 SUS √
Use equation (33) to get the viscosity in SFS
log(visc.blend) = 13.0784 -12.6188 exp [-0.7749(VFblend)3.9578]
log(visc.blend) = 13.0784 -12.6188 exp [-0.7749(0.61319)3.9578] = 1.7948
visc = 62.34 SFS √
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-18
Numerical method for calculating the pour point of distillate blending stocks.
The pour point blending index is given by the following equations instead of Table
In kelvin
PPI(K)i = 255.565 + 4.90211𝗑10-6 exp [-0.016418 (PPK) - 0.0522346 (TbK)
+ 1.5751 𝗑10-4 (PPK)(TbK)] (PPK)1.67057 (TbK)2.37162
13-34
PPI(K)i = pour point index for component i in Kelvin
PPK = pour point in kelvin
TbK = ASTM distillation curve 50% temperature in kelvin (≈average boiling point)
In Fahrenheit
PPIFi = 0.1786 + 0.425117 exp [0.0147 (PPF+70) - 0.00887 (TbF)
+ 4.925 𝗑10-5 (PPF+70)(TbF)] (PPF+70)0.1894 (TbF)0.5855
13-35
PPIFi = pour point index for component i in °F
PPF is pour point in °F
TbF = ASTM distillation curve 50% temperature in °F (≈average boiling point)
The procedure is to calculate the PPI for each component using the above equation then obtain the
pour point of the blend using the following equation
PP = ∑ Xvi PPIKi
13-36
Example 13-10
Applied to the previous example to calculate the pour point, the above equations will yield,
Pour Point (ºF, Eqn. 34)
Stock vol. frac. Pour Point
(ºF) ASTM 50% temp (ºF) Blending Index vol. frac. x index
of blend
A 0.5 10 575 7.8 3.92
B 0.3 50 425 60.6 18.17
C 0.2 65 500 98.3 19.66
Total 1 41.8
Pour Point (K, Eqn. 35)
Stock Xv of
blend
Pour
Point (ºF) ASTM 50%
temp (ºF)
Pour Point
(K) ASTM 50%
temp (K)
Blending
Index
vol. frac. x
index
A 0.5 10 575 261.1 575.0 259.90 129.95
B 0.3 50 425 283.3 491.7 289.16 86.75
C 0.2 65 500 291.7 533.3 310.27 62.05
Total 1 278.8 K
41.8 ºC
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-19
Numerical method for calculating the flash point of blending stocks.
The flash point blending index is given by the following equations
In British units: (FPI)i = (0.3792866 + 2.0855𝗑10-3 FPFi)-12.4108
13-37
In SI Units: (FPI)i = (-0.5800437+ 3.7539𝗑10-3 FPKi)-12.4108
13-38
FPFi = Flash point of component i in ºF
FPKi = Flash point of component i in Kelvin
Xvi = volume fraction of component i
(FPI)m = Flash point index for the blend
(FPI)m = ∑ Xvi (FPI)i
13-39
The flash point is then calculated for the blend using the following equations
In British units: FPFm = [327.0522 -27.1872 ln(FPIm)]/[1+ 0.071016 ln(FPIm)
-2.766222𝗑-5 ln(FPIm)2]
13-40
In SI units: FPKm = [437.250592356 + 4.0809276 ln(FPIm)]/[1+ 0.0733857193 ln(FPIm)
+ 1.40131821823232𝗑-4 ln(FPIm)2]
13-41
where
FPF = flash point of the blend in degrees °F
FPK = flash point of the blend in K
Example 13-11
Applied to the previous example to calculate the flash point, the above equations will yield,
Flash point (ºF)
Stock vol. frac. of blend Flash point (ºF) Blending Index vol. frac. x index
A 0.5 100 730.7 365.3
B 0.3 90 1143.9 343.2
C 0.2 130 208.2 41.6
Total 1 750.2
→ from Eqn 40 Flash = 100.1 ⁰F
Flash point (K)
Stock vol. frac. of
blend
Flash point
(K) Blending Index
vol. frac. x
index
A 0.5 311.1 730.7 365.3
B 0.3 305.6 1144.0 343.2
C 0.2 327.8 208.2 41.6
Total 1 750.2
→ from Eqn. 41 Flash = 311.2 K or 100.1 ⁰F
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-20
Numerical method for calculating the aniline point of distillate blending stocks.
The aniline point blending index is given by the following equations
In British units:
APIi = 49.11 (1 + 0.05 APFi)1.3004
13-42
In SI Units:
APIi = − 4852.435 + 14.7655 APKi + 73778706
𝐴𝑃𝐾𝑖2 (more accurate)
13-43
APIi = 1437.69 + 1618.79 COS (0.007435 APKi + 1.7832)
13-44
where
APFi = Aniline point of component i in °F
APKi = Aniline point of component i in Kelvin
Xvi = volume fraction of component i
APIm = Aniline point index for the blend
APIm = ∑ Xvi APIi
13-45
The aniline point is then calculated for the blend using the following equations
In British units:
APFm = (213932+16375.8 (API𝑚)0.7788)
(17287.78+(API𝑚)0.7788)− 32
13-46
In SI units:
APKm = (4093333+9025 (API𝑚)0.77911)
(16731+(API𝑚)0.77911) (more accurate)
13-47
or
APKm = 2427.82 − 2182.923 exp (− 0.0002259 (APIm) 0.7898)
13-48
where
APF = Aniline point of the blend in °F
APK = Aniline point of the blend in K
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-21
Numerical method for calculating the mixed aniline point of distillate blending stocks.
The mixed aniline point blending index is given by the following equations
In British units use one of the following equations:
MAPIi =1090 + 2221 cos (0.005425 MAPFi + 3.7453) (more accurate)
13-49
MAPIi = (−740.124+8.8357 𝑀𝐴𝑃𝐹𝑖)
(1−2.456×10−3𝑀𝐴𝑃𝐹𝑖+6.629×10−6𝑀𝐴𝑃𝐹𝑖2)
13-50
In SI Units use one for the following equations:
MAPIi = - 10323.5 + 29.064 MAPKi + 140904757
𝑀𝐴𝑃𝐾𝑖2 (more accurate)
13-51
MAPIi = (−650.1+2.796 𝑀𝐴𝑃𝐾𝑖)
(1−4.448×10−3𝑀𝐴𝑃𝐾𝑖+5.8987×10−6𝑀𝐴𝑃𝐾𝑖2)
− 1000
13-52
MAPIi = 1090.1 + 2221.5 cos (0.009764 MAPKi +1.2502)
13-53
where
MAPFi = Mixed aniline point of component i in °F
MAPKi = Mixed aniline point of component i in Kelvin
Xvi = volume fraction of component i
MAPIm = Mixed aniline point index for the blend
MAPIm = ∑ Xvi MAPIi
13-54
The mixed aniline point for the blend is then calculated using the one of the following
In British units:
MAPFm = (83.783+0.113208 𝑀𝐴𝑃𝐵𝐼𝑚)
(1+2.184×10−4𝑀𝐴𝑃𝐼𝑚−7.166×10−8𝑀𝐴𝑃𝐼𝑚2 )
13-55
In SI units:
MAPKm = 1
[3.9884×10−3+1.432×10−4 ln(𝑀𝐴𝑃𝐼𝑚+1000)−5.058×10−6 (ln(𝑀𝐴𝑃𝐼𝑚+1000))3]
(more accurate)
13-56
MAPKm = 1
(4.8173×10−3−1.0622×10−4𝑀𝐴𝑃𝐼𝑚0.3839)
13-57
MAPKm = [231.53+0.3032 (𝑀𝐴𝑃𝐼𝑚+1000)]
[1+8.46×10−4(𝑀𝐴𝑃𝐼𝑚+1000)−7.56×10−8(𝑀𝐴𝑃𝐼𝑚+1000)2 ]
13-58
MAPKm = (1085344+2437 (MAPI𝑚+1000)0.7407)
(4770+(MAPI𝑚+1000)0.7407) (least accurate)
13-59
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-22
Example 13-12 Applied to the previous example to calculate the aniline point, the above equations will yield,
Aniline point (°F)
Stock vol. frac. of blend Aniline point (ᵒF) Blending Index (Eq. 42/49) vol. frac. x index
A 0.5 70 347.2 173.6
B 0.3 160 855.2 256.6
C 0.2 40 (mixed) -424.1 -84.8
Total 1 345.4
→ from Eqn. 46 aniline point = 69.6 ⁰F
→ from Eqn. 55 mixed aniline point = 115.2 ⁰F
Aniline point (K)
Stock vol. frac. of blend Aniline point
(K)
Blending Index
(Eq. 43/51) vol. frac. x index
A 0.5 294.4 346.2 173.1
B 0.3 344.4 855.3 256.6
C 0.2 277.8 -242.0 -84.8
Total 1 344.9
→ from Eqn. 47 aniline point = 294.2 K or 69.5 ⁰F
→ from Eqn. 56 mixed aniline point = 319.6 K or 115.3 ⁰F
Case Study: Refinery blending using optimization
Example 13-13:
Calculate the amount of each blending stock that would produce a 300,000 bbls gasoline
product with the flowing specifications, API = 70 min, ON = 95 min, RVP = 9 psig max
Available blends are as follows
Component bbls API ON RVP SG RVPI = RVP1.25
Tank 1 Reformate 500,000 70 94 10 0.7022 17.7828
Tank 2 Isomerate 400,000 69 92 9 0.7057 15.5885
Tank 3 Alkylate 600,000 72 96 8 0.6953 13.4543
Desired Blend 300,000 70 95 9 0.7022 15.5885
Solution:
Let
N1 = bbls of Tank 1 reformate
N2 = bbls of Tank 2 isomerate
N3 = bbls of Tank 3 alkylate
Objective function N1 + N2 + N3 = 300,000
Constraints:
N1 ≤ 500,000
N2 ≤ 400,000
N3 ≤ 600,000
N1, N2, N3 ≥ 0 (non-negativity)
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-23
for API gravity 0.7022 X1 + 0.7057 X2 + 0.6953 X3 ≤ 0.7022
for ON 94 X1 + 92 X2 + 96 X3 ≥ 95
for RVP 17.7828 X1 + 15.5885 X2 + 13.4543 X3 ≥ 15.5885
where
X1 = n1/(n1+n2+n3)
X2 = n2/(n1+n2+n3)
X3 = n3/(n1+n2+n3)
Solver solution indicates that
N1 = 0
N2 = 59,970
N3 = 240,030
Blend properties
API = 71.4 (giveaway)
ON = 95.2
RVP = 8.2 psig
Figure 13-4: Product blending using linear programming and the solver function of Microsoft Excel.
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-24
Table 13-6: Factors for Volume Blending of Viscosities at Constant Temperatures
Corresponding to values of Kinematic Viscosity, Centistokes (cSt).
cSt
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.5
0.6
0.7
0.8
0.9
0.000
0.056
0.097
0.128
0.154
0.006
0.061
0.100
0.131
0.156
0.013
0.065
0.104
0.134
0.159
0.019
0.069
0.107
0.137
0.161
0.025
0.074
0.110
0.139
0.163
0.030
0.078
0.114
0.142
0.165
0.036
0.082
0.117
0.144
0.167
0.041
0.086
0.120
0.147
0.169
0.046
0.089
0.123
0.149
0.172
0.051
0.093
0.126
0.152
0.174
cSt
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
2
3
4
5
6
7
8
9
0.176
0.290
0.342
0.375
0.398
0.416
0.431
0.443
0.453
0.194
0.297
0.346
0.378
0.400
0.418
0.432
0.444
0.454
0.210
0.303
0.350
0.380
0.402
0.419
0.433
0.445
0.455
0.224
0.309
0.353
0.383
0.404
0.421
0.434
0.446
0.456
0.236
0.314
0.357
0.385
0.406
0.422
0.436
0.447
0.456
0.247
0.320
0.360
0.387
0.408
0.423
0.437
0.448
0.457
0.257
0.325
0.363
0.390
0.410
0.425
0.438
0.449
0.458
0.266
0.329
0.366
0.392
0.411
0.426
0.439
0.450
0.459
0.275
0.334
0.369
0.394
0.413
0.428
0.440
0.451
0.460
0.283
0.338
0.372
0.396
0.414
0.429
0.442
0.452
0.461
cSt
0
1
2
3
4
5
6
7
8
9
10
20
30
40
50
60
70
80
90
0.462
0.515
0.543
0.561
0.575
0.585
0.594
0.601
0.608
0.470
0.519
0.545
0.563
0.576
0.586
0.595
0.602
0.608
0.477
0.522
0.547
0.564
0.577
0.587
0.596
0.603
0.609
0.483
0.525
0.549
0.566
0.578
0.588
0.596
0.603
0.610
0.489
0.528
0.551
0.567
0.579
0.589
0.597
0.604
0.610
0.494
0.531
0.553
0.568
0.580
0.590
0.598
0.605
0.611
0.499
0.533
0.555
0.570
0.581
0.591
0.599
0.605
0.611
0.503
0.536
0.557
0.571
0.582
0.592
0.599
0.606
0.612
0.508
0.538
0.558
0.572
0.583
0.592
0.600
0.607
0.612
0.511
0.541
0.559
0.573
0.584
0.593
0.601
0.607
0.613
cSt
0
10
20
30
40
50
60
70
80
90
100
200
300
400
500
600
700
800
900
0.613
0.648
0.667
0.680
0.689
0.697
0.703
0.708
0.713
0.618
0.651
0.669
0.681
0.690
0.698
0.704
0.709
0.714
0.623
0.653
0.670
0.682
0.691
0.698
0.704
0.709
0.714
0.627
0.655
0.671
0.683
0.692
0.699
0.705
0.710
0.715
0.631
0.657
0.673
0.684
0.692
0.700
0.705
0.710
0.715
0.634
0.659
0.674
0.685
0.693
0.700
0.706
0.711
0.715
0.637
0.661
0.675
0.686
0.694
0.701
0.706
0.711
0.716
0.640
0.662
0.676
0.687
0.695
0.701
0.707
0.712
0.716
0.643
0.664
0.678
0.688
0.696
0.702
0.707
0.712
0.716
0.646
0.666
0.679
0.688
0.696
0.702
0.708
0.713
0.717
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-25
cSt
0
100
200
300
400
500
600
700
800
900
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
0.717
0.743
0.757
0.767
0.775
0.780
0.785
0.790
0.793
0.721
0.745
0.758
0.768
0.775
0.781
0.786
0.790
0.794
0.724
0.747
0.759
0.769
0.776
0.781
0.786
0.790
0.794
0.727
0.748
0.761
0.770
0.777
0.782
0.787
0.791
0.794
0.730
0.750
0.762
0.770
0.778
0.782
0.787
0.791
0.795
0.733
0.751
0.763
0.771
0.778
0.783
0.787
0.791
0.795
0.735
0.752
0.764
0.772
0.778
0.783
0.788
0.792
0.795
0.737
0.754
0.765
0.772
0.779
0.784
0.788
0.792
0.796
0.739
0.755
0.765
0.773
0.779
0.784
0.789
0.792
0.796
0.741
0.756
0.766
0.774
0.780
0.785
0.790
0.793
0.796
cSt
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
0.796
0.817
0.828
0.836
0.842
0.847
0.851
0.854
0.858
0.799
0.818
0.829
0.837
0.843
0.848
0.802
0.820
0.830
0.838
0.843
0.848
0.804
0.821
0.831
0.838
0.844
0.848
0.806
0.822
0.832
0.839
0.844
0.849
0.808
0.823
0.8330
.839
0.845
0.849
0.810
0.824
0.833
0.840
0.845
0.850
0.812
0.825
0.834
0.841
0.846
0.850
0.814
0.826
0.835
0.841
0.846
0.850
0.815
0.827
0.836
0.842
0.847
0.851
cSt
cSt cSt
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
0.860
0.877
0.887
0.894
0.899
0.903
0.906
0.909
0.912
1,000,000
2,000,000
3,000,000
4,000,000
5,000,000
6,000,000
7,000,000
8,000,000
9,000,000
0.914
0.928
0.937
0.942
0.947
0.950
0.953
0.956
0.958
10,000,000
20,000,000
30,000,000
40,000,000
50,000,000
60,000,000
70,000,000
80,000,000
90,000,000
0.960
0.973
0.980
0.985
0.989
0.992
0.995
0.997
0.999
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-26
Table 13-7 Factors for Volume Blending of Viscosities at Constant Temperatures
Corresponding to values of Saybolt Universal Seconds (SUS).
SUS
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
32
33
34
35
36
37
38
39
0.275
0.296
0.314
0.328
0.342
0.353
0.363
0.373
0.278
0.298
0.315
0.330
0.343
0.354
0.364
0.373
0.280
0.300
0.317
0.331
0.344
0.355
0.365
0.374
0.282
0.302
0.318
0.333
0.345
0.356
0.366
0.375
0.284
0.303
0.320
0.334
0.346
0.357
0.367
0.376
0.286
0.305
0.321
0.335
0.347
0.358
0.368
0.377
0.288
0.307
0.323
0.337
0.349
0.359
0.369
0.378
0.290
0.309
0.324
0.338
0.350
0.360
0.370
0.378
0.292
0.310
0.326
0.339
0.351
0.362
0.371
0.379
0.294
0.312
0.327
0.340
0.352
0.363
0.372
0.380
SUS
0
1
2
3
4
5
6
7
8
9
40
50
60
70
80
90
0.381
0.435
0.464
0.483
0.497
0.508
0.388
0.439
0.466
0.485
0.498
0.509
0.395
0.442
0.469
0.486
0.499
0.510
0.402
0.445
0.471
0.488
0.501
0.511
0.408
0.449
0.473
0.489
0.502
0.512
0.413
0.451
0.475
0.491
0.503
0.513
0.418
0.454
0.476
0.492
0.504
0.513
0.423
0.457
0.478
0.493
0.505
0.514
0.428
0.459
0.480
0.495
0.506
0.515
0.431
0.462
0.482
0.496
0.507
0.516
SUS
0
10
20
30
40
50
60
70
80
90
100
200
300
400
500
600
700
800
900
0.517
0.565
0.589
0.605
0.617
0.627
0.635
0.641
0.647
0.524
0.568
0.591
0.607
0.618
0.628
0.635
0.642
0.647
0.531
0.571
0.593
0.608
0.619
0.628
0.636
0.642
0.648
0.537
0.574
0.595
0.609
0.620
0.629
0.637
0.643
0.648
0.542
0.576
0.596
0.611
0.621
0.630
0.637
0.643
0.649
0.547
0.579
0.598
0.612
0.622
0.631
0.638
0.644
0.649
0.551
0.581
0.600
0.613
0.623
0.632
0.639
0.645
0.650
0.555
0.583
0.601
0.614
0.624
0.632
0.639
0.645
0.650
0.559
0.585
0.603
0.615
0.625
0.633
0.640
0.646
0.651
0.562
0.587
0.604
0.616
0.626
0.634
0.640
0.646
0.651
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-27
SUS
0
100
200
300
400
500
600
700
800
900
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
0.652
0.683
0.700
0.711
0.720
0.727
0.733
0.738
0.742
0.656
0.685
0.701
0.712
0.721
0.728
0.733
0.738
0.742
0.660
0.687
0.703
0.713
0.722
0.728
0.734
0.739
0.743
0.664
0.689
0.704
0.714
0.722
0.729
0.734
0.739
0.743
0.667
0.691
0.705
0.715
0.723
0.729
0.735
0.740
0.744
0.670
0.692
0.706
0.716
0.724
0.730
0.735
0.740
0.744
0.673
0.694
0.707
0.717
0.725
0.731
0.736
0.740
0.744
0.676
0.696
0.708
0.718
0.725
0.731
0.736
0.741
0.745
0.678
0.697
0.709
0.719
0.726
0.732
0.737
0.741
0.745
0.681
0.699
0.710
0.719
0.726
0.732
0.737
0.742
0.745
SUS
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10,000
20,000
30,000
40,000
50,000
60,000
0.746
0.770
0.783
0.792
0.799
0.804
0.749
0.771
0.784
0.793
0.799
0.805
0.752
0.773
0.785
0.793
0.800
0.805
0.755
0.774
0.786
0.794
0.800
0.806
0.758
0.776
0.787
0.795
0.801
0.806
0.760
0.777
0.788
0.795
0.802
0.807
0.762
0.778
0.789
0.796
0.802
0.807
0.764
0.779
0.790
0.797
0.803
0.807
0.766
0.781
0.790
0.797
0.803
0.808
0.768
0.782
0.791
0.798
0.804
0.808
SUS
SUS
SUS
SUS
70,000
80,000
90,000
0.809
0.813
0.816
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
0.819
0.838
0.849
0.856
0.862
0.867
0.870
0.874
0.877
1,000,000
2,000,000
3,000,000
4,000,000
5,000,000
6,000,000
7,000,000
8,000,000
9,000,000
0.879
0.895
0.904
0.911
0.915
0.919
0.923
0.925
0.928
10,000,000
20,000,000
30,000,000
40,000,000
50,000,000
60,000,000
70,000,000
80,000,000
90,000,000
0.930
0.944
0.952
0.957
0.961
0.965
0.968
0.970
0.972
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-28
Table 13-8 Factors for Volume Blending of Viscosities at 130 °F corresponding to values of
Saybolt Furol Seconds (SFS) at 122 °F.
SFS at
122 °F
0
1
2
3
4
5
6
7
8
9
20
30
40
50
60
70
80
90
0.570
0.588
0.601
0.611
0.619
0.626
0.632
0.572
0.590
0.602
0.612
0.620
0.627
0.633
0.574
0.591
0.604
0.613
0.621
0.627
0.633
0.576
0.593
0.605
0.614
0.622
0.628
0.634
0.578
0.594
0.606
0.615
0.622
0.629
0.634
0.558
0.580
0.595
0.607
0.616
0.623
0.629
0.635
0.561
0.582
0.597
0.608
0.616
0.624
0.630
0.635
0.563
0.584
0.598
0.609
0.617
0.624
0.630
0.636
0.566
0.585
0.599
0.610
0.618
0.625
0.631
0.636
0.568
0.587
0.600
0.610
0.619
0.626
0.632
0.637
SFS at
122 °F
0
10
20
30
40
50
60
70
80
90
100
200
300
400
500
600
700
800
900
0.637
0.669
0.686
0.697
0.706
0.713
0.719
0.724
0.728
0.642
0.671
0.687
0.698
0.707
0.713
0.719
0.724
0.728
0.646
0.673
0.688
0.699
0.707
0.714
0.720
0.724
0.729
0.649
0.675
0.689
0.700
0.708
0.715
0.720
0.725
0.729
0.653
0.676
0.691
0.701
0.709
0.715
0.721
0.725
0.729
0.656
0.678
0.692
0.702
0.710
0.716
0.721
0.726
0.730
0.659
0.680
0.693
0.703
0.710
0.716
0.722
0.726
0.730
0.661
0.681
0.694
0.703
0.711
0.717
0.722
0.727
0.730
0.664
0.683
0.695
0.704
0.712
0.718
0.723
0.727
0.731
0.666
0.684
0.696
0.705
0.712
0.718
0.723
0.727
0.731
SFS at
122 °F
0
100
200
300
400
500
600
700
800
900
1000
2000
3000
0.732
0.755
0.769
0.735
0.757
0.770
0.738
0.759
0.771
0.741
0.760
0.772
0.743
0.761
0.773
0.746
0.763
0.773
0.748
0.764
0.775
0.750
0.764
0.775
0.752
0.766
0.776
0.754
0.767
0.777
4000
5000
6000
7000
8000
9000
0.778
0.784
0.790
0.795
0.798
0.802
Notes:
Values from this table are for 130 ºF, although the Saybolt Furol seconds are at
122 ºF. This table alone must not be used for any other temperatures. Values
from this table may be used interchangeably with values for kinematic and
Saybolt Universal viscosities if the latter are for 130 ºF.
For SFS at 210 ºF, assume SUS – 10 x SFS and use the Saybolt Universal table.
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-29
Table 13-9: Flash Point Blending Index Numbers. Flash Point,
°F
0
1
2
3
4
5
6
7
8
9
0 10 20 30 40 50 60 70 80 90
100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290
168,000 86,600 46,000 25,200 14,200 8,240 4,890 2,970 1,840 1,170 753 495 331 224 154 108 76.3 54.7 39.7 29.1 21.6 16.1 12.2 9.31 7.16 5.56 4.35 3.43 2.72 2.17
157,000 81,200 43,300 23,800 13,500 7,810 4,650 2,830 1,760 1,120 722 475 318 216 149 104 73.8 52.9 38.4 28.2 20.9 15.7 11.9 9.07 6.98 5.42 4.24 3.35 2.66 2.12
147,000 76,100 40,700 22,400 12,700 7,410 4,420 2,700 1,680 1,070 692 456 305 305 144 101 71.4 51.3 37.3 27.4 20.3 15.2 11.6 8.83 6.80 5.29 4.14 3.27 2.60 2.08
137,000 71,400 38,300 21,200 12,000 7,030 4,200 2,570 1,600 1,020 662 438 294 200 138 97.1 69.0 49.6 36.1 26.6 19.7 14.8 11.2 8.60 6.63 5.16 4.04 3.19 2.54 2.03
128,000 67,000 36,100 20,000 11,400 6,670 4,000 2,450 1,530 978 635 420 283 193 134 93.8 66.7 48.0 35.0 25.8 19.2 14.4 10.9 8.37 6.47 5.03 3.95 3.12 2.48 1.99
120,000 62,900 34,000 18,900 10,800 6,330 3,800 2,330 1,460 935 609 404 272 186 129 90.6 64.5 46.5 33.9 25.0 18.6 14.0 10.6 8.16 6.30 4.91 3.86 3.05 2.43 1.95
112,000 59,000 32,000 17,800 10,200 6,010 3,620 2,230 1,400 896 584 388 261 179 124 87.5 62.4 45.1 32.9 24.3 18.1 13.6 10.4 7.95 6.15 4.79 3.76 2.98 2.37 1.90
105,000 55,400 30,100 16,800 9,680 5,700 3,441 2,120 1,340 857 560 372 252 172 120 84.6 60.4 43.6 31.9 23.6 17.6 13.3 10.1 7.74 5.99 4.68 3.68 2.91 2.32 1.86
98,600 52,100 28,400 15,900 9,170 5,420 3,280 2,020 1,280 821 537 358 242 166 116 81.7 58.4 42.3 30.9 22.9 17.1 12.9 9.82 7.55 5.84 4.56 3.59 2.85 2.27 1.82
92,400 49,000 26,800 15,000 8,690 5,150 3,120 1,930 1,220 786 515 344 233 160 112 79.0 56.5 40.9 30.0 22.2 16.6 12.5 9.56 7.85 5.70 4.45 3.51 2.78 2.22 1.79
Flash Point, °F
0
10
20
30
40
50
60
70
80
90
300 400 500
1.75
0.269 0.063
1.41
0.229 0.056
1.15
0.196 0.049
0.943 0.168 0.044
0.777 0.145 0.039
0.643 0.125 0.035
0.535 0.108 0.031
0.448 0.094 0.028
0.376 0.082 0.025
0.317 0.072 0.022
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-30
Table 13-10: Aniline Point Blending Index Numbers. Aniline Point,
°F 0 -1 -2 -3 -4 -5 -6 -7 -8 -9
-10
0
20.0
49.1
17.4
46.0
14.9
42.8
12.6
39.8
10.3
36.8
8.10
33.8
6.06
30.9
4.17
28.1
2.46
25.3
1.00
22.6
Aniline Point,
°F 0 1 2 3 4 5 6 7 8 9
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
49.1
83.2
121
162
205
250
298
347
398
451
505
560
617
674
733
794
855
917
980
1,044
1,110
1,176
1,242
1,310
1,379
52.4
86.8
125
166
209
255
303
352
403
456
510
566
622
680
739
800
861
923
986
1,050
1,116
1,182
1,249
1,317
1,386
55.6
90.5
129
170
214
260
308
357
408
461
516
571
628
686
745
806
867
930
993
1,057
1,122
1,189
1,256
1,324
1,392
58.9
94.2
133
174
218
264
312
362
414
467
521
577
634
692
751
812
873
936
999
1,064
1,129
1,196
1,262
1,331
1,400
62.3
97.9
137
179
223
269
317
367
419
472
527
582
640
698
757
818
880
942
1,006
1,070
1,136
1,202
1,269
1,337
1,406
65.7
102
141
183
227
274
322
372
424
477
532
588
645
704
763
824
886
948
1,012
1,077
1,142
1,209
1,276
1,344
1,413
69.1
105
145
187
232
279
327
377
429
483
538
594
651
710
769
830
892
955
1,019
1,083
1,149
1,216
1,283
1,351
1,420
72.6
109
149
192
237
283
332
382
435
488
543
599
657
716
775
836
898
961
1,025
1,090
1,156
1,222
1,290
1,358
1,427
76.1
113
153
196
241
288
337
388
440
494
549
605
663
722
781
842
904
967
1,031
1,096
1,162
1,229
1,297
1,365
1,434
79.6
117
157
200
246
293
342
393
445
491
554
611
669
727
788
849
911
974
1,038
1,103
1,169
1,236
1,303
1,372
1,441
Mixed Aniline
Point, °F
0
1
2
3
4
5
6
7
8
9
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
-736
-668
-593
-511
-425
-334
-239
-140
-38.3
66.8
175
285
399
514
632
-730
-660
-584
-503
-416
-324
-229
-130
-27.9
77.4
186
297
410
526
644
-723
-653
-577
-494
-407
-315
-219
-120
-17.5
88.1
197
308
422
538
656
-716
-646
-569
-486
-398
-306
-210
-110
-7.06
98.8
208
319
433
550
668
-709
-639
-561
-477
-389
-296
-200
-100
3.39
110
219
330
445
561
680
-703
-631
-552
-468
-380
-287
-190
-89.6
13.9
120
230
342
456
573
692
-696
-623
-544
-460
-371
-277
-180
-79.4
24.4
131
241
353
468
585
704
-689
-616
-536
-451
-361
-267
-170
-69.2
35.0
142
252
364
479
597
716
-682
-608
-528
-442
-352
-258
-160
-58.9
45.5
153
263
376
491
609
728
-675
-600
-519
-433
-343
-248
-150
-48.6
56.1
164
274
387
503
620
741
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-31
Table 13-11: Pour Point Blending Indices for Distillate Stocks ASTM 50% Temp
300
350
375
400
425
450
475
500
525
550
575
600
625
650
675
700
Pour
Point
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
-35
-40
-45
-50
-55
-60
-65
-70
133
114
99
88
72
60
52
44
37
32
27
23
20
17
14
12
10
8.8
7.5
6.4
5.5
4.6
4.0
3.3
2.8
2.5
2.1
1.8
1.5
131
111
94
79
68
56
48
41
34
29
24
20
17
15
12
10
8.8
7.4
6.3
5.3
4.5
3.7
3.2
2.7
2.3
1.9
1.6
1.4
1.1
129
109
92
77
66
54
46
39
32
27
23
19
16
14
11
9.5
8.0
6.8
5.7
4.7
4.0
3.3
2.8
2.4
2.0
1.7
1.4
1.2
0.99
128
107
90
75
63
52
44
37
31
26
21
18
15
13
10
8.7
7.3
6.1
5.1
4.2
3.6
2.9
2.5
2.1
1.7
1.4
1.2
1.0
0.84
127
105
87
73
61
50
42
35
29
24
20
17
14
12
9.6
8.0
6.6
5.5
4.6
3.7
3.2
2.6
2.2
1.8
1.5
1.2
1.0
0.85
0.71
125
103
85
71
59
48
40
33
27
23
19
16
13
11
8.7
7.2
5.9
4.9
4.1
3.3
2.8
2.3
1.9
1.5
1.3
1.1
0.87
0.72
0.60
123
101
82
68
56
46
38
32
26
21
17
14
12
9.7
7.9
6.5
5.3
4.4
3.6
2.9
2.4
2.0
1.6
1.3
1.1
0.90
0.74
0.60
0.50
120
98
80
66
54
44
36
30
24
20
16
13
11
8.8
7.1
5.8
4.7
3.9
3.2
2.5
2.1
1.7
1.4
1.1
0.93
0.77
0.62
0.50
0.42
118
96
77
63
52
42
34
28
23
18
15
12
9.8
7.9
6.3
5.1
4.1
3.4
2.8
2.2
1.8
1.4
1.2
0.98
0.78
0.65
0.52
0.41
0.36
115
94
74
61
49
40
32
26
21
17
14
11
8.8
7.1
5.6
4.5
3.6
3.0
2.4
1.9
1.5
1.2
1.0
0.82
0.66
0.55
0.43
0.34
0.30
113
91
72
58
47
38
30
24
19
15
12
10
8.0
6.3
5.0
3.9
3.2
2.6
2.1
1.7
1.3
1.0
0.86
0.68
0.56
0.46
0.36
0.28
0.25
110
88
69
56
44
35
28
23
18
14
11
9.0
7.1
5.6
4.4
3.4
2.8
2.2
1.8
1.4
1.1
0.90
0.73
0.58
0.47
0.37
0.30
0.23
0.20
108
85
67
53
42
33
26
21
16
13
10
8.1
6.3
5.0
3.8
3.0
2.5
1.9
1.5
1.2
0.96
0.75
0.62
0.48
0.38
0.30
0.24
0.18
0.15
105
82
64
50
39
31
24
19
15
12
9.1
7.2
5.6
4.4
3.4
2.7
2.2
1.7
1.3
1.0
0.80
0.62
0.51
0.38
0.31
0.24
0.19
0.14
0.11
103
79
62
48
37
29
22
18
14
11
8.3
6.4
5.0
3.8
3.0
2.4
1.9
1.4
1.1
0.90
0.67
0.51
0.41
0.31
0.25
0.19
0.14
0.10
0.08
100
76
60
46
35
27
21
16
13
10
7.5
5.8
4.5
3.5
2.7
2.1
1.6
1.2
0.94
0.72
0.56
0.43
0.33
0.25
0.20
0.15
0.10
0.07
0.05
From Gary & Handwerk
Online Blending
• Many refineries today can use computer-controlled in-line product blending. This
saves on storage tanks that would otherwise be used for blending.
• Inventories of blending stocks, together with cost and physical property data are
maintained in the computer.
• When a certain volume of a given quality product is specified, the computer uses
linear programming models to optimize the blending operations (select the optimum
volume of blending components) to produce the required product at the lowest cost.
• To ensure that the blended streams meet the desired specifications, stream analyzers,
such as boiling point, specific gravity, RVP, and RON and RON are installed to
provide feedback control of blending streams and additives (if necessary).
• Blending components to meet all critical specifications most economically is an
iterative procedure which is easily handled by a computer.
• Nonlinear programming is preferred over linear if sufficient data are available to
define the equations because components blend non-linearly.
• Optimization programs (like PIMS for example) permit the computer to provide the
optimum blend to minimize cost and maximize profit
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-32
Figure 13-5: Refinery online blending facilities
Figure 13-6: Schematic representation of the online blending system for diesel product
Figure 13-7: Tank farm in a petroleum refinery with floating roof tanks
Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering
13-33
Problems
1. Using values from Table 12.1, calculate the number of barrels of n-butane that have to be added to a
mixture of 1250 barrels of HSR gasoline, 750 barrels of LSR gasoline, and 620 barrels of C5 FCC
gasoline to produce a 9 psi Reid vapor pressure. What are the research and motor octane numbers of the
blend?
2. For the blend of components in problem 1, what would be the posted octane number of the 9.0 psi RVP
gasoline if 10 vol% MTBE was added to the gasoline mixture?
3. Calculate the amount of n -butane needed to produce a 12.5 psi RVP for a mixture of 2730 barrels of
LSR gasoline, 2490 barrels of 94 RON reformate, 6100 barrels of heavy hydrocrackate, and 3600 barrels
of C5 + FCC gasoline. How much ETBE must be added to produce a 90 RON product? Calculate the
RVP of the final blend.
4. What is the flash point of a mixture of 2500 barrels of oil with a flashpoint of 120°F, 3750 barrels with
a flashpoint of 35°F, and 5000 barrels with a 150°F flashpoint?
5. Calculate the pour point of the following mixture:
Component
Barrels
ASTM 50%
temp., °F
Pour point, °F
A 5,200 575 10
B 3,000 425 50 C 6,500 500 65 D 3,250 550 45
6. What is the viscosity of a blend of 2000 barrels of oil with a viscosity of 75.5 cSt at 130°F, 3000 barrels with
225 cSt at 130°F, and 5000 barrels with 6500 cSt at 130°F?
7. Calculate the octane numbers of the final blend and amount of n-butane needed for producing a 9.5 psi RVP
gasoline from 5100 BPSD of LSR gasoline, 3000 BPSD light hydrocrackate, 4250 BPSD alkylate, 10,280
BPSD heavy hydrocrackate, 14,500 BPSD FCC C5+ gasoline, 14,200 BPSD of 96 RON reformate, and 2500
BPSD of polymer gasoline.
8. Recommend the best method for increasing the clear posted octane number of the pool gasoline in
problem 7 by 3 numbers. Estimate the cost involved. Assume any necessary processing units are
available and have the necessary capacity.
9. Calculate the number of barrels of n-butane that have to be added to a mixture of 1000 barrels of light
thermal gasoline, 1000 barrels of polymer gasoline, and 1000 barrels of C4= alkylate to produce a
gasoline product having 10 psi Reid vapor pressure.
10. What is the posted octane number and Reid vapor pressure of the gasoline product of problem 3?
11. Calculate the clear octane numbers (RON and MON) and the amount of butane needed for a 12.0 psi RVP
gasoline produced from the following:
Belding component BPSD
LSR naphtha 4,200
Light hydrocrackate 1,800
C5+ alkylate 4,500
Heavy hydrocrackate 9,150
Reformate (94 RON) 11,500
C5+ FCC gasoline 15,600
12. Recommend the best method (lowest capital cost) for increasing the posted octane number of the pool
gasoline in problem 11 by 5.5 octane numbers. Estimate the size of the unit and its 1994 construction cost.
HW solve problems 3, 5, 6, 10