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Petroleum Refining – Chapter 13: Blending Prof. Tareq Albahri 2018 Kuwait University Chemical Engineering

13-1

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


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


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


13-4

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


13-5

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.


13-6

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).


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


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


(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


(PP) blend = Pour point of the blend.

(PPI)i = Pour point index of component i, from Table 13-11


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.


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


(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


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


13-12

Blending for Smoke point

• The smoke point of a blend is given by

(SP) blend = ∑ Xvi (SP)i 13-10

where


(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


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


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


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


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,


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


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 √


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


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


(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


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


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


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


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


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)


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.


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


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


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


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


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.


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


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


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


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


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

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