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Petroleum RefiningChapter 13: Product Blending
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- C
4
+Gases
Figure 13-1: Refinery gasoline blending
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-2
These gasoline blending-stocks have different molecular contents and performancequalities (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, specificgravity, RVP, research octane number (RON) and motor octane number (MON).
The products is designated off spec if it does not meet one or more of the requiredspecifications which could make it unsalable or salable for a lower price. Exceedingone or more of the required product specifications is termed giveaway, which is alsoa loss for the refinery because you are selling higher quality product for lower price.
Basic intermediate streams are usually blended to produce a variety of on-specfinished products. For example, naphtha can be blended into either gasoline or jetfuel, depending upon the product demand.
The objective of product blending is to allocate the available blending components insuch a way as to meet product demands and specifications at the least cost and to
produce incremental products which maximize overall profit.
For example, if a refiner sells about one billion gallons of gasoline per year (about65,000 BPCD), a saving of one-hundredth (1/100) of a cent per gallon results in anadditional profit of $100,000 per year.
Figure 13-2: Refinery tank farm blending & shipping farcicalities
Figure 13-3: Refinery blending facilities
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
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 from1,000 bbls oil 70 API2,000 bbls oil 5 API
Solution:
= 141.5
131.5=
141.570 131.5
= 0.7026
= 141.5
131.5=
141.55131.5
= 1.0374
Ave. sp. gr. = 0.3333(0.7026) + 0.6666(1.0374) = 0.9258API = (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 thefinal 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 (C5180 F)HSR gasoline (200380 F)FCC gasoline (200300 F)Blend (C5380 F)
Blending for Reid Vapor Pressure (RVP)
The theoretical method for blending to the desired RVP requires knowledge of theaverage molecular weight of each of the streams.
A more convenient way developed by Chevron Research Company is to use VaporPressure Blending Indices (VPBI)compiled as a function of the RVP of the blendingstreams as shown inTable 13-3.
The RVP of the blend is closely approximated by the sum of all the products of thevolume fraction (Xv) times the VPBI for each blending component i.
13-1 (VPBI)blend= Xvi(VPBI)i
RVP of a gasoline is controlled by adding n-butane to (C5380F) naphtha. If the volume of the n-butane to be blended for a given RVP is given by,
13-2 V0(VPBI)0+ V1 (VPBI)1+ ... = (V0+V1+ ) (VPBI)m
whereV0= 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
13-3 RVPm1.25 = [V0(RVP0)
1.25+ V1(RVP1)1.25+ .]0.8/ total volume
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Petroleum RefiningChapter 13: Product Blending
13-5
Table 13-3: Reid Vapor Pressure Blending Index Numbers for Gasoline and Turbine Fuels.
VaporPressure,
psi 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
0123456789
1011121314151617181920
212223242526272829
0.001.002.373.945.657.479.3911.413.415.617.820.022.324.727.129.532.034.537.139.742.3
45.047.650.453.155.958.761.564.467.3
0.051.122.524.115.837.669.5811.613.715.818.020.322.624.927.329.832.234.837.339.942.6
45.247.950.653.456.259.061.864.767.6
0.131.252.674.286.017.859.7811.813.916.018.220.522.825.227.630.032.535.037.640.242.8
45.548.250.953.756.559.362.1I65.067.9
0.221.382.8344.46.198.049.9812.014.116.218.420.723.025.427.830.232.835.337.840.443.1
45.848.451.254.056.759.662.465.368.2
0.311.522.984.616.378.2310.212.214.316.418.720.923.325.628.030.533.035.538.140.743.4
46.048.751.554.257.059.862.765.668.4
0.421.663.144.786.558.4210.412.414.516.718.921.223.525.928.330.833.235.838.441.043.6
46.349.051.754.557.360.163.065.868.8
0.521.793.304.956.738.6110.612.614.716.919.121.423.726.128.531.033.536.038.641.243.9
46.649.352.054.857.560.463.366.169.0
0.641.943.465.136.928.8010.812.814.917.119.421.624.026.428.831.233.836.338.941.544.2
46.849.552.355.157.960.763.566.469.3
0.752.083.625.307.109.0011.013.015.217.319.621.924.226.629.031.534.036.639.141.844.4
47.149.852.655.358.161.063.866.769.6
0.872.233.785.487.299.1911.213.215.417.619.822.124.426.829.331.834.336.839.442.044.7
47.450.152.855.658.461.364.167.069.9
3040
70.2101
Example:Calculate the vapor-pressure of a gasoline blend as follows
(nC4) 51.6(iC4) 72.2(C3) 190.0
138210705
Component VolumeFraction
VaporPressure
psi
VaporPressureBlendingIndex No.
VolumeFraction
xVPBI
Equation:
VPBI = VP1.25
n-ButaneLight Straight RunHeavy RefinedTotal
0.0500.4500.5001.000
51.66.751.007.45
13810.91.0012.3
6.904.900.5012.3
From the brochure, 31.0API Iranian Heavy Crude Oil, by arrangement with ChevronResearch Company. Copyright 1971 by Chevron Oil Trading Company.
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
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 trueoctane of the blend.
Blending octane numbers are based on experience. The formula used for calculations is:
Vblend(ON)blend= Vi(BON)iwhere,
Vblend= Total volume of gasoline blended (bbl).Vi= Volume of blending component i (bbl).(ON)blend= Desired true octane of blend.(BON)i= Blending octane number of component i.
If n-butane alone is not sufficient to increase thePool octane number of the gasoline,
different ways are used to improve the octane number. These are:1.
Increase severity of reforming to produce a 98.8 or 100 RONC reformate.(This is not attractive because the aromatics content of the gasoline would
increase and the volume would decrease).
2. Use octane improvers, such as MTBE or ETBE (Table 13-2)to improve thepool 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 at 9
psi).
SolutionRVP values are obtained from Table 13.1VPBI values are obtained from Table 13.2
COMPONENT # (BPDi) (RVPi)
Table 13-1
(VPBIi)
Table 13-3
(BPDi)(VPBIi)
n-butane 2 W 52 139.64 139.64WHSR gasoline 8 1250 1.0 1.0 1250.00LSR gasoline 6 750 11.1 20.3 15225.00C5+FCC gasoline 18 620 4.4 6.37 3949.40
Total for blend 2620 + W 139.64W + 20424.4(BPDi) (BPDi)(VPBIi)
At 9.0 RVP, fromTable 13-3,(VPBI)m= 15.6
Into Equation13-1
(VPBI)m(BPDi) = (BPDi)(VPBIi)15.6 (2620 + W) = 20424.4 + 139.64 W
W = 165 BPD of n-butane
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Petroleum RefiningChapter 13: Product Blending
13-7
b.Component # BPD Vol.
Frac.BMON
Table 13-1BRON
Table 13-1MON x
Vol. frac.RON x
Vol. frac.
n-butane 2 165 0.0592 92.0 93.0 4.85 5.51HSR 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 17.88C5+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. = 64.9RON of the blend = RON x vol. frac. = 71.9
10 % MTBE is equal to 0.1(2785 BPD) = 278.5 BPDMTBE octane number is fromTable 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 5.022HSR gasoline 1250 0.408 58.7 62.3 23.95 25.42LSR gasoline 750 0.245 61.6 66.4 15.1 16.27C5FCC gasoline 620 0.202 76.8 92.3 15.51 18.64MTBE 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 ofthe blending stocks.
One of the most convenient methods of estimating properties, that do not blendlinearly, is to substitute for the true value of the inspection to be blended anothervalue (called blending factor or index) which has the property of blendingapproximately linear.
The Chevron Research Company has compiled factors or index numbers for,Viscosities,Table 13-6Flash points,Table 13-7Aniline points, Error! Reference source not found.
Pour point, Error! Reference source not found.
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 estimatethe viscosity of a blend from the viscosities of its blending stocks.
The method most commonly accepted is the use of special charts developed by andobtainable from ASTM.
The viscosity factor of the blend can be calculated using the equation:(VF)blend= Xvi(VF)i
where, Xvi = Volume fraction.
(VF)i= Viscosity factor for component i (Table 13.4).(VF)blend= Viscosity factor for the blend.
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-8
Blending of kinematic viscosities (centistokes, cSt = mm2/s) may be done at anytemperature, but the viscosities of all components of the blend must be at the sametemperature.
Blending of viscosities in Saybolt universal seconds also may be done at anytemperature and interchangeably with kinematic viscosities at the same temperature.
Table 13-6 may be used to convert viscosities expressed in centistokes (cSt) toSaybolt Universal Seconds (SUS) and vice versa.
Viscosity factors also are given inTable 13-6 for viscosities expressed in SayboltFurol Seconds(SFS).
Saybolt Furol viscosities are blended only at 122F. If SFS viscosities are at any othertemperature, they must be converted to centistokes or SUS before blending.
Viscosity factors for SFS at 122 F may be used interchangeably with viscosityfactors for SUS at 130 F and with centistokes at 130 F.
Table 13-6 may be used also to convert viscosities in SFS at 122 F to eitherkinematic 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 APITechnical Data Book - Petroleum Refining.
Blending for Flash Point
The flash point index of a blend is given by
(FPBI)blend= Xvi(FPBI)i
where
Xvi= Volume fraction.(FPBI)blend= Flash point blending index of the blend.(FPBI)i = Flash point blending index of component ifrom Table 13-5
Blending for Aniline Point
The aniline point index of a blend is given by
(APBI)blend= Xvi(APBI)iwhere
Xvi= Volume fraction.(APBI)blend= Aniline point blending index of the blend.(APBI)i = Aniline point blending index of component ifrom Table 13-6.
Blending for Pour Point
The pour point index of a blend is given by
(PP)blend= Xvi(PPBI)i
where Xvi= Volume fraction.(PP)blend= Pour point blending index of the blend.(PPBI)i = Pour point blending index of component i, from Table 13-7.
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Petroleum RefiningChapter 13: Product Blending
13-9
Example 13-4Calculate the viscosity, flash point, aniline point, and pour point of the blend from the followingblending stocks.
Stock bbls ASTM 50%temp (F)
Viscosity Flash point(F)
Anilinepoint (F)
Pour point(F)
ABC
5,0003,0002,000
575425500
430 SFS at 120 F82.5 SUS at 130 F2.15 cSt at 130 F
10090130
70160
40 (mixed)
105065
Blend 10,000 ? ? ? ?
Solution:
a. Viscosity
Stock vol. frac.of blend
Viscosity Factor(Table 13-6)
vol. frac. xFactor
A
BC
0.5
0.30.2
430 SFS at 120 F
82.5 SUS at 130 F2.15 cSt at 130 F
0.700
0.5000.300
0.350
0.1500.060
Total 1 0.560
Table 13-6 gives the following viscosities for a blend with a factor of 0.5639.5 cSt at 130 F183 SUS at 130 F25.7 SFS at 122 F
b. Flash point
Stock vol. frac. of blend Flash point (F) Blending Index (
Table 13-7)vol. frac. x index
ABC
0.50.30.2
10090130
7531,170224
376.535144.8
Total 1 772
Table 13-7 gives a flash point for the blend of 99.5 F for a blending index of 772.
c. Aniline Point
Stock vol. frac.of blend
Aniline point (F) Blending Index (Table13-6)
vol. frac. x index
A
BC
0.5
0.30.2
70
16040 (mixed)
347
855-425
173.5
256.5-85
Total 1 345
Table 13-6 gives for a blending index of 345 an aniline point for the blend of 69.5 F or a mixedaniline point of 115 F.
d. Pour Point
Stock vol. frac.of blend
ASTM 50%temp (F)
Pour Point (F) Blending Index(Table 13-7)
vol. frac. xindex
AB
C
0.50.3
0.2
575425
500
1050
65
861
98
418.3
19.6Total 1 41.9
The pour point of the blend is 41.9 F or 42 F.
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
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
(FPBI)blend= Xvi(FPBI)iwhere
Xvi= Volume fraction.(FPBI)blend= Freezing point blending index of the blend.(FPBI)i = Freezing point blending index of component ifrom Table.
Table 13-4. Freezing point blending 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 2015
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Petroleum RefiningChapter 13: Product Blending
13-11
Table 13-5 Freezing point blending 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 1.473 280 272.4122 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 1001.3142 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
Blending for Smoke point
The smoke point of a blend is given by
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-12
(SP)blend= Xvi(SP)iwhere
Xvi= Volume fraction.(SP)blend= Smoke point blending index of the blend.
(SP)i = Smoke point blending index of component i
Example 13-5
Calculate the freezing point and smoke point of the blend from the following kerosene blendingstocks.
Stock bbls Freezing point (F) Smoke Point (mm)
ABC
5,0003,0002,000
-55-50-51
252221
Blend 10,000 ? ?
Solution:
Freezing Point (F) using table
Stock vol. frac.of blend
Freezing point (F) Freezing Pointblending index
vol. frac. x index
ABC
0.50.30.2
-55-50-51
7.51999.01358.6928
3.76002.70411.7386
Total 1 8.2027
Table gives a freezing point of -52.7 F for a blend with a factor of 8.2027
In terms of equations
British units
FPBIFi= 55.16793 (1.0368976)FPFiFPBIm= Xvi(FPBI)iFPFm= -111.1628+27.68212 ln (FPBIm)
FPFi= freezing point of component i in F
FPFm= freezing point of the blend in FFPBIi = freezing point blending index for component iFPBIm= freezing point blending index for the blendXvi= volume fraction of component i
Freezing Point (F) using equations
Stock vol. frac.of blend
Freezing point (F) Freezing Pointblending index
vol. frac. x index
ABC
0.50.30.2
-55-50-51
7.51999.01358.6928
3.76002.70401.7386
Total 1 8.2026
Equation gives a freezing point of -52.9 F for a blend with a factor of 8.2026
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Petroleum RefiningChapter 13: Product Blending
13-13
In SI units
FPBIFi= 55.16793 (1.0368976)FPFi
FPBIm= Xvi(FPBI)iFPFm= -111.1628+27.68212 ln (FPBIm)
FPFi= freezing point of component i in FFPFm= freezing point of the blend in FFPBIi = freezing point blending index for component iFPBIm= freezing point blending index for the blendXvi= volume fraction of component i
Freezing Point (K) using table
Stock vol. frac.
of blend
Freezing point (K) Freezing Point
blending index
vol. frac. x index
ABC
0.50.30.2
225227.8227.2
7.51999.02788.7028
3.76002.70831.7406
Total 1 8.2089
Table gives a freezing point of 226.3 K (-52.7 F) for a blend with a factor of 8.2026
Freezing Point (K) using equation
Stock vol. frac.of blend
Freezing point (K) Freezing Pointblending index
vol. frac. x index
ABC
0.50.30.2
-225227.8227.2
7.55809.07128.7233
3.77902.72141.7447
Total 1 8.2450
Equation gives a freezing point of 226.2 K (-52.8 F) for a blend with a factor of 8.2026
Smoke pointStock vol. frac.
of blendSmoke Point
(mm)Smoke Point x
vol. frac.
ABC
0.50.30.2
252221
12.56.64.2
Blend 1 23.3
The smoke point of the blend is 23.3 mm
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-14
Numerical Method for blending viscosity
Table 13-6 maybe digitized and the following equations are obtained,
For blend no. 1
X1= log10(visc.1) (1)
for viscosity in centistokesuse the following Rational function
= 0.17 0.5238
1 0.5124 0.01233
(2)
or
= (X1+ 0.3103)/10
= 0.291694 .
= 1.05593 (3)
for the viscosity in SUS use one of the following two equations
= 0.6068 0.047970.80755
(4)
or
= 97993438 103852082 1 118310078 3052999
(3)
or
VF1= 0.5909 (X1-1.4414)0.25372
for viscosity in SFSuse
VF1= 0.5008X10.345 (5)
For blend no. 2, use the above equations 1 through 4. For example, Equations 1 and 2 wouldbecome,
X2= log10(visc.2)
= 0.17 0.5238
1 0.5124 0.01233
The viscosity factor for the blend
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Petroleum RefiningChapter 13: Product Blending
13-15
1 1 2 2
1 2
V VF V VF ...
V V ...blend
VF
(6)
To calculate the viscosity of the blend in cSt
log. = 0.3148 1.796
1 1.26376 0.4498
(7)
To calculate the viscosity of the blend in SUS use either of the following equations
log. =5.2602 34.83 .
3.7246 .
(8)
log(visc.blend) = 21.0553 -19.6471 exp[-0.446654(VFblend)3.9315] (9)
log. = 1.4123 33.4177 .
3.7246 .
(10)
To calculate the viscosity of the blend in SFS
Log(visc.blend) = 13.07836 -12.6188 exp [-0.7749(VFblend)3.9578] (11)
Example 13-6:Blending for viscosity using above (Albahri Viscosity Blending equations)
visc.i VFi Vi vol frac x factor
500 0.691 0.3333 0.230300 0.669 0.3333 0.223200 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. xFactor
ABC
0.33330.33330.3334
500 cSt at 130 F300 cSt at 130 F200 cSt at 130 F
0.6890.6630.648
0.2300.2210.216
Total 1 0.667
Table 13-6 gives 300 cSt at 130 F for a blend with a factor of 0.667
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-16
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 0.223200 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. xFactor
AB
C
0.33330.3333
0.3334
500 cSt at 130 F300 cSt at 130 F
200 cSt at 130 F
0.6890.663
0.648
0.2300.221
0.216Total 1 0.667
Table 13-6 gives 300 cSt at 130 F for a blend with a factor of 0.667
Example 13-8: Convert the viscosity of an oil sample having 100 cSt to SUS and SFS
Solution: From theTable 13-6 the viscosity factor for 100 cSt is 0.613. This factorcorresponds to 460 SUS and 62 SFS at 122 F.
Numerical Method
From equation (3) get the viscosity factor
X1 = log (vcSt) = log (100) = 2
= (X1+ 0.3103)/10 = 0.23103
= 0.291694 .= 0.3709
= 1.05593 = 0.61319
Then use equation (9) to get the viscosity in SUS
log(visc.blend) = 21.0553 -19.6471 exp[-0.446654(VFblend)3.9315] (9)
log(visc.blend) = 21.0553 -19.6471 exp[-0.446654(0.61319)3.9315] = 2.65visc = 446.8 SUS
Use equation (11) to get the viscosity in SFS
log(visc.blend) = 13.07836 -12.6188 exp [-0.7749(VFblend)3.9578] (11)
log(visc.blend) = 13.07836 -12.6188 exp [-0.7749(0.61319)3.9578] = 1.79477
visc= 62.34 SFS
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Petroleum RefiningChapter 13: Product Blending
13-17
An alternate 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
PPBI(K)i=255.565 + 4.9021110-6exp [-0.016418 (PPK) - 0.0522346 (TbK)+ 1.575110-4(PPK)(TbK)] (PPK)1.67057(TbK)2.37162
PPBI(K)i = pour point blending index for component iin KelvinPPK= pour point in kelvinTbK= ASTM distillation curve 50% temperature in kelvin (average boiling point)
In Fahrenheit
PPBIFi= 0.1786 + 0.425117 exp [0.0147 (PPF+70) - 0.00887 (TbF) + 4.92510-5 (PPF+70)(TbF)](PPF+70)0.1894(TbF)0.5855
PPBIFi= pour point blending index for component iin FPPFis pour point in FTbF= ASTM distillation curve 50% temperature in F (average boiling point)
The procedure is to calculate the PPBI for each component using the equation then add to obtain thepour point of the blend
PP = XviPPBIKi
Example 13-9
Applied to the previous example to calculate the pour point, the above equations will yield,
d. Pour Point (F eqn)
Stockvol. frac. Pour Point
(F)ASTM 50% temp
(F)Blending Index (Table
13-7)vol. frac. x
indexof 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
d. Pour Point (K eqn)
Stock
vol.frac.
PourPoint(F)
ASTM 50%temp (F)
PourPoint(F)
ASTM 50%temp (K)
Blending Index(Table 13-7)
vol. frac.x index
ofblend
(F) (K)
A 0.5 10 575 261.1 575.0 259.90 129.95
B 0.3 50 425 283.3 491.7 289.16 86.75C 0.2 65 500 291.7 533.3 310.27 62.05
Total 1 278.8
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-18
41.8
An alternate method for calculating the flash point of blending stocks.
The flash point blending index is given by the following equations instead of the Table
In British units: (FPBI)i= (0.3792866 + 2.085510-3FPFi)-12.4108
In SI Units: (FPBI)i= (-0.5800437+ 3.753910-3FPKi)-12.4108
FPFi = Flash point of component i in FFPKi = Flash point of component i in KelvinXvi= volume fraction of component i(FPBI)m= Flash point index for the blend
(FPBI)m= Xvi(FPBI)i
The flash point is then calculated for the blend using the following equations
In British units: FPFm= [327.0522-27.1872 ln(FPBIm)]/[1+ 0.071016 ln(FPBIm)-2.766222-5ln(FPBIm)2]
In SI units: FPKm= [437.250592356+ 4.0809276 ln(FPBIm)]/[1+ 0.0733857193 ln(FPBIm)+1.40131821823232-4ln(FPBIm)2]
FPF = flash point of the blend in degrees FFPK = flash point of the blend in K
Example 13-10
Applied to the previous example to calculate the flash point, the above equations will yield,
b. Flash point (F)
Stock vol. frac. of blend Flash point (F) Blending Index (Table 13-5) 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 Flash = 100.1 F
Flash point (K)
Stockvol. frac. of
blend
Flash point
(K)
Blending Index
(Table 13-5)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 Flash = 311.2 K or 100.1 F
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Petroleum RefiningChapter 13: Product Blending
13-19
An alternate numerical method for calculating the aniline point of distillate blending stocks.
The aniline point blending index is given by the following equations instead of the Table
In British units:
APBIi= 49.11 (1 + 0.05 APFi)1.3004
In SI Units:
APBIi= 4852.435 + 14.7655APKi+
(more accurate)
APBIi= 1437.69 + 1618.79 COS (0.007435 APKi+ 1.7832)
where
APFi = Aniline point of component i in FAPKi = Aniline point of component i in KelvinXvi= volume fraction of component iAPBIm= Aniline point index for the blend
APBIm= XviAPBIi
The aniline point is then calculated for the blend using the following equations
In British units:
APFm=(+. APBI.)
.+APBI. 32
In SI units:
APKm=(+ APBI
.)
(+APBI.)
(more accurate)
APKm= 2427.82 2182.923 exp ( 0.0002259 (APBIm)0.7898)
APF = Aniline point of the blend in FAPK = Aniline point of the blend in K
An alternate numerical method for calculating the mixed aniline point of distillate blendingstocks.
The mixed aniline point blending index is given by the following equations instead of theTable
In British units:
MAPBIi=1090 + 2221 cos (0.005425 MAPFi+ 3.7453) (more accurate)
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-20
MAPBIi=.+.
(.+.)
In SI Units use one for the following equations:
MAPBIi= - 10323.5 + 29.064 MAPKi+
(more accurate)
MAPBIi=.+.
(.+.)
1000
MAPBIi= 1090.1 + 2221.5 cos (0.009764 MAPKi+1.2502)
where
MAPFi= Mixed aniline point of component i in FMAPKi= Mixed aniline point of component i in KelvinXvi= volume fraction of component iMAPBIm= Mixed aniline point index for the blend
MAPBIm= XviMAPBIi
The mixed aniline point for the blend is calculated using the following equations
In British units:
MAPFm=.+.
(+.. )
In SI units:
MAPKm=
.+. n+.n+ (more
accurate)
MAPKm=
(...)
MAPKm= .+. +[+.+.+ ]
MAPKm=(+ MAPBI+
.)
(+MAPBI+.)
(least accurate)
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Petroleum RefiningChapter 13: Product Blending
13-21
Example 13-11
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 (F) Blending Index (Eq.) vol. frac. x indexA 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. aniline point = 69.6 F from eqn. mixed aniline point = 115.2 F
Aniline point (K)
Stock vol. frac. of blend Aniline point (K)
Blending Index
(Eq.) 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. aniline point = 294.2 K or 69.5 F from eqn. mixed aniline point = 319.6 K or 115.3 F
Real blending industrial example
Example 13-12: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 maxAvailable blends are as follows
Component bbls API ON RVP SG RVPI = RVP1.25
Tank 1 Reformate 500,000 70 94 10 0.7022 17.7828Tank 2 Isomerate 400,000 69 92 9 0.7057 15.5885Tank 3 Alkylate 600,000 72 96 8 0.6953 13.4543
Desired Blend 300,000 70 95 9 0.7022 15.5885
Solution:
LetN1 = bbls of Tank 1 reformateN2 = bbls of Tank 2 isomerateN3 = bbls of Tank 3 alkylate
Objective function N1 + N2 + N3 = 300,000
Constraints:
N1 500,000N2 400,000N3 600,000
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Petroleum RefiningChapter 13: Product Blending
13-23
Table 13-6: Viscosity Blending Index Numbers
Factors for Volume Blending of Viscosities at Constant Temperatures Corresponding tovalues 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
0.50.60.70.80.9
0.0000.0560.0970.1280.154
0.0060.0610.1000.1310.156
0.0130.0650.1040.1340.159
0.0190.0690.1070.1370.161
0.0250.0740.1100.1390.163
0.0300.0780.1140.1420.165
0.0360.0820.1170.1440.167
0.0410.0860.1200.1470.169
0.0460.0890.1230.1490.172
0.0510.0930.1260.1520.174
cSt0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
123456789
0.1760.2900.3420.3750.3980.4160.4310.4430.453
0.1940.297
0.3460.3780.4000.4180.4320.4440.454
0.2100.303
0.3500.3800.4020.4190.4330.4450.455
0.2240.3090.3530.3830.4040.4210.4340.4460.456
0.2360.3140.3570.3850.4060.4220.4360.4470.456
0.2470.3200.3600.3870.4080.4230.4370.4480.457
0.2570.3250.3630.3900.4100.4250.4380.4490.458
0.2660.3290.3660.3920.4110.4260.4390.4500.459
0.2750.3340.3690.3940.4130.4280.4400.4510.460
0.2830.3380.3720.3960.4140.4290.4420.4520.461
cSt0 1 2 3 4 5 6 7 8 9
1020304050607080
90
0.4620.5150.5430.5610.5750.5850.5940.601
0.608
0.4700.5190.5450.5630.5760.5860.5950.602
0.608
0.4770.5220.5470.5640.5770.5870.5960.603
0.609
0.4830.5250.5490.5660.5780.5880.5960.603
0.610
0.4890.5280.5510.5670.5790.5890.5970.604
0.610
0.4940.5310.5530.5680.5800.5900.5980.605
0.611
0.4990.5330.5550.5700.5810.5910.5990.605
0.611
0.5030.5360.5570.5710.5820.5920.5990.606
0.612
0.5080.5380.5580.5720.5830.5920.6000.607
0.612
0.5110.5410.5590.5730.5840.5930.6010.607
0.613
cSt0 10 20 30 40 50 60 70 80 90
100200300400500600
700800900
0.6130.6480.6670.6800.6890.697
0.7030.7080.713
0.6180.6510.6690.6810.6900.698
0.7040.7090.714
0.6230.6530.6700.6820.6910.698
0.7040.7090.714
0.6270.6550.6710.6830.6920.699
0.7050.7100.715
0.6310.6570.6730.6840.6920.700
0.7050.7100.715
0.6340.6590.6740.6850.6930.700
0.7060.7110.715
0.6370.6610.6750.6860.6940.701
0.7060.7110.716
0.6400.6620.6760.6870.6950.701
0.7070.7120.716
0.6430.6640.6780.6880.6960.702
0.7070.7120.716
0.6460.6660.6790.6880.6960.702
0.7080.7130.717
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-24
cSt0 100 200 300 400 500 600 700 800 900
1,0002,0003,0004,0005,0006,0007,0008,0009,000
0.7170.7430.7570.7670.7750.7800.7850.7900.793
0.7210.7450.7580.7680.7750.7810.7860.7900.794
0.7240.7470.7590.7690.7760.7810.7860.7900.794
0.7270.7480.7610.7700.7770.7820.7870.7910.794
0.7300.7500.7620.7700.7780.7820.7870.7910.795
0.7330.7510.7630.7710.7780.7830.7870.7910.795
0.7350.7520.7640.7720.7780.7830.7880.7920.795
0.7370.7540.7650.7720.7790.7840.7880.7920.796
0.7390.7550.7650.7730.7790.7840.7890.7920.796
0.7410.7560.7660.7740.7800.7850.7900.7930.796
cSt0 1000 2000 3000 4000 5000 6000 7000 8000 9000
10,00020,00030,00040,00050,00060,00070,00080,00090,000
0.7960.8170.8280.8360.8420.8470.8510.8540.858
0.7990.8180.8290.8370.8430.848
0.8020.8200.8300.8380.8430.848
0.8040.8210.8310.8380.8440.848
0.8060.8220.8320.8390.8440.849
0.8080.8230.8330.8390.8450.849
0.8100.8240.8330.8400.8450.850
0.8120.8250.8340.8410.8460.850
0.8140.8260.8350.8410.8460.850
0.8150.8270.8360.8420.8470.851
cSt cSt cSt
100,000200,000300,000400,000500,000600,000700,000800,000900,000
0.8600.8770.8870.8940.8990.9030.9060.9090.912
1,000,0002,000,0003,000,0004,000,0005,000,0006,000,0007,000,0008,000,0009,000,000
0.9140.9280.9370.9420.9470.9500.9530.9560.958
10,000,00020,000,00030,000,00040,000,00050,000,00060,000,00070,000,00080,000,00090,000,000
0.9600.9730.9800.9850.9890.9920.9950.9970.999
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Petroleum RefiningChapter 13: Product Blending
13-25
Factors for Volume Blending of Viscosities at Constant Temperatures Corresponding tovalues of Saybolt Universal Seconds (SUS).
SUS0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
3233343536373839
0.2750.2960.3140.3280.3420.3530.3630.373
0.2780.2980.3150.3300.3430.3540.3640.373
0.2800.3000.3170.3310.3440.3550.3650.374
0.2820.3020.3180.3330.3450.3560.3660.375
0.2840.3030.3200.3340.3460.3570.3670.376
0.2860.3050.3210.3350.3470.3580.3680.377
0.2880.3070.3230.3370.3490.3590.3690.378
0.2900.3090.3240.3380.3500.3600.3700.378
0.2920.3100.3260.3390.3510.3620.3710.379
0.2940.3120.3270.3400.3520.3630.3720.380
SUS0 1 2 3 4 5 6 7 8 9
405060708090
0.3810.4350.4640.4830.4970.508
0.3880.4390.4660.4850.4980.509
0.3950.4420.4690.4860.499
0.510
0.4020.4450.4710.4880.501
0.511
0.4080.4490.4730.4890.5020.512
0.4130.4510.4750.4910.5030.513
0.4180.4540.4760.4920.5040.513
0.4230.4570.4780.4930.5050.514
0.4280.4590.4800.4950.5060.515
0.4310.4620.4820.4960.5070.516
SUS0 10 20 30 40 50 60 70 80 90
100200300400500600700800
900
0.5170.5650.5890.6050.6170.6270.6350.641
0.647
0.5240.5680.5910.6070.6180.6280.6350.642
0.647
0.5310.5710.5930.6080.6190.6280.6360.642
0.648
0.5370.5740.5950.6090.6200.6290.6370.643
0.648
0.5420.5760.5960.6110.6210.6300.6370.643
0.649
0.5470.5790.5980.6120.6220.6310.6380.644
0.649
0.5510.5810.6000.6130.6230.6320.6390.645
0.650
0.5550.5830.6010.6140.6240.6320.6390.645
0.650
0.5590.5850.6030.6150.6250.6330.6400.646
0.651
0.5620.5870.6040.6160.6260.6340.6400.646
0.651
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-26
SUS0 100 200 300 400 500 600 700 800 900
1,0002,0003,0004,0005,0006,0007,0008,0009,000
0.6520.6830.7000.7110.7200.7270.7330.7380.742
0.6560.6850.7010.7120.7210.7280.7330.7380.742
0.6600.6870.7030.7130.7220.7280.7340.7390.743
0.6640.6890.7040.7140.7220.7290.7340.739
0.743
0.6670.6910.7050.7150.7230.7290.7350.7400.744
0.6700.6920.7060.7160.7240.7300.7350.7400.744
0.6730.6940.7070.7170.7250.7310.7360.740
0.744
0.6760.6960.7080.7180.7250.7310.7360.7410.745
0.6780.6970.7090.7190.7260.7320.7370.7410.745
0.6810.6990.7100.7190.7260.7320.7370.7420.745
SUS
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
10,00020,00030,00040,00050,00060,000
0.7460.7700.7830.7920.7990.804
0.7490.7710.7840.7930.7990.805
0.7520.7730.7850.7930.8000.805
0.7550.7740.7860.7940.8000.806
0.7580.7760.7870.7950.8010.806
0.7600.7770.7880.7950.8020.807
0.7620.7780.7890.7960.8020.807
0.7640.7790.7900.7970.8030.807
0.7660.7810.7900.7970.8030.808
0.7680.7820.7910.7980.8040.808
SUS SUS SUS SUS
70,00080,00090,000
0.8090.8130.816
100,000200,000300,000400,000500,000600,000700,000800,000900,000
0.8190.8380.8490.8560.8620.8670.8700.8740.877
1,000,0002,000,0003,000,0004,000,0005,000,0006,000,0007,000,0008,000,0009,000,000
0.8790.8950.9040.9110.9150.9190.9230.9250.928
10,000,00020,000,00030,000,00040,000,00050,000,00060,000,00070,000,00080,000,00090,000,000
0.9300.9440.9520.9570.9610.9650.9680.9700.972
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Petroleum RefiningChapter 13: Product Blending
13-27
Factors for Volume Blending of Viscosities at 130 F corresponding to values of SayboltFurol Seconds (SFS) at 122 F.
SFS at122 F 0 1 2 3 4 5 6 7 8 9
2030405060708090
0.5700.5880.6010.6110.6190.6260.632
0.5720.5900.6020.6120.6200.6270.633
0.5740.5910.6040.6130.6210.6270.633
0.5760.5930.6050.6140.6220.6280.634
0.5780.5940.6060.6150.6220.6290.634
0.5580.5800.5950.6070.6160.6230.6290.635
0.5610.5820.5970.6080.6160.6240.6300.635
0.5630.5840.5980.6090.6170.6240.6300.636
0.5660.5850.5990.6100.6180.6250.6310.636
0.5680.5870.6000.6100.6190.6260.6320.637
SFS at122 F 0 10 20 30 40 50 60 70 80 90
100200300400500600700800900
0.6370.6690.6860.6970.7060.7130.7190.7240.728
0.6420.6710.6870.6980.7070.7130.7190.7240.728
0.6460.6730.6880.6990.7070.7140.7200.7240.729
0.6490.6750.6890.700
0.7080.7150.7200.7250.729
0.6530.6760.6910.7010.7090.7150.7210.7250.729
0.6560.6780.6920.7020.7100.7160.7210.7260.730
0.6590.6800.6930.7030.7100.7160.7220.7260.730
0.6610.6810.6940.7030.7110.7170.7220.7270.730
0.6640.6830.6950.7040.7120.7180.7230.7270.731
0.6660.6840.6960.7050.7120.7180.7230.7270.731
SFS at122 F 0 100 200 300 400 500 600 700 800 900
100020003000
0.7320.7550.769
0.7350.7570.770
0.7380.7590.771
0.7410.7600.772
0.7430.7610.773
0.7460.7630.773
0.7480.7640.775
0.7500.7640.775
0.7520.7660.776
0.7540.7670.777
400050006000700080009000
0.7780.7840.7900.7950.7980.802
Notes:Values from this table are for 130 F, although the Saybolt Furol seconds are at122 F. This table alone must not be used for any other temperatures. Valuesfrom this table may be used interchangeably with values for kinematic andSaybolt Universal viscosities if the latter are for 130 F.
For SFS at 210 F, assume SUS10 x SFS and use the Saybolt Universal table.
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-28
Table 13-7: Flash Point Blending Index Numbers.Flash Point,
F 0 1 2 3 4 5 6 7 8 9
0
10
20
3040
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
25,20014,200
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
23,80013,500
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
22,40012,700
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
21,20012,000
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
20,00011,400
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
18,90010,800
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
17,80010,200
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
16,8009,680
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
15,9009,170
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
15,0008,690
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
May be used to blend flash temperature, determined in any apparatus but, preferably, not to blend closed cup with
open cup determinations.
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Petroleum RefiningChapter 13: Product Blending
13-29
Table 0-1: Aniline Point Blending Index Numbers.Aniline Point,
F0 -1 -2 -3 -4 -5 -6 -7 -8 -9
-100
20.049.1
17.446.0
14.942.8
12.639.8
10.336.8
8.1033.8
6.0630.9
4.1728.1
2.4625.3
1.0022.6
Aniline Point,F
0 1 2 3 4 5 6 7 8 9
0102030405060708090
100110120130140150160170180
190200210220230240
49.183.2121162205250298347398451505560617674733794855917980
1,0441,1101,1761,2421,3101,379
52.486.8125166209255303352403456510566622680739800861923986
1,0501,1161,1821,2491,3171,386
55.690.5129170214260308357408461516571628686745806867930993
1,0571,1221,1891,2561,3241,392
58.994.2133174218264312362414467521577634692751812873936999
1,0641,1291,1961,2621,3311,400
62.397.9137179223269317367419472527582640698757818880942
1,006
1,0701,1361,2021,2691,3371,406
65.7102141183227274322372424477532588645704763824886948
1,012
1,0771,1421,2091,2761,3441,413
69.1105145187232279327377429483538594651710769830892955
1,019
1,0831,1491,2161,2831,3511,420
72.6109149192237283332382435488543599657716775836898961
1,025
1,0901,1561,2221,2901,3581,427
76.1113153196241288337388440494549605663722781842904967
1,031
1,0961,1621,2291,2971,3651,434
79.6117157200246293342393445491554611669727788849911974
1,038
1,1031,1691,2361,3031,3721,441
Mixed AnilinePoint, F 0 1 2 3 4 5 6 7 8 9
010
2030405060708090
100110120
130140
-736-668
-593-511-425-334-239-140-38.366.8175285399
514632
-730-660
-584-503-416-324-229-130-27.977.4186297410
526644
-723-653
-577-494-407-315-219-120-17.588.1197308422
538656
-716-646
-569-486-398-306-210-110-7.0698.8208319433
550668
-709-639
-561-477-389-296-200-1003.39110219330445
561680
-703-631
-552-468-380-287-190-89.613.9120230342456
573692
-696-623
-544-460-371-277-180-79.424.4131241353468
585704
-689-616
-536-451-361-267-170-69.235.0142252364479
597716
-682-608
-528-442-352-258-160-58.945.5153263376491
609728
-675-600
-519-433-343-248-150-48.656.1164274387503
620741
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
13-30
Table 0-2: Pour Point Blending Indices for Distillate StocksASTM 50% Temp
300 350 375 400 425 450 475 500 525 550 575 600 625 650 675 700
PourPoint
7065605550454035302520151050
-5-10-15-20-25-30-35-40-45-50-55-60-65-70
13311499887260524437322723201714
12108.87.56.45.54.64.03.32.82.52.11.81.5
13111194796856484134292420171512
108.87.46.35.34.53.73.22.72.31.91.61.41.1
12910992776654463932272319161411
9.58.06.85.74.74.03.32.82.42.01.71.41.20.99
12810790756352443731262118151310
8.77.36.15.14.23.62.92.52.11.71.41.21.00.84
1271058773615042352924201714129.6
8.06.65.54.63.73.22.62.21.81.51.21.00.850.71
1251038571594840332723191613118.7
7.25.94.94.13.32.82.31.91.51.31.10.870.720.60
12310182685646383226211714129.77.9
6.55.34.43.62.92.42.01.61.31.10.900.740.600.50
1209880665444363024201613118.87.1
5.84.73.93.22.52.11.71.41.10.930.770.620.500.42
11896776352423428231815129.87.96.3
5.14.13.42.82.21.81.41.20.980.780.650.520.410.36
11594746149403226211714118.87.15.6
4.53.63.02.41.91.51.21.00.820.660.550.430.340.30
11391725847383024191512108.06.35.0
3.93.22.62.11.71.31.00.860.680.560.460.360.280.25
110886956443528231814119.07.15.64.4
3.42.82.21.81.41.10.900.730.580.470.370.300.230.20
108856753423326211613108.16.35.03.8
3.02.51.91.51.20.960.750.620.480.380.300.240.180.15
1058264503931241915129.17.25.64.43.4
2.72.21.71.31.00.800.620.510.380.310.240.190.140.11
1037962483729221814118.36.45.03.83.0
2.41.91.41.10.900.670.510.410.310.250.190.140.100.08
1007660463527211613107.55.84.53.52.7
2.11.61.20.940.720.560.430.330.250.200.150.100.070.05
From Gary & Handwerk
Online Blending
Because of limited storage space, many refineries today (MAB refinery) have theability to use computer-controlled in-line product blending.
Inventories of blending stocks, together with cost and physical property data aremaintained in the computer.
When a certain volume of a given quality product is specified, the computer useslinear programming models to optimize the blending operations (select the optimumvolume 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 research and motor octane areinstalled to provide feedback control of blending streams and additives (if necessary).
Blending components to meet all critical specifications most economically is a trial-and-error (iterative) procedure which is easily handled by a computer.
The large number of variables leads to a number of equivalent solutions that give theapproximate equivalent total overall cost or profit.
Optimization programs (like PIMS for example) permit the computer to provide theoptimum blend to minimize cost and maximize profit.
Both linear and nonlinear programming techniques are used.
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Petroleum RefiningChapter 13: Product Blending
13-31
Nonlinear programming is preferred if sufficient data are available to define theequations because components blend non-linearly and values are functions of thequantities of the components and their properties (specs).
Figure 13-4: Refinery online blending facilities
Figure 13-5: Schematic representation of the online blending system for diesel product
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 C5FCC 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 of2730 barrels of LSR gasoline, 2490 barrels of 94 RON reformate, 6100 barrels of heavyhydrocrackate, 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 flashpointof 120F,3750 barrels with a flashpointof 35F, and 5000 barrels with a 150F flashpoint?
5.
Calculate the pour point of the following mixture:
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Dr. Tareq Albahri, Chemical Engineering, Kuwait University, 2016
Compone
Barrel
ASTM50%
Pourpoint,
A 5,200 57
10
B 3 000 42
50C 6 500 50
65
D 3,250 55 45
6. What is the viscosity of a blend of 2000 barrels of oil with a viscosity of 75.5 cSt at 130F,3000 barrels with 225 cSt at 130F, and 5000 barrels with 6500 cSt at 130F?
7. Calculate the octane numbers of the final blend and amount of n-butane needed forproducing 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 ofC4= 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 ofproblem 3?
11. Calculate the clear octane numbers (RON and MON) and the amount of butane needed fora 12.0 psi RVP gasoline produced from the following:
Belding component BPSD
LSR naphtha 4,200Light hydrocrackate 1,800C5+ alkylate 4,500
Heavy hydrocrackate 9,150Reformate (94 RON) 11,500C5+ FCC gasoline 15,600
12. Recommend the best method (lowest capital cost) for increasing the posted octane numberof the pool gasoline in problem 11 by 5.5 octane numbers. Estimate the size of the unitand its 1994 construction cost.
HW solve problems 3, 5, 6, 10