D86 and TBP
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Transcript of D86 and TBP
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Asst. Prof. Dr. Pakamas Chetpattananondh
In House Practical Training(IHPT)
Department of Chemical Engineering, Faculty of Engineering, PSU
Distillation (D-86) True Boiling Point
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Vaporization of pure component
70 F
212 F
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Does "Boiling " Mean "Hot"?
• Boiling occurs when the vapor pressure inside the bubble equals atmospheric pressure.
• What would happen if the atmospheric pressure would drop?
• The simple example of this is the case of a camper who is on the top of a 10,000 ft mountain . While water boils at 100 degrees C at sea level (where the atmospheric pressure is 760mm Hg ) the atmospheric pressure at
10,000 ft altitude is about 530 mm Hg .• Because the boiling point of water is about 90 degrees C
at this altitude, not only will our camper find that his food will cook a little slower than normal, any attempt to
boil water to kill germs and pathogens may be unsuccessful since the water isn't getting hot enough.
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Vaporization of mixtures
Pure ethanolBP = 173 F
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Batch distiallation
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Continuous distillation
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Volatility• A fuel’s ability to vaporize or change from li
quid to vapor is referred to as its volatility.• T he volatility characteristics of a spark igni
tion (SI) engine fuel are of prime importance.
• Fuels that do not vaporize readily may caus e hard starting of cold engines and poor ve
- hicle driveability during warm up and acceleration.
• Conversely, fuels that vaporize too readily at higher operating temperatures will caus
e too much vapor to form causing a decreas e in fuel flow to the engine (known as “vapo r lock’).
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VolatilityVolatility too low Volatility too high
Poor cold start Poor warm up performance
Poor cold weather driveability Unequal fuel distribution in
carbureted vehicles Increased deposits :crankcase, spark
plugs, combustion chamber
High evaporative emissions, Canister overload & Purge
Hot driveability problems, Vapor
lock Fuel economy may
deteriorate
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Volatility• The main parameters to establish volatility limits
are Vapor/Liquid Ratio (V/L), Vapor Pressure (RVP), and Distillation Curve .
• The vapor/liquid ratio uses a test to determine the temperature required to create a V/L ratio of 20 .
• More volatile fuels require lower temperatures to achieve this ratio while less volatile fuels require higher temperatures to create the same ratio .
• The V/L ratio assists in defining a fuel's tendency to contribute to vapor lock .
• The V/L ratio and RVP are measurements of a fuel's "front end volatility", or more volatile components which vaporize first .
• The distillation test is used to determine fuel volatility over the entire boiling range of gasoline.
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• ASTM-D2892:
True Boiling Point (TBP)
• ASTM-D86: Distillation method for light petroleum products
• ASTM D-1160: Distillation method for heavier fractions (>500°F) carried out in vacuum
Classification methods of petroleum fractions by boiling point
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• 86D is used to ooooooooo ooo
l vol ati l i ty ac ross the enti re
boi l i ngrange of fuel.• A = Front End (0–20% evaporated)• B = Mid-range (20-90% evaporated)• C = Tail End (90-100% evaporated)
How is D-86 important ?
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How is - 86D important ?• 10The % evaporated temperature must be l
oo oooooo oo ooooooo oooo oooo oooooooo ooo oooo oooooo oo oooooooo ooooo oooo oo oooo oo o otdr i veabi l i t y pr obl ems.
• The 50%evaporated temperature must be lowoooooo oo ooooooo oooo oooo oo ooo oooo ooooooo o riveabiitywi t hout bei ng so l owas t o cont r i but e t o h otdr i veabi l i t y and vapor l ocki ng pr obl ems.
• 90%The and end point evaporation temperatu r es must be l owenough t o mi nimize ooooooooo ooo ooo
bustion chamber deposits as well as spark plu g fouling and dilution of engine oil.
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Flexible Volatility Index (FVI)This is a parameter calculated from the RVP and the measured value of E70, and is an indicator of the hot running performance (the tendency for vapour lock).FVI = RVP + (0.7 x E70)
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Using distillation curve
15 10 3 50 90DI = . x T + x T + T
In New ZealandE 70C at 25-45%E 100C at 45-67%
oo for UL 91 is about 495DI 550 cause driveability problem in cold
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True boiling point
• ASTM D-2892 is used for samples with a wide boiling
range such as crude petroleum up to a final cut
temperature of 400°C (752°F) atmospheric equivalent
temperature (AET).
• Theoretical plate = 14-18 (15)
• Distillation pot, volume = 15 L
• Volumetric of feed 5 – 10 L
• Reflux ratio = 5:1
• Temperature of distillation ≤ 350C (AET)
• Weight loss ≤ 4%
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True boiling point
• It is often useful to extend the boiling point data to hi gher temperatures than are possible in the fractionati
ng distillation method and for this purpose a vacuum distillation in a simple still with no fractionating colum
- n (ASTM D 1 1 6 0 ) can be carried out.• Thisdistillation, whichisdoneunderfractionatingconditionsequivalenttoonetheoreticalplate, allowst he boi l i ng poi nt dat a t o be ext ended t o a
bout 6 0 0 °C (1 1 1 2 °F) with many crude oils.• This method gives useful comparative and reproducib
le results that are often accurate enough for refinery purposes, provided significant cracking does not occu
r.• Usual l y seven f r act i ons pr ovi de t he basi s f or a r
easonabl y t hor ough eval uat i on of t he di st i l l at i on pr oper t i es of t he f eedst ock:
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True boiling point
• 1 155 60. Gas, boiling range: < . °C ( °F)• 2. () , :5.5–149° (60–300°)• 3. Kerosene (medium naphtha), boiling range:
149 232 300 450– °C ( – °F)• 4 232 343 4. Gas oil, boiling range: – °C (50 650– °F)
• 5 343. Light vacuum gas oil, boiling range: – 371 650 700°C ( – °F)
• 6 371. Heavy vacuum gas oil, boiling range: – 566 700 1050°C ( – °F)
• 7 5661050. Residuum, boilingrange: > °C( °F)
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Typical Refinery Products Product Boiling Range
Deg. C Boiling Range
Deg. F
LPG -40 - 0 -40 - 31
Gasoline 30 - 200 80 - 400
Kerosene, Jet Fuel, #1 Diesel 170 - 270 340 - 515
#2 Diesel, Furnace Oil 180 - 340 350 - 650
Lube Oils 340 - 540 650 - 1000
Residual Oil 340 - 650 650 - 1200
Asphalt 540 + 1000 +
Petroleum Coke Solid
From: Schmidt, G.K. and Forster, E.J., “Modern Refining for Today’s Fuels and Lubricants,” SAE Paper 861176, 1986.
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Crude Assay
Ta
Tb
Te
Cut points
{
EP
IBP
0% 20% 40% 60% 80% 100%
naphthakerosene light gas
oil
heavy gasoil
vacuum gasoil
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Specification Parameter Limit
New Zealand T85 350°C max.
Euro 3 (2000) E25019
E350T95
<65 % by volume85% by volume min.350°C max.
World-Wide Fuel Charter
T90T95Final boiling point
340°C (Cat.1) - 320°C (Cat. 3&4)355°C (Cat.1) - 340°C (Cat. 3&4)365°C (Cat.1) - 350°C (Cat. 3&4)
Australia T95 370°C max. from 1 January 2002360°C max. from 1 January 2006
Japan T90 330 - 360? C depending on cold weather class
USA T90 338°C max.
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For vacuum residues a typical true boiling point (TBP) cut point is 538C, but it may be lower or higher depending on the crude. The TBP cut point will define the concentration of Conradson
carbon residue (CCR), sulfur, and metals in the feed and thereby affect yields and product quality.
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Thanks for your attention