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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