1 Asst. Prof. Dr. Pakamas Chetpattananondh In House Practical Training (IHPT) Department of Chemical Engineering, Faculty of Engineering, PSU Distillation (D-86) True Boiling Point

2 Vaporization of pure component 70 F 212 F

3 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.

4 Vaporization of mixtures Pure ethanol BP = 173 F

5 Batch distiallation

6 Continuous distillation

7 Volatility A fuel’s ability to vaporize or change from liquid to vapor is referred to as its volatility. The volatility characteristics of a spark ignition (SI) engine fuel are of prime importance. Fuels that do not vaporize readily may cause hard starting of cold engines and poor vehicle driveability during warm- up and acceleration. Conversely, fuels that vaporize too readily at higher operating temperatures will cause too much vapor to form causing a decrease in fuel flow to the engine (known as “vapor lock’).

8 Volatility Volatility too lowVolatility 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

9 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.

10 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

11 D 86 is used to determine fuel volatility across the entire boiling range of fuel. A = Front End (0– 20% evaporated) B = Mid-range (20- 90% evaporated) C = Tail End ( % evaporated) How is D-86 important ?

12 How is D-86 important ? The 10% evaporated temperature must be low enough to provide easy cold starting but high enough to minimize vapor lock as well as hot driveability problems. The 50% evaporated temperature must be low enough to provide good warm up and cold weather driveabiity without being so low as to contribute to hot driveability and vapor locking problems. The 90% and end point evaporation temperatures must be low enough to minimize crankcase and combustion chamber deposits as well as spark plug fouling and dilution of engine oil.

13 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)

14 Using distillation curve DI = 1.5 x T x T50 + T90 In New Zealand E 70  C at 25-45% E 100  C at 45-67% DI for UL 91 is about 495 DI 550 cause driveability problem in cold

15 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 = (15) Distillation pot, volume = 15 L Volumetric of feed 5 – 10 L Reflux ratio = 5:1 Temperature of distillation ≤ 350  C (AET) Weight loss ≤ 4%

16 True boiling point It is often useful to extend the boiling point data to higher temperatures than are possible in the fractionating distillation method and for this purpose a vacuum distillation in a simple still with no fractionating column (ASTM D-1160) can be carried out. This distillation, which is done under fractionating conditions equivalent to one theoretical plate, allows the boiling point data to be extended to about 600°C (1112°F) with many crude oils. This method gives useful comparative and reproducible results that are often accurate enough for refinery purposes, provided significant cracking does not occur. Usually seven fractions provide the basis for a reasonably thorough evaluation of the distillation properties of the feedstock:

17 True boiling point 1. Gas, boiling range: <15.5°C (60°F) 2. Gasoline (light naphtha), boiling range: l5.5–149°C (60–300°F) 3. Kerosene (medium naphtha), boiling range: 149–232°C (300–450°F) 4. Gas oil, boiling range: 232–343°C (450– 650°F) 5. Light vacuum gas oil, boiling range: 343– 371°C (650–700°F) 6. Heavy vacuum gas oil, boiling range: 371–566°C (700–1050°F) 7. Residuum, boiling range: >566°C (1050°F)

18 Typical Refinery Products ProductBoiling Range Deg. C Boiling Range Deg. F LPG Gasoline Kerosene, Jet Fuel, #1 Diesel #2 Diesel, Furnace Oil Lube Oils Residual Oil Asphalt Petroleum CokeSolid From: Schmidt, G.K. and Forster, E.J., “Modern Refining for Today’s Fuels and Lubricants,” SAE Paper , 1986.

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21 Crude Assay TaTa TbTb TeTe Cut points { EP IBP 0% 20%40%60%80%100% naphtha kerosenelight gas oil heavy gas oil vacuum gas oil

22 SpecificationParameterLimit New ZealandT85350°C max. Euro 3 (2000)E E350 T95 19 <65 % by volume 85% by volume min. 350°C max. World-Wide Fuel Charter T90 T95 Final 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) AustraliaT95370°C max. from 1 January °C max. from 1 January 2006 JapanT ? C depending on cold weather class USAT90338°C max.

23 For vacuum residues a typical true boiling point (TBP) cut point is 538  C, 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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27 Thanks for your attention