17.2 Refining petrolem

Question 1

What does refining mean? And by what process is it carried?

Answer 1

Separating the compounds into groups with molecules of a similar size.

It is carried by Fractional Distillation.

Question 2

How do you refine petroleum in the lab? List the steps.

Answer 2

1. Heat the petroleum in a flask, compounds start to evaporate.

The ones with smaller lighter molecules go first.Since it takes less energy to free them from the liquid.

2. As hot vapours rise, so does the thermometer reading.
3. Vapours condense in a cool test tube.
4. When the thermometer reads 100 degrees Celsius, replace the first tube with an empty one.

The liquid condensed in the first tube is you first FRACTION from the distillation.

5. Collect 3 other FRACTIONS, in the same way. At 150 degress C, 200, and 300 degrees Celsius.

Question 3

What do you compare between frictions?

Answer 3

1. Their viscosity (how funny they are)

2. How easily they burn

Question 4

What can you predict from the proprieties of a fraction such as viscosity and burning ability?

Answer 4

1. You can predict how volatile a fraction is from viscosity (How runny) and how easily it burns.
2. You can predict size of molecules from how easily it burns and how runny it is.

Question 5

If a fraction has large molecules, how easily will it burn, how volatile is it, and how runny is it? Boiling point?

Answer 5

It burns only with a wick, it is the least volatile, it’s very viscous. = Boiling point = HIGH

Question 6

Describe how fractional distillation is carried out in a refinery (the tower)?

Answer 6

Petroleum is pumped in T the base. The compounds start to boil off. Smallest molecules boil off first and rise to the top of the tower. Others raise only part of the way depending on their boiling points and then condense.

Question 7

Name the 8 fractions and their uses in petroleum. (IN ORDER)

Answer 7

1. Refinery gas - bottled gases for cooking/ heating
2. Gasoline/ petrol - Fuel for cars
3. Naphtha - Starting point (feedstock) for many chemicals and plastics
4. Paraffin/ Kerosene - fuel for aircrafts, oil stoves, lamps
5. Diesel Oil - fuel to Diesel engines
6. Fuel Oil - fuel for power stations, ships , home heating systems
7. Lubricating Fraction -oil for car engines and machinery, waxes, polishes
8. Bitumen - for road surfaces

Question 8

As molecules get larger…

Answer 8

Fractions get less runny, more vicious, less flammable. (So cannot be used as fuels)