Fill in the blanks with appropriate words selected from those given below.
|heights, condense, lower, bitumen, hydrocarbons,
high, fractional distillation, cool, fractionating column,
diesel oil, petrol, refinery, higher up, lower down
(a) Crude oil is made up of many different ___________. In an oil ___________, the hydrocarbons are separated into different products by a process called _____________ ___________. The crude oil is heated to a high temperature and passed into the____________ __________. As the vapours rise towards the top the different hydrocarbons ___________ at different ___________ and are withdrawn separately.
(b) Substances with _____________ boiling points condense first, in the column. Substances with ___________ boiling points condense ______________. Light products like ___________ are withdrawn from near the top of the column. Heavier products like ___________ and fuel oil are taken out lower down. The heaviest hydrocarbons, such as __________ are left at the bottom.