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206 Science and Technology

Crude oil from oil fields around the world is shipped to refineries.

The thick, black crude is not a single substance, but a mixture

of many different carbon compounds (groups of atoms). At the

refinery, the compounds are separated by fractional distillation.

WHAT CAN WE MAKE FROM OIL?

Using further treatments, lighter compounds can be

turned into important fuels, such as petrol and

kerosene for motor vehicles and aircraft. They can

also make fibres and plastics, solvents for paints, inks,

adhesives, cosmetics, and pharmaceuticals. Heavier

molecules are used for lubricant oils and bitumen.

WHAT IS FRACTIONAL DISTILLATION?

At a refinery, crude oil is heated until it boils and

turns into a mixture of vapours. Different compounds

in the vapours cool and condense at different levels

inside a tall distillation tower, allowing them to be

separated out. Heavy industrial fuels condense at the

bottom of the tower, lighter petroleum fuel at the top.

HOW ARE ACIDS AND ALKALIS USED?

Sulphuric acid is made from sulphur, air, and water. It

is the biggest single product of the chemical industry.

It is used in batteries, dyes, detergents, fertilizers, and

synthetic fibres. Other acids make rocket fuel, varnish,

and explosives. Sodium carbonate is a common alkali

used to make both soap and glass, for example.

WHAT DOES A CHEMICAL PLANT DO?

Chemicals found in nature, such as salt, sulphur,

nitrogen, and natural gas, are the raw materials of the

chemical industry. At a chemical plant, these materials

are mixed, heated, and refined. The chemical reactions

that take place transform the raw materials into acids,

alkalis, and other valuable chemical compounds.

Chemical Industry

OIL REFINERY

DRILLING FOR OIL 3

Crude oil is extracted from under

the sea bed by offshore oil rigs.

These enormous platforms are the

largest sea-based structures in

the world. Anchored to the sea

bed, the rig supports the drill and

all the machinery needed to run

the drilling operation.

1 OIL REFINERY

Oil refineries break down crude

(untreated) oil into many of the

chemical compounds used by

the chemical industry. A refinery

operates around the clock – at

night its illuminated pipes, tanks,

and towers look like a small city.

Massive legs

support the

platform. They

may stand directly

on the sea bed, or

may be filled with

air to provide a

floating base

which is anchored

to the sea bed

Derrick

supports the drill

and the drill string

(the pipes that lead

down to the drill

head in the sea

bed)

Rig platform

supports the derrick,

as well as offices,

canteens, recreation

rooms, and sleeping

quarters for the

workers

Communication

towers keep the rig

in constant touch

with the mainland

Plastics,. AGROCHEMICALS,. PHARMACEUTICALS,

paints, and detergents are just a few of the products of

the chemical industry. Chemicals are manufactured in

huge chemical plants or extracted at. OIL REFINERIES.

chemical

industry