CIEC Promoting Science at the University of York, York, UK

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Basic chemicals Ethene (Ethylene)
Ethene (Ethylene)

Ethene (ethylene) is the most important organic chemical, by tonnage, that is manufactured. It is the building block for a vast range of chemicals from plastics to antifreeze solutions and solvents.

 

A panoramic photograph of the site at Grangemouth in Scotland at night where ethene is produced by steam cracking of naphtha.
Figure 1  On the site at Grangemouth in Scotland, ethene is produced by steam cracking of naphtha.
By kind permission of INEOS Manufacturing Scotland.

Uses of ethene (ethylene)

The principal uses of ethene are to produce:
a) polymers

b) other chemicals

Poly(ethene) accounts for about half of the world demand for ethene.  However, there are considerable variations.  For example, in Europe the polymer accounts for 59% of ethene consumed (LDPE 22%,  LLDPE 14%, HDPE 23%).

Annual production of ethene (ethylene)

World 156 million tonnes1
Europe 19 million tonnes2
US 24 million tonnes3
Russia 5.5 million tonnes4
China 20 million tonnes1
Middle East 28 million tonnes1

Data from:
1.  ICIS 2013.  Data for 2012
2.  APPE (Association of Petrochemicals Producers in Europe 2013,  Data for 2012
3.  American Chemistry Council 2013.  Data for 2012
4.  Federal State Statistics: Russian Federation 2011

Manufacture of ethene (ethylene)

Ethene is produced from the cracking of fractions obtained from distillation of natural gas and oil.
The processes are:
a)the steam cracking of ethane and propane (from natural gas and from crude oil)
b) the steam cracking of naphtha from crude oil
c) the catalytic cracking of gas oil from crude oil. The choice of feedstock depends on availability, price
(which can vary considerably), and what other products from cracking are needed.
The vast majoriy of ethene is produced by steam cracking. Some crackers are capable of producing 3 600 tonnes of ethene a day.

A map of Europe on which he pipelines carrying ethene are shown. They include pipelines across the UK, France, Belgium, the Netherlands, Spain and Germany, connecting refineries
Figure 2  Distribution of ethene by pipeline across Europe.

Within Europe, the ethene that is not needed at the site at which it is produced is fed into pipelines which connect other chemical plants and refineries (Figure 2).

A new wave of crackers is being built in the Middle East to take advantage of a large supply of ethane. Indeed, the cracking of ethane will soon account for 30% of the production of ethene.

New plants based on bioethanol produced from sugar cane are in operation and are also being constructed in Brazil.

High yields are obtained by dehydrating ethanol vapour using a catalyst containing a mixture of magnesium oxide, alumina and silica at 600-750 K:

The ethene is used principally to produce poly(ethene), which can thus be classified as 'green'.

 

Date last amended: 2nd January 2014