Petrochemicals (also known as petroleum distillates; and sometimes abbreviated as petchems) are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.
The two most common petrochemical
classes are olefins (including ethylene and propylene) and aromatics (including
benzene, toluene and xylene isomers).
Oil refineries produce olefins and aromatics by fluid
catalytic cracking of petroleum fractions. Chemical plants produce olefins by steam
cracking of natural gas liquids like ethane and propane. Aromatics are produced by catalytic reforming of
naphtha. Olefins and aromatics are the
building-blocks for a wide range of materials such as solvents, detergents, and
adhesives. Olefins are the basis for polymers and oligomers used in plastics, resins,
fibers, elastomers, lubricants, and gels.
Global ethylene and propylene production
are about 115 million tonnes and 70 million tonnes per annum, respectively.
Aromatics production is approximately 70 million tonnes. The largest petrochemical industries are
located in the USA and Western Europe; however, major growth in new production
capacity is in the Middle East and Asia. There is substantial inter-regional
petrochemical trade.
Primary petrochemicals are divided into
three groups depending on their chemical structure:
- Olefins
includes Ethene, Propene, Butenes and butadiene. Ethylene and propylene
are important sources of industrial chemicals and plastics products. Butadiene is used in making synthetic rubber.
- Aromatics
includes Benzene, toluene and xylenes, as a whole referred to as BTX and
primarily obtained from petroleum refineries by extraction from the
reformate produced in catalytic reformers using Naphtha obtained from
petroleum refineries. Alternatively, BTX can be produced by aromatization
of alkanes. Benzene is a raw
material for dyes and synthetic detergents, and benzene and toluene for isocyanates
MDI and TDI used in making polyurethanes. Manufacturers use xylenes to
produce plastics and synthetic fibers.
- Synthesis
gas is a mixture of carbon monoxide and hydrogen used to make ammonia and methanol.
Ammonia is used to make the fertilizer
urea and methanol is used as a solvent and chemical intermediate. Steam
crackers are not to be confused with steam reforming plants used to
produce hydrogen and ammonia.
- Methane,
ethane, propane and butanes obtained primarily from natural gas processing
plants.
- Methanol
and formaldehyde.
In 2007, the amounts of ethylene and
propylene produced in steam crackers were about 115 Mt (megatonnes) and 70 Mt,
respectively. The output ethylene
capacity of large steam crackers ranged up to as much as 1.0 – 1.5 Mt per year.
Like commodity chemicals, petrochemicals
are made on a very large scale. Petrochemical manufacturing units differ from
commodity chemical plants in that they often produce a number of related
products. Compare this with specialty chemical and fine chemical manufacture
where products are made in discrete batch processes.
Petrochemicals are predominantly made in
a few manufacturing locations around the world, for example in Jubail & Yanbu
Industrial Cities in Saudi Arabia, Texas & Louisiana in the US, in Teesside
in the Northeast of England in the United Kingdom, in Rotterdam in the
Netherlands, in Jamnagar, Dahej in Gujarat, India and in Singapore. Not all of
the petrochemical or commodity chemical materials produced by the chemical
industry are made in one single location but groups of related materials are
often made in adjacent manufacturing plants to induce industrial symbiosis as
well as material and utility efficiency and other economies of scale. This is
known in chemical engineering terminology as integrated manufacturing.
Speciality and fine chemical companies are sometimes found in similar
manufacturing locations as petrochemicals but, in most cases, they do not need
the same level of large scale infrastructure (e.g., pipelines, storage, ports
and power, etc.) and therefore can be found in multi-sector business parks.
The large scale petrochemical
manufacturing locations have clusters of manufacturing units that share
utilities and large scale infrastructure such as power stations, storage tanks,
port facilities, road and rail terminals. In the United Kingdom for example,
there are 4 main locations for such manufacturing: near the River Mersey in
Northwest England, on the Humber on the East coast of Yorkshire, in Grangemouth
near the Firth of Forth in Scotland and in Teesside as part of the Northeast of
England Process Industry Cluster (NEPIC). To demonstrate the clustering and
integration, some 50% of the United Kingdom's petrochemical and commodity
chemicals are produced by the NEPIC industry cluster companies in Teesside.
History
In 1835, Henri Victor Regnault, a French
chemist left vinyl chloride in the sun and found white solid at the bottom of
the flask which was polyvinyl chloride. In 1839 Eduard Simon discovered
polystyrene by accident by distilling storax. In 1856, William Henry Perkin discovered the
first synthetic dye, Mauveine. In 1888, Friedrich
Reinitzer, an Austrian plant scientist observed cholesteryl benzoate had two
different melting points. In 1909, Leo
Hendrik Baekeland invented bakelite made from phenol and formaldehyde. In 1928 synthetic fuels were invented using Fischer-Tropsch
process. In 1929, Walter Bock invented
synthetic rubber Buna-S which is made up of styrene and butadiene and used to
make car tires. In 1933, Otto Röhm polymerized
the first acrylic glass methyl methacrylate. In 1935, Michael Perrin invented polyethylene.
After World War II, polypropylene was discovered in the early 1950s. In 1937, Wallace Hume Carothers invented nylon.
In 1946, he invented Polyester. Polyethylene terephthalate (PET) bottles are
made from ethylene and paraxylene. In
1938, Otto Bayer invented polyurethane. In 1941,Roy Plunkett invented Teflon. In 1949, Fritz Stastny turned polystyrene into
foam. In 1965, Stephanie Kwolek invented Kevlar.
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