Ethylene is the lightest olefinic hydrocarbon as well as the organic hydrocarbon consumed in the greatest quantity worldwide. It is produced by heating either natural gas, especially its ethane and propane components, or petroleum to 800–900 °C (1,470–1,650 °F), giving a mixture of gases from which the ethylene is separated. The melting point of ethylene is −169.4 °C [−272.9 °F], and its boiling point is −103.9 °C [−155.0 °F].
Ethylene appears to have been discovered by Johann Joachim Becher, who obtained it by heating ethanol with sulfuric acid. He mentioned the gas in his Physica Subterranea (1669).One of the first patents for the commercial production of ethylene is credited to Union Carbide in 1922. Just three years later, the first commercial plant for ethylene product was built in West Virginia in the United States. Since then, the olefins industry has gradually evolved. Starting with “worldscale” ethylene plants in the early 1950’s with capacities of around 20,000 to 50,000 MTY, plants have become bigger, more energy efficient, and more environmentally friendly. The global nameplate capacity can well be over 1,000,000 MTY of ethylene. Naphtha is the predominate feed for steam crackers, followed by ethane, propane, gas oil, butane and others.
By itself,, ethylene is used either alone, as in the production of polyethylene, or in reaction with other chemicals, as in the production of polyvinyl chloride, polystyrene and polyester resins and a variety of other derivatives used in applications such as detergents, antifreeze, adhesives and lubricants.
The largest outlet, accounting for 60% of ethylene demand globally, is polyethylene.
Low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) mainly go into film applications such as food and non-food packaging, shrink and stretch film, and non-packaging uses. High density polyethylene (HDPE) is used primarily in blow moulding and injection moulding applications such as containers, drums, household goods, caps and pallets. HDPE can also be extruded into pipes for water, gas and irrigation, and film for refuse sacks, carrier bags and industrial lining.
The next largest consumer of ethylene is ethylene oxide (EO) which is primarily used to make ethylene glycol. Most monoethylene glycol (MEG) is used to make polyester fibres for textile applications, PET resins for bottles and polyester film. MEG is also used in antifreeze applications. Other EO derivatives include ethyoxylates (for use in shampoo, kitchen cleaners, etc), glycol ethers (solvents, fuels, etc) and ethanolamines (surfactants, personal care products, etc).
LyondellBasell, Dow Chemical Co., ExxonMobil, ChevronPhillips, Shell and Ineos, National Petrochemical Co., BASF, Fina Petrochemicals, Formosa, Sabic, Sinopec, Total AS, Westlake Petrochemicals and Reliance Industries Ltd are some of the leading producers of Ethylene.
The Global Ethylene capacity is projected at around 164 MMT for 2016 with demand estimated at 146 MMT in 2016..
In India, Reliance Industries is slated for major capacity expansion in Jamnagar 3 project leading to increase in their ethylene capacity to 3.2 MMT from 1.9 MMT. The ethylene capacity in India for 2016-17 is projected at 4.8 MMT which includes Reliance J3 expansion commencing from Q4 as well as Opal having commissioned its mega petrochemical complex at Dahej. The total ethylene capacity in India is projected to be 7.2 MMT in 2017-18.
By 2020, global demand growth is poised to become stronger assuming that the global economy does not fall into another recession.
Over the next five years China, the Middle East and North America will continue to be the largest drivers of global ethylene demand growth; however, most of the Middle East demand for ethylene will be for export in the form of primary derivatives, such as polyethylene and ethylene glycol.
Ethylene demand growth in the Indian Subcontinent, Southeast Asia, CIS & Baltics, and Africa is projected to remain considerably above the global average. In contrast, consumption volumes in North America and Europe are forecast to grow slowly for the next few years but after 2017 and 2018 the large scale investments in North America will result in a substantial rise in ethylene production and conversion to derivatives, which are destined for some domestic growth, but primarily to feed ethylene derivative exports into the global market.
Global ethylene demand will continue to be dominated by the production of polyethylene (HDPE, LDPE and LLDPE), which is used in a wide variety of non-durable goods applications such as packaging materials. More than 60% of global ethylene production was consumed by HDPE, LDPE, and LLDPE in 2015. Ethylene oxide (used in antifreeze, polyester fibers, PET resins, and detergents), ethylene dichloride (used in PVC films, coatings, and pipes), and ethylbenzene/styrene (used in polystyrene packaging and ABS resins) are also important ethylene consumers.
In addition to traditional pyrolysis and recovery technologies, new routes to ethylene and propylene production are being explored. These include methanol-to-olefins (MTO), methanol-to-propylene (MTP), the Fischer-Tropsch process and refinery off-gas recovery.
MTO Process: Lurgi and UOP/HYDRO are commercializing the MTO process that catalytically converts methanol to short chain olefins. In this process, methanol is converted to light olefins, primarily ethylene and propylene. If the site includes gas reforming, methanol syntheis, and the UOP/HYDRO MTO Process, the facility is often referred to as a gas-to-olefins (GTO) complex as shown.
Fischer-Tropsch Process: The Fischer-Tropsch process, so called because it converts coal to synthetic fuel (synfuels), also produces a range of olefins, alcohols and ketones. This method was developed by Sasol in S Africa. Sasol embarked on a program to extract ethylene, propylene, and other chemicals from its synfuel stream and to add further value. This process can also be used to convert biomass into liquified fuels.
Refinery-off gas recovery: A small amount of ethylene is also recovered from the dry gas streams produced by fluidized calalytic cracking (FCC) units in oil refinerie