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 creditedto Union Carbide in 1922. Just three years later, the first commercial plant for ethyleneproduct 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 nameplate capacity for today’s worldscale crackers 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.
There are several major licensors of conventional commercial olefin technologies, including: Lummus Technology, KBR, Linde, Technip, and the Shaw Group. In addition to the traditional pyrolysis and recovery technologies, new routes to ethylene and propylene production are being developed. These include methanol-to-olefins (MTO), the Fischer-Tropsch process and refinery off-gas recovery.
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.
Global ethylene capacity was 147.4MMT in 2011 against a demand of 120 MMT. The capacity is expected to increase to 165 MMT in 2015 with demand reaching 151 MMT.Westlake, Ineos, Chevron Phillips, Dow, Equistar, Oxychem, Formosa, Shell, Nova, Braskem/Idesa, Williams, Borouge, and CPC Corp. -Taiwan are some of the companies which announced ethylene capacity expansion plans starting 2012 to 2017. In India total ethylene capacity is expected to reach 7087 KTA by 2016-17 and Reliance Industries Ltd has planned capacity expansion to 3240 KTA by 2016-17 followed by ONGC OPAL at 1100 KTA, GAIL 1000 KTA, IOC at 857 KTA, HALDIA 670 KTA and BPCL Assam GC 220 KTA.
Ethylene production costs are mostly determined by underlying feedstock prices that derive from either natural gas (ethane, butane & propane) or crude oil (naphtha & gas oil).Ethylene price touched its lowest level in last five years in Nov’08 – 408$/MT-SE Asia prices. For the FY 2011-12 ethylene price has been 1172$ MT corresponding to Crude 110.12 $/Barrel and Naphtha 950 $/MT.
Ethylene is the raw material used in the manufacture of polymers such as polyethylene (PE), polyethylene terephthalate (PET), polyvinyl chloride (PVC) and polystyrene (PS) as well as fibres and other organic chemicals.
These products are used in a wide variety of industrial and consumer markets such as the packaging, transportation, electrical/electronic, textile and construction industries as well as consumer chemicals, coatings and adhesives. 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).
Today the Asian region, including Southeast Asia, Northeast Asia and the Indian Subcontinent, accounts for an estimated 45 percent of the global ethylene equivalent consumption contained in derivatives.
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 calalytically 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