Ethylene oxide (EO) is a versatile intermediate used in the production of ethylene glycol and other oxide derivatives such as glycol ethers, polyethylene glycol, polyether polyols, diethylene and triethylene glycols and ethanolamines.
EO is employed in the production of solvents, antifreeze, textiles, detergents, adhesives, polyurethane foam, and pharmaceuticals. Smaller amounts are used in fumigants, sterilants for spices and cosmetics, as well as during hospital sterilisation of surgical equipment.
Almost all of the world’s EO is produced by direct oxidation method – oxygen is generally preferred over the air in larger plants, owing to higher yields and less downtime.
Ethylene, compressed oxygen and recycle gases are mixed and fed into a catalytic reactor. This mixture is passed over a silver oxide catalyst held on a porous carrier at more than 200°C.
Gases from the reactor are first cooled and passed through a scrubber, where the ethylene oxide is absorbed as a dilute aqueous solution.
EO is typically used as an intermediate for many organic syntheses. Derivatives of EO, such as ethylene glycol are commonly used in the plastics industry for manufacturing bottles and to produce polyester fibres for clothing and furniture, automotive and industrial coolants, heat transfer fluids, detergents and surfactants.
EO is also an intermediate used in the manufacture of flexible and rigid polyurethane foams, brake fluids and water-soluble solvents.
Ethylene glycol is the largest user segment for ethylene oxide, accounting for almost 70% of its global consumption.
The second largest user segment is surface-active agents, such as non-ionic alkyl phenol ethoxylates and detergent alcohol ethoxylates.
Monoethylene glycol (MEG) is the primary glycol, which is used mainly to make polyester, followed by automotive antifreeze. MEG demand has shown great promise and is expected to grow at 5-6% per year globally – primarily driven by the strong demand for polyester fibre in Asia.
Demand for polyethylene terephthalate (PET) bottle resin has shown a great deal of potential across the globe.
Ethylene glycol is also used as a plasticizer for adhesives, as a softener for cellulose film, and as solvents in paint, printing inks and adhesives. EO alone, or in combination with other inert gases such as carbon dioxide and nitrogen, is used to sterilise instruments for the healthcare, publication and wood products sectors.
Supply & demand
Overall, EO demand is expected to grow at around 5% per year globally.
World consumption of EO in 2007 was estimated at 19.95 million tones, while EO has maintained a steady growth of 3.5-4% in the last five year period (7% in 2007) and is likely to maintain this growth rate in the near term.
However, there are some production facilities in China and the Middle East/Asia (fourteen new EO plants will come on-stream this year and next: four in Saudi Arabia, two in the Middle East, five in China, and three in India) coming on-stream in the coming year and it might result in a slight oversupply – and slight decrease in prices.
Prices have more or less remained stable in the last six months and are expected to behave so for the next six-month period. Feedstock prices have increased in all the major markets, but sufficient supply has maintained the price stability.