Dimethyl ether DME Fact Sheet
Introduction and basic data on DME
State of the Art for DME production
Major stakeholders in DME in the EU
Introduction
Dimethyl ether (typically abbreviated as DME), also known as methoxymethane, wood ether, dimethyl oxide or methyl ether, is the simplest ether. It is a colourless, slightly narcotic, non-toxic, highly flammable gas at ambient conditions, but can be handled as a liquid when lightly pressurized. The properties of DME are similar to those of Liquefied Petroleum Gas (LPG).
Molecular Formula
Properties of DME
Molecular mass: 46.07 g/mol
Density at 20°C: 668 kg/cm³
Viscosity at 20°C: 0.15 mPa s
Heating value: 28.4 MJ/kg
Vapour pressure at 20°C: 5100 hPa
Utilization
Substitute for diesel fuel; transportation fuel; power generation fuel; domestic gas
Relevant fuel regulations
EN590 (diesel fuel)
Main feedstocks
Black liquor, forest products, agricultural by-products, organic waste, energy crops
Scale of Production
Demonstration scale
Costs and GHG Balance
Assumes crude oil at 50 US-$/bbl
Production process
DME is primarily produced by converting natural gas, organic waste or biomass to synthesis gas (syngas). The syngas is then converted into DME via a two-step synthesis, first to methanol in the presence of catalyst (usually copper-based), and then by subsequent methanol dehydration in the presence of a different catalyst (for example, silica-alumina) into DME.
The following reactions occur:
2H2+ CO 
CH3OH
2CH3OH CH3OCH3 + H2O
CO+H2O CO2+H2
Alternatively, DME can be produced through direct synthesis using a dual-catalyst system which permits both methanol synthesis and dehydration in the same process unit, with no intermediate methanol separation, a procedure that, by eliminating the intermediate methanol synthesis stage, the licensors claim promises efficiency advantages and cost benefits.
Both the one-step and two-step processes are commercially available. DME can also be converted itself into olefins and synthetic hydrocarbons.
State of the Art
Due to its good ignition quality, DME can be used in diesel engines as a substitute for diesel fuel. Compared to diesel DME has a lower viscosity. It is stored under relatively low pressure of 0.5 MPa in the liquid state. Because of this, slight modifications to the engine are necessary, primarily relating to the injection pump and the installation of a pressure tank, similar to that for LPG. Dimethyl ether in diesel engine burns very cleanly with no soot.
According to the EC Directives 2009/28/EC (RED) and 2009/30/ EC (FQD) dimethyl ether is a biofuel if it is produced from biomass and intended for use as biofuel (in diesel engines). For other purposes (e.g. continuous combustion in boilers), DME can be blended with LPG. As part of the FP7 project BioDME under the leadership of the Volvo Group DME production is being optimized, especially for use as a transport fuel.
The demonstration plant in Piteå, which was put into operation in 2010, is the only gasification plant worldwide producing high-quality synthesis gas based on 100% renewable feedstock. The raw material used is black liquor, a high-energy residual product of chemical paper and pulp manufacture which is usually burnt to recover the spent sulphur.
EC-funded projects on DME
See R&D Funding page for further project details
BioDME - Production of DME from Biomass and utilisation as fuel for transport and for industrial use. Funded by 7th Framework Programme and Swedish Energy Agency.
Major stakeholders
Some major DME stakeholders in the EU are listed below:
Volvo Group, Sweden
Chemrec,, Sweden
Haldor Denmark
Preem, Sweden
Total, France
Delphi, Luxembourg
DECHEMAETC, Sweden
Further Information
See the BioDME page for updated project information