Production, distribution and storage
DME can be produced from natural gas, coal or biomass by using gasification and a two-stage process via methanol, or by using Haldor-Topsoe’s single-stage process. For ships, an on-board convertion of methanol into a mixture of DME, methanol and water has been considered (Haldor-Topsoe’s OBATE concept). This would enable an easy onboard storage of alcohol and using ether in the diesel engine.
When produced from biomass, Well-to-Tank greenhouse gas emissions are low for DME. Greenhouse gas potential of DME is 1.2 at 20 years horizon and 0.3 at 100 years horizon. Economics for DME in large-scale plants are estimated to resemble those for CNG and LNG. Costs are estimated to be lower for fuel-grade DME containing small amounts of methanol and water than for chemical-grade DME. (IEA-AMF Task 14, Semelsberger et al. 2006, Haldor-Topsøe, Flesch 1995).
Physical properties of DME resemble those of LPG. Therefore refuelling and storage requirements of these fuels are close to each other. In principle, transport and distribution of DME could use the existing LPG infrastructure with some modifications to the pumps, seals and gaskets. New infrastructure for DME would be needed in the regions where the LPG infrastructure does not exist. (Semelsberger et al. 2006). DME is compatible with diesel-cycle, whereas LPG is compatible with otto-cycle. Therefore consideration is needed, if the same infrastructure is used for these fuels.
DME is not corrosive to metals in the same way as methanol, however, some elastomers are not compatible with DME. Similarly to LPG, DME is heavier than air, which may be a significant factor in some applications. DME is a flammable liquid forming explosive mixtures with air. DME burns with visible blue flame. It does not form peroxides as such or as aerosol. DME smells like ether, and therefore odorants are not required. (Semelsberger et al. 2006, Flesch 1995, Akzo Nobel 2012).
DME is non-carcinogenic, non-teratogenic, non-mutagenic and non-toxic. DME evaporates from water in open systems within hours. DME degrades by a photochemical reaction with OH radicals into carbon dioxide and water. (Semelsberger et al. 2006, Akzo Nobel 2012).