Published: August 2005
This report provides an updated analysis of DME technologies and related commercial developments since the previous PEP Report 245 was published in June 2002. That report appraised the methanol dehydration technology and single-step DME synthesis from natural gas. In this report, three new technologies, not presented in the previous report, are examined and analyzed for technological description and process economics.
Those technologies are:
1) JFE’s slurry-reactor based Direct DME Technology.
2) Haldor Topsoe’s Integrated Methanol-DME Technology.
3) Toyo’s Indirect DME Technology.
In addition, the report evaluates and compares the DME economics (production, shipping and storage costs) with those of methanol, gas-to-liquid (GTL) fuels and liquefied natural gas. Our study indicates that DME slurry-based process involving CO2 recovery from the reactor gases and its subsequent use in reforming is economically less attractive. Haldor Topsoe technology is potentially the most economical technology, having a slight edge over the Toyo technology. Most attractive sites for DME production include Middle East and Persian Gulf countries because of natural gas availability at low prices.
Liquefied natural gas (LNG), due to its current economies of scale of production, has the most attractive economics in terms of energy delivered-cost, followed by methanol and GTL fuels. LNG, thus, provides the best economic option for transporting stranded natural gas from the remote areas to developed markets, especially when the gas is to be used as a fuel, although initial capital outlay for LNG chain may be a few times higher than that for others. For short market distances, the DME and GTL delivered-costs do not differ significantly. However, as market distance is increased, the difference gets wider. When compared with the liquefied petroleum gas (LPG) at its today’s price, the DME has a slightly lower delivered-cost on MMBtu basis. Hence, its economic compatibility with LPG makes it a good substitute for the latter.
If the gas is to be used for a purpose other than fuel, then methanol may be the best choice for the gas conversion; methanol has an advantage over others as it can be used in production of a number of chemicals, e.g., acetic acid, formaldehyde, methyl tertiary-butyl ether, methyl methacrylate and DME itself. In addition, new potential markets (fuel cells, propylene, other olefins, gasoline additive, etc.), which are presently in infancy stage, are also opening for methanol. DME is, however, much superior than methanol as a fuel in terms of environmental friendliness and chemical toxicity. Both GTL and DME have certain shortcomings at the moment to be used as independent auto fuels. Until the time those shortcomings are tackled, for which efforts are going on, both GTL and DME are likely to be used as diesel and LPG additives.