COAL FOUND FEASIBLE TO PRODUCE OXYGENATES

The Department of Energy says research has proved the feasibility of using coal for the chemical "building block" to produce oxygenates for use in cleaner burning gasoline. Air Products & Chemicals Inc., working under a 3 year test program sponsored by DOE, has demonstrated the first use of a one-step process to convert gas derived from coal into dimethyl ether (DME). The chemical can be used to lower emissions from gasoline fueled vehicles. The 1990 Clean Air Act amendments require nearly 25%

July 1, 1991

2 min read

The Department of Energy says research has proved the feasibility of using coal for the chemical "building block" to produce oxygenates for use in cleaner burning gasoline.

Air Products & Chemicals Inc., working under a 3 year test program sponsored by DOE, has demonstrated the first use of a one-step process to convert gas derived from coal into dimethyl ether (DME). The chemical can be used to lower emissions from gasoline fueled vehicles.

The 1990 Clean Air Act amendments require nearly 25% of U.S. gasoline to contain oxygenates by 1995.

DME previously was made from methanol synthesized either from natural gas or coal. The methanol then was dehydrated, chemically removing molecules of water to form DME.

ONE-STOP APPROACH

Air Products developed a one-step approach in which all the methanol and DME synthesis steps take place in a single vessel. In contrast to conventional gaseous techniques, the reactions occur in an inert liquid slurry.

The liquid absorbs heat released as the chemical changes occur, allowing reactions to run at higher, more efficient rates and protecting heat sensitive catalysts required for the process.

DOE said the one-step slurry approach holds promise for reducing costs that previously have been a barrier to making alternative liquid fuels from coal.

It said future methanol/DME production facilities could be built as adjuncts to advanced coal gasificationbased electrical power plants.

When demand for electricity slackens during evening hours, coal-derived gas could be diverted from turbine generators to a methanol/DME synthesis plant.

The methanol/DME mixture either could be stored as a turbine fuel for peak generating periods or sold to the transportation market.

DOE said such a multiproduct plant configuration could produce liquid fuels from coal at prices commercially competitive to producing liquid fuels from natural gas or biomass, beginning perhaps early in the next decade.

WHAT'S NEXT

Air Products now will seek to improve ways to use DME, methanol and coal-based synthesis gas as feedstocks for making oxygenated fuel additives similar to MTBE, an ether that can reduce carbon monoxide emissions and boost octane in gasoline.

The $17 million test program began in October 1990 and will run through the fall of 1993.

Research is being conducted at DOE's LaPorte, Tex., Alternative Fuels Development Unit, which is managed by DOE's Pittsburgh Energy Technology Center.