WATCHING GOVERNMENT

Patrick Crow
Washington, D.C.
[email protected]

One of the most interesting trends in the petroleum industry today is the continuing progress in developing methods to convert natural gas to synthetic liquids.

Robert Kripowicz, a deputy assistant Energy Secretary, recently briefed the Senate energy committee on gas-to-liquids (GTL) research.

He said Alaska's North Slope has 25 tcf of producible gas reserves untapped because there is no cost-effective transportation to markets.

He said chemical conversion of gas into stable hydrocarbon liquids offers potential for significant cost savings over the usual cryogenically liquefied natural gas (LNG) method.

"A chemical gas-to-liquids conversion plant could be less complex with fewer process stages than traditional large-scale LNG manufacturing facilities. Such a plant could be sited on Alaska's North Slope or on offshore platforms or barges to tap natural gas supplies that do not have pipeline access."

Projects

He said DOE has expanded its GTL R&D program to help lower costs.

One conversion method reacts gas with high steam and oxygen to produce carbon monoxide and hydrogen, a mixture called "synthesis gas." Then it is chemically recombined into hydrocarbon liquids.

He said a new ceramic membrane may slash the cost of converting gas to liquid fuels and premium chemicals (OGJ, June 23, 1997, p. 20) and could be used to make a distillate product on the North Slope for $18-20/bbl.

And he said the method may produce lower cost hydrogen, which is a necessary but expensive reactant for upgrading heavy petroleum.

Kripowicz said DOE's Pittsburgh, Pa., laboratory has found gas can be reacted with hydrochloric acid and oxygen to form methyl chloride, a chemical building block for gasoline and other hydrocarbon products.

He said a Dow-Corning project has shown the technology is technically feasible, but low methanol prices make it noncommercial. Dow is working on "an alternative route involving new reaction chemistry and better economics."

Other projects

The Idaho National Engineering & Environmental Laboratory is in the early development phase of producing acetylene by injecting natural gas into a super-hot stream of hydrogen plasma. Acetylene can be used to make hydrocarbon liquids into specialty chemicals.

Kripowicz said DOE is also sponsoring a Cryenco Inc. and Los Alamos National Laboratory project to use sound waves to help liquefy gas.

He said the project lends itself to small, more compact modules than the typical LNG plant. It would burn some of the gas feedstock to generate sound waves, which would drive an "orifice pulse tube" refrigerator.

"Current projections are that the system can make LNG at costs half those of traditional refrigeration of small volumes."

Kripowicz said DOE's R&D strategy envisions the transfer of advanced, lower cost GTL conversion technologies to industry by 2010.

"The ultimate benefit of our research efforts could be to reduce oil imports by 200,000-500,000 b/d," he said.