WATCHING THE WORLD

David Knott
London
[email protected]

Last week, gas-to-liquids (GTL) technology came of age with the announcement that South Africa's Sasol Ltd. has won the race to secure an agreement to build the world's first full-scale, commercial GTL plant.

Sasol signed a memorandum of understanding with Qatar General Petroleum Corp. (QGPC) and Phillips Petroleum Co. to build a 20,000 b/d GTL plant at Ras Laffan, Qatar (OGJ, July 21, 1997, Newsletter).

News of the Qatar plant has been eagerly anticipated. Exxon Corp. was favored to win the first GTL plant deal, having been negotiating with QGPC for some time to build a GTL plant there.

Sasol, Royal Dutch/Shell Group, and Tulsa's Syntroleum Corp. came along later and were competing to build another GTL plant close by.

Sasol's winning design will be based on its proprietary slurry-phase distillate process, which has been proved with a 2,500 b/d plant producing diesel fuel at the company's Sasolburg complex near Johannesburg since 1993.

Sasol said a feasibility study will be conducted in the next 6 months to assess fully the economics and viability of the Qatar plant. No sooner has GTL arrived, however, than someone is already trying to improve it.

R&D program

Air Products plc, Walton-on-Thames, U.K., has been chosen by the U.S. Department of Energy to head an $84 million research program to develop a new membrane technology that will reduce the cost of synthesis gas production.

In addition to a number of laboratories and universities, the project team includes petroleum companies ARCO, Chevron Corp., and Norsk Hydro AS and the Babcock & Wilcox unit of contractor McDermott International Inc., Alliance, Ohio.

Making synthesis gas, a mixture of carbon monoxide and hydrogen, from natural gas and oxygen is the first part of the GTL process and the most costly, accounting for roughly 60% of the entire process.

Dennis Brown, R&D manager for Air Products Europe, told OGJ the new membrane technology may replace current cryogenic methods of making feedstock oxygen.

Membrane

Brown said the new membrane is a wafer-thin rare-earth oxide ceramic sheet through which air is passed. The membrane separates out the air's oxygen.

"The oxygen comes through as ions," said Brown, "which are highly reactive. If there is natural gas at the other side of the membrane, the oxygen will react with it to produce carbon monoxide and hydrogen."

The project will be split into three phases: The first stage is to build a lab-scale plant; the second will be to build a 12 Mcfd experimental unit, and the third will be to construct a "pre-commercial" scale plant at La Porte, Tex., with capacity to produce 15 MMcfd of synthesis gas.

"We think this program will cut the cost of making synthesis gas by a minimum of 30%," said Brown, "and maybe as much as 50%. These projections are based on laboratory experiments. It will be at least 5 years before we have something working in the field."

Further down the line, another major application for the membrane could be production of hydrogen from natural gas. Hydrogen is one of the contenders for transport fuel of the future, either directly or through fuel cells.