Powering into the future Dozens gather to discuss MHD

July 01, 1992|By Frank D. Roylance | Frank D. Roylance,Staff Writer

The same exotic technology that powered the fictional Soviet submarine in Tom Clancy's thriller, "The Hunt for Red October," may one day help toast your muffins and get the acid out of your rain.

It's called "magnetohydrodynamics," or MHD, and nearly 100 scientists and engineers from seven nations are meeting in Baltimore this week to compare notes and see how far they've come toward moving the idea from fiction to fact.

Some are actually working on the development of a Red October-type propulsion system for ships, submarines and torpedoes that would be both efficient and nearly silent, with no moving parts.

Others are building an MHD electrical generator in Montana to test the durability of systems that could lead to more efficient and muchcleaner coal-fired power plants by early in the next century.

People from both fields attending the 30th Symposium on Engineering Aspects of Magnetohydrodynamics, meeting at the Harbor Court Hotel, seemed confident yesterday that their work will one day lead to commercially viable products.

"We see no show-stoppers. I think it's doable," said Michael Petrick, who is working on a MHD propulsion experiment for the Argonne National Laboratory in Chicago.

The Japanese may already be ahead, however. They launched a 100-foot MHD-powered boat last month that is cruising around Kobe

harbor at 7 knots.

Rich Weinstein, of Gilbert Commonwealth, a Reading, Pa., energy consulting firm that is monitoring MHD power plant research for the federal government, says the United States does lead this part of the field. He, too, is confident about the future.

"Does MHD work? Yes, absolutely," he said. "Is it capable of generating electricity? No question.

"Shortly after the turn of the century, you should see the beginning of commercial tests, and then a gradual growth of this technology," Mr. Weinstein said.

What isn't known, he said, is whether the machinery can withstand the high temperatures and stresses of MHD power generation long enough to be practical. Critical durability tests are planned next year at a small, 1.5 megawatt demonstration plant in Montana.

Financing research and construction is another big problem for MHD power plant research in the United States. MHD power plant research received $40 million from the Department of Energy this year but got nothing for 1993.

Researchers are seeking other federal, state and corporate support, he said, but "would you bet on a Boeing 747 based on the Wright brothers' flight?"

As exotic as it seems, MHD is based on a simple, old idea.

Michael Faraday, the 19th-century English inventor of the electrical dynamo, or generator, knew that when you move an electrically conductive material through a magnetic field, you generate electricity.

And that's really how generators work -- by spinning a coil of copper wire inside a magnet.

Faraday thought he could make electricity by moving electrically conductive fluids through a magnetic field, but never succeeded.

The idea lived on, however, and experiments began in the 1960s to develop MHD electrical generators and MHD propulsion systems.

A commercial-scale MHD power plant would burn coal or natural gas at very high temperatures to produce a gas, or plasma, heated to 4,500 degrees Fahrenheit. The plasma would be made electrically conductive by the addition of a metal compound, usually potassium.

Next, the plasma would be blasted at supersonic speed through a pipe surrounded by a superconducting magnet, generating electricity as Faraday predicted.

The more powerful the magnetic field, the more electricity the MHD plant produces. That's why the development of superconducting magnets was critical to the development of MHD technology.

After the plasma passed through the magnet, its heat would be used to produce steam to spin a conventional turbine and electrical generator.

Mr. Weinstein said an MHD power plant would convert 50 percent to 60 percent of the coal's energy to electricity, as compared with 37 percent in a conventional coal-fired plant.

In addition to burning less coal, "recent tests . . . show that MHD is very clean," he said.

The potassium added to make the plasma conduct electricity would combine with the sulfur in the coal, preventing 99 percent of the sulfur from flying up the smokestack. Sulfur from coal-fired power plants is a major contributor to acid rain.

Nitrogen oxides, another contributor to acid rain, would be reduced by nearly 40 percent, he said.

MHD propulsion systems work a bit differently. Sea water entering an MHD power plant flows into a pipe and receives an electrical charge from electrodes powered by batteries, a diesel or nuclear power plant.

The charged water flows through a superconducting magnet. The magnetic field accelerates the water through the pipe like a kind of underwater jet, propelling the boat.

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