Something strange is brewing inside a former ice-cream factory on Florida’s Gulf Coast. There, in a small marine laboratory, stands a clear tube, 6 feet high and 8 inches in diameter, filled with ordinary seawater from the mouth of Tampa Bay. The only sound is the hum of a high-pressure water pump. Ethane, a hydrocarbon gas, is fed into the bottom of the tube. Within minutes tiny crystal shards float to the surface. To the untrained eye they look like bubbles, but the magnified picture on a nearby video monitor shows an icelike consistency. “At first we thought it was dust or something,” says Sarah Holman, a chemical engineer. “Now we know it’s hydrate, and it’s forming almost immediately.” Gradually, larger masses begin to form. A layer of frosty material gathers at the top of the tank, like salt on the rim of a giant margarita. As more and more accumulates, it begins to look like an Italian ice slowly filling the top of the tank.
This is the first step in what could be a revolution in wringing freshwater from the sea. When hydrates form, even in the ocean, salt is excluded from the crystalline structure. Melt the hydrate and it separates into distilled water and gas. Build a large enough structure—say, a tube a thousand feet or longer on the shore or in the sea itself—and you could provide freshwater for an increasingly arid planet, which could quite literally change the world. That is exactly the result Marine Desalination Systems founder Michael Max is gunning for.
Max is one of the world’s ranking experts on hydrates, and he isn’t shy about it. Before you can offer a basic greeting, let alone pull out a pen, he is making declarations: “Up to 500 million gallons of freshwater a day, that’s the goal. . . . Ours is the only group making hydrates from seawater. . . . We’re aiming at a new method that will become a primary source of freshwater on the planet.” At 5 feet 8 inches, Max, 62, is rugby-player stocky with bushy eyebrows, a thick mustache, and all the subtlety of a bulldozer. Arms crossed, he spews out mile-a-minute descriptions of thousand-foot shafts in the sea, where the familiar physics of crystallization, gravity, and pressure gradients will separate salt and produce distilled water.
The key ingredient is gas hydrate, a substance that forms when hydrocarbon gases like methane and ethane come into contact with water at the right temperature and pressure. Gas molecules become trapped inside a lattice structure of water, creating a crystal substance known as clathrate that is superficially similar to ice—except this stuff is flammable. (For more on naturally occurring hydrates, see “Will the Methane Bubble Burst?” in the March 2004 issue of Discover.)
