Can Ethylene Replace Gasoline?

The effort to replace oil-based gasoline in our cars with similar fuels derived from natural gas took a big step forward last week with the announcement that Siluria, a promising start-up, will build a $15-million demonstration plant in Texas

The plant will produce ethylene, the most commonly produced industrial chemical in the world and the feedstock for a whole raft of products in the chemicals and plastics industry. But Siluria, which is not yet a public company, is also planning demonstration plants that will produce gasoline. Initial estimates are that the product could sell at half the price of gasoline derived from oil. If these projections prove to be anywhere close to reality, we could be on a path to a fuel economy that is finally able to cut its dependence on oil.

The idea of producing ethylene from natural gas has been around since the 1980s but achieved little success. Several major oil companies invested millions of dollars in the process but finally gave up on it. Jay Labinger, a Caltech chemist who did much of the initial research, finally wrote a paper in the 1980s warning other researchers that it was a waste of time. He may have given up too soon.

Siluria is a California-based startup that has received much of its funding from Silicon Valley investors who tried to move from computers and the Internet into the energy space over the last decade. So far their success hasn’t been great. In fact Vinod Khosla and other Silicon Valley energy entrepreneurs were the subject of an embarrassing critique on “60 Minutes” only two weeks ago. The Siluria venture, however, may be the gusher that makes up for all the other dry holes.

The 1980s efforts concentrated on heat-activated processes whereby methane is split into carbon and hydrogen and then recombined into the more complex ethylene, which has two double-bonded carbons and four hydrogens. All these efforts proved far too energy-intensive, however, and never became economical.

Siluria has been trying a different approach, seeking catalysts that would facilitate the process at much lower energy levels. Moreover, the company has spurned the more recent approach of trying to design molecules that fit the chemicals just right and gone back to the old shotgun approach where thousands of candidates are tried on a catch-as-catch-can basis.

Defying all expectations, the process seems to have worked. Siluria has come up with a catalyst that it says promotes the breakdown and subsequent reassembly of methane at very low energy levels. It has built pilot plants in San Francisco, Menlo Park and Hayward, California and last week announced plans for building a full-scale demonstration plant in La Porte, Texas in conjunction with Braskem, the largest petrochemical manufacturer in South America. If that isn’t proof that Siluria is on to something, what is

The implications of this development are enormous. Natural gas is two to six times more abundant than oil in the world and is now selling at 1/5th the price for an equivalent amount of energy. The traditional tandem pricing of oil and natural gas prices has now been broken and gas is functioning as a completely different commodity, much cheaper.

The difficulty all along has been that natural gas is hard to put into your gas tank. So far efforts have involved compressing natural gas, which means storing it at 3600 pounds per square inch, or liquefying it, which requires temperatures to be lowered to – 260 degrees F. Neither is very practical and would require a whole new auto engine and delivery infrastructure.

Efforts to convert gas into a liquid have concentrated around methanol, which is the simplest alcohol and has been used to power the Indianapolis 500 racing cars since the 1960s. But methanol is the deadly “wood alcohol” of the Prohibition Era and raises fears about poisoning – although gasoline is poisonous, too. The Environmental Protection Agency has never certified methanol for use in auto engines, although an M85 standard has been permitted in California.

Synthesizing gasoline through Siluria’s ethylene-based pathway could solve all these problems. Ed Dineen, CEO of Siluria, says that the gasoline product could sell at half the price of today’s gasoline. With more natural gas being found all the time – and with $1 billion being flared off uselessly around the world each year – any success in turning natural gas into a readily accessible automobile fuel could have a revolutionary impact on our entire economy.

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