Siluria’s discovery system was invented by MIT bioengineer Angela Belcher, who developed it further in a startup called Cambrios Technologies, which she cofounded. The system was then spun out into Siluria in 2008, when Cambrios focused in on commercializing a transparent electrode for solar cells and other electronic devices. Tkachenko says 95 percent of Siluria’s effort is now devoted to the methane-to-ethylene process.
The company came out of stealth mode this summer because it had identified a novel nanowire catalyst that it believes could be commercially viable. Erik Scher, Siluria’s vice president for R&D, says that Siluria’s nanowire catalyst can activate methane at “a couple of hundred degrees” cooler than the best existing catalysts, which he says operate between 800 °C and 950 °C.
Relatively mild conditions should deliver two benefits, he says. Not only should they keep the methane from burning up, they also mean that the resulting methyl radicals are more likely to stay on the surface of the nanowire in the company of other methyl radicals, which can then react with each other to form ethylene rather than flying off the nanowire to engage in other reactions–including ones that degrade the precious ethylene product.
Tkachenko says the catalyst, if applied widely to ethylene production, could cut costs to the chemical industry by tens of billions of dollars annually and reduce global carbon-dioxide emissions by over 100 million tons per year. The company hopes to use its anticipated financing to move into the pilot process next year. Validation with a lab scale reactor running continuously for thousands of hours would then lead to commercial demonstration plants, hopefully in less than five years–an aggressive pace for a major chemical process.
Experts such as Musgrave say there are plenty of potential pitfalls. Even if Siluria’s catalyst selectively converts methane to ethylene at high yield, he says, it may fail to generate ethylene fast enough to make the process commercially viable. “They might have solved the selectivity problem, but might end up sacrificing the turnover,” says Musgrave.
Roy Periana, director of the Scripps Research Institute’s Energy and Materials Laboratories in Juniper, Florida, and the chemist who led Catalytica’s methane activation effort, says throughput is critical to pay for the multibillion dollar cost of a chemical plant. And the impact has to be “revolutionary,” says Periana. “They’re not about to get rid of their billion dollar plant for a 5 to 10 percent improvement,” he says.