Going After The Methane Locked Up In Limestone
Talk about taking the long view: Researchers at the Tokyo Institute of Technology are looking toward the day, perhaps a century from now, when cheap fossil fuels will be depleted. What will industry burn then? If cold fusion doesn't pan out, would you believe limestone?
Not limestone exactly--but methane from it. A team of chemists led by Tadayoshi Sakata is using catalysts to more efficiently coax methane ingredients from calcium carbonate, or limestone, which harbors roughly 99% of all the carbon locked up in the earth. Liberating this carbon is already possible, yet the process requires about as much energy as it produces. Scientists in Australia are also experimenting with better techniques, but Sakata's team believes it has the best one yet: It uses a nickel catalyst to trigger a reaction between hydrogen gas and limestone heated to about 670F. This yields 3 cubic centimeters of methane per hour from each ounce of limestone--and the methane output can be boosted by mixing in small amounts of other carbonates, such as cobalt carbonate.