Storing CNG in Corncobs

Any news about corn as it relates to alternative fuels is usually reserved for ethanol. It turns out that the abundant cash crop has more to offer in the way of clean-burning energy than simply provid­ing a feedstock for fuel.

Researchers from the University of Missouri-Columbia (MU) and the Midwest Research Institute (MRI) in Kansas City have found a way to use corncobs to store natural gas - and at an all-time high density, no less. With corncob waste as a starting material, the researchers have created carbon briquettes with complex nano-scale pores that can store 180 times their own volume of natural gas at a pressure of 500 psi. Significantly, these corncob-based bri­quettes are the first technology to meet the 180:1 storage-to-volume ratio that the U.S. Department of Energy set as a development goal in 2000. A pickup truck equipped with the corncob-based natural gas storage is currently in regular use by the Kansas City Office of Environmental Quality.

The breakthrough is great news for natural gas-powered transpor­tation. The ability to store more energy per volume means increased driving range without sacrificing interior volume. Furthermore, the relatively low 500 psi storage pressure is the same as that of natural gas pipelines, eliminating the need for compression to the 3600 psi used in today's bulky storage cylinders. The low pressure of this new technology opens the door for flexibility in tank design similar to today's gasoline tanks - a flat, compact shape that could fit under the passenger floor.