A process and related technology that research at the US Department of Energy's National Energy Technology Laboratory (NETL) helped to develop could enhance the use of natural gas and the world's vast methane hydrate resources, DOE's Fossil Energy Office announced. FEO said the method for rapidly forming methane hydrates, along with concurrent development of specialized nozzles to facilitate the process, are breakthroughs that could lead to significant reductions in gas storage and transportation costs.
Although gas provides about 25% of total US and global energy consumption, about one third of the world's gas resources are stranded—in remote places where transportation costs are too high to enable their use, according to DOE. Energy-rich but potentially unstable methane hydrate is present in many high-pressure, low-temperature ocean environments and in Arctic permafrost, it added.
FEO noted that gas hydrates retain large amounts of methane: 1 cu m of solid hydrate can produce 164 cu m of methane. Estimates indicate that hydrate deposits contain more organic carbon in the form of methane than all the world's fossil fuel reservoirs combined, it said.
Stranded gas is conventionally refrigerated and compressed to reduce its volume for transport either as compressed natural gas or LNG, DOE said. This increases costs for the end user, is not particularly energy-efficient, and can lead to some of the gas being lost to being lost through vaporization, particularly as LNG, it said.
NETL researchers have found a way to rapidly and continuously form synthetic gas hydrates with just water and methane, using much less pressure and cooling than is required to liquefy it, DOE said on Aug. 25. "Until now, methane hydrates were formed in a batch process that required hours or even days; NETL's process eliminates the long mixing time associated with the batch process and forms hydrates within minutes," it said. "These synthetic hydrates could represent a more energy efficient way to reduce the volume of natural gas so that it can be stored and transported."
NETL's patent-pending nozzle technologies that increased atomization and produced the exact mix of water and methane to economically form the synthetic hydrates enhanced the experiments, according to DOE. The researchers designed, machined, and assembled a variety of nozzles until selecting one that performed optimally, resulting in the near instantaneous and continuous formation of a snow-like synthetic hydrate, it said.
"With this technology, future operators will have an alternative method for the storage and transport of natural gas," DOE said. "While not as energy dense as LNG or CNG, production of methane hydrate using this method will require less refrigeration, less pressure, and less time than either LNG or CNG production."
More Oil & Gas Journal Current Issue Articles
More Oil & Gas Journal Archives Issue Articles
View Oil and Gas Articles on PennEnergy.com