What is "hydromethanation"

Hydromethanation, [hahy-droh- meth-uh-ney-shuhn] is the process by which methane (the main constituent of natural gas) is produced through the combination of steam, carbonaceous solids and a catalyst in a fluidized bed reactor. The process, developed over the past 60 years by multiple research groups, enables the highly efficient conversion of coal, petroleum coke and biomass (e.g. switchgrass or wood waste) into clean, pipeline quality methane.