Which gas is adsorbed onto coal surfaces?

Which gas is adsorbed onto coal surfaces?

• A. Coal Bed Methane
• B. Natural Gas
• C. Hydrogen
• D. Gas Hydrates

Answer: (A)

Gas stored as an adsorbed phase on coal surfaces is methane within coal beds, and this is what Coal Bed Methane refers to. In a coal seam, methane is held tightly to the internal surfaces and microscopic pores of the coal by adsorption. This adsorbed methane remains there under high pressure and is released as pressure is lowered (for example, by pumping out water), allowing the gas to flow to the surface. This description specifically matches methane bound to coal surfaces, which is why the correct label is Coal Bed Methane. Natural gas is simply the gas phase mixture that exists in reservoirs, not necessarily tied up adsorbed on coal surfaces. Hydrogen can be stored by adsorption on various materials but isn’t the typical association with coal beds. Gas hydrates are a crystalline, solid form where methane is trapped within a water lattice, not adsorbed on coal surfaces.

Gas stored as an adsorbed phase on coal surfaces is methane within coal beds, and this is what Coal Bed Methane refers to. In a coal seam, methane is held tightly to the internal surfaces and microscopic pores of the coal by adsorption. This adsorbed methane remains there under high pressure and is released as pressure is lowered (for example, by pumping out water), allowing the gas to flow to the surface. This description specifically matches methane bound to coal surfaces, which is why the correct label is Coal Bed Methane.

Natural gas is simply the gas phase mixture that exists in reservoirs, not necessarily tied up adsorbed on coal surfaces. Hydrogen can be stored by adsorption on various materials but isn’t the typical association with coal beds. Gas hydrates are a crystalline, solid form where methane is trapped within a water lattice, not adsorbed on coal surfaces.