Enhanced coal bed methane recovery is a method of producing additional coalbed methane from a

source rock In petroleum geology, source rock is rock which has generated hydrocarbons or which could generate hydrocarbons. Source rocks are one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been depo ...

, similar to enhanced oil recovery applied to oil fields.

Carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

(CO₂) injected into a bituminous coal bed would occupy pore space and also adsorb onto the

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

in the coal at approximately twice the rate of

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...

(CH₄), allowing for potential enhanced gas recovery. This technique may be used in conjunction with

carbon capture and storage Carbon capture and storage (CCS) or carbon capture and sequestration is the process of capturing carbon dioxide (CO2) before it enters the atmosphere, transporting it, and storing it (carbon sequestration) for centuries or millennia. Usually th ...

mitigation of global warming Climate change mitigation is action to limit climate change by reducing emissions of greenhouse gases or removing those gases from the atmosphere. The recent rise in global average temperature is mostly caused by emissions from fossil fuels bur ...

where the carbon dioxide that is sequestered is captured from the output of

fossil fuel power plant A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, wh ...

s. A research project at ETH Zurich is studying the process of pumping carbon dioxide into unminable coal seams and recovering the methane that is subsequently displaced. An extensive experimental investigation about the process of desorbing methane by adsorbing carbon dioxide in real coal samples was performed. The proof of principle and the technical feasibility of the method could be verified with these measurements. These research results indicate that CBM can become an alternative to conventional natural gas. ECBM provides additional to CBM the advantage of long-term storage in the underground coal seams. However, without other incentives, enhanced coal bed methane recovery is not economical as the commercial value of the released methane does not completely offset the cost of pumping. Penetration of CO₂ into coal is simulated using a stress-enhanced diffusion model.A. Mikelić and J. Bruining. (2008). Analysis of Model Equations for Stress-Enhanced Diffusion in Coal Layers. Part I: Existence of a Weak solution. ''SIAM J. Math. Anal.'',40:1671-1691

References

{{reflist, 30em Coal technology Energy development Methane

See also

Further reading

References