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Most coalbed methane (CBM) reservoirs contain moisture that can have an impact on adsorption and diffusion of CBM, so moisture content is an important factor that affects CBM production. CO2 can be used to improve CBM production on site. Combined with these two points, regulations of CH4 adsorption and diffusion are sought under different conditions when CO2 is injected into coal seams with moisture. Slit pores with different moisture contents (1%, 2%, 4%, and 6%) and random models are established. Molecular simulations are carried out, respectively, from 0 MPa to 10 MPa at 293.15, 303.15, and 313.15 K. Relative to CO2, the interaction of CH4 and −C–C– is weaker, indicating that CO2 can adsorb more steadily on the surface of coal. Water molecules preferentially adsorb on the oxygen functional groups, and then water molecules adsorb each other with hydrogen bonding to form clusters that can interfere with the adsorption and diffusion of CO2 and CH4. Because of the influence of functional groups, hydrogen bonding, and micropore filling, the adsorption capacity of H2O can increase steeply at very low pressure. The phenomenon is not beneficial to the CBM exploitation.

With a microwave-regime cyclic three-state configuration, an enantiomer-selective state transfer (ESST) is carried out through the two-path interference between a direct one-photon coupling and an effective two-photon coupling. The π-phase difference in the one-photon process between two enantiomers makes the interference constructive for one enantiomer but destructive for the other. Therefore only one enantiomer is excited into a higher rotational state while the other remains in the ground state. The scheme is of flexibility in the pulse waveforms and the time order of two paths. We simulate the scheme in a sample of cyclohexylmethanol (C7H14O) molecules. Simulative results show the robust and high-fidelity ESST can be obtained when experimental concerns are considered. Finally, we propose to employ the finished ESST in implementing enantio-separation and determining enantiomeric excess.

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We present a comprehensive overview of the influence of water on coalbed methane production. The influence of water on coalbed methane production is associated with adsorption of water in pores, capillary condensation, micropore filling, adsorption hysteresis and its effect on methane diffusivity, coal swelling due to adsorption of water and a corresponding change in methane permeability, pore saturation by water (water imbibition into pores), and gas-water two-phase flow in the cleats. We consider methods for reducing the negative impact of water on coalbed methane production: carbon dioxide injection and microwave technology. We identify promising areas of study.

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