Hydrates-Based Separation of CH₄/N₂ Gas Using Copper Foam and Chemical Promoters

Area of Science:

• Materials Science and Engineering
• Chemical Engineering
• Energy & Fuels

Background:

• Hydrate-based gas separation (HBGS) is a promising technology for capturing low-concentration coalbed methane (CH4).
• Effective promoters and formation conditions are crucial for enhancing CH4 hydrate formation and separation efficiency.

Purpose of the Study:

• To investigate the formation behavior of CH4 hydrates promoted by 1,3-dioxolane (1,3-DIOX) and porous copper foam (CF).
• To evaluate the efficiency of the CF/1,3-DIOX system for low-concentration coalbed methane enrichment and separation.

Main Methods:

• Systematic investigation of CH4 hydrate formation using 1,3-DIOX as a promoter and CF as a porous medium.
• Experimental analysis under coupled spraying-stirring mode at varying pressures (3.0 and 4.0 MPa).
• Comparison of CH4 enrichment and recovery rates with other promoters (l-leucine, sodium lignosulfonate) and static systems.

Main Results:

• The combined CF (60 PPI) and 5.56 mol % 1,3-DIOX system markedly accelerated hydrate formation, achieving high CH4 storage capacities (0.1733 mol CH4/mol H2O at 3.0 MPa).
• CH4 content was effectively enriched from 5% to 8.0%-10.25% and from 10% to 17.9%-21.7% after single-stage separation.
• Comparable CH4 recovery rates were achieved in a large-scale reactor (3927 mL), demonstrating industrial applicability.

Conclusions:

• The proposed CF/1,3-DIOX system is an effective strategy for enriching low-concentration coalbed methane.
• This system offers a viable technical route for multistage industrial separation processes, improving safety and efficiency.
• The study highlights the potential of HBGS with optimized promoters and reactor configurations for CBM capture.