Evaluating Regeneration Options of Solid Amine Sorbent for CO₂ Removal

Area of Science:

• Energy Science
• Chemical Engineering
• Environmental Science

Background:

• Biogas is a key renewable energy source, but requires purification to remove impurities like carbon dioxide (CO2) and hydrogen sulfide (H2S).
• Supported amine sorbents (SAS) are promising for CO2 capture, yet their regeneration processes are not well understood.
• Efficient sorbent regeneration is critical for the economic viability of biogas upgrading.

Purpose of the Study:

• To experimentally and theoretically evaluate regeneration methods for supported amine sorbents (SAS) used in biogas upgrading.
• To determine the energy efficiency and operational parameters for SAS regeneration.
• To assess the trade-offs between energy consumption, heat demand, and sorbent inventory for a biogas case study.

Main Methods:

• Experimental investigation of SAS regeneration under various conditions.
• Thermodynamic modeling to identify energy-efficient regeneration strategies, including pressure swing adsorption (PSA).
• Energy analysis and case study evaluation for a typical biogas upgrading scenario.

Main Results:

• Pressure swing adsorption without purge flow is theoretically the most energy-efficient regeneration method (1.7 MJ/kg CO2).
• Desorption rates are significantly influenced by gas-phase equilibrium when using a purge flow.
• Elevated temperatures (>80 °C) substantially increase both working capacity and productivity of the sorbent.
• Using air as a purge gas at 60 °C presents an attractive option, despite slightly higher power consumption, pending cost analysis.

Conclusions:

• SAS regeneration is feasible and can be optimized through careful selection of methods and operating conditions.
• Energy-efficient regeneration is achievable, with PSA offering theoretical advantages.
• Temperature and purge gas selection (e.g., air) are critical factors influencing the performance and economics of SAS-based biogas upgrading.