Bio-methane from an-aerobic digestion using activated carbon adsorption

Area of Science:

• Chemical Engineering
• Environmental Science
• Renewable Energy

Background:

• Global demand for carbon-neutral biomethane from anaerobic digestion (AD) is rising for national gas grids.
• Biogas, rich in methane, requires physical upgrading to biomethane due to impurities like CO2 and H2S.
• Current water washing methods for biogas upgrading face industrial scale-up challenges due to high water consumption.

Purpose of the Study:

• To compare the scale-up economics of water washing versus activated carbon adsorption for biogas upgrading.
• To evaluate the feasibility of activated carbon adsorption as a sustainable alternative to water washing for biomethane production.

Main Methods:

• Process simulation using HYSYS and Aspen Process Economic Analyzer.
• Economic analysis of water washing and activated carbon adsorption technologies at different plant capacities.
• Comparison of capital and operating costs, and water usage for both methods.

Main Results:

• Water scrubbing was more cost-effective for smaller plants (<500 m³/h).
• For larger plants (1000 m³/hr), activated carbon adsorption offered lower treatment costs (0.9 p/kWh) compared to water scrubbing (1.5 p/kWh).
• Activated carbon adsorption demonstrated advantages in lower capital and operating costs, with negligible water losses.

Conclusions:

• Activated carbon adsorption is a promising technology for cost-effective and sustainable biomethane production at industrial scales.
• Both methods require governmental subsidies to be economically competitive with fossil natural gas.
• The study highlights the potential of activated carbon adsorption to significantly boost sustainable biomethane production.