Understanding the Biogas Upgradation Process

As the demand for renewable energy continues to grow, biogas has become an important resource for producing clean, sustainable fuel. But before it can be used effectively, raw biogas must go through a process known as upgradation, where it’s refined into high-quality biomethane. This process removes impurities and increases methane concentration, making the gas suitable for injection into natural gas pipelines, vehicle fuel applications, or on-site energy generation.

What is Biogas?

Biogas is produced through the anaerobic digestion of organic materials such as agricultural waste, wastewater sludge, food scraps, or manure. Raw biogas typically contains:

• Methane (CH₄): ~50–65%
• Carbon dioxide (CO₂): ~35–45%
• Other impurities: small amounts of hydrogen sulfide (H₂S), moisture, nitrogen, and oxygen

While methane is the energy-rich component, the CO₂ and impurities lower the calorific value and limit direct use in many applications. That’s where upgradation comes in.

Why Upgrade Biogas?

The goal of biogas upgradation is to:

• Increase methane concentration to >95%, making it comparable to natural gas
• Remove CO₂, H₂S, water vapor, and other contaminants
• Ensure compliance with safety and quality standards for grid injection or fuel use

By upgrading, raw biogas is transformed into biomethane, a renewable substitute for natural gas with a wide range of applications.

Common Biogas Upgradation Technologies

Several methods are used to refine raw biogas. The choice depends on project scale, gas quality requirements, and cost considerations.

1. Water Scrubbing

• CO₂ and H₂S are absorbed in water under high pressure.
• A widely used, cost-effective option for medium- to large-scale plants.

2. Pressure Swing Adsorption (PSA)

• Uses adsorbent materials to selectively capture CO₂ and impurities under pressure.
• Produces high purity biomethane but requires regular adsorbent regeneration.

3. Chemical Absorption

• Amine or other chemical solutions absorb CO₂.
• Suitable for large volumes and high gas purity but comes with higher operational costs.

4. Membrane Separation

• Semi-permeable membranes separate methane from CO₂ based on molecular size and diffusion.
• Compact and modular, making it a good fit for decentralized projects.

5. Cryogenic Separation

• CO₂ is liquefied and separated by cooling the gas mixture to very low temperatures.
• Enables production of both biomethane and liquefied CO₂ as byproducts.

Applications of Upgraded Biogas (Biomethane)

Once upgraded, biomethane can be used in:

• Pipeline injection – blended with or fully replacing natural gas
• Transportation fuel – as compressed biomethane (Bio-CNG) or liquefied biomethane (Bio-LNG)
• On-site energy generation – combined heat and power (CHP) systems
• Industrial applications – where high-purity methane is required

Atlas Copco Solutions for Biogas Upgradation

A critical part of the upgradation process is reliable and efficient gas compression. At Atlas Copco, we provide advanced compressor technologies designed specifically for biogas and biomethane handling.

One example is our GG-Series oil-lubricated gas screw compressors, engineered for continuous operation in demanding conditions. These compressors are ideal for handling methane-rich gas streams during upgradation and injection processes.

Key features include:

• Wide operating range: designed for pressures up to 500 psig and beyond
• High efficiency: optimized rotor profiles reduce energy consumption
• Robust design: built to handle the variable composition of biogas
• Safety & compliance: engineered to meet international standards for gas handling
• Reliability: continuous-duty operation with low maintenance needs

By integrating Atlas Copco’s GG-Series compressors into biogas facilities, operators can ensure that upgraded biomethane is efficiently compressed for downstream use, whether that’s pipeline injection, storage, or conversion into Bio-CNG/LNG for transportation.

Biogas upgradation is a critical step in transforming waste into a reliable, renewable energy source. By removing impurities and boosting methane concentration, the process ensures biogas can meet the strict standards for modern energy use. With multiple technology pathways available, facilities can select the solution that balances efficiency, cost, and sustainability for their operations.