Biogas is produced when organic material decomposes without oxygen. Raw biogas typically contains methane and carbon dioxide, with moisture and trace impurities such as hydrogen sulphide.
Compressed Biogas (CBG), also called Bio-CNG or renewable natural gas, is biogas that has been cleaned, upgraded, dried and compressed. Upgrading removes a major portion of the carbon dioxide and raises methane concentration, and the gas may be compressed for storage, transport or dispensing, subject to applicable standards.
| Biogas | CBG / Bio-CNG | |
|---|---|---|
| Definition | Raw gas from anaerobic digestion | Cleaned, upgraded, dried, compressed |
| Methane | Lower, variable | Higher after upgrading |
| Storage | Gas holder / balloon | High-pressure cascade |
| Typical use | Cooking, heating, power | Compatible vehicles, industrial fuel |
Nine stages, from receiving feedstock to cascade storage. Select a stage for detail.
By-product stream: digested slurry goes through solid-liquid separation into solid digestate and liquid digestate. Final configuration depends on the selected technology and project requirements.
Suitable organic feedstock is collected, weighed and sorted where required.
Purpose: Records quantity and quality, and keeps contaminants out of the process.
Typical equipment: Weighing and batching system, receiving area, sorting arrangement
Depending on the feedstock and technology, material may be shredded, screened, mixed, pre-hydrolysed or made into slurry.
Purpose: Gives the digester a consistent, digestible feed.
Typical equipment: Shredding / chopping equipment, screens, mixing and slurry tanks
Microorganisms break down organic matter without oxygen, producing raw biogas and digested slurry. Stable running depends on loading rate, retention time, temperature, pH, mixing and nutrient balance.
Purpose: Converts organic material into biogas.
Typical equipment: Digester, mixing system, temperature, pH, pressure and level monitoring
Raw biogas is collected and stored in a gas holder or balloon-type system.
Purpose: Balances variations between gas production and downstream demand.
Typical equipment: Gas holder, flame arrestor, pressure-relief provisions
Hydrogen sulphide and moisture are managed before upgrading, using biological, chemical or adsorption-based methods depending on design.
Purpose: Protects equipment from corrosion and supports fuel-quality compliance.
Typical equipment: H₂S removal unit, gas analysers
Carbon dioxide and other unwanted constituents are removed to raise the methane share. Approaches include water scrubbing, chemical scrubbing, pressure swing adsorption and membrane separation.
Purpose: Increases methane concentration; technology choice depends on capacity, power, water and required gas quality.
Typical equipment: Upgrading skid, gas flow and composition monitoring
Upgraded gas is dried to reduce moisture content.
Purpose: Protects compressors, cylinders and dispensing systems.
Typical equipment: Gas dryer, moisture monitoring
Dried gas is compressed to the pressure needed for storage and distribution.
Purpose: Raises pressure for storage; capacity must match production and offtake.
Typical equipment: Compressor, pressure monitoring, safety and shutdown provisions
Compressed gas is held in high-pressure cascade cylinders before dispensing or distribution to compatible vehicles, industrial users or captive use.
Purpose: Stores CBG ahead of offtake.
Typical equipment: Cascade storage, dispensing / offtake system
Receiving and buffer storage for seasonal supply.
Digestion, mixing and temperature control.
Raw biogas buffer between production and demand.
H₂S removal and CO₂ upgrading equipment.
Compressors sized to expected production.
High-pressure cylinder storage ahead of offtake.
Water, power, compressed air, drainage and fire-fighting utilities.
Monitoring, alarms, relief systems, gas detectors, emergency shutdown.
Results depend on the project, so we explain the factors rather than promise figures. Stable operation rests on consistent feedstock, disciplined process control and well-maintained equipment.
Share your feedstock details, proposed location and target capacity for a technical discussion.