Carbotech Pressure Swing Adsorption (PSA) Gas Upgrading Systems

Biogas can be combusted in a combined heat and power unit (CHP) to produce heat and electricity, or upgraded to renewable natural gas (RNG). RNG can then be used as clean vehicle fuel in the form of compressed natural gas and liquified natural gas or injected into the natural gas pipeline.


Today, legislation, tax credits, and energy demands are all playing a critical role in the rise of economical RNG projects.


BIOFerm offers complete, turnkey gas upgrading systems and gas-to-grid injection units as North America’s exclusive provider of Carbotech Pressure Swing Adsorption (PSA) plants. Our gas upgrading plants utilize PSA technology to scrub raw biogas—from AD systems, landfills, municipalities, wastewater treatment plants, agricultural operations, etc—to create a high-value RNG product .


Over 900 of our Carbotech PSA systems have been installed to-date, including CNG and natural gas pipeline injection projects.

Our pre-manufactured, pre-tested, and pre-assembled PSA systems upgrade biogas in an environmentally-conscious manner and typically result in a methane recovery rate of >99%. Onsite installation costs are often also minimized due to the skid-ready nature.


Key Features

Key Attributes

Unique in the biogas industry is our ability to provide modular, all-inclusive gas upgrading solutions that include all the necessary upgrading components, such as:

  • Compressor

  • Thermal oxidizer

  • Chiller

  • Booster blower

  • Industry-standard control system over all equipment

  • Complete system performance guarantee

  • Capable of meeting stringent pipeline requirements

  • Removes oxygen from the gas

  • Capable of handling high-nitrogen gas

  • In-house volatile organic compound (VOC) removal technology

  • High methane yield and no increased methane losses over time

  • Low operating costs and system efficiency

  • Modular approach

  • Technology emphasis on high processing efficiency

PSA Process

Carbotech PSA gas upgrading is a dry process operating with no water, wastewater or chemical products. It includes the following steps:

  1. Raw biogas is compressed

  2. Condensed water vapor is removed through a cooling system

  3. Trace components removed with activated carbon

  4. Conditioned biogas is channeled through the PSA adsorbers which are filled with carbon molecular sieves designed for adsorption

  5. CO2, H2O, H2S, NH3, siloxanes, odors and parts of O2 and N2 are removed by adsorption

  6. RNG is produced

  7. RNG is injected into the grid, or further upgraded to CNG

Technology Comparison

Compared to typical chemical and water scrubber systems and membrane technology, the PSA technology has: no process water/process water conditioning; no waste water/waste water treatment; no chemicals; and no off gas with toxic contaminants.