From organic waste to energy source: the biogas journey

STEP 1: Feeding the biogas upgrading process

During this step, the ZM oil-free multistage centrifugal blower elevates the relatively low pressure of the raw biogas coming from the anaerobic digester to approximately 15 to 20 psig.

STEP 2: H₂S removal

During this step, the raw biogas is run through a bed of activated carbon which removes a large part of the H₂S and VOCs from the raw biogas. H₂S levels are reduced from approximately 1,000 ppm to less than 100 ppm.

STEP 3: Pressurizing the biogas for upgrading

After the H₂S and VOC’s removal, the raw biogas is compressed in the GG gas screw compressor. Compression is up to 240 psig which is the required pressure for the next step in the biogas upgrading process.

STEP 4: Biogas upgrading – CO₂ removal

To upgrade the raw biogas to renewable natural gas (biomethane), the CO₂ needs to be removed from the raw biogas. This happens through membranes containing specifically designed fibers which separate the CO₂ from the remaining methane in the raw biogas.

STEP 5: CO₂ compression

Finally, the removed CO₂ is compressed using a high pressure CO₂ compressor.