Product Description

GraniteFuel’s CO2 / CH4 Separation

Biogas upgrading involves passing the gas through a CO2/CH4 separation system to filter out the carbon dioxide, leaving very pure biomethane. The high-grade biomethane generated is suitable for pipeline injection, RNG (renewable natural gas) or CNG (compressed natural gas). In the skid, the biogas passes through specialized membranes, which separate the carbon dioxide and methane to ensure the end product meets the required specifications. By choosing membranes with high selectivity rates, we are able to achieve an impressive 99.5% methane retrieval efficiency.

Membrane separation is a key stage in biogas upgrading, and if the membranes become clogged with contaminants, methane retrieval efficiency is greatly reduced. To prevent this, the first step is to remove unwanted particulates and gas constituents with a system of filters, heat exchangers, adsorption and other treatment technologies. The next step is to channel the biogas through the membrane. Due to the high selectivity of the membrane, and the differences in molecule size, some gasses will pass through much faster than others. In this case, the smaller CO2 molecules pass through much more quickly than the CH4 molecules—the gas that has passed through the membrane is called the permeate. The first stage permeate is almost all CO2 and is discharged or processed further. The remaining gas (the retentate), is channeled through a second set of membranes—retentate at this stage is very pure biomethane and is suitable for pipeline injection or for use as CNG. The permeate is recycled to increase the methane recovery rate of the system.

At GraniteFuel, our CO2/CH4 separation systems are designed and manufactured to meet your requirements. We offer precise cooling, measuring and monitoring to ensure your biomethane is compliant with the required specifications for CNG or injection into the gas grid. Our biogas upgrading systems are designed and adapted to suit their intended environment and any other systems with which they may be integrated. Depending on your needs, GraniteFuel systems can be built in an open frame or enclosed and fitted with specialized cladding to meet your climate control requirements.

Contact the GraniteFuel team today or explore our other solutions to find out more about how we help with issues like H2S and siloxane removal, chilling and dehydration and fuel blending. To help you meet strict sustainability standards, we also offer integrated emissions control solutions.

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