Biogas Upgrading Units

Biogas Purification Process

The configuration of the system is determined by the composition and specifications of the feed gas and the quality requirements for the product gas.
Biogas fed from the sludge digester is pre-compressed by a gas blower. Most of the water is removed from the biogas by condensation in the biogas cooler. Carbon columns are commonly used to remove hydrogen sulphide and other pollutants. The gas compressor plant provides the pressure required for the membrane gas separation process. Up to 80% of the heat generated by a compressor can be recovered and used to reduce overall energy costs. The compressed biogas enters the pre-treatment stage of a membrane unit consisting of an auxiliary cooler, a heat exchanger, and a coalescing filter. The feed gas is distributed to the membrane vessels via a manifold. The gas passes through the hollow fibres where rapidly penetrating components such as CO₂ and water penetrate to the outside of the membrane module. The residual stream from the first membrane stage enters the next membrane stage for further separation and then leaves the plant as purified biomethane.