German biogas supply plant builder Streicher Anlagenbau GmbH & Co. KG has installed two Atlas Copco GG 90 compressors with variable-speed drive (VSD) at a plant in Geislingen.
The two units, which have been especially designed for the biogas market, are used to compress the gas to 14 bar for distribution into the medium-pressure network of the local energy supply network.
Treatment plants clean the raw biogas that comes from a producer’s plant and prepare it for delivery to energy suppliers. Processed gas must meet strict regulatory requirements before it is permitted to be fed into the natural gas grid. To do so, adjustments are made to the wobe index value and the pressure, which must be increased from about 1 bar.
Equipment for gas compression must meet more stringent safety requirements than conventional compressors, such as those used for gas-tight and compliance with ATEX Zone 1 and Zone 2 guidelines.
Energy suppliers generally demand an availability rate of 97% from the plant manufacturer as the biomethane production cannot be stopped.
“To achieve and maintain this extremely high figure, all biogas supply plants are built with total redundancy,” said Thomas Kunze, project manager at Streicher Anlagenbau.
To do so, compressors, heaters, gas tanks, pressure regulator fittings, and measuring systems, among other things, are duplicated so that the failure of a system does not disrupt supply.
There are two speed-regulated GG compressors at the plant, each capable of compressing 500 standard cubic meters of gas per hour. The GG gas compressors feature a single-stage compression process and are water-cooled, speed-regulated and directly driven. This means that they also operate in a very energy-efficient manner.
This is the second plant that Streicher has equipped with Atlas Copco gas compressors since September 2013.