Atlas Copco screw compressors supply reliable, energy-efficient compression to biogas supply plant
Wilrijk, Belgium, April 2014. Streicher Anlagenbau GmbH & Co. KG, one of the largest constructors of biogas supply plants in Germany, has installed two Atlas Copco GG 90 compressors with variable speed drive (VSD) at a plant in Geislingen.
The two compressors, which have been specially 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 net.
Streicher Anlagenbau constructs biogas treatment and supply plants, among other facilities. Biogas treatment plants clean the raw biogas that comes from a producer's biogas plant and prepare the gas to be passed on to energy suppliers. Supply plants condition the biogas to be fed into the local gas network. The processed gas must meet strict regulatory requirements before it is permitted to be fed into the natural gas grid. To do so, adjustments need to be made to the wobe index value and especially the pressure. "We receive the treated biogas at a pressure of around one bar," explains Thomas Kunze, Project Manager at Streicher Anlagenbau. "However, we have to supply it at a pressure of 10 to 14 bar."
To bring the gas up to this higher
pressure, Atlas Copco GG 90 VSD gas screw compressors are used in the supply
plant. Atlas Copco entered the biogas market several years ago and has
developed machines especially suited to this industry. The GG VSD series, is one example of these specially developed
Equipment for gas compression must
meet more stringent safety requirements than conventional compressors, such as
being gas-tight and compliance with ATEX Zone 1 & 2. Furthermore, gas
production continuously varies. The gas compressor therefore must continuously
adjust to this changing inlet conditions yet keeping constant delivery
pressure. This is achieved with variable speed compression.
"The GG can take in gas at a pressure of 1.1 to
1.4 bar(a) and compress it up to a pressure of 16 bar(a). " explains Robert Liebl, biogas expert at Atlas Copco. "The GGs also operate reliably because the
oil-lubricated screw element is very similar to its counterpart in the GA
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,"
clarifies Thomas Kunze. 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.
For this purpose, there are two
speed-regulated GG compressors at the plant in Geislingen, each of which is
capable of compressing 500 standard cubic meters of gas per hour. The
compressors adapt to conditions by means
of suction pressure control. "The expertise is in the control
system," stresses Thomas Kunze. "All the components must be
precisely attuned to each other."
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
This is the 2nd plant
that Streicher has equipped with Atlas Copco gas compressors since September
2013. "We have had very good experiences with the GGs to date,"
says Kunze. "The machines are simply constructed, operate absolutely
reliably and, therefore, guarantee the high level of availability that we
need." Ultimately, the plants are intended to supply gas for at least
is a world-leading provider of sustainable productivity solutions. The Group serves customers with innovative compressors, vacuum solutions and air treatment systems, construction and mining equipment, power tools and assembly systems. Atlas Copco develops products and service focused on productivity, energy efficiency, safety and ergonomics. The company was founded in 1873, is based in Stockholm, Sweden, and has a global reach spanning more than 180 countries. In 2013, Atlas Copco had revenues of BSEK 84 (BEUR 9.7) and more than 40 000 employees.
Atlas Copco’s Compressor Technique business area
provides industrial compressors, vacuum solutions, gas and process compressors and expanders, air and gas treatment equipment and air management systems. The business area has a global service network and innovates for sustainable productivity in the manufacturing, oil and gas, and process industries. Principal product development and manufacturing units are located in Belgium, Germany, the United States, China and India