The client is Stockholm Vatten AB (a municipal water, waste water and waste management company), which operates one of the world's largest underground waste water treatment plants in Henriksdal. The facility is located on the edge of the capital city and is used to treat waste water from about one million inhabitants. The company extracts biogas from the sewage sludge and this will now be purified using the PSA process and upgraded to natural gas quality. This leading method of gas upgrading is characterised by low power consumption, efficient heat extraction and a high methane yield.
The plant has a capacity to upgrade 3,000 m³/h of raw biogas. The gas that is produced has a methane content of 97 percent after purification and is used as biofuel in natural gas vehicles. Once the plant has been completed in early 2016, it will produce about 180 million kilowatt hours of biomethane annually. It will thus cover up to 40 percent of the annual CNG fuel needs of the metropolitan area of Stockholm[1]. And this need is comparatively high, as 60 percent of public buses already use fuel from renewable energy sources (biogas, bioethanol or biodiesel).
The demand for and acceptance of environmentally friendly technologies is high in Sweden: forty percent of newly registered cars are powered by biogas or electricity. By using biofuels in its public transport system, Stockholm saves 130,000 tonnes of environmentally harmful CO2 per year.
The Carbotech plants in Sofielund and Henriksdal will enable almost 17 percent of Sweden's natural gas vehicles to run on climate-neutral fuel in the future.
Schmack Carbotech
Schmack Carbotech GmbH is considered a biogas processing pioneer in Europe, and is one of the leading suppliers of complete systems for biogas supply projects. The pressure swing adsorption (PSA) process developed by Carbotech itself features high quality and low energy consumption. Active in the biogas segment since over 30 years, the company has been a member of the Viessmann Group since January of 2010. Carbotech also offers integrated gas purification and gas production process solutions for nitrogen, hydrogen, landfill gas and synthetic gas.
[1] Source: Statistics Sweden: http://www.scb.se/...