We are witnessing the rapid growth in the number of plants producing biogas energy derived from anaerobic digestion which occurs in the treatment of organic matter and biomass. The target set by the European Biogas Association (EBA) for the year 2020 is that 20% of total energy consumption be renewable energy.

Fluiten has developed technically advanced and economical solutions for new applications in the digester sector, i.e. the production of methane obtained from organic waste. Each solution is designed according to the specific needs of clients.

Anaerobic digestion is a biologic process in which, in the absence of oxygen, organic substances are transformed into biogas (methane and carbon dioxide). The transformation occurs at temperatures of between 20 and 70 degrees inside large tanks. The most common plants use continuous digesters which are equipped with blades mounted onto a shaft to mix the product and to improve the digestive reaction. As the shaft is usually of considerable length, there are large axial and radial movements for which the mechanical seal must compensate to avoid leakage.

The product loaded into the tank is a fluid with suspended solids which may vary in concentration from 5 to 20% depending on the plant. The process fluid tends to crystallise and accumulate when in contact with the atmosphere and may cause: leakage of unpleasant odours, dispersion of organic pollutants in the environment such as salmonella bacteria, nitrogen compounds and acids in addition to the biogas spill with subsequent loss of productive capacity.

The technical solution developed in Fluiten includes:

• Clean profile that prevents any deposits that solidify and block the seal rings
• Lip to prevent possible leakages
• Connections for washing with water
• Roller or ball bearings to minimise shaft run-out.

In the GTA model, customised for each plant, great care is taken to ensure that the stationary seal has no fissures. The clean product-side profile prevents the formation of solid deposits in the inaccessible parts of the machine, deposits that would compromise the correct functioning of the mechanical seal. The innovative positioning system facilitates the installation of even large shafts. The mechanical seal is fitted with a drive system which allows for shaft enlargement, while maintaining the position of the sealing rings.

The winning synergy of all components and materials has enabled us to provide our customers with a highly performing and durable product, essential to limit plant downtimes which would interrupt the fermentation process.