Press release BoxID: 404833 (sera ProDos GmbH)
  • sera ProDos GmbH
  • sera-Str. 1
  • 34376 Immenhausen
  • Contact person
  • Dipl.-Wirtsch.-Ing.Andreas Schwarzer
  • +49 (5673) 99902

100 % Biogas through optimal dosing technology

Hydrogen sulphide elimination in modern biogas plants

(PresseBox) (Immenhausen, ) Along with photovoltaics and wind energy, biogas has been one of the rapidly growing areas of renewable (energy for some years now.) Biogas plants nowadays constitute state-of-the-art production facilities that become increasingly efficient from year to year.

The biogas sector has been one of the economic growth industries for years and enjoys increasing popularity. More than 4000 plants are already operating in Germany.

The right preparation is the key!

The preparation of the biogas is the central process where the elimination of hydrogen sulphide (H2S) has become a key issue in regard to optimising biogas plants. Corrosion and increased repair and wear on parts of the cogeneration unit (CHP) are the result if the concentration of hydrogen sulphide is too high. The lower the H2S that is achieved, the longer the service life of the cogeneration unit.

However, elimination can only take place in the liquid phase of the fermenter, or subsequently in the gas flow, since H2S is also generated during the methane formation. Fighting the hydrogen sulphide at that point, however, would be detrimental to biogas production.

The substrate determines the H2S content

Biogas plants are very variable and able to utilise a large variety of substrates. The level of hydrogen sulphite concentration in the substrate depends on the starting situation. The type of design of the individual plants always depends on the operating company and the availability of the regional -resources.

Modern dosing technology helps efficiently and effectively

Many different options for reducing hydrogen sulphide content are offered on the market. Apart from the biologic desulphurization via biofilters and bio-washers, the chemical approach via activated carbon is also a successful option. However, effort and costs rarely justify such measures.

Dosing with iron-II-chloride using a compact dosing system is much better. Dosing simply takes place by injecting the iron-II-chloride into the liquid phase of the substrate. The modern and precise dosing pumps permit the exact dosing of the preselected quantities and, in some plants, can also be run by th process control system (PCS) directly via the measured sulphur content.

According to demand and hydrogen sulphide content, more or less dosing through optimal process control takes place. The dosing pumps are installed in a dosing cabinet and they signal diaphragm breakage and leaks in the pressure system directly to the PCS. The pump then stops dosing immediately. The dosing cabinet protects the user from the chemicals at all times.

The pipe assemblies on the suction and pressure sides may consist of hoses and the connection to the iron-II-chloride tank is usually made via suction lance. This permits the simple exchange of the chemistry drums and prevents the suction line from running empty.


Another advantage of the robust sera dosing pumps is the variable use with alternating chemicals. For example, the same pump can be used to meter defoaming agents, enzymes, additives and a variety of acids and lyes.

The optional manual stroke length and frequency adjustment permits further adaptations to the respective application.

Drip pan, back pressure valve and leakage sensors are always part of the standard system and ensure safe and optimal operation.

sera ProDos GmbH

The independent, privately owned company Seybert & Rahier ("sera") has been developing customized product and system solutions in the field of dosing and compressor technology for a wide range of trades and innovative industries for over 65 years. As a leading manufacturer of dosing pumps, dosing units and diaphragm compressors, sera with their national subsidiaries sera ProDos GmbH and sera ComPress GmbH has more than 30 representative offices worldwide, as well as international subsidiaries in the United Kingdom and South Africa.

Objects of sera ProDos GmbH:

- Sales of dosing, handling/conveying and process technology
- Technical support, assembly and commissioning, spare parts
- Service, maintenance and repair service, customer training

Objects of sera ComPress GmbH:

- Sales of compressors, gas and fluid technology
- Technical support, assembly and commissioning, spare parts
- Service, maintenance and repair service, customer training

Robust and durable products of the highest quality, 100% "made in Germany".