Technological process description
Technological process description
Thanks to the technological process control and protection system (CPS) the biogas plant (BGP) works and is operated automatically.
The operating personnel controls the BGP by means of a computer and visually.
Any possible deviations from the norm or failures in the operation of the BGP are automatically transmitted to the operator's mobile phone. The operator corrects the deviations in compliance with the operator's manual.
Filling of the receiving tank
Fermentation residues together with the technical water are conveyed into the receiving tank by means of an automatic unit. Then, manure, corn silage and other coferments are added with a front loader or similar machines. Solid substrates are added every day. Their amount is weighed and registered.
Filling of the hydrolysis
The hydrolysis is filled 1-2 times a day. The material in the hydrolysis is a well-intermixed mixture of substrates that has acquired the temperature of liquid manure. The feeding and further conveying into the fermenter is performed with the CPS. Thanks to the hydrolysis, the microbiological process in the BGP is carried out in two stages. Volatile organic fatty acids, in particular the acetic acid, are formed here during approximately one day. The oxidating bacteria are very strong, active and rich in energy, the oxidation process thus going very quickly. The conditions for the oxidating bacteria in the hydrolysis are more favourable than in the fermenter.
As a result of this process we have the following advantages:
- increased energy output;
- stable biogas production;
- better use of the fermenter capacity;
- better processing of substrates;
- decreased floating layers;
- no foam formation in the fermenter;
- possibility to change substrates, "digestion" of substrates with harmful substances without any influence on the stability of biogas production. The last advantage is especially important, as nobody can guarantee continuous availability and formula of substrates for several years to come.
The automatic control and protection system (CPS) for the technological process is also a very important part of our offer, as when controlled manually, the biogas plant and its componentes cannot work in an optimal way.
Fermenter
From the hydrolysis the prewarmed and pre-oxidated hydrolysate is pumped into the fermenter by means of an automatic unit in small batches about 20 times a day. The methane bacteria thus regularly receive "pre-digested" food and can start the methane formation process. The fermentation period takes about 35 days.
After-digester
In the after-digester the remaining 10-15% of methane is worked out. Simultaneously the after-digester serves as a container for preliminary storage. The fermentation residues that are conveyed into the lagoon contain less than 4% of methate after it.
Biogas
The biogas which is formed in the fermenter and the after-digestor is collected in the gas holder under the roof.
The biogas level and pressure are controlled in the CPS, and these data are transmitted to the CHP to control the input data for biogas.
The biogas flows from the gas holder in the fermenter into the gas holder in the after-digester and from there via an underground pipeline through a filter into the CHP.
Filter for hydrogen sulphide removal
Unlike many other producers, we prefer biogas cleaning through an activated carbon filter und by doing so we achieve almost complete removal of H2S (hydrogen sulphide) from the biogas (10 ppm), thus, creating a partial load moad for the CHP.
Biogas pressure is continously monitored and serves as the major parameter for the torch.
CHP unit
CHP units are equipped with their own control system and are connected to the CPS of the biogas plant. Based on the biogas amount and pressure, as well as the hydrogen sulphide ultimate level data, the maximum power of the CHP is set. The CHP control system transmits the major operating parameters to the CPS of the BGP. The CHP is started by the personnel via the control cabinet and from then on the CHP's operation is automatically regulated. After all the process values and parameters have been set, the automation system reacts to any deviation directly.