Biogas Plants Made from Stainless Steel

Biogas plants by WELtec BioPower® are made from stainless steel. The biogas forming in the fermenter contains amounts of hydrogen sulfide and ammonia. These aggressive chemicals attack unprotected components. That’s why we use: Stainless steel V2A (1.4301/AISI 304) in the area of the fluid level Stainless steel V4A (1.4571/AISI 316Ti) in the area of gas That ensures the quality and guarantees a long service life of the entire system. Even after 20 years of operation, stainless steel still maintains a very high value.

Control system

Several individual factors determine the optimal operation of a biogas plant. To ensure that these factors are optimally matched with each other WELtec BioPower® has equipped the plants with a central control system that controls and manages all processes. Smaller plants require a relatively simple system that will reliably control all major factors. More comprehensive plant types require normally a more sophisticated control system. We therefore individually match our control systems depending on the individual requirements of the required plant.

Denitrification-Nitrification

Denitrification is a process where the nitrogen bonded in the nitrate is transformed into molecular nitrogen by bacteria. As a result, the nitrogen is no longer usable as a source of nutrients for plants. It has no impact anymore as a fertilizer and thus is no longer environmentally relevant. Denitrification takes place in a sequential batch reactor (SBR). The SBR is a specially designed stainless steel vessel that is mounted on a concrete foundation. Oxygen is supplied by venturi nozzles which take air in via piping above the filling level and blow it in at ground level of the SBR. Adjustable submersible motor-driven agitators ensure optimum mixing of the substrate and activated sludge during the reaction phases. The submersible motor-driven agitators can be adjusted in terms of direction and height by using a cable pull in order to ensure the optimum mixing. Internal heating pipes, which provide the right temperature in the SBR, are located in the bottom part of the tank. These may be utilised for heating and cooling. Substrate is supplied and sludge is removed via the piping. In the middle of the SBR there is a frame, which accommodates the feed hopper for clear water and the nine nozzles for suppressing the formation of foam. The formation of foam is suppressed by pumping the contents of the SBR through the nozzles and spraying onto the surface. A measuring section is installed outside of the SBR for monitoring such parameters as temperature, oxygen content and pH value.

Fermenter on the inside

A reliable system is the result of optimally and finely tuned technologies: The substances used have to be comminuted, mixed together and heated, the gas obtained is further processed and harnessed efficiently. That’s why WELtec BioPower only utilises plant components that have proven themselves in use and develops the majority of the technologies independently.

Long arm agitator

The task of a long arm agitator is to mix the substrate evenly and carefully. At approx. 40 rpm it creates a fl ow and motion in the vessel and ensures that the gas creating bacteria will have continuous and optimal conditions. The electric excitation is done by a frequency inverter, which depending on the fed subs trate can be adjusted stepless and adequately in accordance with the individual mixing requirements. The motor and bearing support is located outside the fermenter and is guided at an angle trough a gas-tight wall opening into the vessel.

Perfect Solutions for Waste and Disposal Engineering

Biogas plants by WELtec are not only renewable resource plants: In the area of waste and disposal engineering, WELtec BioPower realises optimum solutions in order to dispose of substrates that are subject to the EC hygiene regulations. For instance, a biogas plant by WELtec BioPower offers individual sanitation solutions that can be adapted to the respective requirements and which satisfy the statutory guidelines. Measurement Technology Offers Security The sanitation is necessary for substrates which should not be disposed of agriculturally without treatment in accordance with EC hygiene regulations. The sanitation process begins if the necessary minimum temperature of 70° is attained with the closure of the sanitation tank. Only after the prescribed time expires does the drain valve open and the pasteurised substrate is transported to the sanitized area via separate pumps. The entire process is documented by the control system such that there are verifiable values regarding temperature and duration of sanitation available at any time. To this end, all measured values concerning the temperature profile and the period of sanitation are outputted and stored in a database. The temperature profile is recorded in a set frequency and may be presented as a graph at any time. By documenting the minimum and maximum values, it is possible to ensure that the preset temperature is not undershoot or surpassed.

Submersible agitators

In addition to the long arm agitators we also use submersible agitators. These agitators ensure a fast and targeted mixing of fl oating and sedimenting substrates and are used to maintain a minimum crust formation in the digester, and to break up larger problematic crust formations in the