RotaCut: Running a biogas plant efficiently and reliably
Case study - Biogas plant Hofmann


Thick floating layers and clogging in the external heater


Vogelsang RotaCut® with AutomaticCutControl (ACC®)

The customer and the problem

We run our 360 kW plant as a dry digestion plant with wet fermentation. We use renewable raw materials, nearly 50% mainly chopped grass and corn silage and a little solid manure.
This is fed in dry via a vertical mixer. The digester is heated by an external heat exchanger.

Due to the material we were using, the heat exchanger kept clogging up. In addition to this, thick floating layers would form as soon as the mixers failed. Therefore, we decided to use a macerator.

Although the macarators which we tested at first reduced the problems, the retensioning system was awkward. After only a short running time, the blades were no longer fully in line with the cutting screen which meant that the device could not cut and began to clog up.

The solution

The ACC (AutomaticCutControl) of the RotaCut offers a key advantage: the blades are readjusted automatically, so maceration is continuous and manual realignment is not required.

In addition the suspension in the digester and the brewing residues are completely homogenous. Even if the mixers fail, the mass now remains homogenous and does not immediately begin to unmix. This result was not achievable by any other service provider we went to with our mixer problems. In all other cases, there was noticeable unmixing after a very short time. With the RotaCut, the plant simply runs better.