GRASS / HAY PROCESSING

The structure and composition of the substrate used in a biogas plant has a significant influence on the yield of gas.

Substances such as lignin and cellulose cannot be biologically degraded by bacteria of anaerobic digestion. Furthermore, the bacteria cannot come into contact with readily biodegradable organic substances while they are encased in lignin or cellulose.

Our thermo-mechanic grass and hay digestion method (GaH-processing) enables us to increase the bioavailability of persistent organic substances. A twin screw extruder has been developed for the digestion of biomass.

By means of disintegration, the contact surface of the original substance is increased and the bacteria digest the substrates more intensely.

The degree of disintegration is influenced by the opening of the port at the end of the twin screw extruder. The narrower it is, the higher the success rate of the disintegration of the GaH-digestion method becomes.

The image shows that GaH-processing leads to a significantly higher yield of methane from fresh grass silage. The results of the yields of gas are depicted in litres per kilogramme of organic dry substance (l _N / kg ods).

In addition, GaH-processing influences the chronological course of the biogas production.

The substrates digested in the GaH-processing denote a considerably faster increase in the yield of methane; due to the disintegration of the fresh grass silage via twin screw extruder, the curve shows a longer exponential course and, in comparison to the original, a higher yield can be obtained in the same amount of digestion time.

As of the eighth day from a total of 30 test days, fresh grass silage reaches the final value of the original substrate due to the acceleration of decomposition.

GaH-processing enables a better availability of organic matter for the bacteria, since the contact surface of the particles is increased and organic matter is released respectively. This way, during the experiment, it was possible to increase the yield of methane by 26% in comparison to the initial substrate.

Further positive effects of GaH-processing:

Reduction of the agricultural land required for substrate allocation (renewable primary products) for biogas production