Estimating the nutrient degradation in biogas-batch processes

By introducing the renewable energy law (EEG) in 2000 energy production out of energy crops increased significantly in Germany. Contrary to the increasing importance of biogas production the operation of agricultural biogas plants still is a trial and error process. Changes in substrate input, besides technical/mechanical problems, have major effects on the stability of the biogas production and fermentation parameters. Simulation models are needed to predict the behaviour and the biogas production rates of full scale agricultural biogas plants. Existing models and equations do not consider the real degradation rates of different plant components. By the use of the GRW (Göttingen, Rostock, Wahlstedt)-Batch Test and the In-Sacco-Batch-Test (ISBV) the degradation kinetics of energy crops and other different substrates can be evaluated. Biomass to be analysed is given into the anaerobic process in nylon bags with a pore size of 40 μm. The bags avoid contamination of the biomass with the inoculum, hence subsequent analysis are not affected by the inoculum. By knowing the digestibility of the different plant components it is possible to calculate the biogas yield on an analytical basis.

With a developed mathematical model based on the plant components analysis it was possible to predict the course of the biogas production rate of a full scale agricultural biogas plant. Using only the analysis data of the substrates fed into the fermenter the crash of biogas production and microbial activity could be reproduced in the computer. By the use of the presented tools (GRW, ISBV, simulation model 'Biogasanlage�)

− different substrates can be compared and monetary assessed

− pre-disintegration of substrates can be assessed

− impacts of changes within the biogas regime can be determined and pre-estimated

− Optimized substrate mixes can be evaluated

− Following the methodology of the different tests are presented and first results in estimating the degradation kinetics of the maize silage components are depict.

 

 

Erfahrungen bei der Beratung von Vergärungs- und Kompostierungsanlagen
© Witzenhausen-Institut für Abfall, Umwelt und Energie GmbH (4/2024)
Die Verwendung von Biogut- und Grüngutkompost ist eine Möglichkeit, Nährstoffdefizite im Ökolandbau zu vermeiden sowie die Bodenfruchtbarkeit zu erhalten und sogar zu steigern.

Klimaresilienter Städtebau
© Lexxion Verlagsgesellschaft mbH (12/2023)
Instrumente, Chancen und Hindernisse bei der Klimaanpassungsplanung

Klimawandelbewältigung im Non-ETS Sektor in Deutschland und Österreich
© Lexxion Verlagsgesellschaft mbH (12/2023)
Ein neues Rechtsgebiet im Vergleich

 

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