TY  - JOUR
A1  - Rieke, Christian
A1  - Stollenwerk, Dominik
A1  - Dahmen, Markus
A1  - Pieper, Martin
T1  - Modeling and optimization of a biogas plant for a demand-driven energy supply
JF  - Energy
N2  - Due to the Renewable Energy Act, in Germany it is planned to increase the amount of renewable energy carriers up to 60%. One of the main problems is the fluctuating supply of wind and solar energy. Here biogas plants provide a solution, because a demand-driven supply is possible. Before running such a plant, it is necessary to simulate and optimize the process. This paper provides a new model of a biogas plant, which is as accurate as the standard ADM1 model. The advantage compared to ADM1 is that it is based on only four parameters compared to 28. Applying this model, an optimization was installed, which allows a demand-driven supply by biogas plants. Finally the results are confirmed by several experiments and measurements with a real test plant.
Y1  - 2018
U6  - http://dx.doi.org/10.1016/j.energy.2017.12.073
SN  - 0360-5442
VL  - 145
SP  - 657
EP  - 664
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Röhlen, Desiree
A1  - Pilas, Johanna
A1  - Dahmen, Markus
A1  - Keusgen, Michael
A1  - Selmer, Thorsten
A1  - Schöning, Michael Josef
T1  - Toward a Hybrid Biosensor System for Analysis of Organic and Volatile Fatty Acids in Fermentation Processes
JF  - Frontiers in Chemistry
N2  - Monitoring of organic acids (OA) and volatile fatty acids (VFA) is crucial for the control of anaerobic digestion. In case of unstable process conditions, an accumulation of these intermediates occurs. In the present work, two different enzyme-based biosensor arrays are combined and presented for facile electrochemical determination of several process-relevant analytes. Each biosensor utilizes a platinum sensor chip (14 × 14 mm²) with five individual working electrodes. The OA biosensor enables simultaneous measurement of ethanol, formate, d- and l-lactate, based on a bi-enzymatic detection principle. The second VFA biosensor provides an amperometric platform for quantification of acetate and propionate, mediated by oxidation of hydrogen peroxide. The cross-sensitivity of both biosensors toward potential interferents, typically present in fermentation samples, was investigated. The potential for practical application in complex media was successfully demonstrated in spiked sludge samples collected from three different biogas plants. Thereby, the results obtained by both of the biosensors were in good agreement to the applied reference measurements by photometry and gas chromatography, respectively. The proposed hybrid biosensor system was also used for long-term monitoring of a lab-scale biogas reactor (0.01 m³) for a period of 2 months. In combination with typically monitored parameters, such as gas quality, pH and FOS/TAC (volatile organic acids/total anorganic carbonate), the amperometric measurements of OA and VFA concentration could enhance the understanding of ongoing fermentation processes.
Y1  - 2018
U6  - http://dx.doi.org/10.3389/fchem.2018.00284
IS  - 6
PB  - Frontiers
CY  - Lausanne
ER  -