title: NIRS-aided monitoring and prediction of biogas yields from maize silage at a full-scale biogas plant applying lumped kinetics.
abstract: The aim of this study was to apply near-infrared spectroscopy (NIRS), available biogas plant data and lumped degradation kinetics to predict biogas production (BPr) of maize silage. A full-scale agricultural biogas plant was equipped with NIRS-metrology at the feeding station. Continuously NIR-spectra were collected for 520 d. Substrate samples were analyzed by means of feedstuff analysis. Biogas potential of the samples was calculated from the laboratory analysis results and for a sample-subset practically assessed by "Hohenheim biogas tests". NIRS-regression-models for all mentioned parameters were calibrated. Continuously gathered spectra, NIRS-models, actual plant-feeding data and degradation kinetics were used to calculate time-series of theoretically expectable BPr. Results were validated against measured gas quantity. Determination coefficients between calculated and measured BPr were up to 58.2%. This outcome was mainly due to the positive correlation between BPr and input amount since the substrate was very homogeneous. The use of NIRS seems more promising for plants with stronger substrate heterogeneity.
authors: Institute of Agricultural Engineering, Christian-Albrechts-University of Kiel, Max-Eyth-Str. 6, 24118 Kiel, Germany. fjacobi@ilv.uni-kiel.de
authors: H Fabian
authors: HF
authors: Jacobi
authors: Susanne
authors: S
authors: Ohl
authors: Eiko
authors: E
authors: Thiessen
authors: Eberhard
authors: E
authors: Hartung
mesh_terms: D056804:Biofuels / Q000032:analysis*; D001709:Biotechnology / Q000379:methods*; D002138:Calibration; D007700:Kinetics; D016018:Least-Squares Analysis; D008697:Methane / Q000032:analysis; D008956:Models, Chemical; D012015:Reference Standards; D012820:Silage / Q000032:analysis*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013997:Time Factors; D003313:Zea mays / Q000737:chemistry*
chemical_list: D056804:Biofuels; D008697:Methane