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Author: Idler, Christine × Type: Text ×

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Now showing 1 - 8 of 8
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    Methanbildungspotenziale verschiedener Pflanzenarten aus Energiefruchtfolgen
    (Darmstadt : KTBL, 2016) Herrmann, Christiane; Plogsties, Vincent; Willms, Matthias; Hengelhaupt, Frank; Eberl, Veronika; Eckner, Jens; Strauß, Christoph; Idler, Christine; Heiermann, Monika
    Das Methanbildungspotenzial ist ein entscheidendes Qualitätsmerkmal von Biomassen bei ihrer Nutzung als Einsatzstoff für die Biogasproduktion. Von 769 unter einheitlichen Bedingungen silierten Erntegütern aus Energiefruchtfolgen wurden mittels Batch-Gärtests in zwei verschiedenen Versuchsanlagen spezifische Methanausbeuten ermittelt. Daraus konnten Richtwerte für mittlere Methanausbeuten je Fruchtart und Fruchtfolgestellung, Schnitt bzw. Trockenmassebereich oder Entwicklungsstadium zur Ernte für 93 verschiedene pflanzliche Biomassen abgeleitet werden. Die Ergebnisse stellen eine umfassende Datengrundlage dar, die in Verbindung mit Biomasseerträgen für die Abschätzung von Methanhektarerträgen zur ökonomischen und ökologischen Bewertung von Energiefruchtfolgen, zur Planung und Auslegung von Biogasanlagen sowie zur Entscheidung hinsichtlich des Anbaus alternativer pflanzlicher Kosubstrate und der Konzeption nachhaltiger Biogasfruchtfolgen genutzt werden können.
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    Storage problems of poplar chips from short rotation plantations with special emphasis on fungal development
    (Warsaw : Sciendo, 2012) Horváth, Zsuzsanna; Marosvölgyi, Béla; Idler, Christine; Pecenka, Ralf; Lenz, Hannes
    There are several problems in storing wood chips freshly harvested from short rotation plantations, which result in quality losses as well as in dry matter and energy losses. The factors influencing the degradation of raw material are examined in this paper with special focus on fungal development. An excessive growth of fungi is connected to dry matter losses and also to an increased health risk during raw material handling. The following factors were measured during 6 months storage of poplar wood chips depending on particle size: box temperature, moisture content, pH-value, appearance of fungi in the storage and the concentration of fungal particles in the air. The results show a close connection between particle size, temperature and attack of fungi. During the storage mesophilic and termophilic species of the genera Alternaria, Aspergillus, Cladosporium, Mucor and Penicillium appeared. The concentration of fungal particles is the highest for fine chips and decreases in bigger particles. There was a special focus on the investigation of the properties of coarse chips (G 50), which represent a good compromise between handling, storage losses and health risk due to fungal development.
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    Improving aerobic stability and biogas production of maize silage using silage additives
    (Amsterdam : Elsevier, 2015) Herrmann, Christiane; Idler, Christine; Heiermann, Monika
    The effects of air stress during storage, exposure to air at feed-out, and treatment with silage additives to enhance aerobic stability on methane production from maize silage were investigated at laboratory scale. Up to 17% of the methane potential of maize without additive was lost during seven days exposure to air on feed-out. Air stress during storage reduced aerobic stability and further increased methane losses. A chemical additive containing salts of benzoate and propionate, and inoculants containing heterofermentative lactic acid bacteria were effective to increase aerobic stability and resulted in up to 29% higher methane yields after exposure to air. Exclusion of air to the best possible extent and high aerobic stabilities should be primary objectives when ensiling biogas feedstocks.
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    Biogas crops grown in energy crop rotations: Linking chemical composition and methane production characteristics
    (Amsterdam : Elsevier, 2016) Herrmann, Christiane; Idler, Christine; Heiermann, Monika
    Methane production characteristics and chemical composition of 405 silages from 43 different crop species were examined using uniform laboratory methods, with the aim to characterise a wide range of crop feedstocks from energy crop rotations and to identify main parameters that influence biomass quality for biogas production. Methane formation was analysed from chopped and over 90 days ensiled crop biomass in batch anaerobic digestion tests without further pre-treatment. Lignin content of crop biomass was found to be the most significant explanatory variable for specific methane yields while the methane content and methane production rates were mainly affected by the content of nitrogen-free extracts and neutral detergent fibre, respectively. The accumulation of butyric acid and alcohols during the ensiling process had significant impact on specific methane yields and methane contents of crop silages. It is proposed that products of silage fermentation should be considered when evaluating crop silages for biogas production.
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    Establishment of a Laboratory Scale Set-Up with Controlled Temperature and High Humidity to Investigate Dry Matter Losses of Wood Chips from Poplar during Storage
    (Basel : MDPI, 2022) Hernandez-Estrada, Albert; Pecenka, Ralf; Dumfort, Sabrina; Ascher-Jenull, Judith; Lenz, Hannes; Idler, Christine; Hoffmann, Thomas
    The aim of this work was to improve the understanding of dry matter losses (DML) that occur in wood chips during the initial phase of storage in outdoor piles. For this purpose, a laboratory scale storage chamber was developed and investigated regarding its ability to recreate the conditions that chips undergo during the initial phase of outdoor storage. Three trials with poplar Max-4 (Populus maximowiczii Henry  Populus nigra L.) chips were performed for 6–10 weeks in the storage chamber under controlled temperature and assisted humidity. Two different setups were investigated to maintain a high relative humidity (RH) inside the storage chamber; one using water containers, and one assisted with a humidifier. Moisture content (MC) and DML of the chips were measured at different storage times to evaluate their storage behaviour in the chamber. Additionally, microbiological analyses of the culturable fraction of saproxylic microbiota were performed, with a focus on mesophilic fungi, but discriminating also xerophilic fungi, and mesophilic bacteria, with focus on actinobacteria, in two trials, to gain a view on the poplar wood chip-inhabiting microorganisms as a function of storage conditions (moisture, temperature) and time. Results show that DML up to 8.8–13.7% occurred in the chips within 6–10 storage weeks. The maximum DML were reached in the trial using the humidifier, which seemed a suitable technique to keep a high RH in the testing chamber, and thus, to analyse the wood chips in conditions comparable to those in outdoor piles during the initial storage phase.
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