Institut für Agrartechnik

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A unified appraisal framework for the assessment of biorefinery technologies : an approach and first steps to application
(2016) Suwelack, Kay; Kruse, Andrea
As part of the desired bio-economy, biomass will find a wide industrial application in the future, re-placing fossil resources and reducing the need of their import from insecure third countries. However, such an increased industrial application of biomass holds its own problems e.g. like an intensifying competition between food and fuel (and so an increasing competition for arable land) and sometimes other serious social problems, such as the so-called Tortilla-Crisis in Mexico in 2007. Therefore, (political) decision making within a bio-economy has not only to account for economic and ecologic aspects, but also for societal ones in the fields of human rights and justice. Moreover, the three aspects of sustainability (economics, environment, and societal aspects) are to be aligned and balanced within those decisions. A standardized assessment methodology for biorefinery technologies, acknowledging all these aspects, has not been presented in literature so far. However, the need for such a standardized assessment framework was already discussed and demanded in the literature. In the present work, a basic architecture for such an assessment methodology as well as a standardized procedure for the selection of biorefinery technologies is presented (Section 2). The methodology includes thoroughly executed technology analysis by Technology Design Assessments (data level). It concerns explicit values and ethics by the use of the triple bottom line approach of sustainability on the impact level. On the decision making level a tailor-made multi-criteria decision making method (Multi-criteria Based Benchmarking) is proposed and Advanced Radar Plots are used for transparent and easy visual comparison of different policy options. The appraisal framework proposed goes beyond the literature on bioenergy appraisal frameworks and can be used as a baseline for future research. Furthermore, first steps towards the implementation of the proposed methodology are undertaken. In this context, hydrothermal carbonization is used as an example as a promising technology in a new developing bio-economy. Based on data from lab experiments, model equations are derived using a severity approach for proper mass balancing (Section 3 and 4). With these equations the product yields of hydrothermal carbonization (of biogas digestate and wheat straw) as well as the degree of carbonization of the hydrochar produced are quantified as functions of different process parameters using a severity approach. In contrast to other studies, a logarithmic dependence on process severity was applied. Process severity itself was calculated from temperature, retention time and catalyst concentration. By these models basing on few selected reaction conditions, a wide range of process conditions can be covered and the yields for the solid, liquid, and gaseous product phase can be predicted. The equations form the necessary data input for the basic Technology Design Assessment of HTC defined within the proposed standardized appraisal framework.
Die Abscheidefunktion von Hordenschüttler und Reinigungsanlage in Mähdreschern
(1993) Böttinger, Stefan
Das Durchsatzoptimum von Mähdreschern wird bei dem maximalen Gutdurchsatz mit noch akzeptablen Kornverlusten der Trennelemente Hordenschüttler und Reinigungsanlage erreicht. Dem Mähdrescher-Fahrer müssen Hilfsmittel für das Erkennen des Durchsatzoptimums zur Verfügung gestellt werden, da es in Abhängigkeit der Stoffeigenschaften des Erntegutes stark schwankt. Es werden physikalische Modelle für die Trennprozesse im Mähdrescher aufgestellt und die mathematische Beschreibung der Kornabscheidung über der Länge der Trennelemente daraus abgeleitet. Aus Messwerten der Kornabscheidung an verschiedenen Stellen eines Trennelementes werde aktuelle Parameter der Abscheidefunktion bestimmt und verschiedenen Prozesskenngrößen berechnet. Die Korrelation zwischen den berechneten Prozesskenngrößen und dem Betriebsverhalten der Trennelemente wird im labor- und Feldversuch experimentell untersucht.
Adaption and assessment of a UHF-RFID system for livestock management
(2018) Adrion, Felix; Gallmann, Eva
A prerequisite for the implementation of concepts of precision livestock farming is data acquisition on the level of the individual animal, which is only possible on a large scale by applying electronic animal identification. Radio-frequency identification (RFID) systems in the ultra-high frequency range (UHF, 860 – 960 MHz) offer the possibility of simultaneous detection of transponders and a variably adjustable read range of more than 3 m. Until now, these systems were, however, only insufficiently adapted to the operating conditions in livestock farming. In collaboration with industry partners, passive UHF-RFID transponders for integration into ear tags for cattle and pigs and readers have been developed and tested. The objective of this thesis was the adaption and assessment of this UHF-RFID system for livestock farming. In particular, 1) the construction and test of a static test bench for UHF-RFID ear tags, 2) the development of a method of measuring the influence of ear tissue on the performance of UHF-RFID ear tags, and 3) the application and validation of the UHF-RFID system for monitoring of trough visits of growing-finishing pigs should be carried out. The experiments supported the selection and further development of UHF transponder ear tags and reader antennas for application in livestock farming. A suitable test method for UHF-RFID technology in the fields of research covered was established and applied for the first time. It repeatedly became clear during the experiments that the greatest challenge for the application of UHF transponders in ear tags is the reduction of the sensitivity against ear tissue. In addition to the monitoring of animal health with UHF-RFID, further research could be carried out regarding the positioning of animals for measurement of motion activity, the combination of transponders with sensors, for example, to measure body temperature, and the utilisation of the technology for implementation of the Internet of Things in food supply chains.
Adaptive operator systems in tractors : analysis of potentials and methods for specification and evaluation
(2024) Schempp, Timo Thomas
Der Ackerschlepper wird in der Landwirtschaft, auf dem Bau, im Forst und im Kommunalbereich als Universalmaschine eingesetzt. Dazu wird er wechselnd mit einer Vielzahl von Maschinen gekoppelt, um diese zu betreiben. Es ergeben sich wechselnde Bedienszenarien mit unterschiedlichen Anforderungen an die Bedienung der gekoppelten Maschinen. Heutige Bediensysteme sind statisch und müssen daher als Kompromisslösung für diese unterschiedlichen Anforderungen an die Bedienung eingeordnet werden. Adaptive Bediensysteme können sich hingegen an wechselnde Bedienszenarien anpassen. Diese Arbeit beleuchtet den Stand der Technik der Bediensysteme in Ackerschleppern allgemein und explizit an drei ausgewählten Beispielen. Ferner werden zwei Methoden beschrieben, mit denen ein adaptives Bediensystem spezifiziert werden kann. Für die Bewertung der kognitiven und physischen Ergonomie von Bediensystemen allgemein werden zwei weitere Methoden vorgestellt. Alle Methoden sind für einen auf dem V-Modell basierenden Entwicklungsprozess geeignet. Die beschriebenen Ergebnisse einer theoretischen und praktischen Potentialanalyse motivieren den Einsatz adaptiver Bediensysteme im Ackerschlepper. Die theoretische Potentialanalyse stützt sich auf die Grundlagen der Ergonomie und auf die Art und Weise wie die Funktionen in einem Ackerschlepper genutzt werden. Die praktische Potentialanalyse stützt sich auf die Auswertung und Analyse von Messdaten aus dem Feld mit fast 500 Arbeitsstunden aus 14 Bedienszenarien. Ferner beschreibt diese Arbeit die Anwendung der Methoden zur Spezifikation, das entwickelte und funktionsfähige adaptive Bediensystem und die Anwendung der Bewertungsmethoden, die für das adaptive Bediensystem eine signifikante Verbesserungen der physischen und kognitiven Ergonomie zeigen.
An expert system for planning and designing dairy farms in hot climates
(2008) Samer Mohamed, Mohamed; Jungbluth, Thomas
Planning and designing dairy farm facilities is a sophisticated work where a multitude of procedures should be carried out which requires time and efforts; moreover, making mistakes is also possible. Therefore, it is necessary to develop computer tools that have the ability to pre-process the data so as to produce value-added information, in order to accelerate analyses and to improve decision-making. Eleven simulation models were developed to plan and design several dairy farm facilities. Subsequently, an electronic spark map (decision tree) was developed for each simulation model, and then the simulation models were integrated into the relevant spark maps. Afterwards, C# language (C Sharp), which is an object-oriented programming language, was used to develop an expert system via the simulation models and the electronic spark maps. The developed expert system is able to plan and design several dairy farm facilities, e.g. housing system (corrals system), shade structure and roof material, concrete base, cooling system, milking parlor, forage storage, and manure handling system. Subsequently, it plans the farmstead layout, and it leads to implement the technologies, equipments, and machines required for performing several farm operations. Furthermore, it studies water and electricity requirements of the planned dairy farm and the available sources on site. Moreover, it calculates the capital investment and the fixed, variable, and total costs. Data of 6 dairy farms were used to carry out the expert system validation and evaluation. The differences between the actual and calculated values were determined and the standard deviations were calculated. The coefficients of variation range between 3% and 7%. The required input data are 358 thereof a multitude will be recommended by the expert system itself; consequently, it computes and displays 372 output data with the ability of saving and retrieving data. Besides, the system?s accuracy had been calculated using the actual and calculated values of the different outputs and it was found 98.6%. However, the system?s syntax includes 22106 lines. It can be concluded that the developed expert system can be used successfully for planning and designing dairy cow farms in hot climates.
Analyse der Maschinenkosten mittels automatisierter und manueller Maschinendokumentation im ackerbaulichen Produktionsprozess
(2023) Lattke, Justus; Böttinger, Stefan
“Smart Farming”, “Agriculture 4.0” and the “Internet of Things” are terms set to define the future of global agriculture. Many studies predict that these new technologies will have more impact on agricultural productivity than the “Green Revolution” of the 1970s. Upstream and downstream agricultural suppliers claim that their products and services will benefit farmers and their businesses. In this study, several farm management software programs were tested for their capacity to add value to the cropping division of a large and diversified farm. The evaluation showed that a farm management software program based on automatic collection of machinery cost data, gave more precise and timely information than a process relying on manual data collection. This conclusion was arrived at by calculating total cropping equipment costs over a full season using two cost accounting methods – an adaptable planned cost calculation and a process cost calculation – and comparing the results from the automatic and the manual collection of data. To determine the most suitable method and to select the various software programs to evaluate, various trade fairs and companies were visited, and websites searched. The most promising software programs were then tested for functionality and ease of use at the Horsch farm, “Agrovation”. It turned out difficult to establish an incentive system for employees to use the new technologies. For this reason, the farm machines at Agrargesellschaft Pfiffelbach were equipped with the 365FarmNet application without employee registration. The entire production period of crops harvested in 2018 was included. Both automatic and manual data collection took place from August 1, 2017 to December 31, 2018. To evaluate the quality of the two methods of data acquisition, the actual hours worked were compared with the hours recorded according to the type of cost collection.
Anforderungen an Marketingkonzepte für Großtraktoren unter Berücksichtigung des Wandels landwirtschaftlicher Rahmenbedingungen
(2017) Thiel, Jörg; Köller, Karlheinz
Influenced by the volatility of markets, socio-political and sales-oriented measures, the agricultural equipment industry has always been subject to constant change. In particular, in terms of the currently focused aspect of sustainability in agricultural production systems, the design of innovative approaches for more efficient and resource-saving methods is required. Increasingly directed by the recent tense situation in the entire agricultural sector, the expectations of farmers and contractors towards modern agricultural technology change, which plays a key role in this context. From this result both new courses of action and increased challenges for the agricultural engineering industry. The internationalization of markets and the high level of saturation, especially in the European tractor market, in conjunction with increasing homogenization of products due to decreasing unique selling propositions characterize the problem discussed. With concomitant competitive pressure it is therefore very difficult for manufacturers to implement a stable customer loyalty. In addition to the development of agritechnical innovations in the range of products, the service and consulting field with focus on customer orientation gain in importance. Modern marketing strategies with the central goal of customer loyalty provide the basis for successful implementation and marketing of products and services. In this research study considering the changes of agricultural and agritechnological conditions the essential requirements for marketing concepts in agricultural technology are shown, in particular in the product segment of large tractors The radical structural changes in German agriculture caused and influenced by both agricultural and economic policy as well as socio-economic aspects, implicate increasing requirements for todays agricultural engineering industry. The current trends regarding technology and market trends combined with the changes named above accelerate this development evidently. Based on the developed basics of marketing on the current state of scientific knowledge the agricultural engineering sector is examined. Same Deutz-Fahr is focused first followed by the status quo of competitors. By a Germany-wide empirical assessment of farmers and contractors customer requirements in the area of large tractors are determined. Current methods of introducing new products in agricultural technology as well as additional services from manufacturers, as known from comparable sectors, are the main focus of the survey. A clear trend towards expressive marketing concepts from the customers perspective, such as field days or leasing and rental machines, is indicated. Furthermore, the respondents showed a keen interest in additional services and advice to increase efficiency in the sense of an optimized use of machinery. The introduction and establishment of possible approaches was equally considered useful and desirable. Based on the results of this data collection, the concept of operational and project consulting of Zeppelin Baumaschinen GmbH is further investigated using a guided interview with experts. A number of benefits on enquirer as well as on the supply side could be identified. In addition to the sales decisive factor of customer loyalty on the one hand, the counterpart is benefiting by an expanded service and consultancy of professional support in its daily business. Taking into account the similarities and differences in service and consulting the transferability of abovementioned services from the construction equipment industry to the agricultural equipment is exemplified checked on SDF. The subsequent analysis designed to determine how the survey results in case of an implementation are taken into account, reflects the positive expectations. In addition to image profits across the industry this can result in an increased customer loyalty and a strengthened brand positioning of SDF. In the future modern marketing concepts in combination with advanced services and advice from the manufacturers are going to gain in importance for the reasons stated. Innovative ideas are able to increase the emotional bond of the customers by personalized service and added value for its public image. Especially in times of economic volatility the shown approach has a lot of potential, to win confidence and promote the willingness to invest even of skeptical customers.
Anforderungs- und einsatzgerechte Auslegung von Fahrantrieben mobiler Erntemaschinen
(2019) Häberle, Steffen
Fahrantriebe mobiler Erntemaschinen werden im Rahmen einer fortschreitenden Automatisierung zunehmend zum integralen Bestandteil der Prozessführung. Komplexe Anforderungen, die sich aus deren Einsatz ergeben, haben zu einer Etablierung hydrostatischer Fahrantriebe geführt. Der zunehmende legislative Druck und die steigenden Vermarktungschancen kraftstoffsparender Technologien rücken die Effizienzbewertung von Antriebssystemen stärker in den Fokus der Forschung und Entwicklung. Standardisierte Bewertungssysteme lassen sich bei mobilen Arbeitsmaschinen, wegen deren Heterogenität und Vielfältigkeit ihrer Aufgaben, allerdings nur schwer umsetzen. Die vorliegende Arbeit zeigt einen allgemeingültigen methodischen Ansatz zur Effizienzbewertung anhand von Lastkollektiven und eines Simulationsmodells auf. Dieser lässt sich auf alle mobilen Arbeitsmaschinen mit quasistationären Lastanteilen anwenden. Am Beispiel eines Mähdreschers werden typische Einsatzbedingungen mit gemessenen Einsatzprofilen und Lastkollektiven ermittelt und in den Gesamtkontext möglicher Nutzungsszenarien kategorisiert. Mittels eines Antriebsstrangmodells wird damit die Energieausnutzung des Fahrantriebs, entsprechend den Einsatzbedingungen, berechnet. Basierend auf diesen Ergebnissen und einer detaillierten Anforderungsanalyse sind neue Antriebslösungen erarbeitet und entsprechenden Leistungsklassen zugeordnet worden. Für einen Referenzmähdrescher wird ein methodisch ausgewähltes Fahrantriebskonzept, ein sogenannter Summierungsantrieb, ausgelegt und modellbasiert bewertet. Die berechneten Ergebnisse der optimierten Antriebsvariante zeigen deutliche Verbesserungen der Energieausnutzung bei einem erhöhten Kundennutzen.
Application of infrared imaging for early detection of downy mildew (Plasmopara viticola) in grapevine
(2022) Zia-Khan, Shamaila; Kleb, Melissa; Merkt, Nikolaus; Schock, Steffen; Müller, Joachim
Late detection of fungal infection is the main cause of inadequate disease control, affecting fruit quality and reducing yield of grapevine. Therefore, infrared imagery as a remote sensing technique was investigated in this study as a potential tool for early disease detection. Experiments were conducted under field conditions, and the effects of temporal and spatial variability in the leaf temperature of grapevine infected by Plasmopara viticola were studied. Evidence of the grapevine’s thermal response is a 3.2 °C increase in leaf temperature that occurred long before visible symptoms appeared. In our study, a correlation of R2 = 0.76 at high significance level (p ≤ 0.001) was found between disease severity and MTD. Since the pathogen attack alters plant metabolic activities and stomatal conductance, the sensitivity of leaf temperature to leaf transpiration is high and can be used to monitor irregularities in temperature at an early stage of pathogen development.
Applikationstechnische Untersuchungen im Weinbau an Pflanzenschutzgeräten mit Einrichtungen zur Rückführung nicht angelagerter Spritzflüssigkeit
(1990) Kleinlagel, Bernd; Kutzbach, Heinz Dieter
Zur Verringerung der Umweltbelastung bei Pflanzenschutzmaßnahmen sind u.a. technische Weiterentwicklungen der Pflanzenschutzgeräte notwendig. Die erst seit kurzer Zeit im deutschen Weinbau anzutreffenden Pflanzenschutzgeräte mit Einrichtungen zur Rückführung nicht angelagerter Spritzflüssigkeit, kurz Recyclinggeräte genannt, versprechen neben einer deutlichen Reduzierung von Abdrift und Bodensedimentation der Pflanzenschutzmittel auch eine Verbesserung der Wirtschaftlichkeit durch Wiederverwendung der nicht zur Anlagerung gelangten Spritzflüssigkeit. Die unter Laborbedingungen durchgeführten Versuche zur Bestimmung der Auffangraten liefern grundlegende Daten zu den verschiedenen technischen Lösungen. Ziel der unter praxisüblichen Bedingungen durchgeführten Freilanduntersuchungen war es, aufzuzeigen, inwieweit diese neue Applikationstechnik Spritzmittelverluste mindert und dennoch eine qualitativ und quantitativ ausreichende Wirkstoffanlagerung auf den Rebblättern ermöglicht.
Aspects of incorporating biodegradable textiles to improve sports turf
(2023) Stürmer-Stephan, Bastian; Griepentrog, Hans
Due to climate change and the need to save water, water consumption must be reduced not only in agriculture but also in urban areas. There are 55,072 sports fields in Germany that have to be irrigated in summer. In order to reduce the amount of irrigation, two approaches were researched and discussed in this thesis. The first approach is to adapt new sports fields to the local weather conditions. This approach is a decision support system, based on a model. The input variables are recorded weather data from the German Weather Service for the location where the new sports field is to be built, the hydrological properties of the substrates, and the expected costs. An optimized dimensioning of the rootzone layer is calculated by an EA solver of Microsoft Excel. This thickness of the layer can be used for the construction project. This was calculated exemplary for 3 locations. The presented model needs to be further evaluated through field trials. For existing sports fields, the root zone layer can only be changed with great effort. In this case, a biodegradable nonwoven can be installed in an existing sports field with drainage layer structure. This nonwoven transport water from the deeper drainage layer into the root zone of the turf through the capillaries, so that the water is available to the turf. To achieve this function, the 150 mm wide nonwoven must be installed vertically at a depth of 170 mm +-20 mm. During installation, the ground cover must not be reduced and the roughness of the surface must not be increased. In the present work, a device is presented, that cuts the turf, opens a furrow, incorporates the nonwoven and then closes the furrow. The device is mounted on the tractor and consists of a height guide, a cutting disc, a box coulter and a pressure roller. The device was tested on three plots with a layer structure in Stuttgart. The cutting disc works properly because no clogging was observed. A measurement frame equipped with an ultrasonic sensor, a laser range finder and a feeler wheel determined the surface roughness before and after incorporating the nonwoven. The results showed a significant increase in roughness. In order to reduce the negative impact to the ground surface, it would be possible to increase the ballasting of the device. However, harmful soil compaction must be avoided. The uniform working depth of the developed device was determined with a tachymeter and showed a deviation from the nominal depth of less than 20 mm. The results show that this meets the requirements for the device. Ground cover was measured before and after installing the nonwoven. The turf damage was less than 15 % of the ground cover, which meets the playability requirements. Reconsolidation was determined by penetrologger and evaluated in profile. The soil recompaction, measured as penetration resistance, was similar to the status quo, except in the area close to the nonwoven, where the recompaction failed. The furrows of the developed device can be recompacted more effectively by using two pressure roller, attached V-shaped. But it must be verified that the two pressure rollers do not cause ridge formation, as is the case with seed drills. Overall, the performance of the device can be considered positive, but improvements are still needed to improve reconsolidation. These improvements can be verified in future investigations. At the same time, the effectiveness of the nonwoven must be evaluated in the future. Preliminary tests have shown that the capillary action is sufficient to transport water from the drainage layer to the root zone.
Attraktives Beschäftigungsmaterial zur Reduktion von Schwanz- und Ohrschäden beim Schwein
(2021) Kauselmann, Karen; Schrader, Lars
Tail biting is a behavioural disorder that often occurs in commercially housed domestic pigs. It may affect welfare of involved pigs and cause economic losses for the farm. The causes of tail biting are multifactorial, which is why preventive tail docking is the most comon method to reduce tail damages in pigs until today. However, besides invasive interventions, the use of enrichment materials can reduce tail biting by increasing species-specific exploration behaviour. Thereby, the rapid habituation of pigs poses a challenge in the selection of enrichment materials. Within the research project “Label-Fit – Schweinehaltung fit für das Tierschutzlabel”, different plant-based enrichment materials for rearing and fattening pigs were investigated, which can be used in conventional housing systems with slatted floors. The aim of the present study was to identify attractive enrichment material based on the exploration duration. Furthermore, the influence of the enrichment materials on tail and ear damages was investigated in pigs with undocked tails. Prior to three long-term investigations, two choice tests were carried out for better delimination of plant-based enrichment materials considered attractive for pigs. Therefore, pigs were offered enrichment materials of different structure or, in the second test, straw with different edible additives. In both tests materials were offered in parallel in six boxes. By means of the individually recorded exploration durations, pigs showed clear preferences for pelleted materials and preferred chopped straw with edible additives, such as maize kernels. These results were used to select enrichment materials for further long-term investigations. In the three long-term investigations, material dispensers were equipped with an UHF-RFID system to record exploration durations of the pigs at the material dispenser filled with enrichment materials. Enrichment materials were offered in an alternating order and at each change of material the tails and ears of the pigs were recorded according to the “Deutscher Schweine Bonitur Schlüssel” (DSBS) regarding partial losses and skin injuries. In the first long-term investigation, rearing and fattening pigs received four enrichment materials with different structures (lucerne pellets, straw pellets, chopped hay and chopped straw) in a two-weekly change. Rearing pigs preferred pelletized materials, while fattening pigs showed preferences for chopped hay and lucerne pellets. Furthermore, exploration duration increased from rearing to fattening. When offering the enrichment materials that achieved the highest exploration durations in rearing (lucerne pellets or straw pellets), the fewest partial losses of the tails were recorded. However, when offering straw pellets in rearing, most injuries at the tails occurred. The second long-term investigation dealed with the question, if exploration duration of rearing and fattening pigs for chopped straw can be increased by adding maize kernels. Compared with pigs that received chopped straw without maize, pigs that received chopped straw with maize kernels showed higher exploration durations at the material dispenser during rearing and fattening. Furthermore, exploration duration could be increased from rearing to fattening, although there was no change of the material within the groups. Additionally, saisonal differences in the diurnal pattern of exploration of pigs were found. Interestingly, pigs that received chopped straw without maize kernels showed fewer length losses of the tails compared to pigs that received chopped straw with maize kernels. In the third long-term investigation, rearing and fattening pigs received different flavoured straw pellets in a weekly change. Different preferences for flavours were found between rearing and fattening pigs. During rearing, highest exploration durations were recorded for straw pellets with fried onion flavour or almond flavour. During fattening, pigs explored straw pellets without flavour or with strawberry flavour longest. Exploration duration could be maintained at a constant level from rearing to fattening. Most skin injuries at the tails occurred when using vanilla flavour or fried onion flavour during rearing, whereby vanilla, unlike fried onion, was one of the flavours with the lowest exploration durations. On the basis of the present investigations clear preferences of pigs for specific plant-based enrichment materials could be shown, which increased species-specific exploration behaviour. However, enrichment materials for which high exploration durations were recorded could not reduce tail damages, such as partial losses or skin injuries. This illustrates that, apart from the access to enrichment material, further factors influence the prevalence of tail damages, which have to be considered in relation to each other.
Auswirkungen der flexiblen Biogasproduktion auf die Effizienz von landwirtschaftlichen Biogasanlagen
(2020) Kress, Philipp; Jungbluth, Thomas
In future energy systems based on renewable energies, biogas plants can make a significant contribution to stabilizing the electricity grids. However, this requires demand-flexible and load-driven electricity production, which is only made possible by flexible biogas production with extremely versatile feed management. From the process engineering and process biology point of view, this demand-flexible operation represents a major challenge for the operation of biogas plants. Technically, this demand-flexible biogas production requires a complete utilization of the existing fermenter volume, which in turn requires an optimal mixing of the substrates in the fermenter. Similarly, a continuous high-resolution monitoring of the produced biogas composition is also necessary to detect process disturbances or overloads that begin at an early stage. The objective of this work was to test and optimize new measuring methods for the flow velocity measurement and the mixing quality in the biogas reactor. Furthermore, to achieve a high-resolution gas quality measurement, practical scale tests were conducted. From these results, conclusions about possibilities and limitations of a flexibilisation of the biogas production shall be derived. Stirring is one of the most important processes in biogas production. The power input was intended to generate turbulent flows and thus ensure uniform distribution of nutrients and homogeneous temperatures throughout the reactor and avoid sinking and floating layers. In order to be able to assess and optimize these mixing processes, investigations of flow velocities in the fermenter were carried out using a magnetic-inductive measuring system. Additionally, flow profiles were created as a function of the DM content and the viscosity of the fermentation substrate. At a DM content of 9.45% in the fermenter, the average flow velocity measured was 87.5 cm/s. The DM content and the viscosity of the fermenting substrate were also taken into account. This dropped to 0.96 cm/s with a DM content of 9.95%. For the further description of the mixing quality, spatially dissolved nutrient samples were taken from the entire fermenter to determine the biological parameters. It was proven that the punctual input of the solid biomass via the solid input leads to a locally increased DM content and increased concentrations of organic acids in the vicinity of the input. In contrast to the laboratory tests using the process tomography method, no zone was found in the fermenter at which process disturbances were present. Furthermore, in contrast to laboratory tests, no biologically inactive zones could be detected in the fermenter of the research biogas plant. In further investigations, a photoacoustic sensor with a newly developed measuring system for determining the methane and carbon dioxide concentrations of the biogas was installed, tested and optimized for the first time in a biogas plant in the field. The basic applicability of such a system in biogas plants could be demonstrated. The achieved data density was significantly higher than that of conventional devices with a very high precision of the measured values. Using this innovative measuring technique, a flexible substrate supply and its influence on the product gas quality was subsequently evaluated. Substrates with different degradation behavior and different specific methane yields were fed to the fermenter. The influence of the specific substrate used in biogas production was reflected in the biogas quality. In particular, the relation between the relative change in gas quantity and quality makes it possible to detect process changes at an early stage. The presented studies have created a basis that enables a demand-oriented biogas production: Even with high substrate quantities that are fed to the fermenter, a high mixing quality can be achieved in the fermenter with an appropriate design of the agitators, which also prevents local process overloads. The investigations prove that, despite very low flow rates, there is sufficient nutrient supply for the microorganisms. The newly developed sensors for determining the biogas composition provide measured values with high precision and high temporal resolution, so that possible process disturbances can be detected very early. The investigations contribute to optimizing future demand-oriented electricity production on the basis of demand-flexible feeding in biogas plants. As a result, biogas plants can fulfil an important system service in a renewable energy based grid by decentrally stabilizing the electricity supply.
Beitrag zur Untersuchung des Innovationsgeschehens und ausgewählter Unternehmen der deutschen Landmaschinenindustrie von den Anfängen bis in die 1970er Jahre
(2017) Krombholz, Klaus; Köller, Karlheinz
Industrial production of agricultural equipment had already begun in the 18th century in England. First of all, the USA and from the middle of the 19th century onwards also Germany increasingly followed this development. Though this sector had primarily been characterized by crafts enterprises and small establishments for a long time, already in the 19th century the first large companies had arisen. During the following time, however, the small and mediumsize enterprises still dominated. Only as from the middle of the 20th century a gradual trend to large companies was to be found that began to prevail more and more also in Germany from the end of the 20th century. Within the agricultural engineering of the GDR this development had already taken place some decades earlier. After a relatively continuous development during the first decades essential changes in the corporate landscape occurred after a time of economic boom in the 1920s. This process was fortified by inflation and the depression. The majority of the large concerns established in the time of startups were affected thereby. The overcapacity generated again from a boom in the 1950s resulted in serious structural changes and in reducing the potential. Though the agricultural engineering of West Germany experienced a short special boom by the reunification at the beginning of the 1990s, the decrease in turnover as from the middle of the 1980s decisively influenced the corporate landscape during the 1990s. In this period foreign companies became active on the market to a great extent and advanced the globalisation of the sector. The agricultural industry in East Germany had diminished to a negligible dimension already in the middle of the 1990s. The German agriculture at first supplied themselves with agricultural engineering by imports primarily from England and the USA. However, already in the first decades of the 20th century the German industry of agricultural machinery could overcome the dependence on imports to a large extent and in the following they could achieve first places within the export rates in the international comparison by increasing own export rates. Beside the first own developments of the products, initially, the reproduction and replication of English and American prototypes dominated. In the second half of the 20th century, German developments were, above all, derived from American products in decreasing tendency. Finally, as from the 1990s, when the highest requirements were given to the agricultural machinery of the East German agricultural large enterprises on the local market, the German agricultural engineering grew to a leading driver of innovation. Though the German agricultural technicians also innovatively dealt with the whole range of the mechanisation solutions for the agricultural sector already very early, the product groups ripened at different times and were accepted and applied by the farming practice. Under this aspect, the innovation process was divided up into the former and later innovation areas. In the initial period the whole current agricultural technical product line was prevalently offered in the German agricultural machinery industry, whereas the assortment was subdivided in own developments, follow-up developments and reproductions as well as trading goods. At first, the enterprises only little focused on specialising in a limited assortment. This development increasingly began only as from the 1920s. From this point of view also the larger concerns only very rarely could aim at high-volume production. Especially the German production of tractors that was distributed among a large number of enterprises up to the 1960s had been burdened by comparatively low quantities and therefore by predominantly small-lot and medium-sized serial production for a long time. By contrast, the agricultural machinery of the GDR with its relatively small assortment was, in most of its product programmes, oriented towards high-sized serial production with extremely high export shares already from the 1960s onwards.
Beurteilung von Geruchsimmissionen aus der Tierhaltung
(2011) Gallmann, Eva; Jungbluth, Thomas
Odours from farm animal production can cause significant problems. It is therefore appropriate to develop suitable procedures for their assessment and limitation in the sense of immission control. The challenge comprises the objectification of the odours, bearing in mind that their effect is very individual, subjective and emotion-based. The resultant work offers a contribution towards the classification and further development of procedures for assessment of odours from farm animal production. The latest knowledge of the various aspects of measurement and evaluation of farm animal production odour immissions will be analysed in detail through ongoing literature assessment and from results of own investigations. The perceived nuisance effect relies on multiple stimulus-based variables associated with context and person. Measuring the associated effect can take place through psychometric surveys. Assessment of a significant nuisance effect within a group is conventionally based on the proportion of subjected persons that can be regarded as tolerable. Odours from farm animal production in particular are considered on the basis of investigations and data concerning odour components and their emission, transmission and immission. The extent of available data including results from own odour emission measurements give a high degree of scatter. This scatter is caused by the multiplicity of influences on emissions and also through the imprecision of measurements based on olfactometry. There are limitations on the extent to which reduction measures can be quantified. Dispersion modelling is an important tool for assessing odour immissions, but is also associated with limitations as shown by validation and sensitivity investigations. Particularly decisive are the appropriate illustration of the transmission and the choice and modification of the model structure and input parameters. The modelling of diffuse and varying sources near the ground surface remains a challenge. The consideration of cold air outflows is essential for immission assessment. The common odour threshold distances from pig and cattle production units determined via odour plume measurements are discussed using numerous trial results as examples. The results of own grid measurements at four locations are detailed, also with regard to the effect of a plausibility control, the variation of the odour hour criterion, and compared with dispersion calculations. Grid measurements help in the differentiated measurement of the immission situation. In the interpretation of absolute values, the imprecision area around the real value must be considered. The effect of immission reduction measures is hardly quantifiable nor able to be generalised. The knowledge is based, above all, on flow simulations and on experience. Main points of influence are the dilution of outflow air, the transmission conditions and the location circumstances. The immission hedonics from farm animal production odours were compared and recorded for own investigations and within the framework of a cooperative project “Odour assessment in agriculture“. The hedonic differences were not, however, nuisance-relevant as shown by evaluation of the exposition effect relationships within the same trial framework. The differences regarding type of farm animal are, however, relevant. The results from various epidemiological studies were thoroughly analysed because these were oriented on the assessment procedure for immissions and their effects. The starting point for assessing odour emissions from farm animal production can differ more through source-oriented distance rules or immission regulations for the limitation of odour hour frequency or odour concentration. Both points provide possibilities for recognition of animal type differences via factor weighting of animal mass, animal numbers or key immission figures. The assessment principle for distance standards that apply to all types of farm animals with factor weighting for source, transmission and immission parameters, or as empirical distance model, are explained and assessed based on examples from Switzerland, Austria and Germany. The methods and the establishment of factors are less well able to be appreciated as the degree of differentiation increases. The determinations within the odour immission guideline are compared with the regulations for odour exposition limits in the Netherlands, and in other countries. The suitability of the assessment bases and procedures for assessment are finally evaluated for assessment in practical conditions and recommendations for further developments suggested.
Biochemical composition of biomass and its impact on the prediction of the specific methane yield potential
(2017) Mukengele, Michael Mutombo; Jungbluth, Thomas
This thesis analyzes the biomass biochemical composition and its influence on the specific methane yield potential of energy crops. The influence of the ensiling technique and the specific methane yield potential gained using a batch-test scaled up to semi-continuous flow system were also assessed. The results show that through ensiling process the risk of over-estimating the specific methane yield potential was particularly high for silages of low DM content. Through ensiling up to 8.6% higher methane yield potential could be achieved. The impact was different depending on the maturity index of the crop material. The evaluation of the bioconversion efficiency in batch and semi-continuous flow digester showed that 80% to 87% of the theoretical methane yield potential could be recovered in a batch-test. By scaling up batch the bioconversion efficiency decreased of up to 19%. The investigation on maize showed that the absolute values of the biochemical crop traits and in-vitro estimates of digestibility for whole-crop were poor predictors for high specific methane yield potential (R² = 0.31 to 0.32). Other crops alternative to maize showed a wider variation range in specific methane yield potential. Reproductive crop fractions of lipid rich crops revealed higher specific methane yields reaching 0.455 mN³ CH4/ kg ODM in sunflower crown and 0.598 mN³ CH4/ kg ODM in rape seed. The stalk/stem fraction of these crops seemed to be the most limiting factor for degradability. Conversely, carbohydrates rich crops (rye and sorghum) showed methane yields slightly lower or equal to those of maize.
Biochemical methane potential of a biorefinery’s process-wastewater and its components at different concentrations and temperatures
(2022) Khan, Muhammad Tahir; Huelsemann, Benedikt; Krümpel, Johannes; Wüst, Dominik; Oechsner, Hans; Lemmer, Andreas
A sustainable circular bioeconomy requires the side streams and byproducts of biorefineries to be assimilated into bioprocesses to produce value-added products. The present study endeavored to utilize such a byproduct generated during the synthesis of 5-hydroxymethylfurfural as a potential feedstock for biogas production. For this purpose, biochemical methane potential tests for the full process-wastewater, its components (5-hydroxymethylfurfural, furfural, levulinic acid, and glycolic acid), together with furfural’s metabolites (furfuryl alcohol and furoic acid), and phenols (syringaldehyde, vanillin, and phenol), were conducted at mesophilic and thermophilic temperatures to assess their biodegradability and gas production kinetics. 0.1, 0.2, 0.3, and 0.4 g COD of the test components were added separately into assays containing 35 mL of inoculum. At their lowest concentrations, the test components, other than the process-wastewater, exhibited a stimulatory effect on methane production at 37 °C, whereas their increased concentrations returned a lower mean specific methane yield at either temperature. For similar component loads, the mesophilic assays outperformed the thermophilic assays for the mean measured specific methane yields. Components that impaired the anaerobic process with their elevated concentrations were phenol, vanillin, and 5-hydroxymethylfurfural. Poor degradation of the process-wastewater was deduced to be linked to the considerable share of 5-hydroxymethylfurfural in the process-wastewater governing its overall characteristics. With excessive recalcitrant components, it is recommended to use such waste streams and byproducts as a substrate for biogas plants operating at moderate temperatures, but at low rates.
Biogas production vs. dung combustion as household energy in rural Ethiopia
(2011) Müller, Joachim; Barfuss, Isabel; Gwavuya, Stanley; Abele, Steffen
The objective of the study was to investigate the potential of dung as primary and secondary energy source, i.e. direct combustion of dung and combustion of its secondary products biogas or dried digestate, under consideration of its quality as fertilizer. The results of the analysis show the similarity of dung and digestate regarding combustion characteristics. Fertilizer values proved better for digestate. However, calorific value of dung proved much lower than those of biogas. Thus, biogas represents a good alternative energy source with double benefit. Besides its better combustion characteristics compared to dried dung, it also delivers a superior fertilizer.
Biologische Wasserstoffmethanisierung in Hochdruck-Rieselbettreaktoren für Power-to-Gas-Konzepte
(2018) Ullrich, Timo; Jungbluth, Thomas
In order to achieve climate protection targets, intermittent and decentralised energy sources such as wind power and photovoltaics will be expanded in the future. However, the power grids are not designed for the large-scale expansion and connection of different decentralised and fluctuating generation plants. This represents a major challenge for grid stability and requires an increasing expansion of energy storage. Power-to-Gas technology, a process for converting electrical energy into chemical energy, will play a central role in this process. In this two-stage process, hydrogen is first produced by electrolysis, which then reacts with carbon dioxide to form methane. It can be stored and transported in the natural gas grid almost indefinitely and can be used flexibly in a wide variety of applications. In addition to the chemical-catalytic methanation of hydrogen, there is also the biological methanation process. Characteristic features are a flexible load change behaviour and a marked robustness regarding the educt gas composition. Compared to chemical-catalytic methanation, however, the gas flow rates are significantly lower, which is the greatest challenge of this process. For this reason, the aim of this work was to optimize the performance of trickle-bed reactors for biological hydrogen methanation. The focus was on improving the gas-liquid-mass-transfer as described in the literature, but not yet which has not yet been investigated in the context of this promising concept. In an automated and continuous test plant, the operating pressure was initially varied in stages of 1.5, 5 and 9 bar in the first publication. With increasing pressure, conversion rates were improved and gas quality increased by 34%. Furthermore, the circulation of the process liquid to the trickling bed of the reactors was paused for periods up to 1440 min in the second publication. As the circulation pause rose, there was a noticeable increase in all performance parameters with maximum methane contents > 97 Vol.-%. Finally, different temperature levels of 40 - 55 °C were also examined. In spite of the continuous increase in gas volumes in the three publications, the performance parameters increased again. Overall, the combined optimization measures more than doubled the output with an MFR of 4.28 ± 0.26 m3 m-3 d-1 to 8.85 ± 0.43 m3 m-3 d-1, while simultaneously increasing the methane content in the product gas. Periodical analyses of the process liquid, especially the acid concentrations, as well as the stable conversion rates indicated a stable biological process in all experiments. The tests were done with three identical reactors, underlining the high degree of reproducibility. It was noticeable that the microorganisms quickly adapted to the changing operating parameters within a maximum of 24 hours. The performance increases could thus be related to the successful increase in the gas-liquid-substance exchange rate and not to a changed microorganism concentration or selection. The studies have also revealed further optimisation potential. In particular, the properties of the process liquid with regard to pH and nutrient composition should be the subject of further investigations. Thus, the present study not only successfully demonstrated the goal of increasing performance; with stable and uncomplicated operation over several months and a wide range of operating parameters, it also demonstrated that trickle bed reactors for the biological methanation of hydrogen are a reliable, flexible and thus promising concept in the context of power-to-gas applications.
Biomethane production in an innovative two-phase pressurized anaerobic digestion system
(2015) Chen, Yuling; Jungbluth, Thomas
Generation of biogas from biomass through anaerobic digestion is receiving increasing attention. Over the past decade, the biogas industry has been developing rapidly in Germany, as well as the rest of the world. In Germany, biogas is generally used in a heat and power plant (CHP) for electricity and heat production. However, most biogas plants are located in a rural area, where heating demands are quite low. Except for biogas plant thermal control, a huge amount of cogenerated heat is often wasted. In order to increase the overall energy utilization efficiency, biogas can be alternatively converted to biomethane of natural gas quality and injected into existing gas grids. By making use of the mature gas transportation and storage systems, biogas production and end utilization can be temporally and spatially separated. Therefore, it is regarded as an efficient and flexible solution to energy issues. Nevertheless, in terms of this application, raw biogas requires, above all, gas purification and upgrading. Carbon dioxide content, in particular, must be reduced from 40–50% in the raw biogas to approximately 4% in the purified gas. Conventional technologies are generally expensive in investment and/or operation. Therefore, an economical option is desired. Within this research project, a two-phase pressurized anaerobic digestion system was developed. The innovative concept aimed to reduce the cost involved in biomethane conversion and injection into the natural gas grids by integration of biogas production, purification and compression in one system. It was expected that a great amount of carbon dioxide could be directly removed from the pressurized digester due to its high solubility. In addition, the methane-rich biogas could be produced at an elevated pressure which could meet the injection standard, and therefore could reduce or even avoid the expenses for further compression. In order to gain better understanding of two-phase pressurized anaerobic digestion, three major studies were conducted: - The pressure effects on two-phase anaerobic digestion - Effects of organic loading rate (OLR) on the performance of a pressurized anaerobic filter in two-phase anaerobic digestion - Effects of liquid circulation on two-phase pressurized anaerobic digestion By this means, the system performance could be examined and the technical feasibility and potential of the new concept could be explored. Moreover, an optimization of the process in a two-phase pressurized anaerobic digestion system could be realized. From both economic and ecological perspective, two-phase pressurized anaerobic digestion offers an interesting process option for biomethane production, making a great contribution to sustainable energy supply.

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