04 Fakultät Energie-, Verfahrens- und Biotechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/5
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Item Open Access Process model and life cycle assessment of biorefinery concept using agricultural and industrial residues for biohydrogen production(2024) Gamero, Edgar; Ruppert, Sophia; Miehe, Robert; Sauer, AlexanderSustainable waste management strategies are urgently needed due to an increasing global population and increased waste production. In this context, biorefineries have recently emerged as a promising approach to valorize waste streams and supply a broad range of products. This study presents the process model and life cycle assessment (LCA) of a biorefinery concept using a novel biochemical method, a so-called “dark photosynthesis” conversion. This process is coupled to a photo-fermentation using microalgae. Overall, the biorefinery concept can produce hydrogen, lutein, β-carotene, and proteins for animal feed. Apple pomace from apple juice production is used as feedstock for the primary conversion step. A process model was created with the process simulation software Aspen Plus ® using experimental and literature data. Results from this model were then used in an LCA. The environmental impacts of the proposed biorefinery concept are relatively high, showing the need for process optimization in several areas. Energy system integration, stream recycling, and higher hydrogen yields are recognized as especially important for improving the environmental performance of this concept. Despite these findings, the model shows the feasibility of implementing the biochemical conversion technologies in a biorefinery concept for effectively utilizing residue streams.Item Open Access Defining material compliance : a comprehensive analysis(2021) Buckreus, Lorena; Nuffer, Anne-Kathrin; Miehe, Robert; Sauer, AlexanderThe increase in the number of environmental regulations has resulted in great challenges for corporations in the manufacturing industry, especially within the electronic and electrical and the mechanical engineering sector. To address these compliance requirements, specialized management fields such as environmental compliance, substructures and management approaches have been implemented in industry. Recently, adherence to requirements concerning the composition of products and the use of materials and substances within products has become increasingly important and is referred to as material compliance (MC). Although the topic is of increasing importance, there is no generally accepted definition for MC nor a management framework. Corporations are thus unable to systematically address MC, and compliance violations occur frequently. We derived a definition for MC based on extensive literature research, which we subsequently evaluated in a quantitative survey. Our results indicate that MC is commonly understood as the adherence to requirements concerning the composition of a product and the use of substances and materials within products. By proposing a definition for MC, we aim to introduce a common understanding, enable future research to systematically address the topic and develop a framework for the management of MC.Item Open Access Comparative life cycle sustainability assessment of mono- vs. bivalent operation of a crucible melting furnace(2022) Schutzbach, Maximilian; Kiemel, Steffen; Miehe, Robert; Köse, Ekrem; Mages, Alexander; Sauer, AlexanderThe benefits of energy flexibility measures have not yet been conclusively assessed from an ecological, economic, and social perspective. Until now, analysis has focused on the influence of changes in the energy system and the ecological and economic benefits of these. Therefore, the objective of this study was to perform a life cycle sustainability assessment of energy flexibility measures on the use case of a bivalent crucible melting furnace in comparison with a monovalent one for aluminum light metal die casting. The system boundary was based on a cradle-to-gate approach in Germany and includes the production of the necessary process technologies and energy infrastructure and the utilization phase of the crucible melting furnaces in non-ferrous metallurgy. The LCSA is performed for different economic and environmental scenarios over a 25-year lifetime to account for potential adjustments in the energy system and volatile energy prices. In summary, it can be said that over the entire service life, no complete ecological, economic, and social advantage of energy flexibility measures through a bivalent system can be demonstrated. Only a temporarily better life cycle sustainability performance of the bivalent furnace can be shown. All results must be considered with the caveat that the bivalent crucible melting furnace has not yet been investigated in actual operation and the calculations of the utilization phase are based on the monovalent crucible melting furnace. To further sharpen the results, more research is needed and the use of actual data for bivalent operation.Item Open Access A conceptual framework for biointelligent production : calling for systemic life cycle thinking in cellular units(2021) Miehe, Robert; Buckreus, Lorena; Kiemel, Steffen; Sauer, Alexander; Bauernhansl, ThomasA sustainable design of production systems is essential for the future viability of the economy. In this context, biointelligent production systems (BIS) are currently considered one of the most innovative paths for a comprehensive reorientation of existing industrial patterns. BIS are intended to enable a highly localized on-demand production of personalized goods via stand-alone non-expert systems. Recent studies in this field have primarily adopted a technical perspective; this paper addresses the larger picture by discussing the essential issues of integrated production system design. Following a normative logic, we introduce the basic principle of systemic life cycle thinking in cellular units as the foundation of a management framework for BIS. Thereupon, we develop a coherent theoretical model of a future decentralized production system and derive perspectives for future research and development in key areas of management.