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Lignin-based carbon fibres may replace both glass fibres and fossil-based carbon fibres. The objective of this study was to determine the environmental impact of the production of lignin-based carbon fibres using life cycle assessment. The life cycle assessment was done from cradle to gate and followed an attributional approach. The climate impact per kg of lignin- based carbon fibres produced was 1.50 kg CO2,eq. In comparison to glass fibres, the climate impact was reduced by 32% and the climate impact of fossil-based carbon fibres was an order of magnitude higher. A prospective analysis, in which the background energy system was cleaner, showed that the environmental impact of lignin-based carbon fibres will decrease and outperform the glass fibres and fossil-based carbon fibres from a climate impact point-of-view. The constructed LCA model can be applied in further studies of products that consist of or use lignin-based carbon fibres.

The LignoJet project aimed to achieve an intermediate lignin-oil product miscible with fossil feedstock and with a significantly reduced oxygen content. A technical concept for production has been studied that involves combined catalysed depolymerisation and hydrodeoxygenation, so called hydrogenolytic depolymerisation, of kraft lignin. Kraft lignin was separated through membrane ultrafiltration from softwood and eucalyptus black liquor followed by precipitation through LignoBoost technology. A difference in lignin properties was observed between ultrafiltration of softwood and eucalyptus black liquor through 15 and 150kDa ceramic membranes. Lignin-oils with similar oxygen content were produced regardless of origin and fractionation technique. A lignin-oil with favourable properties as precursor for refinery integration for jet fuel production as produced in small-scale batch experiments using nickel-based catalyst. Stable pumpable oils with melting point of less than 25-50 deg C and with 20-30% lower oxygen content and aromatic content were obtained that would be suitable as jet fuel precursors. The estimated production cost was found to be competitive with that of other liquid biofuels, while additional revenues could potentially be achieved by also producing chemical and materials from suitable fractions of the lignin-oil.

RISE Research Institutes of Sweden is a group of research and technology organisations. RISE is a leading innovation partner working global cooperation with academia, enterprise and society to create value, growth and competitiveness through research excellence and innovation. In the area of Energy, RISE has developed innovation Roadmaps covering: Energy Efficient Transport Electric Power System Energy Efficient and Smart Buildings Sustainable Thermal Processes Efficient Energy Use in Industry Decarbonisation of Basic Industries These Roadmaps describe development pathways for technologies, non-technical elements (market design, user behaviours, policies, etc.) and key actors that deliver on a plausible, desirable vision for each respective innovation area in 2030. These Roadmaps are intended to support RISE’s strategic planning and development, but should be relevant reading for anyone interested in energy innovation in Sweden.

Physikalisch basierte Grundwassermodelle auf Einzugsgebietsebene sind als ein wesentlicher Bestandteil räumlich verteilter hydrologischer Modelle ein unverzichtbares Werkzeug der Global Change Forschung geworden. Dabei erfordert die Größe der Einzugsgebiete in der Regel eine sehr grobe Diskretisierung, um Gesamtmodelle mit akzeptablen Laufzeiten und Speicheranforderungen zu erhalten. Aber selbst bei fortschreitender Computerentwicklung verhindert die Datenlage eine genauere Auflösung, die der Heterogenität des Untergrundes gerecht wird. Als wesentliche Fragestellung folgt daraus, wie sich die Geometrie von Aquiferen auf einem groben Raster darstellen lässt und inwieweit diese Geometrie und die eingesetzten Parameter der letztendlich entwickelten Modelle mit den vorhandenen Messungen in Verbindung gebracht werden können. Die Beschreibung des Modellraumes (Aquifergeometrien, Flussläufe usw.) auf einem groben Raster wird besonders schwierig, wenn Strukturen abgebildet werden müssen, deren durchschnittliche Ausdehnung in der Größenordnung der Rasterweite liegt. Im Einzugsgebiet der Oberen Donau (78.000 km2 bis zum Pegel Passau-Achleiten), das ein Untersuchungsschwerpunkt des BMBF-Projektverbundes GLOWA ist, wurde ein Quadratkilometerraster als Grundlage der Modellierung gewählt. Dort existieren allerdings einige hydrologisch wichtige alluviale Aquifere, deren Ausdehnung im Bereich von einigen 100 Metern bis zu ein oder zwei Kilometern reicht. Diese Aquifere müssen abgebildet werden, da ohne sie der Wassertransfer aus den alpinen Bereichen zur Donau nicht gewährleistet ist. Für die Anpassung von hydrogeologisch wirksamen Grenzflächen, insbesondere der Aquiferbasis der alluvialen Grundwasserleiter, bietet sich eine Berechnung von klar definierten Gradienten auf diesen Grenzflächen an. Damit ist - analog zu den Fließrichtungen auf einem DGM - gewährleistet, dass das Grundwasser bis zum Auslass des Einzugsgebietes akkumuliert werden kann. Desweiteren können nicht plausible Modellergebnisse aufgrund von Interpolationsfehlern oder fehlerhafter Ausgangsdaten mit diesem Ansatz verhindert werden. Dieser neu entwickelte Ansatz wird in der vorliegenden Arbeit auf das Einzugsgebiet der Oberen Donau angewendet und getestet. Als numerischer Code wurde hierfür das Programm MODFLOW gewählt. Um den Einfluss der Diskretisierung auf die Modellergebnisse zu untersuchen, wurden für ein kleineres Einzugsgebiet (Einzugsgebiet der Ammer, 709 km2 bis zum Pegel Fischen am Ammersee) innerhalb des Gesamteinzugsgebiets zwei weitere Grundwassermodelle auf unterschiedlichen Skalen (100 bzw. 1000 m entwickelt. Das 100 m-Modell wurde als Referenzmodell kalibriert und validiert. Danach wurden diverse Upscaling-Techniken angewandt, um Durchlässigkeiten und Speicherkoeffizienten für das grobe Modell auf Basis des Referenzmodells zu optimieren. Letztendlich werden mit diesem Vergleich die Einsatzmöglichkeiten grob diskretisierter Modelle (z.B. in der Global Change Forschung) untersucht und diskutiert., When assessing the effects of global change upon regional water resources, distributed hydrological models are valuable tools for understanding interactions between the hydrological cycle, the biosphere, land use or the change of land cover. Since these tools are supposed to be applied under changing conditions, they should be as physically-based as possible. One approach to achieve this is to separate the hydrological (and biological) cycle in several components and to represent these components by sets of partial differential equations interrelated by the concepts of continuity of mass and momentum. A spatial and temporal discretization must be chosen for solving these equations numerically. The major advantage of such models is that their parameters are comparable with measured data in the field or have at least a measurable meaning. Additionally, they provide a more detailed description by computing spatially distributed state variables, for example the groundwater level. These results can also be compared to field data. The greatest disadvantage of these models is the amount of parameters they generally need and which are often not known. To apply a physically-based approach on a regional (catchment) scale, the discretization has to be quite coarse in order to achieve reasonable calculation times of the models and manageable storage demand of the output data. At the same time, the coarser the discretization, the less physically-based are the determined parameters of the models. A current example of a distributed complex hydrological model built within the framework of global change research is the model DANUBIA of the program GLOWA-Danube, a research project funded by the German Federal Ministry of Education and Research (BMBF). The project aims at the development and utilization of a decision support system to investigate approaches of sustainable future water use. Therefore modelling the hydrological cycle under changing conditions is a decisive part of this project. The applied spatial discretisation of the overall model is a raster with a cellsize of 1000 m * 1000 m, a compromise between the participating scientific diciplines. For the groundwater component a finite difference scheme was chosen, since it is quite stable, fast and fits very well to a raster-based modelling approach. The research area of GLOWA-Danube, the Upper Danube Basin up to gauge Passau-Achleiten, covers 78.000 km2 in Germany, Austria and Switzerland. Following the identification of the important structures of the regional aquifer system and the creation of a hydrogeological conceptual model, it is important to implement this concept into a groundwater model such that a stable numerical solution of the model is attainable. The main problem in the Danube catchment is achieving a connected alluvial aquifer system which is able to receive the groundwater recharge in the mountain areas and which yields a reasonable base flow at existing gauging stations in the forelands. Due to the discrepancy between the finite difference cell size and the extent of the narrow, highly permeable aquifers, additional highly permeable cells have to be added in order to achieve a closed solution for groundwater flow using a finite difference scheme. In addition, it has to be ensured that each cell of the aquifer has at least one neighbouring cell (in the direction of groundwater flow) with a lower base to guarantee the connectivity of the aquifer. The connectivity can be ensured by upgrading the concept of the hydrological catchment drainage analysis. In this approach, the surface runoff is routed to the catchment gauge by changing the landsurface (the digital elevation model) in such a way that every point (raster cell) has a clearly defined flow direction. To reach this, all sinks in the digital elevation model have to be filled. Thereafter, the flow direction in flat areas must be determined. In this thesis, this concept is expanded to the groundwater runoff. The basis of the alluvial aquifers is adjusted in a similar way as the landsurface so that the groundwater flow can be accumulated to the catchment gauge and the connectivity of the groundwater flow is guaranteed. The landsurface is the upper boundary condition and a minimum aquifer thickness is required. Additionally, it is ensured that the river bottom lies between the aquifer top and bottom. With this approach, a consistent modelling of the geometry of the important components of runoff concentration is possible even with a coarse discretization. The results of this thesis demonstrate that modelling of important hydrogeological structures (here the alluvial aquifers) on a (necessarily) coarser scale than the extent of these structures is possible. The developed extended approach of the hydrological drainage analysis is easy to implement and the designed models are stable and fast and provide useful results for the basinwide analysis of groundwater flow.

This thesis encompasses CO2 mitigation using three different processes: i) natural gas-fired combined cycle with chemical looping combustion (CLC), ii) trigeneration of electrical power, hydrogen and district heating with extended CLC, iii) steam-based gasification of biomass integrated in an advanced power cycle. In CLC, a solid oxygen carrier circulates between two fluidised-bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an inherent CO2 separation occurs. In this thesis, CLC has been studied as an alternative process for CO2 capture in a natural gas-fired combined cycle (NGCC). The potential efficiency of such a process using a turbine inlet temperature of 1200 °C and a pressure ratio of 13 is between 52 and 53 % when including the penalty for CO2 compression to 110 bar. It is shown that this efficiency cannot be further improved by including an additional CO2 turbine. Two conceivable reactor designs for CLC in an NGCC are presented. Top-firing has been studied as an option to overcome a temperature limitation in the CLC reactor system. The degree of CO2 capture is shown versus the temperature in the CLC reactor and its combustion efficiency. CLC has the potential to reach both a higher efficiency and a higher degree of CO2 capture than conventional post combustion CO2 capture technique. However, further research is needed to solve technical problems as, for example, temperature limitations in the reactor to reach this potential. Extended CLC (exCLC) is introduced, in which hydrogen is not only produced but also inherently purified. The potential efficiency of a novel tri-generation process for hydrogen, electricity and district heating using exCLC for CO2 capture is investigated. The results show that a thermal efficiency of about 54% might be achieved. A novel power process named evaporative biomass air turbine (EvGT-BAT) for biomass feedstock is presented. This process contains a steam-based gasification of biomass, which is integrated in an externally fired gas turbine cycle with top-firing. In the EvGT-BAT process, the steam-based gasification is conducted in an entrained-flow tubular reactor that is installed in the SFC as a heat exchanger. The EvGT-BAT process has the potential to generate electrical power from biomass with an efficiency of 41 %.