Browsing by Subject "Ethanol"

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    Biomass quality of miscanthus genotypes for different bioconversion routes
    (2017) Iqbal, Yasir; Lewandowski, Iris
    Currently, a wide range of biomass based resources (wood, agricultural residues, municipal waste, perennial dedicated energy crops) are being tested for different bioconversion routes such as combustion and ethanol production. In Europe, combustion is the most prevalent bioconversion route being adopted to produce heat and electricity. By 2020, in Europe out of 139 Mtoe biomass based energy production, 110.4 Mtoe will be heat and electricity. Along with combustion, EU (European Union) focuses on increasing the share of biofuels production to achieve the EU 2020 target to reach 10% share of renewables in the transportation sector. For both aforementioned bioconversion routes, large amount of feedstocks, produced in a sustainable way, are required. Miscanthus, being a perennial dedicated energy crop has the potential to deliver high yields by using the soil resources efficiently. However, the per unit energy yield depends not only on biomass yield but also quality of biomass relevant for a specific end use. For miscanthus based combustion, high lignin contents increase the energy yield of the biomass. The main challenges are high emissions (e.g. NOx) and combustion relevant problems such as corrosion, fouling and low ash melting temperature. Other than for combustion, the high lignin content is the main problem during miscanthus based ethanol production. Presently, M. x giganteus is the only commercially grown genotype, however a wide range of genotypes are being tested under the European conditions to select the most promising ones for both combustion and ethanol production. Therefore, the focus of this study is to evaluate the biomass quality of different miscanthus genotypes for combustion and ethanol production and relevant measures for each bioconversion route to optimize biomass quality at field level to fit the user demand. To realise the aim of this study, two different field trials were used: 1) long term field trial with 15 miscanthus genotypes (four M. x giganteus, one M. sacchariflorus, five M. sinensis hybrids and five M. sinensis genotypes) was established as randomized block design with three replications; 2) field trial with M. x giganteus and switchgrass was established as a randomized split plot design with different crops as main plots, divided into three subplots with different N levels (0, 40, and 80 kg N ha-1a-1). The biomass samples collected from these field trials were processed and analysed in laboratory to test the biomass quality parameters for combustion (mineral analysis, silicon, chloride, ash, moisture and ash melting behaviour) and ethanol production (fiber analysis, acid/base based pre-treatment). The outcomes of this study show that at biomass production level, crop management practices such as selection of appropriate genotypes, fertilization and time of harvesting determine the yield, biomass quality, overall cost of production and environmental performance of the crop for a specific bioconversion route (combustion, ethanol production). The ash melting behavior during combustion process can be improved through appropriate genotype selection from an ash deformation temperature of 800 °C up to 1100 °C. For ethanol production, fiber composition can be improved up to 16% through appropriate genotype selection by decreasing the lignin content and improving the cellulose content. This improvement will not be completely translated to increase in ethanol yield. However, it can improve the overall efficiency of conversion process by decreased the lignin content and subsequently lowering the energy and chemical inputs required for pre-treatment. In this study, no quantification is made about improvement in final ethanol yield. In fertilization, N fertilization is very important because it constituted up to 72% of the emissions in the conducted LCA described in chapter-1. Therefore, in case of high N fertilization, it not only affects the biomass quality but also increases the cost of biomass production and decreases the environmental performance of the crop. Based on the outcomes of this study, it can be concluded that at this location 40 kg N ha-1a-1 fertilization is sufficient to achieve good yield and quality biomass under late harvest regimes (March). At 40 kg N ha-1a-1 fertilization, the N content in the harvested biomass was still well below the threshold level set (0.3-1%) for biomass by the ENplus wood pellets. The other important factor which offers opportunity to optimize biomass quality is time of harvesting. Through appropriate harvesting time, biomass combustion quality can be improved up to 30% through decreasing the mineral, chloride and ash content whereas for ethanol production, fiber composition can be improved up to 12% by decreasing the lignin content. In practical terms, the delay in harvest will help to meet the set quality standards and counter the relevant challenges for each bioconversion route. In current study, none of the biomasses harvested from the different miscanthus genotypes, except for M. sinensis, could meet the ENplus-B wood pellet standards. For combustion, early ripening thin stemmed genotypes such as M. sinensis are recommended under late harvest regime (March). However, the low yield of these genotypes is a major concern because low biomass quantity decreases the final energy yield. Considering the high dry matter yield, cellulose and hemicellulose content, M. x giganteus and M. sacchariflorus are recommended for ethanol production under early harvest regimes (September-October). However, the high lignin content of M. x giganteus and M. sacchariflorus reduces the efficiency of overall process. Therefore, in this study recommendations were given to breeders about development of new genotypes for combustion by combining interesting traits such as high yield and lignin content of M. x giganteus, low ash content of M. sacchariflorus, low mineral content especially K and Cl of M. sinensis, whereas for ethanol production low lignin content of M. sinensis can be combined with high yield of M. x giganteus. This study suggests that optimization of biomass quality for a specific end use can be achieved through adoption of appropriate crop management practices such as selection of appropriate genotype and time of harvesting. This is the most cost-effective way with least environmental implications.
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    Optimierung und Bewertung der Produktion von Getreidekorngut als Rohstoff für die Bioethanolerzeugung
    (2001) Rosenberger, Alexander; Aufhammer, Walter
    Varied cultivation of high yielding winter cereals to be used as bioethanol grains were examined regarding agronomic and fermentation traits as well as with respect to energetic, economic and environmental aspects. Empirical data were taken from biennial factorial field trials with winter cereals at two different experimental sites of Hohenheim University. These are the central conclusions: A-state-of-the-art conversion process presupposed, the cultivation of high-yielding cereals in crop rotations including previous legume crops is an energetically and economically efficient option to optimize the production of bioethanol grain and hence of bioethanol. From the ecologic view, crop production aligned to high grain yields is conflicting with respect to the enhancement of fossil primary energy conservation and thus the avoidance of greenhouse gas emissions relative to the reference fossil fuel and incremental releases of other ecologically relevant substances as compared to low-input crop management.
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    Ultraschallbasierte simultane Konzentrationsbestimmung der Komponenten Zucker und Ethanol in wässrigen Fermentationsfluiden
    (2014) Schöck, Thomas; Hitzmann, Bernd
    At alcoholic fermentation processes in aqueous solutions there are converted various sugars (mono-, di- and polysaccharides) into ethanol and carbon dioxide by diverse intermediate steps. In the industrial production, ultrasound based methods for the analysis of the composition of the fermentation fluid are advantageous due to their robustness, price cheapness and the possibility for the accomplishment of on line measurements. Within the scope of the present work there are presented several methods for the simultaneous determination of the sugar and ethanol content in the fermentation fluid based on the analysis of ultrasound parameters, also at the presence of dissolved carbon dioxide gas, and compared with respect to the accuracy of their predictive values. Initially there is investigated the behavior of the parameters sound velocity and adiabatic compressibility in standardized aqueous fluids in dependency of the concentration of the components sugar (2 -16 mass percent) and ethanol (1- 6 mass percent), the CO2 partial pressure (0 – 3,013E+05 Pa) and the temperature (2 – 30° C). Thereby the disaccharide saccharose acts as a model substance for the sugar fraction. From the data field of the sound velocity two polynomial calibration models for the sugar / ethanol concentration are extracted with the methods of the multiple linear regression (MLR) and the partial least squares (PLS-) analysis. The minimal accessible standard deviation of the concentration values determined by the particular model from the reference values lies for the MLR method at 0,6 mass percent for the sugar and 0,2 mass percent for the ethanol fraction. The PLS-analysis yields a standard deviation for the sugar and ethanol values of 0,36 and 0,13 mass percent respectively (fluids without a CO2 fraction), as well as 0,5 / 0,17 mass percent (fluids including a CO2 fraction). A further analytic method uses a linearized model of the adiabatic compressibility and the density for the sugar / ethanol determination. The analysis of two physical parameters at this method yields a significant increase of the model quality. For fluids without a CO2 fraction there is reached a minimal standard deviation of 0,06 mass percent for the sugar and 0,07 mass percent for the ethanol concentration. For CO2 containing fluids the corresponding values results to 0,06 / 0,13 mass percent.
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    Verbesserung der Energie-, Stoff- und Emissionsbilanzen bei der Bioethanolproduktion aus nachwachsenden Rohstoffen
    (2010) Fleischer, Sven; Senn, Thomas
    In this thesis, a process was realized that uses starchy raw material (triticale) as well as lignocellulosic biomass (corn silage) in one ethanol production process. In contrast to other so called 2nd generation ethanol processes, which only use lignocellulosic material, the problem of the very low potential ethanol concentration (