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Unter fossilen Energieträgern verstehen sich energie- und kohlenstoffhaltige Stoffe, die in mehreren Millionen Jahren aus Biomassen unter dafür günstigen Bedingungen (Sauerstoffausschluss) gebildet wurden. Das geologische Alter von Steinkohle beträgt über 250 Millionen Jahre, das von Braunkohle ca. 50 Millionen. Derzeit werden deutlich mehr fossile Energieträger verbraucht als nachgebildet. Während in Deutschland die Stilllegung von Dampfkraftwerken, die mit Steinkohle befeuert werden, begonnen hat, steigt global der Verbrauch dieser Brennstoffe weiterhin an. Die Steinkohleförderung erreichte im Jahr 2019 weltweit den Wert von 7,3 Milliarden Tonnen, mit einer Steigerung von immerhin fast 3 % gegenüber dem Vorjahr 2018 nach [1]. Dieser Anstieg erfolgte hauptsächlich in China und Indonesien – in Deutschland ging der Kohleverbrauch in diesem Zeitraum zurück.
Wasserkraftwerke
(2022)
Die Wasserkraft ist global die bedeutendste erneuerbare Energiequelle zur Stromerzeugung. Sie hat in Deutschland allerdings einen stagnierenden Anteil von nur ca. 3,5 % der gesamten Stromerzeugung. In Deutschland wurde die Wasserkraft bei der Stromerzeugung durch die Windkraft, Photovoltaik und sogar von der Biomassevergasung überholt. Die Wasserkraft ist allerdings eine gut berechenbare Energiequelle und unterliegt nicht den nur kurzfristig vorhersehbaren Schwankungen der Wind- und Solarenergien.
Auxiliary power units (APUs) are used in mobile applications to supply electrical power in the range of 3 to 10 kW. The state of the art generators are driven by a diesel engine at constant speed. They have a low efficiency (high fuel consumption) as they operate mostly in partial load conditions. A higher efficiency for partial loads is feasible by adjusting the speed of the diesel engine to its optimum efficiency. A frequency converter provides a constant electric frequency at variable speed of the generator. The resulting higher investments for such a variable speed generator (VSG) need a proof of economics, which is demonstrated by this investigation.
Time Resolved Measurements of Soot Concentrations and Mean Particle Sizes during EUDC and ECE Cycles
(2002)
Kolbenmotoren finden in der Energieversorgung vielfältig Verwendung als Notstromaggregate, als Antrieb für Pumpen in Großkraftwerken und in dezentralen Blockheizkraftwerken (BHKW). Motoren für Notstromaggregate und zum Antrieb von Arbeitsmaschinen werden meist mit Diesel-Kraftstoff betrieben. In BHKW dominieren Gasmotoren, wobei Erdgas, Bio-, Deponie- oder Klärgas bevorzugt sind. Die wesentliche Thermodynamik der Otto-, Diesel- und Stirling-Motoren wird in Kürze behandelt, während die Gasmotoren tiefere Behandlung finden. Die Motoren für die Energieversorgung stammen i. Allg. von mobilen Anwendungen ab und werden an die energietechnischen Anwendungen angepasst. Technische Details der Motoren sind in der Fachliteratur zu finden, z. B. [1]. Die Website [2] gibt einen umfassenden Überblick über Hersteller und deren Kolbenmotoren.
Particle and Gaseous Emissions of Diesel Engines Fuelled by Different Non-Esterified Plant Oils
(2007)
The particulate matter and gas emissions of several plant oils are analyzed in the hot exhaust gas under various engine conditions at different speeds and loads The measurement data are compared to the emission values of conventional diesel fuel (gas oil). The investigation concentrates on a modern common rail TDI light duty diesel, four cylinders, for passenger cars. The differences in the gas and particulate matter emission - compared to conventional diesel fuel - are remarkably low for the diesel engine which is properly adjusted for the plant oils. Emission data of an old heavy duty diesel engine are also shown for comparison reasons and reveals large differences. Differences are found in the pressures of the indicator diagram, time resolved over the crank angle. Plant oils consistently exhibit a higher cylinder pressure. The TEM investigation confirms the differences found by the LPME (long path multi-wavelength extinction) on-line analysis.
The importance of obtaining simultaneous particle size and concentration values has grown up with continuing discussion of the health effects, of internal combustion engine generated particulate emissions and in particular of Diesel soot emissions. In the present work an aerosol measurement system is described that delivers information about particle size and concentration directly from the undiluted exhaust gas.
Using three laser diodes of different wavelengths which form one parallel light beam, each spectral attenuation is analysed by a single detector and the particle diameter and concentration is evaluated by the use of the Mie theory and shown on-line at a frequency of 1 Hz. The system includes an optical long-path-cell (White principle) with an adjustable path length from 2.5 to 15 m, which allows the analysis within a broad concentration range.
On-line measurements of the particulate emissions in the hot, undiluted exhaust of Diesel engines are presented under stationary and transient engine’s load conditions. Mean particle diameters well below 100 nm are detected for modern Diesel engines. The measured particle concentration corresponds excellently with the traditional gravimetrical measurements of the diluted exhaust. Additionally, measurements of particle emissions (mostly condensed hydricarbons) from a two-stroke engine are presented and discussed.
A system for the on-line/in-line measurement of soot particle sizes and concentrations in the undiluted exhaust gas of diesel engines was developed and successfully tested. The unit uses the individual attenuations of three different laser wavelengths and is combined with an optical cell (white principle) with adjustable path lengths from 2.5 to 15 meters.
Das Wort Geothermie kommt aus dem Griechischen und setzt sich aus „Geo“ = Erde und „Thermie“ = Wärme zusammen. Bei der Geothermie wird die Wärme des warmen Untergrunds genutzt. Geothermie ist eine regenerative (CO2 freie), stetig verfügbar, von Witterungseinflüssen, Tages- und Jahreszeiten unabhängige Energiequelle, was sie von anderen regenerativ/erneuerbaren Energien wie z. B. Wind und Photovoltaik unterscheidet. Tiefengeothermische Kraftwerke sind grundlastfähig und können andere CO2 intensive Grundlastkraftwerke wie Steinkohlekraftwerke ersetzen. Es wird die oberflächennahe (0–400 m) und die tiefe Geothermie (> 400 m) unterschieden. Oberflächennahe Geothermie wird zur Wärmeversorgung von Gebäuden eingesetzt. Tiefe Geothermie kommt zur Strom- und Wärmeerzeugung zum Einsatz.
Pflanzenöle können einen gewissen Beitrag für eine erneuerbare, nahezu CO2-neutrale Kraftstoffversorgung leisten. Die nicht-veresterten Pflanzenöle haben im Gegensatz zu veresterten Ölen eine günstige Energie- und CO2-Bilanz. Deshalb werden hier die naturbelassenen, aber raffinierten Pflanzenöle auf ihre Eignung als Kraftstoff in Dieselmotoren und deren Emissionen detailliert untersucht. Versuche wurden mit drei verschiedenen Dieselmotoren durchgeführt.
Non-Esterified Plant Oils as Fuel -Engine Characteristics, Emissions and Mutagenic effects of PM-
(2009)
Plant oils may be used as a sustainable, nearly CO2 neutral fuel for diesel engines. This work investigates experimentally the particulate and gaseous emissions of diesel engines fuelled with non-esterified, pure plant oils with the quality standard of DIN V 51605 (Weihen-stephan RK-Qualitätsstandard 05/2000). The data are collected from three engines:
Common rail passenger car engine from OPEL AG
Truck engine from VOLVO
Truck engine from MAN AG
All engines have been correctly adjusted to plant oil operation.
The OPEL and VOLVO engines served for the basic investigations. The emissions of the MAN engine have been used to perform AMES tests to analyze possible health impacts of plant oil operation.
The experimental data show a reduction of particulate matter compared to traditional gasoil which may yield up to 50 % for. The particulate matter shows same primary particle sizes but the agglomerates as collected on TEM grids are different - the plant oil soot particles tend to form larger aggregates [4]. The gaseous emissions of CO and hydrocarbons HC are generally lower compared to the operation with gasoil. However, the NOX emissions are slightly higher. This may be contributed to the measured higher combustion chamber pressures and temperatures when fuelled by plant oils.
Emission samples have been extracted from ESC cycles of 13 step tests to perform the AMES test which give indication on carcinogen substances. The AMES test results gave no indication of mutagenic effects exceeding the detection limits. No significant differences could be found comparing the emissions of plant oil and gasoil operation. Thus, it can be stated that the emission from plant oil operation does not have a health impact different to traditional gas oil. This is in contrast to some other publications — a deeper insight shows that these investigations did not properly modify the engine for plant oils. It is mandatory to make the engine modification to pre-warm the plant oils to approx. 90°C prior to injection. The engine's warm-up phase needs special care to avoid any coking at the injection system and combustion chamber surfaces. The publications where a higher health risk was claimed to be found in the exhaust of plant oil fuels, did not pre-warm the plant oils — cold plant oils have been injected in the combustion chamber instead. This results in incomplete atomization and incomplete combustion with a lot of hazardous emission species (see also [4,11]. Such an operation will damage the engine after relatively short times and is, therefore, not realistic.
The investigated fuels had some influence on the engine characteristics. Higher temperatures and pressures in the cylinder have been detected for some plant oils compared to gasoil. This increase is explained by the higher oxygen content within the plant oils.
Plant oils may be used as a sustainable, nearly CO2neutral fuel for diesel engines. This work investigates experimentally the particulate and gaseous emissions of diesel engines fuelled with different non-esterified, pure plant oils. The data are collected from three engines: a) Common rail 1.7 liter passenger car engine from Opel AG b) 12.8 liter truck engine from VOLVO c) Truck engine from MAN AG.
The emissions of the MAN engine have been used to perform AMES tests to analyze possible health impacts of plant oil operation. Finally, all emission results with plant oils have been compared to traditional gas oils.
The flow field-flow fractionation (FIFFF) technique is a promising method for separating and analysing particles and large size macromolecules from a few nanometers to approximately 50 μm. A new fractionation channel is described featuring well defined flow conditions even for low channel heights with convenient assembling and operations features. The application of the new flow field-flow fractionation channel is proved by the analysis of pigments and other small particles of technical interest in the submicrometer range. The experimental results including multimodal size distributions are presented and discussed.
Non-esterified plant oils gain ecological and economical importance, particularly in the EU where it is intended to increase the share of renewable energies. Plant oils do not require any chemical treatment so do not cause secondary pollution. The importance of plant oil will increase in Germany for mobile and stationary applications. The generation co-generation of heat and power is subsidized by the German “Erneuerbares Energiegesetz” and the “Kraft-Wärme-Kopplungsgesetz” when renewable fuels are used such as plant oils..
Plant oils have a much higher viscosity than conventional gas oil. It is mandatory to decrease the oil viscosity by heating prior to injection to assure proper injection and to avoid engine damage due to coke formation in the combustion chamber and at the injection nozzle. The German quality standard of Weihenstephan (RK-Qualitätsstandard 05/2000) for rape seed oil should be followed for use as diesel fuel. The chemical composition of plant oils is appreciably different in comparison to diesel fuels derived from mineral oils suggesting also different emission behavior.
The three wavelength extinction method (3-WEM) was applied for the on-line particle analysisof suspensions of monodisperse latex beads and polydisperse metal oxide particles of industrialinterest. Comparative measurements were performed by photon correlation spectroscopy (PCS). Thedata of latex particles obtained by 3-WEM and PCS are in good agreement with the manufacture’svalues. Also, the values of oxide particles measured by means of the two techniques are in reasonableagreement despite of the irregular particle shape.Discrepancies are observed by comparing the oxideparticle size results with those of scanning electron microscopy, which is due to the broad sampledistributions and shape irregularities.
Zur Messung geringer Massenkonzentrationen und der Partikelgrößenverteilung unter hohen Druck- und Temperaturbedingungen, wie sie z.B. bei Überwachung des Gasstromes in Druckwirbelschichtfeuerungen oder in Druckkohlestaubfeuerungen vorkommen, wird ein kompensiertes Streulichtfotometer vorgeschlagen. Streulicht- und Transmissionswerte des Partikelkollektivs werden erfasst und miteinander verknüpft. Als Vorteil dieses Mess- und Auswerteprinzips ergibt sich im Gegensatz zu konventionellen Fotometern eine weitgehende Unempfindlichkeit gegenüber Fenster-Verschmutzung und Alterung von Komponenten. Das neue Konzept ist bis etwa 900 ºC einsatzfähig.