Stefan Retschitzegger - Academia.edu (original) (raw)
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Papers by Stefan Retschitzegger
Glycerol is an interesting compound with a medium heating value that can produce good quantities ... more Glycerol is an interesting compound with a medium heating value that can produce good quantities of hydrogen, when converted through pyrolysis (even equal to 50%v at 800°C). Glycerol is a waste of biodiesel production. In Europe about 1.2 Mm 3 /y of waste glycerol are available. In this work the energy use of glycerol will be analyzed by an economical point of view, focusing on the production of pellet made of 10%w glycerol and 90%w saw dust and its conversion through pyrolysis, to produce heat and electricity in a rotary kiln plant. This study will be based on data retrieved from two experimental campaigns: the first performed at University of Perugia, Biomass Research Centre, and the second at Bioenergy 2020+ and Graz University of Technology. The second experimental campaign was performed in the framework of the European project BRISK and was used also to check the reliability of the first. The purpose of the work is to determine an optimal way to convert in energy waste glycerol...
Fuel Processing Technology, 2016
Fuel Processing Technology, 2015
Energy & Fuels, 2013
To systematically investigate high-temperature corrosion of superheaters in biomass combined heat... more To systematically investigate high-temperature corrosion of superheaters in biomass combined heat and power (CHP) plants, a long-term test run (5 months) with online corrosion probes was performed in an Austrian CHP plant (28 MW NCV ; steam parameters: 32 t/h at 480°C and 63 bar) firing chemically untreated wood chips. Two corrosion probes were applied in parallel in the radiative section of the boiler at average flue gas temperatures of 880 and 780°C using the steel 13CrMo4-5 for the measurements. Corrosion rates were determined for surface temperatures between 400 and 560°C. The results show generally moderate corrosion rates and a clear dependence upon the flue gas temperatures and the surface temperatures of the corrosion probes, but no influence of the flue gas velocity has been observed. The data are to be used to create corrosion diagrams to determine maximum steam temperatures for superheaters in future plants, which are justifiable regarding the corrosion rate. Dedicated measurements were performed at the plant during the long-term corrosion probe test run to gain insight into the chemical environment of the corrosion probes. From fuel analyses, the molar 2S/Cl ratio was calculated with an average of 6.0, which indicates a low risk for high-temperature corrosion. Chemical analyses of aerosols sampled at the positions of the corrosion probes showed that no chlorine is present in condensed form at the positions investigated. Deposit probe measurements performed at the same positions and analyses of the deposits also showed only small amounts of chlorine in the deposits, mainly found at the leeward position of the probes. Subsequent to the test run, the corrosion probes have been investigated by means of scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses. The results confirmed the deposit probe measurements and showed only minor Cl concentrations in the deposits and no Cl at the corrosion front. Because, in the case of Cl-catalyzed active oxidation, a layer of Cl is known to be found at the corrosion front, this mechanism is assumed to be not of relevance in the case at hand. Instead, elevated S concentrations were detected at the corrosion front, but the corrosion mechanism has not yet been clarified.
Glycerol is an interesting compound with a medium heating value that can produce good quantities ... more Glycerol is an interesting compound with a medium heating value that can produce good quantities of hydrogen, when converted through pyrolysis (even equal to 50%v at 800°C). Glycerol is a waste of biodiesel production. In Europe about 1.2 Mm 3 /y of waste glycerol are available. In this work the energy use of glycerol will be analyzed by an economical point of view, focusing on the production of pellet made of 10%w glycerol and 90%w saw dust and its conversion through pyrolysis, to produce heat and electricity in a rotary kiln plant. This study will be based on data retrieved from two experimental campaigns: the first performed at University of Perugia, Biomass Research Centre, and the second at Bioenergy 2020+ and Graz University of Technology. The second experimental campaign was performed in the framework of the European project BRISK and was used also to check the reliability of the first. The purpose of the work is to determine an optimal way to convert in energy waste glycerol...
Fuel Processing Technology, 2016
Fuel Processing Technology, 2015
Energy & Fuels, 2013
To systematically investigate high-temperature corrosion of superheaters in biomass combined heat... more To systematically investigate high-temperature corrosion of superheaters in biomass combined heat and power (CHP) plants, a long-term test run (5 months) with online corrosion probes was performed in an Austrian CHP plant (28 MW NCV ; steam parameters: 32 t/h at 480°C and 63 bar) firing chemically untreated wood chips. Two corrosion probes were applied in parallel in the radiative section of the boiler at average flue gas temperatures of 880 and 780°C using the steel 13CrMo4-5 for the measurements. Corrosion rates were determined for surface temperatures between 400 and 560°C. The results show generally moderate corrosion rates and a clear dependence upon the flue gas temperatures and the surface temperatures of the corrosion probes, but no influence of the flue gas velocity has been observed. The data are to be used to create corrosion diagrams to determine maximum steam temperatures for superheaters in future plants, which are justifiable regarding the corrosion rate. Dedicated measurements were performed at the plant during the long-term corrosion probe test run to gain insight into the chemical environment of the corrosion probes. From fuel analyses, the molar 2S/Cl ratio was calculated with an average of 6.0, which indicates a low risk for high-temperature corrosion. Chemical analyses of aerosols sampled at the positions of the corrosion probes showed that no chlorine is present in condensed form at the positions investigated. Deposit probe measurements performed at the same positions and analyses of the deposits also showed only small amounts of chlorine in the deposits, mainly found at the leeward position of the probes. Subsequent to the test run, the corrosion probes have been investigated by means of scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses. The results confirmed the deposit probe measurements and showed only minor Cl concentrations in the deposits and no Cl at the corrosion front. Because, in the case of Cl-catalyzed active oxidation, a layer of Cl is known to be found at the corrosion front, this mechanism is assumed to be not of relevance in the case at hand. Instead, elevated S concentrations were detected at the corrosion front, but the corrosion mechanism has not yet been clarified.