THERMAL STABILITY OF HEXAMETHYLDISILOXANE (MM) FOR HIGH TEMPERATURE APPLICATIONS asme-orc2015 Tracking Number 11Presentation: Session: Session 1: Working fluids Room: 1A Europe Session start: 11:00 Mon 12 Oct 2015 Markus Preißinger markus.preissinger@uni-bayreuth.de Affifliation: Institute of Engineering Thermodynamics and Transport Processes, Center of Energy Technology, University of Bayreuth Dieter Brüggemann brueggemann@uni-bayreuth.de Affifliation: Institute of Engineering Thermodynamics and Transport Processes, Center of Energy Technology, University of Bayreuth Topics: - Working Fluids (Topics), - I prefer Oral Presentation (Presentation Preference) Abstract: The design of efficient ORC units for the usage of industrial waste heat at high temperatures requires direct evaporating systems without an intermediate thermal oil circuit. Therefore, the thermal stability of high temperature working fluids gains importance. In this study, the thermal degradation of hexamethyldisiloxane (MM) is investigated in an electrically heated tube. The results include qualitative remarks on degradation products as well as the annual degradation rate as quantitative parameter. It is shown that MM is stable up to a temperature of 300 °C with annual degradation rates of less than 3 %. Furthermore, the break of a silicon-carbon bond can be a main chemical reaction that influences the thermal degradation. Finally, the impact of the results on the future design of ORC units is discussed. |