Coordination Funds

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The Research Unit 1993 investigates possibilities of using flexible engine processes for the polygeneration of useful chemicals, work, and heat. Based on the state-of-the-art in combustion research, thermodynamically favorable processes in homogeneous-charge compression-ignition (HCCI) engines will be investigated experimentally, guided by theory. The research unit covers the entire chain from model development, exergo-economic analysis and evaluation, optimization, experimental-kinetics investigations to engine testing. The fuels or starting chemicals considered are mainly methane and small oxigenated hydrocarbons, which are expected to remain available for a long time, also as bio-fuel or e-fuel. Due to the low reactivity of these fuels, either high fresh gas temperatures or additives need to be used to promote ignition. Various additives, in particular small ethers, have proven their suitability in the work carried out to date and have led to practical engine processes that are thermodynamically and economically advantageous. The disadvantage of the additives studied to date, however, is that they must be applied at comparably high concentrations and thus a relatively large fraction of the energy is supplied by the additives. Recently the effectiveness of a few ppm ozone in promoting ignition in lean HCCI engines was demonstrated. Preliminary studies within the research unit show great potential also for the application of ozone in the context of fuel-rich mixtures that are relevant for polygeneration processes. The detailed information required for enabling these new processes is however not yet available. Therefore, the research unit will focus in the proposed project phase on the mechanistic, thermodynamic, kinetic and engine-based investigation of the role of ozone in polygeneration. On the one hand, the question arises as to the mechanism of action of ozone, since it is already converted before the actual ignition and therefore forms further reactive intermediates. This will be investigated experimentally and theoretically to elucidate the reaction mechanism. Furthermore, the question arises as to the quantity of additive to be used, its influence on the engine process and the thermodynamic balance of the engine and an overall process based on it, including species separation and energy integration. The formation of soot is a limiting parameter in the process parameter range used. The influence of ozone and small oxigenated hydrocarbons on soot formation shall also be investigated with the aim to avoid soot formation as far as possible. Finally, the optimization of the engine process and its exergo-economic analysis and evaluation will take place with reference to comparable separate processes for the production of useful chemicals, work and heat. The overarching aim of the research group is to develop thermodynamically and economically advantageous processes and to contribute to rational multifunctional species and energy conversion.