To further expand the knowledge base on the use of innovative fuels in the micro gas turbines (MGT), this paper provides insight into interrelation between specific fuel properties and their impact on mixture formation, combustion and emission formation phenomena in a MGT for stationary power generation as well as their impact on material corrosion and deposit formation. The objective of this study is to identify potential issues that can be related to specific fuel properties and to propose counter measures for achieving stable, durable, efficient and low emission operation of the MGT while utilizing advanced/innovative fuels. In addition, cross influences of particular co unter measures are also addressed as the MGT system needs to be addressed holistically. To ensure sufficiently broad range of fuel properties two different fuels with significantly different properties were analysed, i.e. tire pyrolysis oil (TPO) and liquefied wood (LW). Holistic approach is reflected also in the scope of the analysis that covers entire fuel and gas path as well as in the applied methods, which are listed below with some main findings. Corrosion studies confirmed that lower preheating temperature of fuels with low pH value increases corrosion resistance of austenitic stainless steels and partial neutralization is a suitable measure to offset the negative influences of fuels with low pH value on materials. Analysis of spray velocity field via fast spray imaging revealed promoted mixture formation process and thus reduced spray penetration lengths by increasing the atomizing air pressure and the fuel temperature, which is of particular importance for the fuels with high viscosity. Cross - relation of these results with exhaust emissions provided boundaries of the multi - objective constraint space in terms of fuel composition, temperature, primary air temperature (PAT) and turbine inlet temperature (TIT) for efficient operation of the MGT with teste d fuels. Cross influences as for example positive effect of low pH neutralization, should be balanced with increased NO x emissions imposed by the neutralization, while both need to be balanced with optimum fuel temperature in the case of high viscosity fuels. Considering the deposits, sulfur content and several sulfate as well as oxide deposits are critically influencing hot-corrosion phenomena and abrasion damage of hot components.
COBISS.SI-ID: 14256923
With the increasing number of alternative fuels used as energy carriers, an overall approach from modeling of combustion process up to utilization on a macro level is necessary. To support this procedure, a series of tools is being developed to research and analyze the suitability of fuels in advanced combustion devices. Starting with fundamental combustion research which is further applied to case-models, prototype development and pilot studies are often necessary to provide realistic data on overall system response or to be used as validation tools for state of the art numerical models. This study is specifically focused on the intermediate level where transferring of virtual findings to real-life energy systems needs to be backed up by experimental data oriented toward interrelated influences of fuel properties and required engine operating characteristics which often limit the design and operation space of internal combustion engines. Attention will be mainly dedicated to turbine engines considering two different innovative/alternative fuels; liquefied wood (LW) and tire pyrolysis oil (TPO) by covering fuel conditioning process, mixture formation and emission response together with durability studies to provide a holistic experimental assessment of advanced combustion system.
COBISS.SI-ID: 14266139
A tire pyrolysis oil (TPO) produced from waste tires was tested in a 6-cylinder, compression ignition, turbocharged, 6.9 L heavy-duty engine. The thermodynamic parameters, engine performance and exhaust emissions of the engine fuelled with TPO were benchmarked against results of the engine fuelled with commercial diesel fuel (D2). Experiments were conducted in two operating modes, with and without intercooler, at two different engine speeds and at various loads. Impact of thermodynamic and engine performance parameters on combustion process were systematically analyzed in terms of cause and effect phenomena through mechanisms initiated by the fuel properties. The original contribution of this analysis arises from holistic assessment of combustion phenomena, engine performance and emission characterization of a modern turbocharged CI engine fuelled by the pure TPO. Results indicate that TPO can be efficiently used in turbocharged non-intercooled CI engines at high loads, which opens its use in power generation.
COBISS.SI-ID: 13902363