Titolo della tesi: Modeling and Analysis Energy and Environmental Characterization of a Micro Gas Turbine Fueled with H2NG Blends
The increase in energy production from fossil fuels will contribute to an increase in greenhouse gas emissions. The world community recognized the necessity of transitioning from fossil fuel-based to renewable energy sources. Transitioning from fossil fuels to alternative sources cannot be sudden. Instead, it can occur in phases, coexisting with traditional sources until they are entirely replaced. The power to gas strategy effectively corrects production and demand imbalances, especially in countries with extensive natural gas systems. The hydrogen can be used either directly to generate power by fuel cell technologies or co-firing applications with several fossil fuels. In this research deals with one of these pathways and consists of the characterization of a Micro Gas Turbine fueled with Hydrogen and Natural Gas blends. the hydrogen has been added to natural gas in a stepwise fashion with different volumetric concentration ranging in 0% vol. up to 10% vol, by means of a 2% vol. step. By obtaining data from direct measurements and analysis, it was possible to prove that the MGT can be fed with such fuel mixture compositions of H2. An overview of a Micro Gas Turbine system is presented in Chapter one of this research. An experimental micro gas turbine fueled with hydrogen and natural gas blends is described in the second chapter. A MATLAB/Simulink model is presented in Chapter three. An analysis for seasonal energy and environmental characterization is provided in Chapter four. In Chapter five, an artificial neural network model is used to predict the performance of a micro gas turbine fueled by H2NG blends. Based on the results obtained, the environmental conditions outside have reduced the MGT's net electric power output; the maximum achievable load during summer tests was 22 kW, while 27.2 kW was achieved during winter tests. During the hot season, the highest marginal efficiency gain, one percentage point, was recorded at maximum load (22 kW) and with H2NG at 10% vol. In partial load conditions, very close to the minimum power output, that gain does not exceed 0.5 percentage points. Consequently, in the cold season, when MGT runs at its rated power, hydrogen addiction is basically unaffected. Nevertheless, at partial loads, beyond the threshold value of 6% vol. of hydrogen fraction, energy penalties have been registered. The heat recovery efficiency shows a marginal gain of 0.5 percentage points only at 22 kW in the hot season and using 10% vol. of hydrogen, while in all other cases, it is penalised by hydrogen addiction. A similar trend has been registered in the cold season. Specifically, as the hydrogen fraction increases, the heat recovery efficiency lessens by three percentage points, except for a 10-kW setup with H2NG at 10% vol. Furthermore, hydrogen has significantly reduced CO and CO2 emissions, but NOx emissions have slightly increased. Furthermore, using hydrogen in addition to microturbine fuel is also positive factor within the framework of a national policy for Power-to-Gas development and decarbonization.