Analysis of a Micro Gas Turbine Fed by Natural Gas and Synthesis Gas: Test Bench and Combustor CFD Analysis

In recent years, the interest in the research on energy production systems fed by biofuels is increased. Gaseous fuels obtained through biomass conversion processes such as gasification, pyrolysis and pyrogasification are generally defined as synthesis gas. The use of synthesis gas in small-size energy systems, such as those used for distributed micro-cogeneration, has not yet reached a level of technological maturity that could allow a large market diffusion. For this reason, further analyses (both experimental and numerical) have to be carried out to allow these technologies to achieve performance and reliability typical of established technologies based on traditional fuels. In this paper, an experimental and numerical analysis of a combustor of a 100-kW Micro Gas Turbine fed by synthesis gas is presented. The work has been developed in the framework of a collaboration among the Department of Engineering of the University of Ferrara, the Istituto Motori CNR of Naples, and Turbec SpA of Cento (FE). The main features of the microturbine MGT Turbec T100, located at the Istituto Motori CNR of Naples, are firstly described. A decompression and distribution system allows to feed the MGT with gaseous fuels characterized by different compositions. Moreover, a system of remote monitoring and control together with a data transfer system have been developed in order to set the operative parameters of the machine for the current test. The results of the tests performed under different operating conditions are then presented. Subsequently, the paper presents the numerical analysis of a model of the MGT combustor. The combustor model is validated against manufacturer performance data and experimental data with respect to steady state performance, i.e. average outlet temperature, emission levels, pressure drops. Then, a syngas, composed by different ratios of hydrogen, carbon monoxide, methane, carbon dioxide and water, is simulated and the results analyzed.