No abstract

Miniature gas turbines (MGT) are an important part of the production of electric energy in distributed systems. Due to the growing requirements for lower emissions and the increasing prices of hydrocarbon fuels, it is becoming more and more important to enhance the efficiency and improve the quality of the combustion process in gas turbines. One way to reduce NOx emissions is to add water to the fuel in the form of a water-based emulsion (FWE). This article presents the research results and the analysis of the impact of the use of FWE on CO and NOx emissions as well as on fuel consumption in MGT GTM-120. Experimental tests and numerical calculations were carried out using standard fuel (DF) and FWE with water content from 3% to 12%. It was found that the use of FWE leads to a reduction in NOx and CO emissions and reduction in the consumption of basic fuel. The maximum reduction in emissions by 12.32% and 35.16% for CO and NOx, respectively, and a reduction in fuel consumption by 5.46% at the computational operating point of the gas turbine were recorded.

The innovative use of the Fuel-Water emulsion in a small gas turbine for distributed energy generation is proposed. The FWE in this situation is considered as a nonhomogeneous mix of water and fuel, where water is a dispersed phase in the continuous fuel phase with an addition of surfactants. The Fuel-Water emulsion has a great mainly due to two mechanisms: temperature reduction due to heat absorption by the water phase and enhanced homogeneity of the fuel-air mixture due to micro-explosion of the superheated water phase inside the emulsion droplet. Proposed paper presents theoretical background on Fuel-Water emulsion combustion mechanism. Finally initial results of numerical research of fuel-water emulsion injection to miniature gas turbine are presented. Theoretical predictions of NOX pollutant emissions are compared with accuracy of the gas analyzer planned to be used during experimental research.

Fuel with the addition of water, forming fuel-water emulsions, is a potential way to reduce the emission of pollutants from gas turbines powered by any liquid fuel. This article analyzes the available work on the combustion of fuel-water emulsions in gas turbines. The literature analysis was preceded by a theoretical introduction on fuel-water emulsion, taking into account the factors influencing its micro- and macroscopic properties. The basic features of the agents used to stabilize the emulsion were also discussed and the process of its combustion was described. The analyzed research differed in terms of the test stands on which the experiments were conducted, the fuel constituting the continuous phase of the emulsion, the amount of water contained in the mixture and the method of producing the emulsion. On the basis of the conducted analysis, conclusions were drawn concerning the influence of feeding a gas turbine with a fuel-water emulsion on the emission of nitrogen oxides, carbon monoxide and exhaust smoke. Conclusions were formulated regarding the influence of the water additive to fuel-on-fuel consumption. In addition, the impact of the presence of water on the conversion of nitrogen contained in the fuel to nitrogen oxides was indicated, and areas requiring further research were presented.

In an effort to reduce the emissivity of transport and energy, numerous studies are being carried out on the impact of the combustion of alternative fuels on the emission and operating parameters of propulsion and energy units. One of the observed trends is the use of emulsion fuels. The addition of an emulsifier to an emulsion fuel reduces the interfacial tension between two liquids, which allows obtaining an emulsion fuel with the expected stability. The research conducted on self-ignition engines and gas turbines (TG) does not give an unambiguous answer as to the influence of the use of fuel-water emulsion on CO emissions. One of the reasons for the discrepancy in the obtained results may be the type and amount of the emulsifier used in the emulsion fuel. Tests were carried out on the GTM-120 gas turbine to compare the operating parameters and emissions between the cases in which TG was supplied with three fuel mixtures—the standard fuel for TG (DF) and DF with 2% and 5% emulsifier addition. It was shown that the addition of 2% of the emulsifier to DF causes an increase in CO emission, with the remaining measured parameters unchanged. On the other hand, increasing the amount of emulsifier in DF to 5% reduces CO emissions to the level observed in the case in which DF was burned reduces NOx emissions and reduces the thermal efficiency of TG.