Assessing the Environmental Impact of Alternative Fuels in Green Engines: Potential Damages and Protective Measures
Keywords:
Gas turbine; Alternative fuel; Ceramic matrix composite; Environmental barrier coatingAbstract
The use of alternative fuels like syngas and biofuels is highly intriguing due to the rising cost of fossil fuels and the associated greenhouse gas emissions like NOx and COx. In the meantime, ceramic matrix composites that do not require film cooling in combustors, vanes and other hot section components are becoming more and more desirable for green engines because they increase gas turbine engine efficiency and lower NOx and COx emissions. However, compared to traditional jet fuels, alternative fuels have a higher hydrogen to carbon ratio, which results in more water vapour being produced during combustion. The protective oxide scale that has formed on the gas turbine hot section components, especially on those composed of SiC/SiC ceramic matrix composites (CMC), would be affected by the rising water vapour level, hastening the deterioration of the turbine parts. In addition, some biomass-based alternative fuels may contain alkali elements like potassium, sodium, and calcium, as well as chlorine, sulphur, and/or phosphorus, which could cause gas turbine hot section components to corrode and fail early in operation. This essay will examine a few alternative fuels, their combustion byproducts, potential harm to gas turbine hot section components, and proposed protective coatings that could lessen such harm.
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