Application of Bio-fAEG: A Biofouling Assessment Model in Gas Turbines and the Effect of Degraded Fuels on Engine Performance Simulations

Abstract

The recent advances for flexible fuel operation and the integration of biofuels and blends in gas turbines raise concern on engine health and quality. One of such potential threats involves the contamination and the growth of microorganisms in fuels and fuel systems with consequential effect on engine performance and health. In the past, the effects of microbial growth in fuels have been qualitatively described; however their effects in gas turbines have not necessarily been quantified. In this paper, the effects of fuel deterioration are examined on a simulated aero-derivative gas turbine. A diesel-type fuel comprising of thirteen (13) hydrocarbon fractions was formulated and degraded with Bio-fAEG, a bio fouling assessment model that defines degraded fuels for performance simulation and analysis, predicts biodegradation rates as well as calculates the amount of water required to initiate degradation under aerobic conditions. The degraded fuels were integrated in the fuel library of Turbomatch (v2.0) and a twin shaft gas turbine was modeled for fuel performance analysis. The results indicate a significant loss in performance with reduced thermal efficiency of 1% and 10.4% and increased heat rate of 1% and 11.6% for the use of 1% and 10% degraded fuels respectively. Also parameters such as exhaust gas temperature and mass flow deviated from the baseline data indicating potential impact on engine health. Therefore, for reliable and safe operation, it is important to ensure engines run on good quality of fuel. This computational study provides insights on fuel deterioration in gas turbines and how it affects engine health.