Evaluation of Offline Compressor Water Washing and its Effect on Siemens SGT-400 Gas Turbine Performance

Abstract

Compressor fouling is a major cause of performance degradation in industrial gas turbines operating in humid and particulate-laden environments. This study evaluates the effect of offline compressor water washing on the performance of a Siemens SGT-400 gas turbine operating in the Niger Delta region of Nigeria. Operational data were obtained from plant station log sheets and analyzed by comparing six months of pre-wash performance with results from a 72-hour post-wash reliability test following offline compressor cleaning. Key performance indicators including compressor pressure ratio, generated power output, thermal efficiency, specific fuel consumption, and heat rate were calculated using standard gas turbine performance relations to quantify the impact of compressor fouling and the effectiveness of the washing process. Statistical evaluation was conducted using a paired-sample t-test to determine the significance of performance changes before and after washing. The results show that offline compressor washing resulted in a 19.8% recovery in generated power and a 16.9% increase in compressor pressure ratio. Thermal efficiency improved by 26.4%, while specific fuel consumption and heat rate decreased by approximately 20.9%. Statistical analysis confirmed that these improvements were significant at the 95% confidence level (p < 0.05). The findings demonstrate that offline compressor water washing is an effective maintenance strategy for restoring both aerodynamic and thermodynamic performance of industrial gas turbines operating under severe fouling conditions and provide field-based evidence to support maintenance planning in high-humidity oil and gas environments.