Session: 20-02: Gas Turbine Operation and Maintenance

Paper Number: 152089

On-Field End-of-Life Filters Fouling Survey of Two 260 MW Gas Turbines 

The life of gas turbines can be severely affected by the airborne contaminants in the atmosphere. Natural and anthropogenic sources combined with the operating condition of the machine determine the contamination characteristics and intensity. Micro-sized particles ingested by the compressor units can adhere to the blades leading to performance deterioration over time, which phenomenon is known as compressor fouling. Multistage filtration systems are fundamental to reducing the contamination severity at the intake of land-based units. High-efficiency media filters are commonly installed in the last stages to remove smaller particles from the airflow. However, the filter's exposure to contaminants leads to the increment of the pressure drop and consequently, maintenance operations have to be accurately scheduled to prevent excessive efficiency reduction. Performance prediction is still a challenging task for gas turbine manufacturers and end-users, who must increase efficiency and reduce consumption while keeping the same reliability and service.

In this work, a detailed analysis of the contamination experienced by two 260 MW land-based units operating in different contaminated environments was carried out. The analysis comprises the on-field detection and collection of deposits taken from the two filter stages, i.e. class M6 and F9 according to the EN779:2012 standard, of the respective filter house. The composition of the deposits was characterized from chemical, physical, and mineralogical perspectives. X-ray Powder Diffraction (XRD) identified the crystalline phases present in the particulate, with quantitative analysis performed through Rietveld refinement of the diffraction patterns. High-resolution imaging using optical and scanning electron microscopy (SEM) provided detailed morphological insights, while energy-dispersive X-ray Spectroscopy (EDS) offered semi-quantitative elemental analysis. Additionally, the bulk chemical composition of the samples was determined via Inductively Coupled Plasma Mass Spectrometry (ICP-MS) following acid digestion with HNO₃. The findings dive into the structure, morphology, and chemical composition of deposits for both filter stages, while the dust-particulate was interpreted in relation to the surrounding environment based on the mineralogical examination. A critical analysis was carried out to correlate the findings of this on-field survey with the historical contamination data of each operating site with an open-source database.

Presenting Author: Nicola Zanini DE – Department of Engineering, University of Ferrara

Presenting Author Biography: He obtained the Ph.D. in 2025 at the University of Ferrara. Actually he is assistant researcher in the turbomachinery research group. His main research activity is focused on the performance prediction of axial and centrifugal compressors when affected by fouling or erosion phenomena.

Authors:

Alessio Suman DE – Department of Engineering, University of Ferrara
Nicola Zanini DE – Department of Engineering, University of Ferrara
Annalisa Fortini DE – Department of Engineering, University of Ferrara
Andrea Bisciotti Department of Physics and Earth Science, University of Ferrara
Mattia Piovan DE – Department of Engineering, University of Ferrara
Giuseppe Cruciani Department of Physics and Earth Science, University of Ferrara
Michele Pinelli DE – Department of Engineering, University of Ferrara