Investigation of the Impacts of Pitting and Fouling Corrosion on Plate Heat Exchanger Effectiveness

Abstract

In power plants, heat exchangers remove heat from a hot fluid to a cooler fluid. Due to their outstanding heat transfer capabilities and corrosion resistance, plate heat exchangers (PHE) manufactured of 316L stainless steel are frequently employed. Fouling and pitting corrosion, on the other hand, can seriously harm PHEs, resulting in lower heat transfer effectiveness, shortened lifespans, and even catastrophic failure. This research investigates how well PHEs (Plate Heat Exchangers) can be preserved from fouling and pitting corrosion, with the Olorunsogo power station as a case study. The research involves analyzing PHE plates using Metallography protocols ASTM E-407-9 standards, Chemical analysis of raw water, reverses osmosis water, CT (Cooling Tower)  feed, and CT bleed water, and Cleaning and Maintenance for mitigation of fouling and pitting corrosion. The analysis of CT water indicated that the chloride levels in the CT feed (142 ppm) and bleed water (709 ppm) were elevated beyond the limits specified by the gas turbine manufacturers. The high levels of total dissolved solids (TDS) in the raw (2020 ppm) and CT bleed water (3060 ppm), combined with a more notable corrosion potential of the plate sample (47.62 mV) compared to CT feed water (71.43 mV), led to severe fouling and pitting corrosion in the plates and CT piping network. After cleaning and maintenance, the calculated COP of 2.256 confirms that the PHEs are functioning effectively.