A comprehensive model has been developed for the computation of corrosion rates of carbon steels in the presence of lithium bromide (LiBr)-based brines that are used as working fluids for absorption refrigeration cycles. The model combines a thermophysical module that provides realistic speciation of aqueous systems with an electrochemical module for partial cathodic and anodic processes on the metal surface. The electrochemical module includes the adsorption of halides, which strongly influences the corrosion process. Also, the model takes into account the formation of passive films and their interactions with solution species. The model has been verified by comparing calculated corrosion rates with laboratory data for carbon steels in LiBr solutions. Good agreement between calculated and experimental corrosion rates has been obtained. In particular, the model is capable of reproducing effects of pH-adjusting components and selected inhibitors on the rates of general corrosion. The model has been incorporated into a program that makes it possible to analyze effects of various conditions such as temperature, pressure, solution composition, or flow velocity on corrosion rates.

Subject
Thermodynamics, Ions, Corrosion rate, Electrochemical models, Passive current, Adsorption, Halides, Dissolution, Density, Experimental data, Corrosion modeling, Carbon steel, Risk reduction
Keywords:
electrochemical kinetics, inhibitors, lithium bromide, modeling, prediction, refrigeration, thermodynamics
NACE International
2000
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