WAYS TO REDUCE CORROSIVE-ABRASIVE WEAR OF A CENTRIFUGAL FAN IMPELLER OPERATING IN AN AGGRESSIVE GAS ENVIRONMENT

Abstract

Impellers of centrifugal fans used in industrial plants to transport aggressive gases and discharge them from process systems are simultaneously exposed to chemical, mechanical, and hydrodynamic effects. Under such conditions, corrosion of the metal surface can occur together with erosive-abrasive wear caused by moisture, chemically active components, and solid particles contained in the gas flow. This paper analyzes the operating condition of a centrifugal fan impeller working in the aggressive gas environment of a superphosphate production process and identifies structural zones that are particularly susceptible to wear. Observations of protective-coating damage and metal corrosion at blade-to-disk joints, on the rear disk surface, at edges, and in zones subjected to intensive flow action substantiate the need for differentiated protection of individual structural zones. To extend the service life of the impeller, it is proposed to improve surface preparation, increase coating adhesion to the metal, and form a protective system adapted to the intensity of corrosive-abrasive action.