Análise comparativa de diferentes processos de limpeza química de caldeiras utilizadas em uma termoelétrica do RS.

Abstract

Thermal Power Plants in the internal corrosion of boiler has always been a major concern. Although there is a huge investment in technology for corrosion control, there are several forms of attack in which it is difficult to diagnose and combat. The failure can be attributed to corrosion caused by exposure of the incorrect steel material of the boiler to the cleaning during operation of washing chemical or exposure to different operating conditions (high temperature, high pressure). As a result, operational shutdowns occur with great frequency for replacement of damaged components. In this work we studied the comparative analysis of a treatment chemical cleaning of boilers, using hydrofluoric acid and citric acid, which will analyze the effect on the ASTM A213 T2 from laboratory tests of mass loss in media with different chemical composition. The studies in this paper were made with samples of boiler tubes donated by UTE Presidente Médici, in which it also provided information on the chemical cleaning procedure, thus allowing the measurement of the oxide layer, particularly magnetite. This evaluation of the oxide layer is used to verify the degree of impairment of tubular boilers. The identification and measurement of the oxide layer on the inside of boiler tubes aquatubular was studied through the techniques of Raman spectroscopy and scanning electron microscopy.