Use of Impedance Spectroscopy to Characterize Lining Performance in Simulated Flue Gas Desulfurization Systems

Abstract

Three organic linings — epoxide (E), vinylester (V), and modified silicon (S) — were investigated under laboratory conditions to determine the best type of high-performance lining for flue gas desulfurization systems. The state of the lining during exposure in 1% sulfuric acid (H2SO4) + 0.2% chloride (Cl-) at pH 1 at 80°C (353 K) and in 70% H2SO4 at 80°C (353 K) was monitored using electrochemical impedance spectroscopy (EIS). Results from tests of resistance to thermal shock were presented. Detailed analysis of impedance results gave information on performance of the linings under these conditions. A new approach for lining behavior analyses was developed based upon coating resistance as a function of exposure time.