Determination of filming and alkalizing amines using LC-MS and the influence of these amines on ion exchange resin properties

Abstract

In steam turbine power plants, filming amines are injected into the steam header to coat and protect pipe surfaces against corrosion. Alkalizing amines are added to the boiler feed water to control pH of the condensate in order to prevent corrosion. Higher concentrations of these amines in the condensate can corrode copper alloys. Moreover, properties and performance of polishing ion exchange resins used to purify the process water can be affected by the use of filming and alkalizing amines. Hence, it is important to monitor and maintain the amine concentration in the condensate. Understanding the effect of the use of these amines on ion exchange resin properties is also very crucial.

In this work, a simple method has been developed for determination of filming and alkalizing amines using liquid chromatography mass spectrometry (LC-MS). Four filming and four alkalizing amines were successfully analyzed. Cyclohexylamine uptake capacity of DOWEX 650C was also determined using the method. To investigate the effect of exposure, one anion and three cation exchange resins were treated with ten different amines including two commercial filming amines. Resin properties were determined for the standard, amine exposed and regenerated forms.

All the resins were fouled due to amine exposure; higher adsorptions were observed by the cation exchange resins compared to the anion exchange resin. A decrease in exchange capacities were found and regeneration did not achieve complete recovery of the ion exchange resin properties. Adsorption of amines and their presence after regeneration were confirmed by LC-MS and fluorometric analysis.

Salt splitting kinetic experiments were also performed. At the end of this research, nanometric aggregates of molybdenum (VI) oxide and tungsten (VI) oxide were prepared using ion exchange resins that can be used for environmental and catalytic applications.