ERYTHORBATE, AN ALTERNATIVE TO SULFITE IN THE PREVENTION OF CORROSION IN SUGAR MILL BOILERS

SULPHITE BASED OXYGEN scavengers have previously been shown to not react as expected with dissolved oxygen in sugar mill feed water to effectively remove it. Alternative oxygen scavengers were studied with respect to their ability to react with dissolved oxygen in sugar mill feed water. An erythorbate based product was able to reduce the dissolved oxygen concentration in the feed water and the oxidation reduction potential (ORP) of the system compared to periods of dosing with sulphite. A tannin based product did not appear to have any measureable impact on either dissolved oxygen or ORP. Measurements of typical corrosion product concentrations, iron and copper, in the feed water suggested that the reduction of oxygen and ORP by the erythorbate also resulted in reduced corrosion rates. Further, extended, trials will be needed to confirm this.