EVALUATION OF LITHIUM HYDROXIDE FOR ALKALINITY CONTROL OF BOILER WATER SOFTENED WITH EDTA CHELATING AGENT

Abstract : An experimental boiler water treatment for 1200 psi boilers, using lithium hydroxide (LiOH) and the disodium salt of ethylenediaminetetraacetic acid, was evaluated in a series of 30-day studies in model boilers. This combination was found preferable to the present method (low-phosphate control treatment) or to a modification of the present method in which LiOH was substituted for NaOH for pH control (previously reported). When LiOH and NaOH were used independently, without other additives, LiOH was shown, by metallographic examination, to have superior corrosion inhibitive properties. When LiOH was combined with Na2EDTA and dilute seawater (0.5 epm chloride), slight corrosion was detected, but inhibition was superior to that exhibited by NaOH alone.