STUDY OF THE INHIBITORY PROPERTIES OF SODIUM TRIPOLYPHOSPHATE IN THE "OIMASH SALT-H2O- NaTPP" SYSTEM

Abstract

Abstract. Introduction. Water inhibitors should be used to prevent corrosion of the pipelines and heat exchangers. The phosphorus containing compounds include phosphates, polyphosphate, thiophosphates, pyrophosphates, phosphonates, etc., as the corrosion inhibitors. They are anode inhibitors and, when used on a metal surface, form soluble compounds of oxides, hydroxides and salts, which slow corrosion. The goal of the work. Study the influence of sodium tripolyphosphate concentration on the corrosive aggressiveness in the “Oimash salt – H₂O –NaTPP” system, depending on the type of waters used. Methods. The studies have been carried out by the gravimetric method at the room temperature. Results and discussion: It follows from the obtained results that in the marine water with the addition of NaTPP in concentrations from 20 to 100 mg/l within each of the studied concentrations of the Oimash salt, the corrosion rate V_corr decreases as compared with the control experiment (V_corr– 0.762mm/year). The results have shown that an increase in the Oimash salt concentration up to 30% in the
“Oimash–H₂O–NaTPP” salt system leads to an increase in the solution density from 1.090g/cm³ up to 1.165 g/cm³, and the corrosion rate of steel is reduced intensively. At sodium tripolyphosphate concentrations of up to 250 mg/l, V_corr decreases down to 125 mm/a and at specified C_NATPP  the protection level is 83.58%.  The addition of NaTPP to the “Oimash Salt – Waste H₂O” system increases the corrosion rate of steel, while the corrosion rate of steel relative to the test experience decreases 0.118-0.165 mm/year. The highest protection (50.6%) is achieved at C_NaTPP = 20 mg/l. Conclusions: In the composite systems a high degree of protection is found in marine (83.58%) water. The marine water with the additives of Oimash salt and NaTPP can be used for the preparation of the composite fluids jamming.