Polyphosphate performance for inhibiting corrosion of heat exchanger materials

• A. Nikitasari, Sundjono, G. Priyotomo and A. Royani

Research Center for Metallurgy and Material, Indonesian Institute of Sciences, Puspiptek 470 Building, South Tangerang, 15313, Indonesia

Abstract: The inhibitive performance of polyphosphate on the corrosion of heat exchanger materials, i.e., carbon steel A192 and C1015, in ammonia plant was explored. This research analyzed the inhibitive performance of polyphosphate by comparing the corrosion rates (CR) of heat exchanger materials treated with polyphosphate and those without polyphosphate. Three polyphosphate concentrations and three temperatures were used in this experiment: 75 ppm, 100 ppm, 150 ppm, and 32°C, 37°C and 50°C, respectively. This experiment was conducted using an exposure test at Kujang Ammonium Plant and a laboratory test at Research Center for Metallurgy and Material. The exposure test specimens were exposed in a corrosion chamber for 28 days, 56 days, 84 days and 140 days. Visual observations and weight loss measurements were performed to analyze the results of the exposure test. Furthermore, electrochemical tests were carried out at the laboratory. Based on the exposure test, carbon steel A192 has a lower corrosion rate than carbon steel C1015 at each time of exposure. In addition, the corrosion rates of carbon steel A192 and C1015 decreased since 56 days of the exposure test due to the formation of thicker corrosion products. The laboratory test indicated that the corrosion rates of carbon steel A192 and C1015 decreased in the presence of polyphosphate. This result revealed the effectiveness of polyphosphate for inhibiting corrosion of heat exchanger materials. The efficiency of polyphosphate boosts with concentration and diminishes with temperature.

Keywords: polyphosphate, A192 steel, C1015 steel, heat exchanger, ammonia plant

Int. J. Corros. Scale Inhib., 2020, 9, no. 2, 745-756 PDF (838 K)
doi: 10.17675/2305-6894-2020-9-2-22

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