Please help analyze the reasons for corrosion under the same operating conditions
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The plate heat exchangers used by the company are made of 254 steel; the medium being heated is sulfuric acid with a concentration of around 130 g/L, and the heating medium is hot water. The temperature of the sulfuric acid after heating is approximately 55 degrees. The heat exchange fins of a heat exchanger at the end of the sulfuric acid main pipe are constantly corroding, while the 5 heat exchangers in other locations under similar operating conditions are in good condition; they have already been replaced three times in less than 2 years, all using 254 steel. Now, we need to analyze whether it could be the high pressure at the end of the pipeline, or excessive flow rates, that are causing an increased corrosion rate.
More detailed parameters are needed for analysis. The analysis involves comparing this unit with 5 other units under the same operating conditions, focusing on differences such as heat exchange area, temperature on the hot side, sulfuric acid concentration, and the temperature of the sulfuric acid after heating
This post was last edited by Anhui Dabang Anti-corrosion on 2016-9-14 09:43. The corrosion phenomena are as follows: ① Corrosion of the plates occurs due to improper selection of materials, resulting in cracks or perforations. ②The operating conditions do not meet the design requirements. ③Residual stresses resulting from the cold stamping of sheet metal, combined with overly tight clamping dimensions during assembly, cause stress corrosion. ④There is a slight leak at the plate leakage groove, which causes harmful substances in the medium to concentrate and corrode the plates, resulting in fluid leakage between them. Factors such as operating temperature, flow rate, and concentration are very important; in summary, corrosion was likely caused by a leakage issue within the equipment.
Thank you for the analysis; it shouldn’t be that reason, as it’s happened 3 times already.
Thank you for the analysis; it shouldn’t be that reason, as it’s happened 3 times already.
No, apply an anti-corrosion coating to the heat exchange fins; give it a try. Isolate the material from contact with the sheet.
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Is there such a big difference under the same operating conditions? What’s the supervisor’s version? Flow rate? Is it the same as the other 5 units as well? Has the pressure been measured? Is there any change? I suspect that an increase in flow rate is exacerbating the corrosion.
Sandblasting equipment can be used for treatment
We analyzed it in the same way; the flow rate at the end of that pipe might be too high