Does the pressure of condensate water have an effect on pipe corrosion?
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For condensate pipes, given the same conditions, one at 5 bar g and the other at 0 bar g: which one will experience more severe corrosion, or is there no difference? Thank you!
The effect of condensate pressure on pipe corrosion? ? ? What should be considered are the corrosive elements contained in the condensate, right? ? ?
Assuming all other factors remain the same, to put it simply: what effect does temperature have on condensate?
It’s just a matter of how much gets condensed.
Could you please explain it in more detail? I don’t quite understand it.
First, the problem must be defined specifically, and then discussions should revolve around it. Regarding the title, the magnitude of the condensate pressure has little to no effect on pipe corrosion.
This is a very interesting question. Many people without any professional knowledge draw conclusions based on their actual work experience. In high school, we all came across the concept of solubility. In professional experiments, one will also be exposed to this kind of content. Specifically, under the same operating conditions, the most common form of corrosion in condensate pipes is caused by the dissolution of carbon dioxide. Carbon dioxide dissolves and ionizes in the condensate, making it acidic—essentially forming common H2CO3. Although it is a weak acid, it can lead to hydrogen evolution due to corrosion, which poses significant hazards. I just checked specifically: when condensate water contains 1 mol/L of carbon dioxide, its pH value can drop from 7.0 to 5.5. This data was found online; it remains to be confirmed. Then, we come to solubility. Besides being related to temperature, solubility is also related to pressure. The greater the pressure, the higher the solubility; conversely, the lower the pressure, the lower the solubility. As we all know, in the special equipment industry, what is commonly referred to as “pressure” is actually pressure intensity. I couldn’t find any values regarding the pressure-solubility relationship of carbon dioxide for now; however, I did find data related to hydrogen. Those can be used as a reference (Source: Baidu). At 20°C, the pressure of hydrogen is 1.013×10^5 Pa, and the solubility of hydrogen in one liter of water is 0.01819 liters ； Also at 20°C and 2×1.013×10⁵ Pa, the solubility of hydrogen in one liter of water is 0.01819×2 = 0.03638 L. Therefore, the answer is obvious. Stress and corrosion are related. It’s just a contrast between strong and weak.
The reasoning is very logical. Are there any comparisons with real-world cases?
In this real-world engineering project, it can basically be disregarded. Because other types of corrosion are much more severe than solubility issues. That’s why I said that the experts on the forum, based on their actual work experience, concluded that it doesn’t matter. The expert isn’t exactly wrong; however, drawing a definitive conclusion like that is imprecise. This problem often arises in pilot-scale experiments; the process conditions limit the stability of the operating conditions, which may affect the accuracy of the data.