Does the corrosion inhibitor cause corrosion in the pipelines?
Thread Content
This unit injects a corrosion inhibitor into the overhead line of the main stripping tower; I would like to know whether injecting an excessive amount of this corrosion inhibitor (the amount intended for one day as if it were the amount for a week) can cause corrosion in the pipeline
A corrosion inhibitor is a substance that reduces the occurrence of corrosion
In our hydrogenation unit, the amount of corrosion inhibitor injected per shift is about 20 kilograms, which is just enough to keep the iron ion concentration in the acidic water of the stripping column reflux tank between 1 and 3 PPM.
The main function of a corrosion inhibitor is to form a passivation film on the surface of the vessel walls in order to delay corrosion. Once this passivation film has been formed, increasing the amount of corrosion inhibitor added has little effect; it is simply a waste. Unless your company has so much money it doesn’t know where to spend it. Furthermore, the vast majority of corrosion inhibitors contain chloride ions, and excessive amounts of them can still cause some degree of corrosion.
Currently, the content of acidic ferric ions in the water at the top of towers is generally controlled to ≤1 ppm.
During the initial injection phase, a higher volume of fluid is injected; this lasts for about 15 days, after which the injection volume returns to normal levels. The amount of fluid injected is also determined by the results of corrosion tests conducted on samples of acidic water from the top reflux tank
It’s a waste when it’s too large, and it doesn’t cause corrosion to the pipes.
The injection amount is generally between 15 ppm and 30 ppm
Your corrosion inhibitor tank is a great example of this