What medium should be injected at the top of the catalytic fractionation tower for corrosion prevention?
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What medium should be injected at the top of the catalytic fractionation tower to prevent corrosion? Neutralizing and corrosion-inhibiting agents or ammonia water can be used – what is the difference between these two, and which one do you use?
I haven’t worked on catalytic cracking units for many years; I’ll check the data for you
800,000 tons per year of wax catalyst, with an injection rate of 5 L per hour.
The specific neutralizing agent to be used is determined based on the pH value analysis of the acidic water in the reflux tank. Nowadays, there are few devices that use ammonia water for this purpose; instead, organic amines such as ethylenediamine are predominantly used, mainly to prevent the formation of ammonium salts inside the tower. If corrosion is severe, it is recommended to consider water injection; this should be done before the dew point of the oil and gas at the top of the tower, with an appropriate amount of water injected to ensure good atomization. In fact, water injection is the best method for preventing corrosion.
The dosage of corrosion inhibitors and neutralizers is generally maintained at around 10PPm.
Is the iron ion level in your acidic water high? It used to be 30 ppm, but it has now been reduced to 13 ppm
High – it’s already quite high. Currently, most refineries keep it at ≤3 ppm, while some newly built refineries maintain it at ≤1 ppm.
What is the pH value of the acidic water in the tower top reflux tank? Is there a test for chloride content?
The dosage of the corrosion inhibitor is generally kept between 10–20 PPM (based on the distillate from the top of the fractionator), and the iron content in acidic water remains below 2. Since corrosion inhibitors are alkaline, they cause the pH of acidic water to rise.