Q&A

(2010) Question 61: In your experience, what is the effect of crude oil compatibility on crude unit preheat exchanger fouling? Are there any correlations used to predict fouling?

Since there are only isolated instances of fouling in the “cold train” exchangers prior to the desalter(s), we will assume this question is directed more towards the “hot train” exchangers.

(2010) Question 62: What are the refiners experiences using static mixers in place of, or in conjunction with, traditional mixing valves at the desalter?

Years ago, many refiners installed static mixers in desalters, as opposed to traditional mix valves, to improve contacting of water and oil at a lower pressure drop. In theory, this was a good idea, but in practice it has not worked well.

(2010) Question 63: Certain crudes are treated with H2S scavenger to meet a 10 ppm or less specification in the vapor space. In your experience, what is the disposition of the reacted and unreacted scavenger additive through the crude unit? Will this product and/or associated byproducts create corrosion or product quality issues in the crude unit or downstream units?

The majority of H2S scavengers used today are water-soluble, cyclic amines which can quickly react with H2S, forming a water-soluble reaction product. However, these amine-based scavengers are not without potential problems. As formulated, these scavengers often contain un-reacted amines.

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Q&A

(2010) Question 61: In your experience, what is the effect of crude oil compatibility on crude unit preheat exchanger fouling? Are there any correlations used to predict fouling?

(2010) Question 62: What are the refiners experiences using static mixers in place of, or in conjunction with, traditional mixing valves at the desalter?