Hello all, We have had a problem of pH variation in our Crude desalting system. To find out the root cause of variations in pH at similar caustic injection, we checked the pH of water drain from crude tank (after giving 24 hours settling time to received crude ) and pH was found in the range of 1 ~ 2. We have been trying to figure out the problem by randomly checking the crude lorries but we haven't found any thing relevant. We have analyzed TAN of crude also and it ranges between 0.02 ~ 0.06 which is quiet normal for our case.
What could be the reason for such a low pH and what tests can be run on received crude to find out the problem?