Hi, Try and get a sample of ...

Hi,

Try and get a sample of the scale to determine the exact composition thereof.  Your feed composition is high in calcium and sulphates and therefore I would think that it is calcium sulphate scaling that occurs.  I worked on a falling film evaporator (FFE) where we had similar feed and issues which required regular shutdown for ultra high pressure cleaning.  Luckily there was more than one FFE and the cleaning could be staggered.  At that stage no one could provide us with a working cleaning in place program to prevent the scaling, only dosing programs to increase the runtime of the plant before mechanical cleaning was necessary.  The most common suggestion was to remove the calcium from the feed through pretreatment in order to prevent the scaling from happening.  We once introduced a softened feed to the FFE and could increase the cycles of concentration tremendously without any scaling taking place.

Good luck with finding a workable solution.