Q & A > Question Details
We are facing rapid chocking problem of our feed bottom exchangers of sour water feed/stripped water. In last maintenance, tube side of these exchagers (Sour Water) there were found amonium salts deposited in form of lumps, that ultimately traveld through tower and back in the shell of these exchangers. These have cuased serious flow restrictions at stripped water pump due to insufficent suction. To examine this phenomena suction straniner of feed pump were opened but found almost clean. That shows nothing is coming from the feed tank. Please guide upon possible cause of this salt built up in shell and tube type feed bottom exhangers.
04/06/2014 A: Egbert van Hoorn, Hocon B V, Egbertvh@hotmail.com
It is questionable if the deposits are related to ammonia salts. Which analysis are available? Can you share any pictures?
Deposits can certainly occur in the feed effluent exchanger. Ammonia salts are not likely the reason.
04/06/2014 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Normally ammonia salts are very water soluble. I have never heard of them causing fouling in this service. Most common fouling causes in this service are from heavy hydrocarbons coming in with the feed or from some hard water source making it into the sour water, which results in solids dropping out as the water is heated.
04/06/2014 A: Mike Watson, Tube Tech International Ltd, mike.watson@tubetech.com
Whilst not directly involved in process, I have noticed a similar occurrence before, which was due to precipitation suspension caused by incorrect temperature differentials.
As far as the cleaning is concerned. We do have in situ, high-speed and even online mechanical cleaning technology to remove deposits whilst the unit is still running.
Please check the acid gas temperature. Probabaly it is on lower side (we had 82 to 93°C in one of the past projects), which is facilitating the ammonium bisulphide salts formation.