LGO salt

[Anonymous]

We are having salts foul and corrode our exchangers, piping and fin fan coolers in our LGO circuit.
We have replaced the suction piping to the pumps twice within the past year and had two exchanger failures one on the shell and the other on the bundle of the 1st exchanger on the outlet of the LGO pump.
Has anyone else experienced this and if so how do you remove the salts?
The salt is either Amine or Ammonia or both.
 
Thanks

[Claus GrafParticipant]

Does your fractionator have a water wash coalescer drum ?
 
Regards C.G.

[Anonymous]

Yes
But the Salt is coming out in the LGO before it reaches the overhead.

[Lucibar DavalilloParticipant]

I have never experienced it in Delayed Cokers; in fact, I found it very rear in Delayed Cokers considering the high steam /HC ratio; it is more typical in Flexi /Fluid Cokers.
 
What’s your overhead temperature? Are you dropping lot of naphtha in your LGO?

[Anonymous]

The Overhead temperature is 230 F.
We are leaving some Naphtha in the LGO about 10%.
Thanks

[antonio saura CebrianParticipant]

In order to exists salts must have water condensation and once formed the salt, the same  can travel in the tower, to a temperature of 230ºF could be condensing water in the tower, as a rule FW designed so that the tower operates to a temperature in the top between 240 to 260ºF (25ºF over the dew point), all depend of the water content in the top current (molar fraction of the water)
This unit handles enough water, which comes from the steam or water for speed in the furnace, the steam  purge to the valves and instruments, the steam going to the LCGO or HCGO stripper (if it has them)
Maybe you can  make a water balance  and calculates this temperature in the top (dew point), to be sure that you dont have below the dew point during the different step of the operation (switching, stripping to the fractionator….)
Im sorry for my english, best regards

[Anonymous]

I agree you should calculate the dew point. After that adjust top temperature 10 degrees F above dew point.
If the salt is amonium chloride, it can crystallize depending on partial pressure of choride and ammonia, and the temperature in the top of the fractionator.
In both cases, raising top temperature might help.
 
Regards.
 
Sergio

[Anonymous]

The Salt is in our LGO pump suction and the exchanger downstream of the pump.
The pump suction is at 430 degrees F and 15 psig. The exchanger is 200 psig and 385 degrees F.
 
Thanks

[Anonymous]

What your Lab says? is it Ammonia or Chlorides? if chlorides present, is it possible having a leaking cooling water exchanger in your sponge oil circuit back to the Fractionator?

[Anonymous]

Look at all the pump around return temperatures

[Author]

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