Questions about ammonium salt crystallization in hydrocracking units?
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Is there a problem with ammonia hydrosulfide crystallization in the hydroprocessing unit?
The reaction system has water injection; I just want to know more about it
I’ve never encountered it; however, the areas prone to crystallization are regularly flushed with water, and not much crystallization was seen during maintenance
Ammonium salt crystallization occurs in all hydrogenation units; the sulfur, nitrogen, and chlorine removed through hydrogenation can form ammonium chloride and ammonium hydrosulfide at low temperatures. A certain amount of water must be injected to wash away these ammonium salts, thereby preventing blockages in pipes and equipment.
The reaction water injection rate for the unit is 10 percent of the feed volume; why then do ammonium salt crystals still form in the butane removal system? Is there insufficient water injection?
It has happened that shutdowns were caused by ammonium salt crystals blocking the system; in some areas water is injected intermittently, while in other areas it is injected continuously~~~
Salt formation in the hydrodesulfurization fractionation system occurs because the reaction products carry a small amount of H2S and NH3 into the low-pressure system, where these substances combine with H2S to form ammonium hydrosulfide as they rise to the top of the tower. The water injection amount in the reaction system should be determined by the ammonium hydrogen sulfide content in the highly acidic solution, with a general control level of ≤8%.
Yes, in our units, high-pressure air cooling systems have experienced one instance of blockage caused by ammonium salt crystals; it was a localized blockage that occurred when the external temperature was too low, as well as due to the low temperature of the medium during operation – which is quite dangerous
Why is it continuous in some places and intermittent in others?