What is the crystallization temperature of hydrogen sulfide ammonia in a hydrogenation unit?
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In the reaction process of hydrogenation units, what are the crystallization temperatures of hydrogen sulfide ammonia and ammonium chloride? What process parameters are related to changes in the crystallization temperature?
Personally, I think there is no exact temperature at which this can be measured; it can only be said that the lower the temperature, the more severe the crystallization becomes. In hydrogenation processes, it mainly depends on the partial pressures of ammonia, hydrogen chloride, and hydrogen sulfide; crystallization occurs when these partial pressures reach certain values. Also, the original poster made a typo: it should be “ammonium sulfide”, not “ammonia sulfide”.
This is related to the physical properties of salts; ammonium sulfide salts crystallize at temperatures below 150 degrees, while ammonium chloride salts crystallize at temperatures below 200 degrees! However, these salts are all highly soluble in water; therefore, injecting brine before it enters the high-pressure air cooler, as well as injecting brine intermittently at the inlet of the high-pressure heat exchanger, can effectively alleviate the problem of ammonium salt crystallization
What was said upstairs isn’t entirely accurate either; our device has been exposed to high salinity conditions of 220 degrees. I think salt formation can occur at temperatures below 250 degrees!
To correct what was said on the second floor: hydrogen sulfide and ammonia can form two compounds; in refineries, it is generally ammonium hydrosulfide, with the molecular formula NH4HS – the 4 should be a subscript.
The crystallization of NH4HS is related to the concentrations of hydrogen sulfide and ammonia, while the crystallization of NH4Cl is related to the concentrations of hydrogen sulfide and hydrogen chloride. There are no fixed criteria for this; generally, in hydrogenation units, water is injected continuously before entering the high-pressure air cooler, and water is injected intermittently at the inlet of the high-pressure heat exchanger, depending on the crystallization situation