Types of salt formation in diesel hydrogenation
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What are the locations of salt formation, the types of salts involved, their dissolution temperatures, and the preventive measures for diesel hydrogenation?
The areas where scaling occurs in hydrogenation units are the same – those where there are changes in concentration and temperature: air coolers, heat exchangers, compressors
Here, we use a cold high-pressure process combined with anhydrous distillation; one step takes place in a high-pressure air-cooled unit, and the other at the bottom of the fractionation tower. In fact, washing it with water is sufficient!
The location of salt deposition is generally in the high-pressure air cooling and high-exchange sections. Water injection is generally used to prevent ammonium salt crystallization.
The salt formation occurs in the high-pressure air cooling and heat exchange sections. High exchange is ammonium chloride, while air cooling is ammonium sulfide. Water injection prevents ammonium salts from crystallizing, which affects heat transfer and can cause severe blockages in the pipes.
In the 1960s, the problem of ammonium salt crystallization in hydrogenation units was resolved technically through the use of water injection, and clear guidelines were established for this in the operating procedures.
Generally, there are ammonia hydrosulfide and ammonium chloride in areas such as air-cooled units, high-pressure heat exchangers, and the inlet pipelines of hydrogen circulation compressors