Regarding acidic water stripping, what is the difference between hydrogenated acidic water and non-hydrogenated acidic water?
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As the title suggests: Why do hydrogenated and non-hydrogenated acidic waters need to be treated in different stripping units?
The acidic water produced by hydrogenation units has much higher concentrations of hydrogen sulfide and ammonia compared to that from non-hydrogenation units; moreover, the acidic water from non-hydrogenation units contains more impurities. Therefore, current design approaches typically involve treating these two types of water separately. Similarly, the amine solution regeneration unit also has similar problems.
If it’s the same, then isn’t hydrogen being added for no reason?
Hydrogenated water generally comes from hydrogenation units, such as hydrofining, hydrocracking, residue hydrogenation, and lubricant hydrogenation. Due to their process flows, these hydrogenation units are characterized by high sulfur and ammonia levels as well as low levels of solid impurities. Unlike hydrogenation, it is produced by non-hydrogenation process units such as atmospheric and vacuum distillation, catalysis, and coking; it has low sulfur and ammonia content, but contains impurities such as coke powder and catalyst powder. Non-hydrogenated stripping is generally a full-blowout process, while hydrogenation is a side-stream ammonia extraction process.
In hydrogenated acidic water, the ammonia nitrogen concentration is high; generally, a single-tower pressurized side-stream ammonia extraction process is used. This approach allows for the recovery of liquid ammonia as a product, while also reducing the adverse effects of ammonia present in the acidic gas on the operation of downstream sulfur processing units. In non-hydrogenated acidic water, the ammonia nitrogen concentration is low; therefore, a single-tower low-pressure full-blowout process is generally used for treatment. Due to the low ammonia nitrogen concentration, the ammonia content in the acidic gas is also low, which results in a relatively minor impact on sulfur processing units. Additionally, with low ammonia nitrogen levels, the value of recovery is not high either.
Hydrogenation-type acidic water has a low chloride content; treating the two types of water separately also facilitates the reuse of the purified water obtained after desulfurization and deammonification of the hydrogenation acidic water in the hydrogenation unit, thereby improving the efficiency of using this purified water.
Hydrogenated water generally comes from hydrogenation units, such as hydroprocessing, hydrocracking, residue hydrogenation, and lubricant hydrogenation. Due to their process flows, these hydrogenation units produce water that is high in sulfur and ammonia, low in solid impurities, and has a low chloride content in terms of hydrogenation-related acidity. The hydrogenation unit also needs to reuse the injection water.
The simplest hydrogenation-type acidic water direct steam method can be used to strip out ammonia and hydrogen sulfide, as these substances are mostly in a free state. Hydrogenation-type methods, on the other hand, are primarily based on catalysis and coking; in cases involving coke dust, most of the ammonia is present in the form of ammonium salts. During the stripping process, a small amount of alkaline solution or alkali slag needs to be added, which results in higher levels of ammonia nitrogen in the purified water.
If it’s the same, then isn’t hydrogen being added for no reason?
I’ll learn from it; thanks to everyone for their answers