What are the ammonia nitrogen and sulfide levels in the sulfur-containing wastewater with high scores from the hydrogenation unit?
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What are the ammonia nitrogen and sulfide levels in the sulfur-containing wastewater with high scores from the hydrogenation unit? Recently, less water has been added, resulting in an ammonia nitrogen level of 12,000 mg/L.
The high-sulfur wastewater from hydrogenation units is the waste water generated after the reaction effluent undergoes high-pressure separation; its main components are H₂S, NH₃ (present in the form of ammonium salts), suspended oils, and small amounts of hydrocarbons. The concentrations of ammonia nitrogen and sulfides are influenced by the properties of the feed oil, the reaction conditions, and the amount of water added. Typical ranges are as follows: Ammonia nitrogen (NH₃-N): generally 500–3000 mg/L; higher concentrations may occur when processing heavy feedstocks (such as residue hydrogenation) or feedstocks with high nitrogen content； Sulfides (as H₂S): Generally, it ranges from 1000 to 5000 mg/L. The sulfide content is directly proportional to the sulfur content of the feed oil; in some hydrogenation units using high-sulfur feedstocks, the sulfide concentration can exceed 6000 mg/L. Such wastewater, due to its high concentrations of sulfides and ammonia nitrogen, is highly toxic and corrosive industrial wastewater; it must be pre-treated using an acidic vapor stripping unit to remove most of the H₂S and NH₃ before it can be sent to the plant’s wastewater treatment facility for further processing.