The color of the water purified by sewage stripping is very dark, and no one in the entire plant can solve this problem.
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Previously, the acidic water from wastewater stripping in our plant was supplied directly from the diesel hydrogenation process; however, for certain reasons, this supply was stopped, and the acidic water from hydrogenation was sent directly to the storage tanks. Later on, hydrogenation was no longer allowed; after a few months, it became permissible to use the sewage stripping unit. Acidic water stored in the tank area was used as raw material, and the operation procedure remained the same as before. However, the purified water turned green or dark green, with little odor. Now that the coking unit is in operation, its acidic water is stripped together with the hydrogenation water stored in the tanks previously; the water is dark green in color, with sulfide levels of over 100 and ammonia nitrogen levels of over 1,000. Previously, when only hydrogenation was carried out, the purified water was just as good as tap water. The device is running this way now, and no one can do anything about it. What to do. ? Is there a master to give a lecture?
What are the levels of sulfides and ammonia nitrogen in your raw water? What are the operating parameters of a stripping tower?
Hehe, if it deviates from the original design requirements, the results will also deviate. It’s best to come up with ideas or report problems; this is not something that ordinary people can resolve on their own. The key is to take responsibility for environmental inspections. It’s best to report this upwards to seek a solution. It’s troublesome to avoid causing trouble. It is just a suggestion for reference.
The sulfides in the raw water are over 10,000, I forgot about the ammonia nitrogen. The main equipment of the unit is a stripping tower, an acidic water reflux tank, and pumps. Bottom temperature of the tower: 115, top temperature: 105, feed temperature: 75.
It is speculated that it might be possible that the pH value of the hydrogenated acidic gas water is low; the tanks used for storage in the tank area lack anti-corrosion treatment, and as a result of prolonged contact between the acidic water and the tank walls, ferrous ions are formed, causing the purified water to turn green. You can test the level of divalent iron ions in the water to purify it. Additionally, after treating the acidic water stored in the tanks, proceed directly to treating the hydrogenated acidic water and check whether its color is normal.
Is the pH of the purified water within the acceptable range? Have tests for sulfur and ammonia nitrogen been conducted? Leaks inside the feed and discharge heat exchangers must be ruled out. Is the concentration of acidic ferric ions high? If the pH is too high or too low, some fresh water can be added appropriately, and an alkaline solution can be used to adjust the pH during air stripping. The operating temperature of your tower seems significantly low!
Hydrogenated water generally doesn’t pose many problems; if it is green in color, check whether the iron ion level is above the limit. Also, check whether there are any leaks in the heat exchanger for raw water