What is the color of the quench water in the quench tower?

When the system is stable, it remains very clean, similar to clear water; it turns dark when disturbed, and if it turns yellow, that indicates the presence of sulfur.

The normal color of the quench water is relatively clean; if it turns black, this is caused by fluctuations in the operation of the sulfur production and hydrogenation systems, and such fluctuations can affect the start-up and shutdown of the system. Whether there is sulfur or sulfur dioxide that has not fully reacted, it is taken to the quench tower where it reacts to form sulfur.

Under normal conditions, the color of the quench water is fairly clear. When there are problems in the sulfur production section, the quench water turns black, has an unpleasant odor, with a hydrogen sulfide smell. If the capture efficiency of the third cooling unit and the exhaust gas separation tank is poor, or if hydrogenation in the exhaust gas system is incomplete, sulfur can enter the quench tower, blocking the packing in the quench tower as well as the quench water coolers. In such cases, the water becomes gray and turbid; I have never encountered a situation where the water turned yellow

The quench water here is mostly clear, but it contains some black substances, with a hydrogen sulfide concentration of around 1000!

Under normal conditions, the quench water is a saturated aqueous solution of hydrogen sulfide; therefore, it does not absorb hydrogen sulfide but only serves to cool down. If there are issues with the operations in the subsequent processes or other problems arise, a series of issues will occur, which will be evident in aspects such as the color of the water and its pH value. Under normal conditions: the water is clear and transparent, with a pH value generally above 6. Excessive air supply: The pH level gradually decreases, reaching as low as 1-2. If the pipelines are made of carbon steel, severe corrosion will occur. Ferrous ions (light green in color) are present in the water, and these ions further oxidize to ferric ions (brown in color). Over time, ferric ions further oxidize to white iron oxide, as well as black magnetite and red hematite. As a result, the color of the water changes from green to yellow, then to brown, and finally to black, and the deposition of impurities also increases. Insufficient air supply: The pH level will decrease to some extent, usually around 5-6. Excessively high temperatures in the third-stage sulfur cooler and in the steam generator, as well as damaged foam breakers, excessive air supply, and insufficient hydrogen supply, can all lead to sulfur being carried downstream; as a result, sulfur sand may be present in the water.

Apart from having an unpleasant odor and being clean, if ammonia is added too frequently while water changes are not done often, it can easily cause the color to turn black

It is basically clear water; however, if there are abnormalities in the previous section or if the catalyst in the system becomes powdered, the water will take on a blackish appearance. If yellow water appears, it indicates that sulfur dioxide has penetrated and reacted inside the quench tower; in severe cases, this can cause the system to become clogged.