After hydrogenation, the hydrogen sulfide content in the oil is too high, making it difficult to remove
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Recently, a new batch of raw materials was used. After hydrogenation, the hydrogen sulfide content in the naphtha remained high. However, the tests conducted by the doctor were successful. It is suspected that the efficiency of separation in the stabilizer tower is not good, but no severe fluctuations such as tower overpressure have occurred recently; therefore, the likelihood of problems with the tower trays is low. It is also possible that the issue lies in the composition of the raw materials, but the hydrogenation process before the materials enter the stabilizer tower worked fine with no changes observed. Thus, the problem must be in the separation unit. But whether it is due to equipment issues, operational problems, or changes in the raw material composition, I would appreciate it if experts could help analyze this situation
Our company is facing the same problem as well; we hope that the experts here can offer some guidance!
I have a few suggestions: 1. Has there been any change in the sulfur content of the crude oil? 2 What is the change in reaction temperature after oil replacement, does it increase or decrease? If sulfur levels rise, you can appropriately increase the reactor bed temperature. 3 What is the hydrogen sulfide level in the hydrogen system? If it is too high, the amount of stripping steam used in the vulcanization machine can be appropriately reduced; it should not be excessive, and should range from 1% to 3% by volume of the feed volume. 5. Have you checked the sulfur content at the bottom of the hydrogen sulfide gas tower? 6. Are all the temperature levels normal? 7. Is the instrument working properly? Is the instrument working properly? If you don’t mind, you can send me your split-flow diagram
If it is hydrogen sulfide, it indicates that the hydrogenation reaction is fine; if it is in another form such as organic sulfur, then it is a problem with the reaction itself.
This problem only appeared after the change in raw materials, but the sulfur content did not increase after the reaction; the tests conducted by the doctor were successful, which indicates that there should be no issues with the reaction process. After sampling, the sulfur content dropped below 10 ppm after about 10 minutes of evaporation in an open environment. Therefore, we believe the issue lies with the desulfurization tower, but it is not clear exactly what the problem is. The stripping steam was not supplied; the desulfurization tower is a pressurized tower with an operating pressure of 0.25 Mpa, while the distillation tower is a vacuum tower with an operating pressure of -0.068 Mpa
Doesn’t the distillation tower have stripping steam? Is the distillation tower always operated under negative pressure? All the fractionation towers I have seen operate under positive pressure, with pressures ranging from 0.1 Mpa to 0.6 Mpa. Hydrogen sulfide stripping towers use superheated steam (around 400°C) to remove hydrogen sulfide gas. Make sure that the pressure of the stripping steam is higher than that in the hydrogen sulfide stripping tower; otherwise, the steam will not be able to enter the tower