The issue of excessive sulfur content in the feedstock for reformed refined naphtha
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I have a question for everyone: The sulfur content in the feedstock for reformation and refining naphtha has been measured at 1–1.2 ppm for two consecutive days. However, there is hardly any change in the temperature drop during the reformation reaction, and the hydrogen sulfide level in the recycle hydrogen used in this reaction remains between 0.1 and 0.2 ppm. The hydrogen sulfide level in the fuel gas at the top of the pentane removal tower is also always below 1 ppm. Is this normal? If the sulfur content in the feed for the reforming reaction is slightly too high, will it take a long time before the sulfur content in the recycle hydrogen reflects this?
What about the purity of the recycled hydrogen? Have the liquid yield from the stabilizer column and the liquefied gas production increased?
The changes are not significant; the trend remains similar to before.
We have had feed materials containing about 0.8–1.0% S for periods of up to a week; H2S in the reforming cycle hydrogen could not be detected using colorimetric tubes with a sensitivity range of 10 ppm, but it could be detected at levels of over 10 ppm using an H2S detector； There won’t be much of a reaction in the short term
If the outlet temperature of the reforming heater (i.e., the reaction temperature) is not increased, it will gradually be observed that the catalyst activity is affected by sulfur poisoning, resulting in a decrease in the octane number or aromatic content of the reformate.
There’s no problem; don’t worry. Just reduce the pre-treatment sulfur content!
There’s no problem; don’t worry. Just reduce the pre-treatment sulfur content!
Yes, the effect of small amounts of hydrogen sulfide and similar substances in the feed on the reforming catalyst is reversible poisoning; by properly controlling pre-hydrogenation to reduce the sulfur content in the reforming feed, the catalyst’s activity can be restored.
Oh, in that case, our situations are quite similar – I can’t detect it either with test tubes, and we don’t have a hydrogen sulfide detector.:)
Raising the pre-hydrogenation temperature by 20° had no effect, so no further adjustments were made. As a result, after 2 days, the test results dropped below 0.5 on their own; during these two days the value remained below 0.6 most of the time, with occasional readings around 1.0. . . I think there are significant problems with sample preparation in the laboratory. . .
Yes, a few days ago the temperature started to rise, and the stripping tower was operated at its maximum capacity; yet the sulfur content in the refined oil remained at 1.0, with no change at all. We’re also unable to measure organic sulfur or inorganic sulfur, so it’s not possible to determine where the problem lies. . .