Gasoline hydrogenation results in high sulfur content in the light gasoline
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Recently, the company had to deal with a batch of high-sulfur oil, and the sulfur content in the light gasoline increased suddenly. After etherification, the sulfur content in the gasoline was between 30-50PPM. The temperature in the pre-hydrogenation reactor was also increased, but it didn’t have any effect. Has anyone encountered this situation? The sulfur content of the stabilized gasoline is 1100 PPM, and the nitrogen content is 25
Most of the sulfur in stabilized oil exists in the form of thioether sulfur and thiophene sulfur. When the sulfur content in stabilized oil reaches 1100, either the processing capacity of the facility is insufficient or the sulfur content in the heavier components is too high. Raising the temperature for selective hydrogenation yields limited results. It might be necessary to adjust the separation between light and heavy gasoline based on the degree of vacuum, as well as to increase the temperatures used for desulfurization in the first and second stages; however, this approach results in significant losses in octane rating
It is recommended to check the maximum sulfur content in crude gasoline that the plant’s design allows, and also to measure the level of thiol sulfur in the crude gasoline. If this value exceeds the plant’s maximum processing capacity, raising the temperature in the pre-hydrogenation reactor will not yield satisfactory results, and it will also be harmful to the catalysts. A few days ago, we also processed a batch of high-sulfur oil; the pre-hydrogenation temperature was increased from 152 to 170. It took the plant a whole day to produce hydrogenated oil with sulfur levels that were just acceptable, and the dry point of the light gasoline was only around 38 degrees, resulting in significant loss of octane rating. Then a batch of low-sulfur oil was purchased and blended in for mixing.
The load is too high; light gasoline can be reprocessed; otherwise, the space velocity will be too high and the sulfur content in the light gasoline will definitely be high
These past few days, after replacing the raw materials, the light gasoline has become compliant again
Mm-hmm, so it’s a problem with the raw materials.
Regarding your raw material issue, the sulfur content in the light gasoline produced from conventional raw materials is in the teens, with some values reaching the twenties. It is recommended to adjust the cutting ratio so as to reduce the amount of light gasoline cut, without affecting the load on the subsequent reflux tanks and towers. If that doesn’t work, analyze the sulfur form in light gasoline to identify which stage in the upstream process results in abnormal sulfur content in the gasoline components.