Reformation pre-hydrogenation
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I would like to know whether, after pre-hydrogenation, in addition to removing the head and separating out C5 and C6, the tail is also separated? In other words, the pre-hydrogenation fraction is heavy and cannot be entirely fed into the reformer.
Generally, the boiling range is controlled at the beginning to ensure the dry point of the reformed gasoline, right? For example, in the diolefin removal unit, the intermediate fraction is separated and used as feed for reforming.
Theoretically it is possible, but it is extremely rare in industrial practice. The main issue is the coordination of the entire plant’s processes. To address this, the temperature of the heating furnace needs to be increased, and a distillation tower must also be installed to extract the heavier components from the bottom of the tower. Since the main material has to be distilled and extracted from the top of the tower, this process requires a large amount of energy, making it uneconomical.
The pre-hydrogenation unit is not that complex; its purpose is to control the quality of refined naphtha
If only naphtha is imported, the distillate itself will be heavier
Pre-hydrogenation generally has two modes: one is hydrogenation followed by distillation, and the other is distillation followed by hydrogenation. Here, hydrogenation is carried out first followed by distillation; the final boiling point is controlled by the atmospheric and vacuum distillation unit. After hydrogenation, a stripping tower is used to separate the light components, which are then obtained as the overhead oil. Adopting a pre-hydrogenation process can improve the quality of the stripping oil, but it increases the load on the hydrogenation unit accordingly.
The upstream unit controls the dry point of the pre-hydrogenation feed properly to meet the requirements of the reforming feed, thereby eliminating the need to separate the heavy fractions from the refined naphtha
We have no suppliers; all raw materials are imported. We don’t dare to rely on procurement at the moment, and we just want to know if such a situation exists
Well, if there’s no upstream device, then there’s nothing that can be done. May I ask what the dry point of the pre-hydrogenation feedstock is at the moment? Normally, the dry point should be kept at no more than 180°C. If the value is high, then there are more diesel components present. If your facility has a diesel hydrogenation unit, the material can be fed directly into its distillation tower; through this tower, some of the heavier components can be separated and incorporated into the diesel fraction, thereby reducing the dry point of the feed for pre-hydrogenation. If that doesn’t work, the pre-hydrogenation fractionator could use mid-stream extraction for the reforming section, with heavy naphtha being obtained directly from the bottom of the tower; I’m not sure whether your company meets such requirements.