The relationship between hydrogenation pressure and cost
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It is well known that the higher the pressure, the greater the capital investment required. Is there a relatively quantitative relationship? For example, in the production of Euro 4 diesel: some companies say that a total pressure of 4–6 MPa is sufficient for production, while others claim that around 8 MPa is required. So what is the difference in investment costs in these cases? The pressure differences in hydrocracking are relatively larger; I hope a more detailed comparison can be provided
There are actually many factors that influence this issue, and there is no linear pattern. For example, issues such as the raw materials mentioned on the second floor, the activity of the catalysts used, and the technology employed in the equipment all have an impact. The pressure in the hydrogenation unit should be determined based on the actual conditions of the unit, the production objectives, and the quality requirements of the product. For some devices, the raw materials used have a low level of impurities and low sulfur and nitrogen contents; therefore, low pressure is sufficient to achieve the production goals, eliminating the need to increase pressure and thus avoid additional costs. On the contrary, in some devices where the impurity content in the raw materials is high, it is necessary to increase the hydrogen partial pressure to complete the hydrogenation process. Therefore, it is meaningless to consider the relationship between pressure and cost in isolation.
Hydrogenation processes mainly refer to hydrofining and hydrocracking, with the latter requiring higher operating pressures than the former. For hydrofining, the pressure is generally around 8 megapascals, while that for hydrocracking is around ten megapascals or so. I’m not aware of the maximum pressure that can be achieved; I still think it’s meaningless to consider operating pressure in isolation. After all, a high operating pressure does not indicate that the process technology is advanced – on the contrary, it may suggest that it is rather outdated. The hydrogenation process involves catalytic processing, and this brings up the issue of catalyst activity. Advanced catalysts available abroad enable the hydrogenation of low-quality feedstocks at lower pressures, yet the quality of the resulting products remains very good. This shows that as technology continues to develop, operating pressures will keep decreasing
For hydrorefining, the pressure is generally around 8 MPa. The pressure in hydrocracking is kept at around 160 MPa. The investment required for hydrorefining is much lower, being approximately 0.4 times that of hydrocracking. Hydrorefining is used to ensure the quality of the oil products, as otherwise they cannot be released for use. Hydrocracking produces a wider range of products, but it is more cost-effective to carry out this process in companies that integrate refining and processing operations