Query regarding the yellowing of the bottom oil from the distillation process in lubricant base oil production facilities
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Dear experts: Our company uses a high-pressure hydrogenation process to process paraffin-based wax oils; this process is used to produce lubricant bases. Since the plant began operating, the bottom product from the vacuum distillation tower (the product with the highest viscosity) has turned yellow. What could be the cause of this? The oils produced by our heterogeneous reactors and post-refining reactors are both water-white in color. The products from these reactions that enter the atmospheric distillation column also have a water-white color, and the oils from the first and second stages of the vacuum distillation column are as well, with a Ziegler color number of 30+. So why is the oil obtained after distillation yellow? Please ask the experts for guidance, thank you
The outlet temperature of the second reduction furnace shouldn’t be too low; it’s normal for there to be a change in color. One possible solution is to increase the amount of steam supplied at the inlet of the second reduction furnace. Another reason could be related to the quality of the raw materials, and this issue cannot be resolved unless you can obtain raw materials with the desired properties from the catalyst manufacturer. For base oils with high viscosity, adding clay treatment or furfural treatment before air cooling can help resolve the color problem.
Thank you. We also adjusted the outlet temperature of the vacuum furnace and increased the amount of steam supplied to the furnace, but nothing worked. There’s nothing we can do with the raw material – its aromatic content is high, and it’s likely that there are some polycyclic aromatics present, which is causing the color to disappear. Additionally, regarding your suggestion to add clay, does that mean the clay needs to be replaced frequently? After all, the cost of dealing with solid waste is also quite high at the moment
If the exit temperature of the vacuum furnace decreases and increasing the amount of steam supplied to the furnace doesn’t help, then it’s a problem with the raw materials. This is true for every company. If we don’t talk about the issues related to raw materials, and yet still expect the products to be of high quality, well… haha. How did you detect the high aromatic content? If white clay seems difficult to handle, furfural can be used.
You are Shell Technology, right? The oil and water turn white because it’s an uncut distillation product. The issue of low color intensity in the base oil stems from the fact that we don’t have suppliers who can provide raw materials; it’s not that the production facilities are inadequate, but rather the components of the raw materials purchased are too complex, leading to excessive blending in order to improve the company’s profits. The production device of the apparatus cannot be controlled.
Is Shell’s dewaxing technology being used?