The impact of the methanol preheater on distillation
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In our plant’s distillation system, the heat source for the crude methanol preheater is the refined methanol from the pressure tower, while the heat source for the preheater feeding into the pressure tower is steam condensate. When the heat sources for these two preheaters cannot supply heat properly, there are significant changes in the temperature of the material entering the tower. Since there is only one inlet for the feed material, what impact will such a design have on the distillation process? I would appreciate your advice.
From a design perspective, this is done to allow methanol to be fed at its bubble point, as well as to save heat. In practical operations, unstable temperatures or large variations in the flow rate often lead to changes in the temperature of the liquid entering the tower. In such cases, if it is necessary to get the product to meet quality standards as quickly as possible, those components can be shut off first, allowing this liquid to take a shorter route. Wait until all the control points in various aspects are stable before gradually introducing it. It’s just a bit more waste of steam.
Chain reactions are likely to occur, affecting the operation of the pressurized distillation tower; this in turn impacts the vaporization of the crude alcohol, resulting in significant operational fluctuations and making operation difficult.
From the perspectives of design and operation, this is done to allow methanol to be fed at its bubble point, as well as to save heat!
Preheating with pure methanol not only improves efficiency but also saves energy consumption. However, it causes large fluctuations in the temperature of the feed to the pre-distillation tower. My suggestion is to avoid feeding directly from the synthesis stage to the distillation stage; instead, use a pump to feed crude methanol, which will help stabilize the amount of feed and thus reduce fluctuations in the temperature of the crude methanol feed.
Our design doesn’t require direct feeding, but I’m concerned about the preheater design before the pre-tower and the pressure tower.
Using a coarse methanol preheater saves energy consumption, but it is troublesome to operate and results in large temperature fluctuations. Our factory cuts it out, and it’s very convenient to use the methanol in the large methanol storage tank for indirect feeding~!
The goal is to save heat, but this results in instability during operation and frequent adjustments
Feeding in small amounts in this way is beneficial for distillation operations and helps save energy; however, since the fluctuations are relatively large, it is better to feed directly from the crude methanol storage tank
Could everyone explain in detail: what is bubble point feeding? What are the benefits?