Long-term operation of the fractionation system
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How does the distillation system prevent coking of the herringbone baffle?
The coking problem must be addressed by starting at the site of the reaction. The fractional distillation baffles ensure adequate contact between vapor and liquid; areas where the liquid phase cannot reach will also experience coking. For example, install a feed distributor and a well-designed anti-clogging liquid dropping tray. Is coking at the distillation section quite severe in your company? Is the preheating temperature of the raw materials very low (for example, around 200 degrees or even lower)? Are the reaction temperature fluctuations large (over ±1°C or as high as ±3°C)?
How can we prevent problems at the bottom of that V-shaped baffle? Can’t the liquid phase reach it either?
This post was last edited by karamay on 2016-3-8 at 12:59. Would drilling holes in the interlocking plates work? I just guessed that; I don’t know if anyone does that. However, Gritsch packing can be used to replace the chevron baffle, which can significantly reduce coking. Experience in using coking fractionation towers is available. The key issue is to address the coking problem by starting with the reaction. A high raw material preheating temperature + a stable reaction temperature are key.
Could you send a picture of coking on your diagonal baffles? We have been in operation here for 10 years, and we’ve never encountered coking on those baffles; they are always shiny and clean during inspections, with only a little sludge on them
When I first started working with catalysis and went out to learn about it, that facility was temporarily shut down for maintenance. I even went inside the distillation tower; the wedge-shaped baffles there were clogged with carbon deposits of almost 10 centimeters thick, with the clogging occurring mainly at the lower part. At that time I was just starting to learn about this field, so I didn’t understand what was going on.
Catalytic coking units seem to generate a lot of coke dust