I have a question: the pressure difference between the top and bottom of the packed tower is high, and the conditions at the top and bottom are not satisfactory
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The methanol recovery tower of this unit is a four-stage packed tower with intermediate feeding, and has been in operation at the specified temperature for 3 years. It has appeared suddenly recently, with substandard quality at both the top and bottom; in particular, the methanol recovered from the tower contains more than 5% water. Specific phenomena: 1. The pressure at the bottom of the tower increases, with a significant rise in the pressure difference. 2. Even though the amount of steam at the bottom of the tower is lower than before, the temperature levels above the feed inlet are higher than usual (with no change in the feed temperature). Why is this happening, and how can it be adjusted? I earnestly request the experts’ guidance!
What is meant is probably Fan Ta. Is there a major maintenance session every year? Has the filler been removed and cleaned? The filler may have broken or become clogged, causing localized flooding. As a result, the pressure at the bottom of the tower increases, the local temperature is high, and the composition at the top of the tower is abnormal.
If flooding or tower blockage is suspected initially, the operating parameter curves can be analyzed more carefully. A crude approach is to shut down the system and restart it; if that doesn’t work, then dismantling the system for maintenance will need to be considered
Blockage of the packing inside the tower, deviation of gas and liquid flow
A few days ago, the tower was inspected and there were no issues with the packing.
I had a tower inspection a few days ago, and the packing was fine
If there’s no issue with the filler, first reduce the load slightly to see how it performs.
Reduce the backflow, further decrease the heat source usage, and lower the amount of production from the top section. Otherwise, pay attention to whether there is a downward trend in the level of the extract; if not, the liquid level can be lowered. Typed by hand, for reference only.
A liquid phase may have formed; it is recommended to stop feeding first and reduce the evaporation rate in the bottom of the tower. Once the pressure difference between the top and bottom of the tower returns to normal, switch to full reflux. After the product at the top of the tower meets the required standards, resume normal reflux ratio for production, and then gradually return to the normal feeding rate
It’s not possible to tell if there’s a problem with the packing just by looking at its surface; it needs to be removed and cleaned, as it may appear clean on the surface