Blockage situation of the heat exchanger in the methanol distillation tower
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Our plant has a distillation tower; the product obtained from the top of the tower is methanol, while the product from the bottom of the tower are pentyl esters. However, recently there has been a blockage in the reboiler, preventing the heating temperature from rising. Even with the steam control valve fully open, this issue persisted. Upon inspection, it was found that roughly half of the tubes inside the reboiler were blocked. After clearing those blocks and restarting the equipment, the temperature began to rise, but in less than an hour it dropped again, and failed to rise any further. The substance removed from the reboiler is soluble and alkaline in nature; therefore, it is speculated that the salts present in the material may have crystallized due to the high temperature. Additionally, it is necessary to figure out how to prevent further blockages
Pentane-like substances have a relatively high boiling point, which results in a higher temperature at the bottom of the tower. Is this caused by coking due to high temperatures? What type of reboiler do you have? Is it a kettle-type or a thermosiphon type? Could a thermosiphon type be considered?
After this period of research, it seems that the salts contained in the raw materials are responsible for high-temperature coking. We have found a solvent that prevents these salts from crystallizing at high temperatures, allowing them to remain together with the material coming out of the bottom of the tower
Thank you for sharing your valuable experience……