Reasons for the high water content (reaching 30%) in the circulating oil wash and corrective measures
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During the new benzene production process launched in our plant, the water content in the washing oil reached 30% within 24 hours, which made it very difficult to operate the entire production system. It was later found that the problem was caused by severe water contamination brought in by low-pressure steam, as well as improper control of the boiler’s water level and water supply. During processing, we adopted two methods simultaneously: first, the oil-washing cycle continued as usual, with the steam temperature behind the tubular furnace raised to over 200 degrees for venting, without allowing it to enter the debenzene tower; meanwhile, the moisture in the rich oil was distilled off ； Another method is called the release method: the temperature of the lean oil before it enters the benzene washing tower is raised to 45°, while the temperature of the gas remains at 27–29°. By increasing this temperature difference, the moisture contained in the lean oil is released into the gas, which then carries away this moisture. I wonder if other sailors have encountered the same problem; could we share our valuable experiences? I hope those with experience can share some insights. Thank you!
Personally, I think all of your methods are fine. If it’s allowed, I suggest switching to a direct changing oil, as otherwise it’s easy for the oil to emulsify, which would be counterproductive. My previous approach was to first heat at high temperatures: the oil-rich gas in the tubular furnace was kept at 150 degrees, while the superheated steam was kept at 300 degrees, followed by separation through an oil-water separator. The entire process must be carried out quickly, otherwise prolonged time can lead to emulsification.
Thank you to the friend above for their advice. At that time, the moisture content in our oil stream was 30%, so the temperature could not rise above 300 degrees. Once the oil temperature exceeded 150 degrees, severe vibrations would occur in the hot lean oil pipeline at the bottom of the benzene removal tower; the presence of both oil and gas posed a significant safety risk.
The temperature of the superheated steam is too low; it should be at least 400 degrees
Now that the problem has been identified, I think we should take action from three aspects: 1. Reduce the amount of water carried by water vapor by methods such as raising the temperature； 2. Reduce the water content in the oil used for furnace cleaning ； 3. As you mentioned, use the temperature difference to reduce the amount of liquid water generated during the production process. Also, have you considered checking for leaks in the delivery pipelines and water contamination caused by the insulation pipes? Our factory has encountered this situation