Problems during the commissioning of the methanol-water separation tower at Dalian University of Technology
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Hello everyone, it’s been a long time since I last visited this forum. We haven’t driven for quite some time now, and I’ve encountered a tricky problem while driving; I’d like to ask for your advice! Our low-temperature methanol washing process follows the technology developed by Dalian University of Technology. During this operation, it was not possible to maintain an appropriate water content in the methanol vapor at the top of the methanol-water separation tower. The specific details are as follows: the temperature at the top of the tower exceeded the specified limit by up to 4°C (the design value is 0.22 MPa with a temperature of 96°C); the temperature remained above 98°C. The pressure difference between the top and bottom of the tower was also very high – it should have been around 30–40 KPa, but in reality it was above 70 KPa. Even after shutting off both the steam supply and the feed, it was difficult to reduce this pressure difference. As soon as a small amount of steam was introduced, the temperature at the top of the tower quickly exceeded the limits again ； The designed steam consumption is 2 tons, but in the past 2.8 tons were always required; this time, however, only 1.1 tons of steam was used, which led to the above situation. The feed rate is also lower than the designed value, while there is no significant change in the return flow rate. I would appreciate your advice. My phone number: Zhang 13403999001. Those who are interested in discussing this, please get in touch! Thank you, it’s urgent
First, determine whether the various logistics flow rates are accurate, such as the steam flow rate, whether there is any leakage of directly supplied steam, and whether the feed flow rate is correct. If everything is fine, it’s possible that the liquid may be trapped due to the trays being dirty or containing oil. The safety valve at the top of the tower can be removed to isolate the water separation tower from the main system. The methanol-water mixture containing water must first be sent to the underground tank for contaminated methanol; steam should then be used in full volume to purge the inside of the tower. The pressure difference inside the tower should be monitored, and once purging is complete, deionized water should be introduced into the tower for rinsing. After that, the process can resume with feedstock added again, and the operation status should be checked.
I agree with the suggestion above; first check the steam flow meter and see if there are any leaks. Also, what is the liquid level at the bottom of the thermal regeneration tower?
1. Considering the long downtime of the system, its dirty condition, and the impurities present on the trays, which cause liquid to overflow. 2. Check the water content in the methanol containing water that comes from the water concentration section at the bottom of the thermal regeneration tower; a high water content may lead to high temperatures ； Consider whether the CO2 content in the methanol feedwater is too high.
What is the methanol content at the bottom of the tower? Has there been any change in the composition of the feed material (compared to the design)?； There is a high possibility of impurity blockage inside the tower
Is the feed temperature too high? Is the methanol content in the feed within the specified range? It is recommended to increase the tower top reflux and check again.
Original poster, everyone has given you so many suggestions – has the problem been solved? If it has, please share a specific solution； If it hasn’t been resolved, has it been confirmed that all of the above methods don’t work, or what? Please give me a reply! !
Are the temperatures in each section deviating from the normal range? How long have you been using your tower? Is the methanol level in the water at the bottom of the tower excessive? Is it PanTa? ! ! !
Was the problem solved? How was it handled? Please let me know the result, thanks