Problems with the desulfurization tower in diesel refining cycle hydrogen
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We currently have a set of diesel hydroprocessing units. The outlet temperature of our reactor is around 365 degrees. The feed oils consist of coker diesel, catalytic reformate diesel, and conventional diesel. The oil skimming line in our recycle hydrogen desulfurization tower is constantly full; it gets full right after oil has been skimming off. Both the on-site glass panels and the DCS level indicators show no problems. The oil from the skimming line of the recycle hydrogen desulfurization tower goes to the rich liquid flash tank, and the liquid level in that tower is 10%； Above 95% of the liquid level in the cyclohydrogen desulfurization tower, from the oil skimming line outlet ； After skimming many times, the liquid level remained the same; as a result, to avoid liquid contamination, skimming is done every day. Sometimes, this leads to liquid present in the liquid separation tank at the inlet of the recycled hydrogen! Please take a look, everyone
Isn’t there a liquid separation tank in front of the desulfurization tower?
What is the feed temperature for high-score operation? ? Reducing the feed temperature can decrease what is carried by the recycle hydrogen
There are several ways to fundamentally solve this problem: 1. Change the raw materials and minimize the amount of catalytic gasoline that needs to be processed; 2. Control the liquid level in the cold high-pressure separator and keep the temperature of the high-pressure air cooler around 49 degrees, as well as increase the number of circulating hydrogen separation tanks. 3. Control the MDEA feed rate and temperature to the tower
Is your high-pressure air-cooled temperature controlled at 49? ? Did there no problems? ? Isn’t it required to be controlled at 45?
No problem. With our process parameters ranging from 40 to 60, there are hardly any cases of liquid carried in the recycled hydrogen. It mainly depends on the amount of coker diesel and gasoline mixed in your raw materials; actually, according to your design, there should be no major issues.
Well, 60 degrees is on the high side. We have a separation tank, so it’s not a big problem even if there are some issues. The maximum amount of gasoline that can be mixed in is 20%, which is basically at the designed level. How about you guys?
Our gasoline level is at 17%； High score with vapor-phase cooling temperature of 35 degrees ； The liquid level in the liquid separation tank at the inlet of the cyclic hydrogen desulfurization tower does not rise, which means that the oil in that tower cannot be completely removed. And is there ethanolamine in the removed oil as well? What’s going on? ? ? ? ? ? ? ? ? ? ?
What is the reaction pressure? Does the circulating hydrogen desulfurization tower use MDEA wet desulfurization? In MDEA wet desulfurization, it is generally required that the temperature of the amine solution be 2-3 degrees higher than that of the circulating hydrogen in order to achieve the best desulfurization results. What should be the temperature of the amine solution? 35 degrees is a bit low; in such cases, no liquid can be separated from the circulating hydrogen tank, which indicates that the liquid essentially makes its way into the circulating hydrogen desulfurization tower, resulting in an excessively high gas flow rate. Check out the \"Q&A on Hydrogenation Technology.\" I remember that the temperature after cooling by high-pressure air cooling has a significant impact on the gas phase velocity and solubility; consider making adjustments based on temperature. Alternatively, you can try reducing the amount of blended gasoline first and see what happens. I haven’t been working with hydrogenation for several years now; I’ve forgotten some things.