Seeking advice on the high mixed aromatic bromine index in aromatic hydrocarbon extraction products
Thread Content
I am using a liquid-liquid sulfolane extraction process; currently, I’m facing a problem – the bromine index of the mixed aromatics has reached 290. I increased the backwash ratio (the supervisor believes it’s due to heavy olefins, so he opened all the backwash valves). What could be the reasons for such a high bromine index in the mixed aromatics? How else should I make adjustments? What are the requirements for the bromine index of the feed to the benzene clay tower? ? The bromine index of benzene products is around 10, which is within the acceptable range! 2. During a certain period earlier, the temperature at the bottom of the deheptanization tower was slightly high; the amount of xylene in the vapor exiting the top of the tower exceeded the specified limit by 2%, while the amount of toluene at the bottom of the tower was less than 0.1%. The bromine index at the bottom of the deheptanization tower ranged from 1400 to 1700 (Is this related to the reforming reaction or the pre-hydrogenation system?) ), could the high temperature cause the unsaturated olefins to evaporate and enter the extraction system? 3. Are there any requirements for the bromine index of the extraction feed?
Is your high physical extraction bromine index related to you?
There are definitely requirements regarding the bromine index; we control the bromine index after the clay tower, before it enters the heptane tower. Otherwise, olefins will be carried into the heptane tower, resulting in an excessively high level of olefins in the extraction feed
Given such a high content of olefins, the backwashing ratio is unlikely to have much effect. The bromine index of the mixed aromatics is so high; I would like to ask what the bromine index of the benzene obtained from the side stream of the benzene tower is Can the clay tower catalyze and adsorb that many olefins, and will it accelerate the deactivation of the clay tower? It’s better to check the olefin content in the feed for extraction; it’s mainly the reforming reaction that matters, in order to avoid too much olefin formation due to high temperatures.
The bromine index of the extracted mixed aromatics is high, which affects the lifespan of the clay ! How is it that it’s okay?! !
After the benzene clay tower (i.e., at the feed to the benzene tower), the bromine index is 170, and sometimes as high as 200; however, the bromine index in the benzene side stream remains around 10. The pressure of the fuel gas system in our plant is unstable, and the composition of the fuel gas varies from time to time; sometimes the nitrogen content is high, and other times it’s the hydrogen content ； The heat of reaction doesn’t increase, and sometimes the flame arrestor gets clogged (with ammonium salts), so the reaction temperature doesn’t rise – it only stays low!