Durene recovery process

摘要

In a method for recovering durene a feed stock containing less than 15 per cent by weight of durene is cooled in a zone 14 (Fig. 1) to a temperature in the range -75 DEG F. to -100 DEG F. crystals are formed in a holding tank 16, and a filter cake containing 15 to 50 per cent by weight of durene separated in a centrifuge 18, the filter cake being melted in a tank 21 and the melt cooled in a zone 24 to 0 DEG F. to form crystals in a holding tank 26; a second filter cake containing 60 to 90 per cent durene is then separated in a centrifuge 28 and melted in a tank 30 and the melt cooled in a zone 32 to 100 DEG F. and a third filter cake separated in a centrifuge 34 as product. The filtrate from the first centrifuge 18 is discarded, the filtrate from the second centrifuge 28 is added to the feed stock entering the first chilling zone 14, and the filtrate from the third centrifuge 34 is added to the melt entering the second chilling zone 24. In a modified method the feed stock mixed with filtrate from the second centrifuge is cooled to 0 to -40 DEG F., seeded with a portion of slurry from the first holding tank and cooled to -75 DEG to -100 DEG F., and a portion of the filter cake from the second centrifuge is added to the slurry in the first holding tank; the melt entering the second chilling zone is also seeded with a portion of slurry from the second holding tank.