Purifiers Kureha Double Screw

Kureha Double-Screw Purifier [Fig. 16.16). This unit employs a double screw with intermeshing blades that express the liquid from the crystal mass as it is conveyed upward. The melt is formed at the top, washes the rising crystals countercurrently, and leaves as residue at the bottom. A commercial unit has an effective height of 2.6 m and a cross section of 0.31 m2. When recovering 99.97% p-dichlorbenzene from an 87% feed, the capacity is 7000 metric tons/yr. The feed stock comes from a tank crystallizer and filter. Data on other eutectic systems are shown, and also on separation of naphthalene and thiophene that form a solid solution a purity of 99.87% naphthalene is obtained in this equipment. 

A third process, the Kureha Double Screw Purifier (Yamada et al. 1982), also called the KCP column, works with a crystal slurry introduced at the bottom of a column. The crystal is transported to the top by a double screw conveyer. There is a melter at the top of the column. The molten crystals are the product and some part is used as reflux. The reflux washes the crystals while moving in a counter current direction. Some residue is taken out at the bottom. 

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See also in sourсe #XX -- [ ]

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