| 摘要 |
1,128,718. Reflux crystallization. INVENTA, AG. FUR FORSCHUNG UND PATENTVERWERTUNG, ZURICH. 1 May, 1967 [2 May, 1966], No. 20052/67. Heading BIG. In a process of reflux crystallization, crystals are conveyed through a column in countercurrent flow to liquid by means of a liquidpermeable screw conveyor of gauze or perforated material rotating at 0.1-300 rpm. The column may be subjected to a pulse having a frequency of 15-400 cycles per min and a stroke of 1-200 mm. Alternatively, the worm may be pulsated. As shown, a liquid mixture to be treated is crystallized in a scraper cooler 2 and is conveyed to the middle section of a reflux column 1 containing a sieve screw conveyor 8 and subjected to the pulsing action of a reciprocating piston 9. A high mp fraction in crystal form is melted by a heater 6 at the base of the column, a portion of the melt being withdrawn and the remainder passing back up the column. A low mp fraction in liquid form is discharged from the top of the column and a portion recycled in crystal form to the upper part of the column after passage through a scraper cooler 5. Caprolactam or phenol may be purified. |
