| 摘要 |
A METHOD FOR PRODUCING PARAXYLENE FROM A XYLENE-CONTAINING FEED-STOCK, WHEREIN A FIRST FRACTION IS ENRICHED TO AT LEAST 30 WT. WITH PARAXYLENE, AND SAID FRACTION IS PURIFIED BY MEANS OF AT LEAST ONE HIGH-TEMPERATURE CRYSTALLISATION STEP PERFORMED IN AT LEAST ONE CRYSTALLISATION ZONE. SPECIFICALLY, SAID FIRST FRACTION ENRICHED TO AT LEAST 30 WT. WITH PARAXYLENE IS CRYSTALLISED IN A CRYSTALLISATION ZONE (50) AT A HIGH TEMPERATURE (T1), ADVANTAGEOUSLY BETWEEN +10 AND -25 °C, A SUSPENSION OF CRYSTALS IN A MOTHER LIQUOR IS RECOVERED, THE CRYSTALS ARE SEPARATED FROM THE MOTHER LIQUOR IN AT LEAST A FIRST SEPARATION ZONE (52), THE RESULTING CRYSTALS ARE PARTIALLY MELTED IN AT LEAST ONE PARTIAL MELTING ZONE (55), A CRYSTAL SUSPENSION IS RECOVERED, THE CYRSTAL SUSPENSION IS SEPARATED AND WASHED IN AT LEAST ONE SEPARATION AND WASHING ZONE (57), AND PURE PARAXYLENE CRYSTALS AND A WASHING LIQUOR (58) ARE RECOVERED, WHEREAFTER SAID PURE CRYSTALS ARE OPTIONALLY COMPLETELY MELTED (61) AND A LIQUID STREAM (60) OF MOLTEN PARAXYLENE IS RECOVERED. THE MOTHER LIQUOR MAY BE CRYSTALLISED IN A SECOND CRYSTALLISATION ZONE AT A HIGH TEMPERATURE (T2) LOWER THAN THE FIRST (TL), AND THE SECOND CRYSTALS MAY BE PARTIALLY MELTED, SEPARATED AND WASHED AS ABOVE (FIG.2)
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