| 摘要 |
PROBLEM TO BE SOLVED: To efficiently extract solvent from waste product discharged from a dope producing apparatus or the like in switching a dope. SOLUTION: The dope 306 containing a TAC 300 and solvent 301 is prepared in the dope producing apparatus 10. In a case where a new dope having components different from that of the dope 306 is produced, a controlling part 29 stops pumps 21, 31, sets valves 26a, 28a to a closing position, and stops supplying the TAC 300 from a hopper 27. Thereafter, a washing liquid 310 is introduced into the respective devices of the dope producing apparatus. The dope 306 remained in the respective devices are discharged as a waste liquid 320 together with the washing liquid 310. The waste liquid is heated in a dry gas until a liquid level of the waste liquid 320 turns into a falling-rate drying state in a dry heating chamber 51 provided in a solvent removing device 43. In a wet heating chamber 52, the waste liquid is heated in wet gas 410. COPYRIGHT: (C)2009,JPO&INPIT
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