| 摘要 |
PROBLEM TO BE SOLVED: To provide a recovery method for obtaining pyromellitic dianhydride (PMDA) as a relatively large crystal in a high recovery rate in recovering PMDA from gas containing the PMDA by precipitation of the PMDA, and also to provide an apparatus used for the same. SOLUTION: The gas containing the PMDA is mixed with cooling gas and then the mixed gas is passed through a filter 14, thus the crystal of the PMDA is precipitated on the filter 14. The filter 14 is bent by backwash air from an air conductive line 16, accordingly, the crystal of the PMDA on a surface of the filter 14 is released and recovered. COPYRIGHT: (C)2004,JPO
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