Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
2006-09-05
2006-09-05
Oh, Taylor Victor (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
C562S485000
Reexamination Certificate
active
07102029
ABSTRACT:
The present invention proposes a crystallization process comprising the steps of feeding a slurry solution in which a terephthalic acid solution or a part of the terephthalic acid is precipitated to a crystallization vessel, precipitating the terephthalic acid in the crystallization vessel, generating a slurry containing crystals and solvent, discharging the slurry, and further comprising the steps of introducing the slurry in a tangential the direction of a hydrocyclone, returning the slurry flowing out as a downward swirling flow from a lower part of the hydrocyclone to the vessel, and discharging the slurry overflowing from the upper part of the hydrocyclone. According to the present invention, crystals of large particle size is obtained and a stable driving ranging long term can be achieved because any adhesion or accumulation of the terephthalic acid crystals does not appear at all in the crystallization vessel.
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International Search Report mailed Jan. 15, 2002.
Supplementary European Search Report, for Application No. EP 01 96 7778, dated May 19, 2005.
Furuya Takahisa
Ohkoshi Fumio
Antonelli, Terry Stout and Kraus, LLP.
Mitsubishi Gas Chemical Company Inc.
Mizushima Aroma Company, Ltd.
Oh Taylor Victor
Toyo Boseki Kabushiki Kaisha
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