The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 1994
Filed:
Mar. 03, 1993
Nobuo Moriya, Yokohama, JP;
Keiji Shimoda, Machida, JP;
Sachio Asaoka, Yokohama, JP;
Takao Kameda, Yokohama, JP;
Kouji Sakashita, Tokyo, JP;
Tetsuo Maejima, Kiyose, JP;
Makoto Yasui, Yokohama, JP;
Hiroaki Nishijima, Ebina, JP;
Nobuhiro Onda, Hachioji, JP;
Takeshi Kouzaki, Yokohama, JP;
Chiyoda Corporation, Yokohama, JP;
Abstract
High purity, crystalline adduct of bisphenol A and phenol is produced multi-stage crystallization of a phenolic slurry of bisphenol A with a crystal separation and washing step being interposed between each of the two stages. Each of the crystallization stage includes a series of crystallization towers operated at decreasing temperatures. The crystallization of the slurry is performed by continuously discharging a portion of the slurry from each of the crystallization towers, introducing the discharged slurry into one or more coolers and then recycling the cooled slurry to the tower. Another portion of the slurry in each crystallization slurry is continuously discharged, heated for dissolving fine crystals of the adduct and then recycled to the crystallization tower so that large crystals are grown in each of the crystallization steps. An apparatus having a plurality of coolers and suitable for effecting the above crystallization is also disclosed.