Patent ID: 6203612
Filing Date: 2001-03-20
Classification: B01D,C07C

Abstract:
A method for cleaning a cooling or crystallization surface surface of a crystallizer fouled with a crystallized bisphenol, said crystallizer containing a slurry derived from the production of bisphenol, comprising the steps of:(a) draining from 20 to 80% of the slurry from the crystallizer;(b) replacing the drained slurry stream with a solvent comprising phenol, thereby forming a diluted slurry;(c) increasing the temperature in the crystallizer to a temperature at which the crystallized bisphenol is dissolved in the diluted slurry, and then rapidly cooling the diluted slurry to a temperature of 45 to 55.degree. C.; and(d) adding a seed slurry containing solid bisphenol at a concentration of at least 5% , said seed slurry having a temperature of 45 to 55.degree. C., until conditions are established at which bisphenol crystals added to the crystallizer do not redissolve.