Patent ID: 8173836

Claim:
A method for drying a wet cake comprising solid particles of terephthalic acid and at least one liquid, comprising: (a) introducing the wet cake comprising the solid terephthalic acid particles and at least one liquid into a drying zone having a heated inner surface; (b) forming a layer of wet cake of at least 10% of the solid terephthalic acid particles having an average thickness of less than 1.5 inches over at least a portion of the heated inner surface contacting the wet cake with a thermally conductive heated wall in the drying zone to convert the at least one liquid to a vapor; (c) drying the wet cake in the drying zone by removing the vapor of the at least one liquid to thereby produce substantially dry solid particles of terephthalic acid, wherein the wet cake comprises from about 2 to about 25 weight percent of the at least one liquid, a feed rate of the wet cake to the drying zone is at least about 20 lbs/hour per square foot of heated surface area of the drying zone, a temperature of the heated wall in the drying zone is from 115 to 265° C., the substantially dry solid particles of terephthalic acid comprises less than about 1 weight percent liquid, an average residence time of the solid terephthalic acid particles in the drying zone is less than about 7 minutes, and an exit temperature of the solid terephthalic acid particles is less than about 250° C. upon exiting the drying zone.