Patent ID: 7498014
Filing Date: 2009-03-03
Classification: B01J,B28B,C01F,C04B,F26B,Y02P

Abstract:
1. A system for the production of alpha type gypsum in board plants wherein the gypsum is produced using heat recovery, the system comprising: a board dryer including a conveyor and a heating element whereby a number of gypsum boards are transported and heated to thereby remove excess moisture from the gypsum boards, the board dryer including one or more stacks to permit excess moisture from the gypsum boards to be removed from the board dryer as steam; a condenser associated with one of the stacks of the board dryer, the condenser using a cooling medium to cool the steam within the stack to produce a condensate with a temperature within the approximate range of 170° F. to 190° F.; a mixing tank wherein condensate from the condenser is mixed with a combination of raw gypsum and moisture in a 50-50 ratio by weight to produce a gypsum slurry with a temperature within the approximate range of 140° F. to 160° F.; a pump for delivering a portion of the gypsum slurry from the mixing tank to the condenser wherein the gypsum slurry is used as the cooling medium to produce condensate; an autoclave for processing the gypsum slurry from the mixing tank, the autoclave pressurizing and heating the gypsum slurry whereby the gypsum slurry is calcined to yield an alpha-type gypsum and steam, the alpha-type gypsum being used in the production of gypsum boards and wherein the steam generated from the production of the alpha-type gypsum is delivered to the mixing tank to further increase the temperature of the slurry to the approximate range of 170° F. to 180° F.