CONTINUOUS WAVE MID-INFRARED GAS LASER UTILIZING RF EXCITATION

摘要

An aqueous clay slurry 7 is partially dewatered by filtration to remove a first portion of water therefrom which is collected as the filtrate 71. The partially dewatered clay slurry 9 is then contacted with a hot drying gas 25 in a spray dryer 20 to remove an additional water therefrom which is entrained as water vapor in the drying gas 27 exhausted from the spray dryer. The drying gas 27 exhausted from the spray dryer 20 is contacted in a cooling tower 40 with cooling liquid 59 to cause at least a portion of the water vapor evaporated from the aqueous slurry to condense. A first portion 43 of the condensate is passed in heat exchange relationship with the aqueous clay slurry 7 passing to the filter means 10 so as to preheat the clay slurry prior to filtration, a second portion 45 of the condensate is passed in heat exchange relationship with the partially dewatered clay slurry 9 passing from the filtration step so as to preheat the partially dewatered clay slurry prior to spray drying, and a third portion 47 of the condensate is passed in heat exchange relationship with ambient drying gas 21 so as to preheat the drying gas being supplied to the spray dryer 20. The cooled condensate streams 53, 55 and 57 are recycled to the cooling tower 20 to serve as cooling liquid 59 for contacting with the drying gas 27 exhausted from the spray dryer 20.