Method and system for crack-free drying of high strength skin on a porous ceramic body

Abstract

A method and system to dry crack-free and high strength skin including an inorganic binder of an average particle size (D 50 ) in a range between 10 nm and 700 nm on a porous ceramic body. The method includes supporting the honeycomb body on an end face such that axial channels and outer periphery are substantially vertical. A gas is flowed past the honeycomb body substantially parallel to the axial channel direction, substantially equally around the outer periphery of the skin, to uniformly dry the skin to form a partially dried skin under mild conditions. Then the partially dried skin may be dried more severely resulting in rapidly dried crack-free and high strength skin.

What is claimed is: 
     
         1 . A system to dry a skin comprising an inorganic binder having an average particle size (D50) in a range between 10 nm and 700 nm disposed on an outer periphery of a porous ceramic honeycomb body comprising a first end face, a second end face, and axial channels and the outer periphery extending from the first end face to the second end face, the system comprising:
 a honeycomb support configured to support the honeycomb body on the first end face such that the axial channels and the outer periphery are substantially vertical;   a blower configured to flow a first gas vertically to the honeycomb body at a first velocity, such that at least a portion of the first flowing gas passes substantially equally around the outer periphery of the skin disposed on the outer periphery of the honeycomb body to uniformly dry the skin to a first dryness forming a partially dry skin and a second gas vertically to the honeycomb body at a second velocity greater than the first velocity to dry the skin to a second dryness;   a heater configured to heat the first gas to a first temperature and the second gas to a second temperature greater than the first temperature; and   
       a controller configured to control the blower to flow the first gas for a first time period and the second gas for a second time period. 
     
     
         2 . The system of  claim 1 , further comprising a humidifier configured to humidify the first gas to a first relative humidity and humidify the second gas to a second relative humidity less than the first relative humidity. 
     
     
         3 . The system of  claim 2 , wherein the first relative humidity is between about 10% and about 40% relative humidity. 
     
     
         4 . The system of  claim 1 , further comprising at least one of:
 a microwave generator configured to subject the skin to microwave radiation during the second time period; and   an infrared generator configured to subject the skin to infrared radiation during the second time period.   
     
     
         5 . The system of  claim 1 , wherein the first temperature is between about 40° C. and about 60° C., and the second temperature is between about 60° C. and 150° C. 
     
     
         6 . The system of  claim 1 , wherein the first velocity is greater than about 3 m/s. 
     
     
         7 . The system of  claim 1 , wherein the first dryness is between about 20% dry and 50% dry and the second dryness is between about 80% dry and 100% dry. 
     
     
         8 . The system of  claim 7 , wherein the first time period is less than about 120 minutes and the second time period is less than about 120 minutes. 
     
     
         9 . The system of  claim 8 , wherein the first time period is less than about 30 minutes and the second time period is less than about 30 minutes.