Filter system

Abstract

The present invention is an improved filtration system, filtering method and unique chemical composition for capturing mercury and other pollutants in flue gases generated by process gas streams. The improved filtration system may take various forms depending on the type of filter system most desired for a particular application; however, the filter system includes at least a filter element or elements and an adsorbent component having a composition suitable for capturing mercury on the downstream side of the filter element.

1 . A filter system comprising 
 at least one particulate collection filter element; and    an insert oriented on the downstream side of said at least one particulate collection filter element, said insert comprising a high surface area support material having on at least a portion thereof a coating composition comprising a binding agent and a promoter, whereby said composition is capable of chemical reaction with elemental and oxidized mercury to bind said elemental and oxidized mercury.    
     
     
         2 . A filter system comprising 
 at least one particulate collection filter element selected from a filter bag and a filter cartridge; and    a removable insert oriented within said at least one particulate collection filter element, said insert comprising a high surface area support material having on at least a portion thereof a coating composition comprising a binding agent and a promoter, whereby said composition is capable of chemical reaction with elemental and oxidized mercury to bind said elemental and oxidized mercury.    
     
     
         3 . The filter system of  claim 2 , wherein said filter element comprises a depth filtration element.  
     
     
         4 . The filtration system of  claim 2 , wherein said filter element comprises a surface filtration element.  
     
     
         5 . The filter system of  claim 2 , wherein said filter element comprises an expanded PTFE membrane.  
     
     
         6 . The filter system of  claim 2 , wherein said coating on said air permeable high surface area support material comprises a binding agent comprising potassium iodide and a promoter comprising zinc acetate.  
     
     
         7 . A filter system comprising 
 at least one particulate collection filter element; and    a mercury collecting filter element oriented separate from and downstream of said particulate collection filter element, said mercury collecting filter element comprising a high surface area support material having on at least a portion thereof a coating composition comprising a binding agent and a promoter, whereby said composition is capable of chemical reaction with elemental and oxidized mercury to bind said elemental and oxidized mercury.    
     
     
         8 . The filter system of  claim 7 , wherein said mercury collection filter element is in the form of a panel filter array.  
     
     
         9 . A filter element comprising 
 an air permeable high surface area support material having on at least a portion thereof a coating composition comprising a binding agent and a promoter, whereby said composition is capable of chemical reaction with elemental and oxidized mercury to bind said elemental and oxidized mercury; and    a sheet of microporous membrane mounted on at least one side of the porous support material, the sheet having a pore structure sufficiently small enough to serve as a barrier to isolate particles in the fluid stream away from the porous support material.    
     
     
         10 . A method of separating particulates and heavy metals from a gas stream comprising: 
 providing a filter system comprising at least one particulate collection filter element; and a mercury collecting filter element oriented downstream of said particulate collection filter element, said mercury collecting filter element comprising an air permeable high surface area support material having on at least a portion thereof a coating composition comprising a binding agent and a promoter, whereby said composition is capable of chemical reaction with elemental and oxidized mercury to bind said elemental and oxidized mercury;    placing said filter system in a gas stream with the particulate collection filter element oriented in an upstream position relative to the mercury collecting filter element to collect the particles suspended in the gas stream;    whereby said particulate is collected on said particulate filter element and said elemental and oxidized mercury is collected downstream of said particulate filter element by said mercury collecting filter element.