Process for producing spherical activated carbon

Abstract

Disclosure is made of a specific process for producing activated carbon in spherical form, starting with organic polymer spherules based on styrene and divinylbenzene, wherein said polymer spherules contain chemical groups leading to the formation of free radicals and thus to cross-linkages by their thermal decomposition, in particular sulfonic acid groups. Furthermore, various application purposes for the thus-produced activated carbon spherules are named.

1 . Process for producing spherical activated carbon (activated carbon spherules) by carbonization (pyrolysis, smoldering) and activation of polymer spherules based on styrene and divinylbenzene, wherein said polymer spherules comprise chemical groups, particularly sulfonic acid groups, said chemical groups leading to the formation of free radicals and thus to cross-linkages by their thermal decomposition, 
 characterized in that 
 said polymer spherules are first subjected to a continuous pre-carbonization step and are then discontinuously treated in re-carbonization and activation step.  
   
     
     
         2 . Process according to  claim 1 , characterized in that said chemical groups, particularly sulfonic acid groups, leading to cross-linkages are already present in the starting material and/or that the weight ratio polymer/sulfonic acid groups is about 2:1 to about 1:1.  
     
     
         3 . Process according to  claim 1  and/or  2 , characterized in that said starting material is selected from the group consisting of ion-exchangers, particularly strongly acid ion-exchangers, and/or acid organic catalysts, such as catalysts for the synthesis of bisphenols or the synthesis of methyl-tert.-butyl ether (MTBE).  
     
     
         4 . Process according to  claim 3 , characterized in that an amount of about 5 to about 25% SO 3 , preferably in the form of sulphuric acid and/or oleum, is added to said ion-exchangers, preferably strongly acid ion-exchangers, and/or to said acid organic catalysts before and/or during said carbonization step.  
     
     
         5 . Process according to  claim 1 , characterized in that said sulfonic acid groups are introduced before and/or during said carbonization step, particularly by addition of SO 3 , preferably in the form of oleum, optionally in mixture with sulphuric acid.  
     
     
         6 . Process according to  claim 5 , characterized in that the weight ratio polymer/oleum 20% is about 1:1.  
     
     
         7 . Process according to  claim 5 , characterized in that the weight ratio polymer/oleum 20%/sulphuric acid is about 1:1: 0.5.  
     
     
         8 . Process according to one or more of the preceding claims, characterized in that said polymer spherules are porous, particularly macroporous, and/or gel-like.  
     
     
         9 . Process according to one or more of the preceding claims, characterized in that said carbonization step is carried out in a reaction vessel, particularly rotary-tube, working continuously and having a temperature-gradient of from about 100° C. to about 850° C., preferably from about 100° C. to about 650° C., and preferably with a total residence time of about 1 to about 4 hours, preferably about 2 to about 3 hours, more preferably about 60 to about 90 minutes, particularly wherein the carbonized material may reach a temperature of about 400° C. to about 800° C., preferably about 550° C. to about 600° C.  
     
     
         10 . Process according to one or more of the preceding claims, characterized in that said the material pre-carbonized is continuously collected in a heat-insulated vessel and, when the filling capacity of said heat-insulated vessel is reached, is then introduced into a reaction vessel, particularly rotary tube, working discontinuously for further pyrolysis (re-carbonization) and subsequent activation.  
     
     
         11 . Process according to one or more of the preceding claims, characterized in that said activation is carried out with a mixture of steam (water-vapor) and nitrogen and particularly at temperatures of from about 850° C. to about 960° C., preferably from about 910° C. to about 930° C., particularly with a residence time of about 2 to about 5 hours, preferably about 2 to about 3 hours.  
     
     
         12 . Process according to one or more of the preceding claims, characterized in that SO 2  continuously expulsed particularly during pre-carbonization is regenerated, in particular by catalytic oxidation to SO 3  and further processing to sulphuric acid and/or oleum.  
     
     
         13 . Activated carbon spherules obtainable by the process according to  claims 1  to  12 , particularly with an inner (internal) surface of from about 800 m 2 /kg to about 1.500 m 2 /kg, preferably from about 900 m 2 /kg to about 1.200 m 2 /kg, and/or with a diameter of from about 0.2 mm to about 1.0 mm, preferably from about 0.3 mm to about 0.8 mm, with an average diameter of from about 0.4 mm to about 0.6 mm and/or with a bursting pressure of from about 5 Newton to about 20 Newton per spherule and/or with an apparent density of from about 400 to about 800 g/l, preferably from about 500 to about 750 g/l.  
     
     
         14 . Use of spherical activated carbon obtainable by the process according to one or several of  claims 1  to  12 , for producing of adsorbent materials such as adsorption (surface) filters, filter mats, odor filters, surface filters for protective suits, particularly for civil and/or military purpose, ambient air purifying filters and adsorbing substrate structures.  
     
     
         15 . Use of spherical activated carbon obtainable by the process according to one or several of  claims 1  to  12 , for a protective material, particularly for protective suits against chemical poisons such as warfare agents, or for filters, particularly for removing of pollutants, toxic agents and/or odorous agents (odorants) originating from air or gas streams.  
     
     
         16 . Adsorbent materials, particularly filters of all kinds such as adsorbent (surface) filters, odor filters, surface filters for protective suits, particularly for civil and/or military purpose, such as protective suits against chemical poisons such as warfare agents, ambient air purifying filters as well as protective suits produced therefrom, gas mask filters, filters for removing of pollutants, toxic agents and/or odorous agents (odorants) originating from air or gas streams, filter mats and adsorbing substrate structures, comprising spherical activated carbon obtainable by the process according to any of  claims 1  to  12 .