Activated carbon sorbent composition with reduced auto-ignition properties

Abstract

An activated carbon sorbent composition comprising activated carbon and a passivation agent, wherein the activated carbon sorbent composition exhibits reduced self-heating or auto-ignition properties as compared to the activated carbon. The activated carbon sorbent composition may be utilized to sequester contaminants such as mercury from a flue gas stream. The passivation agent includes a sulfur species, and may be a sulfur oxide compound, a sulfide compound, or an organic sulfur compound. Methods for the manufacture of the activated carbon sorbent composition and for the sequestration of contaminants in a flue gas stream using the composition are also disclosed.

1 . An activated carbon sorbent composition, comprising:
 activated carbon; and   a passivation agent, the passivation agent comprising a sulfur oxide compound selected from the group consisting of:
 (i) a nonionic sulfur oxide compound defined by the formula SO y , where y=2 or 3; and 
 (ii) an ionic sulfur oxide compound comprising an anion defined by the formula SO x O y   2− , where x=1 or 2 and y=2, 3, 4, 5, or 6. 
   
     
     
         2 . The sorbent composition recited in  claim 1 , wherein the sulfur oxide compound is an ionic sulfur oxide compound. 
     
     
         3 . The sorbent composition recited in  claim 2 , wherein the ionic sulfur oxide compound comprises a cation that is selected from the group consisting of hydrogen, a nitrogen-containing compound, and a metal cation. 
     
     
         4 . The sorbent composition recited in  claim 3 , wherein the cation is hydrogen. 
     
     
         5 . The sorbent composition recited in  claim 4 , wherein the ionic sulfur oxide compound is sulfuric acid. 
     
     
         6 . The sorbent composition recited in  claim 3 , wherein the cation is a nitrogen-containing compound. 
     
     
         7 . The sorbent composition recited in  claim 6 , wherein the nitrogen-containing compound is ammonium. 
     
     
         8 . The sorbent composition recited in  claim 7 , wherein the ionic sulfur oxide compound is ammonium sulfate. 
     
     
         9 . The sorbent composition recited in  claim 6 , wherein the nitrogen-containing compound is an alkylammonium compound. 
     
     
         10 . The sorbent composition recited in  claim 3 , wherein the cation comprises a metal cation. 
     
     
         11 . The sorbent composition recited in  claim 10 , wherein the metal cation is selected from the group consisting of an alkali metal, an alkaline earth metal and a transition metal. 
     
     
         12 . The sorbent composition recited in  claim 11 , wherein the metal cation is an alkali metal. 
     
     
         13 . The sorbent composition recited in  claim 12 , wherein the alkali metal cation is selected from the group consisting of lithium, sodium, and potassium. 
     
     
         14 . The sorbent composition recited in  claim 13 , wherein the alkali metal is sodium. 
     
     
         15 . The sorbent composition recited in  claim 11 , wherein the metal cation is an alkaline earth metal. 
     
     
         16 . The sorbent composition recited in  claim 15 , wherein the alkaline earth metal is selected from the group consisting of magnesium, calcium, and barium. 
     
     
         17 . The sorbent composition recited in  claim 11 , wherein the metal cation is a transition metal. 
     
     
         18 . The sorbent composition recited in  claim 17 , wherein the transition metal is selected from the group consisting of zinc, iron, copper, nickel, titanium, manganese, aluminum, and vanadium. 
     
     
         19 . The sorbent composition recited in  claim 18 , wherein the transition metal is selected from the group consisting of iron, aluminum, and zinc. 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . The sorbent composition recited in  claim 1 , wherein the sorbent composition comprises at least about 0.1 wt. % of the sulfur oxide compound. 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . The sorbent composition recited in  claim 1 , wherein the sorbent composition comprises not greater than about 10 wt. % of the sulfur oxide compound. 
     
     
         27 . The sorbent composition recited in  claim 1 , wherein the sorbent composition comprises not greater than about 5 wt. % of the sulfur oxide compound. 
     
     
         28 . (canceled) 
     
     
         29 . The sorbent composition recited in  claim 1 , wherein the specific enthalpy of the sorbent composition is at least about 10% lower than the specific enthalpy of the activated carbon. 
     
     
         30 . (canceled) 
     
     
         31 . The sorbent composition recited in  claim 1 , wherein the specific enthalpy of the sorbent composition is at least about 30% lower than the specific enthalpy of the activated carbon. 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . The sorbent composition recited in  claim 1 , wherein the peak oxidation rate of the sorbent composition is at least about 10% lower than the peak oxidation rate of the activated carbon. 
     
     
         35 . (canceled) 
     
     
         36 . The sorbent composition recited in  claim 1 , wherein the peak oxidation rate of the sorbent composition is at least about 30% lower than the peak oxidation rate of the activated carbon. 
     
     
         37 . (canceled) 
     
     
         38 . The sorbent composition recited in  claim 1 , wherein the peak oxidation rate of the sorbent composition is at least about 50% lower than the peak oxidation rate of the activated carbon. 
     
     
         39 . The sorbent composition recited in  claim 1 , further comprising an oxidation agent. 
     
     
         40 . The sorbent composition recited in  claim 39 , wherein the oxidation agent comprises a halogen species. 
     
     
         41 . (canceled) 
     
     
         42 . (canceled) 
     
     
         43 . The sorbent composition recited in  claim 1 , wherein the activated carbon sorbent composition comprises substantially free-flowing particulates of powdered activated carbon. 
     
     
         44 . The sorbent composition recited in  claim 43 , wherein the powdered activated carbon has a median particle size of not greater than about 20 μm. 
     
     
         45 . The sorbent composition recited in  claim 43 , wherein the powdered activated carbon has a median particle size of at least about 6 μm. 
     
     
         46 . (canceled) 
     
     
         47 . The sorbent composition recited in  claim 43 , wherein the powdered activated carbon has a median particle size of not greater than about 20 μm, a particle density of at least about 0.4 g/cc, and a total pore volume of at least about 0.2 cc/g. 
     
     
         48 . (canceled) 
     
     
         49 . The sorbent composition recited in  claim 43 , wherein the powdered activated carbon has a median particle size of not greater than about 12 μm, a particle density of at least about 0.4 g/cc, and a total pore volume of at least about 0.2 cc/g. 
     
     
         50 . The sorbent composition recited in  claim 1 , wherein the sulfur oxide compound is in the form of a coating on the activated carbon. 
     
     
         51 . The sorbent composition of  claim 1 , wherein the sulfur oxide compound comprises sulfur oxide compound particulates that are admixed with the activated carbon. 
     
     
         52 - 88 . (canceled)