Sorbent bodies comprising activated carbon, processes for making them, and their use

Abstract

Sorbent bodies comprising activated carbon, processes for making them, and methods of using them. The sorbent bodies can be used to remove toxic elements from a fluid, such as from a gas stream. For instance, the sorbent bodies may be used to remove elemental mercury or mercury in an oxidized state from a coal combustion flue gas.

What is claimed is: 
     
         1 . A process for making a sorbent body comprising an activated carbon matrix, sulfur, and an additive adapted for promoting the abatement of a toxic element from a fluid stream, wherein the additive is distributed throughout the activated carbon matrix, comprising the following steps:
 providing a batch mixture body formed of a batch mixture material comprising:
 a carbon-source material, 
 sulfur, 
 an additive-source material substantially homogeneously distributed in the batch mixture, wherein the additive-source material comprises sulfides selected from the group consisting of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, niobium, or molybdenum, silver, tungsten, lanthanoids, and mixtures thereof, and 
 optional filler material; 
   carbonizing the batch mixture body by subjecting the batch mixture body to an elevated carbonizing temperature in an O 2 -depleted atmosphere; and   activating the carbonized batch mixture body at an elevated activating temperature in a gaseous atmosphere selected from CO 2 , H 2 O, a mixture of CO 2  and H 2 O, a mixture of CO 2  and nitrogen, a mixture of H 2 O and nitrogen, and a mixture of CO 2  and another inert gas.   
     
     
         2 . The process of  claim 1 , wherein in the step of providing the batch mixture body, the carbon-source material comprises: synthetic carbon-containing polymeric material; activated carbon powder; charcoal powder; coal tar pitch; petroleum pitch; wood flour; cellulose and derivatives thereof; wheat flour; nut-shell flour; starch; coke; coal; or mixtures or combinations of any two or more of these. 
     
     
         3 . The process of  claim 1 , wherein the sorbent body further comprises an alkaline earth hydroxide. 
     
     
         4 . The process of  claim 1 , wherein the additive-source material is selected from sulfides of manganese or molybdenum. 
     
     
         5 . The process of  claim 1 , further comprising curing the batch mixture body prior to carbonization. 
     
     
         6 . The process of  claim 5 , wherein the curing is performed in air at atmospheric pressures at a temperature of from about 70° C. to about 200° C. 
     
     
         7 . The process of  claim 1 , further comprising impregnating additional metal catalysts or sulfur into the sorbent body after activation. 
     
     
         8 . The process of  claim 1 , wherein the additional metal catalysts comprise organometallic compounds. 
     
     
         9 . A process for abating As, Cd, Se and/or Hg from a fluid stream, comprising
 providing the sorbent body of  claim 1 ; and   filtering the fluid stream using the sorbent body to abate As, Cd, Se and/or Hg in the fluid stream.   
     
     
         10 . The process of  claim 9 , wherein the sorbent body abates at least 90% of the Hg in the fluid stream. 
     
     
         11 . The process of  claim 9 , wherein the sorbent body abates at least 99.5% of the Hg in the fluid stream 
     
     
         12 . A process for making a sorbent body comprising an activated carbon matrix, sulfur, and an additive adapted for promoting the abatement of a toxic element from a fluid stream, wherein the additive is distributed throughout the activated carbon matrix, comprising the following steps:
 providing a batch mixture body formed of a batch mixture material comprising:
 a carbon-source material, 
 sulfur, 
 an alkaline earth hydroxide, 
 an additive-source material substantially homogeneously distributed in the batch mixture, wherein the additive-source material comprises sulfides of manganese, molybdenum, and mixtures thereof, and 
 optional filler material; 
   carbonizing the batch mixture body by subjecting the batch mixture body to an elevated carbonizing temperature in an O 2 -depleted atmosphere; and   activating the carbonized batch mixture body at an elevated activating temperature in a gaseous atmosphere selected from CO 2 , H 2 O, a mixture of CO 2  and H 2 O, a mixture of CO 2  and nitrogen, a mixture of H 2 O and nitrogen, and a mixture of CO 2  and another inert gas.   
     
     
         13 . A process according to  claim 12 , wherein in the step of providing the batch mixture body, the carbon-source material comprises: synthetic carbon-containing polymeric material;
 activated carbon powder; charcoal powder; coal tar pitch; petroleum pitch; wood flour; cellulose and derivatives thereof; wheat flour; nut-shell flour; starch; coke; coal; or mixtures or combinations of any two or more of these.   
     
     
         14 . The process of  claim 12 , further comprising curing the batch mixture body prior to carbonization. 
     
     
         15 . The process of  claim 14 , wherein the curing is performed in air at atmospheric pressures at a temperature of from about 70° C. to about 200° C. 
     
     
         16 . The process of  claim 12 , further comprising impregnating additional metal catalysts or sulfur into the sorbent body after activation. 
     
     
         17 . The process of  claim 16 , wherein the additional metal catalysts comprise organometallic compounds. 
     
     
         18 . A process for abating As, Cd, Se and/or Hg from a fluid stream, comprising
 providing the sorbent body of  claim 12 ; and   filtering the fluid stream using the sorbent body to abate As, Cd, Se and/or Hg in the fluid stream.   
     
     
         19 . The process of  claim 18 , wherein the sorbent body abates at least 90% of the Hg in the fluid stream. 
     
     
         20 . The process of  claim 18 , wherein the sorbent body abates at least 99.5% of the Hg in the fluid stream.