Chemically-Enhanced Sorbent Activation Process and Method for Using Same

Abstract

The invention in its various embodiments is directed to methods and equipment for generating an activated sorbent from a sorbent precursor with the addition of certain chemicals that enhance the effectiveness of the activated sorbent. The invention in its various embodiments is also directed to the methods and equipment for generating some of the chemicals that are added to the raw carbonaceous material or activated sorbent to enhance its effectiveness. The invention in its various embodiments is also directed to methods and equipment for generating certain chemicals that can be added to a gas stream to convert a given gaseous pollutant to a form that is more easily removed from the gas stream.

What is claimed is: 
     
         1 . A method for generating a sorbent, comprising:
 activating a sorbent precursor in the presence of a chemical to produce a chemically-enhanced activated sorbent that provides increased adsorption of a gaseous pollutant than the same activated sorbent produced in the absence of the chemical.   
     
     
         2 . The method of  claim 1 , wherein said activating is conducted in a gas duct. 
     
     
         3 . The method of  claim 1 , wherein said activating comprises contacting the sorbent precursor with an activating gas stream having a temperature sufficient to activate the sorbent precursor, and further comprising:
 adding the chemical to the activating gas stream.   
     
     
         4 . The method of  claim 3 , wherein said activating further comprises adding the sorbent precursor to the activating gas stream at a first location along a gas duct and wherein said adding comprises adding the chemical to the activating gas stream at a second location along the gas duct that is upstream of the first location. 
     
     
         5 . The method of  claim 3 , wherein said activating further comprises adding the sorbent precursor to the activating gas stream at a first location along a gas duct and wherein said adding comprises adding the chemical to the activating gas stream at a second location along the gas duct that is downstream of the first location. 
     
     
         6 . The method of  claim 3 , wherein said activating further comprises adding the sorbent precursor to the activating gas stream at a first location along a gas duct and said adding comprises adding the chemical to the activating gas stream at the first location and concurrently with the sorbent precursor. 
     
     
         7 . The method of  claim 3 , wherein the activating gas stream comprises a slipstream of gas from a combustion device. 
     
     
         8 . The method of  claim 3 , wherein the sorbent precursor comprises a bed and wherein said contacting comprises passing the activating gas stream through the bed. 
     
     
         9 . The method of  claim 1 , wherein the sorbent precursor comprises a raw carbonaceous material and the chemical comprises a bromide compound. 
     
     
         10 . The method of  claim 1 , wherein the sorbent precursor comprises a raw carbonaceous material and the chemical comprises an iron compound. 
     
     
         11 . The method of  claim 1 , wherein the sorbent precursor comprises a raw carbonaceous material and the chemical comprises a halogen or a halogen compound. 
     
     
         12 . The method of  claim 1 , wherein the sorbent precursor comprises a raw carbonaceous material and the chemical comprises a transition metal or a transition metal compound. 
     
     
         13 . The method of  claim 1 , wherein the sorbent precursor comprises a raw carbonaceous material and the chemical comprises an alkali. 
     
     
         14 . The method of  claim 13 , wherein the alkali is selected from the group consisting of a sodium-based compound, a calcium-based compound, and a magnesium-based compound and combinations thereof. 
     
     
         15 . The method of  claim 1 , wherein the gaseous pollutant comprises a trace metal. 
     
     
         16 . The method of  claim 15 , wherein the trace metal comprises mercury. 
     
     
         17 . The method of  claim 1 , wherein the chemical is selected to convert at least one gaseous pollutant to a form that is more easily removed from a gas stream comprising the at least one gaseous pollutant compared to the at least one gaseous pollutant's original form. 
     
     
         18 . The method of  claim 17 , wherein the chemical is a halogen-based compound. 
     
     
         19 . The method of  claim 18 , where the halogen-based compound is selected from the group consisting of a bromide salt, a chloride sale, an iodide salt, and a fluoride salt and combinations thereof.