Inherently concrete-compatible carbon sorbents for mercury removal from flue gas

Abstract

A sorbent composition and process of making sorbent designed for the removal of contaminants from flue gas and subsequent use in cement or concrete formulations are discussed. The sorbent composition comprises a coal feed stock prepared to have a total BET surface area of at least 350 m 2 /g, and wherein the sorbent has a cumulative surface area less than 10 m 2 /g for pore diameters between 0.01 and 0.1 microns, a cumulative pore volume less than 0.055 cc/g for pore diameters between 0.01 and 0.1 microns, or both.

What is claimed is: 
     
         1 . A process for making a concrete-compatible sorbent, comprising the step of preparing a feedstock to have a total BET surface area of at least 350 m 2 /g and to have a cumulative surface area less than 10 m 2 /g for pore diameters between 0.01 and 0.1 microns, a cumulative pore volume less than 0.055 cc/g for pore diameters between 0.01 and 0.1 microns, or both. 
     
     
         2 . The process of  claim 1  wherein the feedstock is a carbonaceous material. 
     
     
         3 . The process of  claim 1  further comprising the step of incorporating the sorbent into a cement or concrete formulation. 
     
     
         4 . The process of  claim 1  wherein the sorbent has properties inherently favorable to mercury removal yet unfavorable to adsorption of AEA foaming agents when entrained in a fly ash for use in concrete manufacture. 
     
     
         5 . The process of  claim 1  wherein the step of preparing a feedstock results with a sorbent having a total BET surface area of at least 400 m 2 /g, and a Molasses Number no greater than 140. 
     
     
         6 . The process of  claim 1  wherein the step of preparing a feedstock results with a sorbent having the cumulative surface area less than 8 m 2 /g for pore diameters between 0.01 and 0.1 microns. 
     
     
         7 . The process of  claim 1  wherein the step of preparing a feedstock results with a sorbent having a cumulative pore volume less than 0.05 cc/g for pore diameters between 0.01 and 0.1 microns. 
     
     
         8 . The process of  claim 1  further comprising the step of incorporating a halogen or halide with the sorbent to enhance mercury or other contaminant removal. 
     
     
         9 . The process of  claim 1  further comprising the step of incorporating a pore blocking agent with the sorbent to enhance concrete-compatibility.