Pollutant Emission Control Sorbents and Methods of Manufacture and Use

Abstract

Sorbents for removal of mercury and other pollutants from gas streams, such as a flue gas stream from coal-fired utility plants, and methods for their manufacture and use are disclosed. Embodiments include brominated sorbent substrate particles having a carbon content of less than about 10%. Other embodiments include one or more oxidatively active halides of a nonoxidative metal dispersed on sorbent substrate particles mixed with activated carbon in an amount up to 30% by weight. Further embodiments include physical blending of a flow modifier into the sorbent composition.

1 - 15 . (canceled) 
     
     
         16 . A method for preparing a sorbent mixture adapted for mercury capture, the method comprising:
 impregnating a porous support with a bromide species to produce a first plurality of sorbent particles having an average particle diameter of less than 100 micrometers; and   blending the first plurality of sorbent particles with a second plurality of flow modifier particles adapted to reduce agglomeration of the first plurality of sorbent particles when the sorbent mixture is injected into the a gas stream.   
     
     
         17 . The method of  claim 16 , wherein the average diameter of the first plurality of sorbent particles is less than about 20 micrometers. 
     
     
         18 . The method of  claim 16 , wherein the second plurality of flow modifier particles are present in the sorbent mixture in an amount of up to 30 wt % of the sorbent mixture. 
     
     
         19 . The method of  claim 16 , wherein the second plurality of flow modifier particles comprise one or more of heat-treated clay, surface-treated clay, silica, alumina, pseudo boehmite, FCC particles, or fly ash. 
     
     
         20 . The method of  claim 16 , wherein the porous support is selected from a group consisting of alumina, silica, titania, zirconia, iron oxides, zinc oxide, rare earth oxides, metal carbonate, metal sulfate, aluminosilicates, zeolites, heat-treated clays, chemical-surface modified clays, fly ash, fluid cracking catalyst particles, dirt, and combinations thereof. 
     
     
         21 . The method of  claim 16 , wherein the second plurality of flow modifier particles are selected from a group consisting of powdered activated carbon, brominated powdered activated carbon, heat-treated clay, chemical-treated clay, silica, alumina, pseudo boehmite, fly ash, FCC particles, and combinations thereof. 
     
     
         22 . The method of  claim 16 , wherein the first plurality of sorbent particles comprise brominated zeolite and the second plurality of flow modifier particles comprise brominated FCC fines. 
     
     
         23 . The method of  claim 16 , wherein a mass balance greater than 70% after about five injections is obtained when measured using an acoustically driven aerosol injection method. 
     
     
         24 . The method of  claim 16 , wherein blending 20% of the second plurality of flow modifier particles produces a sorbent mixture adapted for total mercury capture of about 85% to about 95% at an injection rate of 4 lb/MMacf to 8 lb/MMacf. 
     
     
         25 . The method of  claim 16 , wherein the second plurality of flow modifier particles is free of bromide species. 
     
     
         26 . The method of  claim 16 , wherein the second plurality of flow modifier particles is impregnated with a bromide species. 
     
     
         27 . A method for preparing a sorbent mixture adapted for mercury capture, the method comprising:
 dispersing a bromide species onto a porous support to produce a first plurality of sorbent particles having an average diameter less than 100 micrometers; and   blending the first plurality of sorbent particles with a second plurality of flow modifier particles adapted to reduce agglomeration of the first plurality of sorbent particles when the sorbent mixture is injected into a flue gas stream.   
     
     
         28 . The method of  claim 27 , further comprising:
 drying the first plurality of sorbent particles.   
     
     
         29 . The method of  claim 27 , wherein the second plurality of flow modifier particles are present in the sorbent mixture in an amount of up to 30 wt % of the sorbent mixture. 
     
     
         30 . The method of  claim 27 , wherein blending the first plurality of sorbent particles with the second plurality of flow modifier particles comprises:
 drying the first plurality of sorbent particles; and   adding the second plurality of flow modifier particles continuously to the dried first plurality of sorbent particles.   
     
     
         31 . The method of  claim 22 , wherein blending the first plurality of sorbent particles with the second plurality of flow modifier particles comprises:
 drying the first plurality of sorbent particles;   contacting the second plurality of flow modifier particles with the dried first plurality of sorbent particles in a batch-wise fashion; and   stirring the first plurality of sorbent particles and the second plurality of flow modifier particles to obtain a uniform composition.   
     
     
         32 . The method for making a sorbent mixture of  claim 28 , wherein a mass balance greater than 80% after about twenty injections is obtained when measured using an acoustically driven aerosol injection method. 
     
     
         33 . The method for making a sorbent mixture of  claim 28 , wherein a mass balance greater than 80% after about three injections is obtained when measured using an acoustically driven aerosol injection method. 
     
     
         34 . The method for making a sorbent mixture of  claim 20 , wherein the average diameter of the first plurality of sorbent particles is less than about 20 micrometers.