Methods and Systems for Synthesizing Iron-Based Materials and Sequestering Carbon Dioxide

Abstract

Methods and systems for sequestering carbon dioxide and generating hydrogen are disclosed. In some embodiments, the methods include the following: dissolving an iron based material that includes a carbonate-forming element into a solution including the carbonate-forming element and iron; increasing a pH of the solution to cause precipitation of iron oxide from the solution thereby generating a first source of Fe 2 O 3 ; reacting the carbonate-forming element in the solution with a first source of carbon dioxide to produce a carbonate thereby sequestering the carbon dioxide; oxidizing the first source of Fe 2 O 3 with a carbonaceous fuel thereby generating a second source of carbon dioxide and iron; and oxidizing the iron with steam thereby generating hydrogen and an iron oxide. Some embodiments include producing iron-based catalysts.

What is claimed is: 
     
         1 . A method of sequestering carbon dioxide, said method comprising:
 producing iron-based sorbents and a carbonate forming material from minerals comprising iron;   consuming a first source of carbon dioxide to produce carbonated minerals from the carbonate forming material;   reducing the iron-based sorbents with a carbonaceous fuel to generate a second source of carbon dioxide; and   regenerating said iron-based sorbents that have been reduced via oxidation with steam.   
     
     
         2 . The method according to  claim 1 , wherein the minerals comprising iron include calcium-bearing minerals, magnesium-bearing minerals, and industrial wastes. 
     
     
         3 . The method according to  claim 1 , further comprising producing iron-based catalysts including Fischer Tropsch catalysts, water-gas-shift catalysts, and biomass conversion catalysts. 
     
     
         4 . The method according to  claim 3 , wherein said iron-based catalysts and iron-based sorbents include iron oxides such as Fe 2 O 3 . 
     
     
         5 . The method of according to  claim 1 , further comprising isolating the iron-based sorbents from the carbonate forming material via a pH swing process. 
     
     
         6 . The method according to  claim 1 , further comprising the step of consuming the second source of carbon dioxide using the carbonate forming material. 
     
     
         7 . The method according to  claim 1 , wherein the step of regenerating said iron-based sorbents further includes the step of generating hydrogen. 
     
     
         8 . A method of sequestering carbon dioxide and generating hydrogen, said method comprising:
 dissolving a material that includes a carbonate-forming element and iron with a chelating agent into a solution;   increasing a pH of said solution to cause precipitation of a first source of iron oxide from said solution;   reacting said carbonate-forming element with a first source of carbon dioxide;   reducing said first source of iron oxide with a carbonaceous fuel thereby generating a second source of carbon dioxide and reduced iron; and   oxidizing said reduced iron with steam thereby generating hydrogen and a second source of iron oxide.   
     
     
         9 . The method according to  claim 8 , further comprising:
 producing iron-based catalysts including Fischer Tropsch catalysts, water-gas-shift catalysts, and biomass conversion catalysts.   
     
     
         10 . The method according to  claim 8 , wherein said material is selected from the group consisting of: calcium-bearing minerals, magnesium-bearing minerals, and industrial wastes containing iron and carbonate-forming elements including magnesium and calcium. 
     
     
         11 . The method according to  claim 8 , wherein said carbonate forming element is selected from the group consisting of: magnesium, calcium, and a combination thereof. 
     
     
         12 . The method according to  claim 8 , further comprising:
 oxidizing said second source of iron oxide with oxygen thereby generating a source of fully oxidized Fe 2 O 3 .   
     
     
         13 . The method according to  claim 10 , wherein the chelating agents are added to said solution before increasing a pH of said solution to dissolve said minerals or said wastes and target Ma, Ca and Fe and include acetic acid, citric acid, iminodiacetic acid, oxalic acid, phosphoric acid, gluconic acid, ascorbic acid, phthalic acid, a salt thereof, and a combination thereof. 
     
     
         14 . The method according to  claim 8 , further comprising:
 reacting said carbonate-forming element in said solution with said second source of carbon dioxide to produce a carbonate thereby sequestering said carbon dioxide.   
     
     
         15 . The method according to  claim 8 , further comprising:
 reacting said second source of iron oxide with said carbonaceous fuel.   
     
     
         16 . The method according to  claim 8 , wherein said carbonaceous fuel includes gaseous fuels including carbon monoxide and hydrogen and methane. 
     
     
         17 . The method according to  claim 8 , wherein precipitation of the first source of iron oxide is conducted in the presence of support materials such as provided Fe 2 O 3  particles. 
     
     
         18 . A system for sequestering carbon dioxide, said system comprising:
 a mineral and waste carbonation module for producing iron-based sorbents and carbonate forming material from at least one of minerals and industrial wastes using pH swing processes and sequestering carbon dioxide using the carbonate forming material; and   a chemical looping module, said chemical looping module configured to reduce said iron-based sorbents and generate carbon dioxide for consumption in the mineral and waste carbonation module and regenerating said iron-based sorbents that have been reduced via oxidation with steam.   
     
     
         19 . The system according to  claim 18 , wherein minerals include magnesium and calcium-bearing minerals including iron and industrial wastes include magnesium and calcium-bearing wastes including steel slag and fly ash containing iron. 
     
     
         20 . The system according to  claim 18 , wherein said iron-based sorbents include Fe 2 O 3 . 
     
     
         21 . The system according to  claim 18 , wherein said pH swing processes include the use of at least one of acetic acid, citric acid, iminodiacetic acid, oxalic acid, phosphoric acid, gluconic acid, ascorbic acid, phthalic acid, a salt thereof, and a combination thereof as a chelating agent to facilitate the extraction of iron from said minerals. 
     
     
         22 . The system according to  claim 18 , wherein said chemical looping module further comprises:
 a fuel reactor for reducing said iron-based sorbents via a carbonaceous fuel to generate carbon dioxide; and   a hydrogen production reactor for regenerating said iron-based sorbents that have been reduced via oxidation with steam to generate hydrogen.   
     
     
         23 . The system according to  claim 18 , further comprising a module for producing iron-based catalysts. 
     
     
         24 . The system according to  claim 22 , wherein said carbonaceous fuel includes gaseous fuels including synthetic gas (carbon monoxide and hydrogen) and methane, and solid fuels including coal, biomass, and municipal solid wastes.