Activation of Waste Metal Oxide as an Oxygen Carrier for Chemical Looping Combustion Applications

Abstract

A process for producing black powder oxygen carriers for use in a chemical looping combustion unit includes the steps of: (a) removing and collecting the black powder waste material that was formed in a gas pipeline; (b) pre-treating the collected black powder to adjust its spherical shape to avoid attrition and fines production; and (c) activating the black powder to increase its reactivity rate and produce the black powder oxygen carrier that is suitable for use in the chemical looping combustion process as an oxygen carrier.

What is claimed is: 
     
         1 . A process for producing an oxygen carrier that is suitable for use in a chemical looping combustion unit, comprising the steps of;
 removing and collecting black powder that is formed within a gas pipeline;   pre-treating the collected black powder; and   activating the collected black powder to increase the reactivity of the black powder to form a black powder oxygen carrier for use in the chemical looping combustion unit.   
     
     
         2 . The process of  claim 1 , wherein the black powder comprises iron hydroxides, iron oxides, and iron carbonates. 
     
     
         3 . The process of  claim 1 , wherein the black powder is removed from a natural gas pipeline and collected using at least one of a separator and cyclone device such that gas laden with black powder passes through the separator or cyclone, and black powder particles are knocked out of the gas stream to walls of the separator or cyclone, where they fall and are collected internally within the separator or cyclone in a collection media. 
     
     
         4 . The process of  claim 1 , wherein the collected black powder is pre-treated via a synthesis method. 
     
     
         5 . The process of  claim 4 , wherein the synthesis method consists one of a spray drying process and a freeze granulation process. 
     
     
         6 . The process of  claim 4 , wherein the synthesis method comprises the steps of:
 forming a powder mixture that comprises about 60.1% black powder and about 39.9% manganese ore;   dispersing the powder mixture in deionized water along with organic additives to form an aqueous suspension;
 homogenizing the aqueous suspension; 
 spray drying the aqueous suspension to form a solid black powder based composition that has a range of particle sizes; 
 sieving the solid black powder based composition to collect particles within a predetermined particle range; and 
 sintering the collected particles. 
   
     
     
         7 . The process of  claim 1 , wherein the activation of the black powder comprises the step of:
 using a flue gas to reduce the black powder and activate the black powder by increasing porosity and surface area of the black powder for improved gas-solid contact, thereby improving the reactivity of the black powder towards other gas, liquid or solid fuels.   
     
     
         8 . The process of  claim 7 , wherein the flue gas contains at least 10-50% of H 2  and at least 10-50% of CO. 
     
     
         9 . The process of  claim 1 , wherein the activation of the black powder comprises the step of increasing the reactivity of the black powder by mixing the black powder with one or more other metal oxides to form a black powder based composition that has increased reactivity. 
     
     
         10 . The process of  claim 9 , wherein the other metal oxide comprises a copper oxide, manganese oxide or a combination thereof. 
     
     
         11 . The process of  claim 9 , wherein the black powder based composition comprises about 60.1% black powder and about 39.9 Mn 3 O 4 . 
     
     
         12 . A process for combustion using a chemical looping combustion while producing a product stream comprising the steps of;
 delivering fuel into a fuel reactor that contains an oxygen carrier which comprises black powder;   reducing the oxygen carrier in the presence of the fuel to provide gas-phase oxygen in the fuel reactor;   combusting the fuel under oxycombustion conditions within the fuel reactor to produce a product stream;   oxidizing the reduced oxygen carrier with air in the air reactor to produce the oxygen carrier; and   delivering the oxidized oxygen carrier back to the fuel reactor.   
     
     
         13 . The process of  claim 12 , wherein the black powder oxygen carrier comprises a fixed bed that is disposed in the fuel reactor and the fixed bed is fluidized by a stream of gas. 
     
     
         14 . The process of  claim 12 , wherein the fuel is a fuel selected from the group consisting of a gas feed; a liquid feed, and a solid feed. 
     
     
         15 . The process of  claim 14 , wherein the fuel is a solid fuel selected from the group consisting of coal and petcoke. 
     
     
         16 . The process of  claim 12 , wherein the black powder comprises iron hydroxides, iron oxides, and iron carbonates recovered from gas pipelines. 
     
     
         17 . The process of  claim 12 , further including the steps of:
 removing and collecting the black powder that is formed in a gas pipeline;   pre-treating the collected black powder; and   activating the collected black powder to increase the reactivity and form the black powder oxygen carrier.   
     
     
         18 . The process of  claim 12 , wherein the black powder is removed from a gas pipeline and collected using at least one of a separator and cyclone device such that gas laden with black powder passes through the separator or cyclone, and black powder particles are knocked out of the gas stream to walls of the separator or cyclone, where they fall and are collected internally within the separator or cyclone in a collection media. 
     
     
         19 . The process of  claim 17 , wherein the collected black powder is pre-treated via a synthesis method. 
     
     
         20 . The process of  claim 19 , wherein the synthesis method consists one of a spray drying process and a freeze granulation process. 
     
     
         21 . The process of  claim 17 , wherein the activation of the black powder comprises the step of:
 using a flue gas to reduce the black powder and activate the black powder by increasing porosity and surface area of the black powder for improved gas-solid contact, thereby improving the reactivity of the black powder towards other gas, liquid or solid fuels.   
     
     
         22 . The process of  claim 21 , wherein the flue gas contains at least 10-50% of H 2  and at least 10-50% of CO. 
     
     
         23 . The process of  claim 17 , wherein the activation of the black powder comprises the step of mixing the black powder with one or more other metal oxides to increase the reactivity of the black powder. 
     
     
         24 . The process of  claim 23 , wherein the other metal oxide comprises a copper oxide, manganese oxide or a combination thereof. 
     
     
         25 . An oxygen carrier for use in a CLC process prepared in accordance with the process of  claim 1 .