Method of sensing and measuring the concentrations of high temperature combustion gases

Abstract

Disclosed herein is a method and apparatus for analyzing, sensing and measuring information related to the concentrations of various gases, including NO x , hydrocarbons, carbon monoxide and oxygen, in a multi-component gas system using chemical sensors and chemical sensor arrays. The sensors and sensor arrays use chemo/electro-active materials to analyze and detect the presence of gases.

1 . An apparatus for analyzing a multi-component mixture of gases comprising (a) an array of at least four chemo/electro-active materials;
 wherein each chemo/electro-active material exhibits a different electrical response upon exposure to the gas mixture than each of the other chemo/electro-active materials;   wherein the chemo/electro-active materials are selected from one or more members of the group consisting of CeO x , NbO x , Nb a Ti b O x , Ni a Zn b O x , Sb a Sn b O x , Ta a Ti b O x , Ti a Zn b O x  and Ga a Ti b Zn c O x ; and   wherein a, b and c are each independently about 0.0005 to about 1, and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound; and   (b) an electrical controller to input the electrical responses obtained from the chemo/electro-active materials to an analyzer for detecting therefrom the presence of, or calculating therefrom the concentration of, one or more individual component gases or subgroups within the gas mixture; wherein the electrical responses are obtained from exposure of the array to no gases other than the component gases of the multi-component mixture.   
     
     
         2 . An apparatus according to  claim 1  wherein the array further comprises one or more members of the group consisting of SnO 2  and ZnO. 
     
     
         3 . An apparatus according to  claim 1  wherein the array comprises Ta a Ti b O x  and at least three members selected the group consisting of CeO x , NbO x , Nb a Ti b O x , Ni a Zn b O x , Sb a Sn b O x , Ti a Zn b O x  and Ga a Ti b Zn c O x . 
     
     
         4 . An apparatus according to  claim 1  wherein the array comprises Ti a Zn b O x  and at least three members selected from the group consisting of CeO x , NbO x , Nb a Ti b O x , Ni a Zn b O x , Sb a Sn b O x , Ta a Ti b O x , and Ga a Ti b Zn c O x . 
     
     
         5 . An apparatus according to  claim 1  wherein the array comprises Ta a Ti b O x  and Ti a Zn b O x  and at least two members selected the group consisting of CeO x , NbO x , Nb a Ti b O x , Ni a Zn b O x , Sb a Sn b O x , and Ga a Ti b Zn c O x . 
     
     
         6 . An apparatus according to  claim 5  wherein the array further comprises one or more members of the group consisting of SnO 2  and ZnO. 
     
     
         7 . An apparatus according to  claim 1  wherein the controller calculates a value related to the resistance of a chemo/electro-active material. 
     
     
         8 . An apparatus according to  claim 1  which detects the presence of, and/or calculates the concentration of, an individual component gas in the multi-component mixture that is selected from the group consisting of oxygen, a nitrogen oxide, a hydrocarbon, and ammonia. 
     
     
         9 . An apparatus according to  claim 1  which detects the presence of, and/or calculates the concentration of, a subgroup of component gases in the multi-component mixture that is selected from the group consisting of (i) oxygen and a hydrocarbon, and (ii) a nitrogen oxide and ammonia. 
     
     
         10 . An apparatus according to  claim 1  wherein one or more of the electro/chemical-active materials further comprises one or more additives to promote adhesion or to alter the conductance, resistance or selectivity thereof. 
     
     
         11 . An apparatus according to  claim 1  wherein the gas mixture comprises an emission from a combustion process. 
     
     
         12 . A vehicle for transportation, or a piece of equipment for construction, maintenance or an industrial operation, comprising an apparatus according to  claim 1 . 
     
     
         13 . An apparatus for analyzing a multi-component mixture of gases, comprising:
 (a) an array of chemo/electro-active materials, each chemo/electro-active material having a different electrical response characteristic upon exposure to the gas mixture than each of the other chemo/electro-active materials; wherein the chemo/electro-active materials comprise
 (i) those in the group consisting of SnO x , ZnO x , Nb a Ti b O x , Ni a Zn b O x , Ta a Ti b O x , and Ti a Zn b O x ; or 
 (ii) those in the group consisting of SnO x , ZnO x , Sb a Sn b O x , Ti a Zn b O x , and Ga a Ti b Zn c O x ; or 
 (iii) those in the group consisting of SnO x , ZnO x , Sb a Sn b O x , Ta a Ti b O x , and Ti a Zn b O x ; or 
 (iv) those in the group consisting of SnO x , ZnO x , Nb a Ti b O x , Sb a Sn b O x , Ta a Ti b O x , Ti a Zn b O x , and Ga a Ti b Zn c O x ; or 
 (v) those in the group consisting of SnO x , ZnO x , Al a Ni b O x , Mn a Y b O x , Nb a W b O x , Ta a Ti b O x , and Nb a Sr b Ti c O x ; or 
 (vi) those in the group consisting of Ce a O x , NbO x , ZnO x , Nb a Ti b O x , Ni a Zn b O x , and Ti a Zn b O x ; or 
 (vii) those in the group consisting of Ce a O x , NbO x , ZnO x , Al a Ni b O x , Nb a Ti b O x , and Ta a Ti b O x ; 
   
       wherein a, b and c are each independently 0.0005 to 1, and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound; and
 (b) an electrical controller to input the electrical responses obtained from the chemo/electro-active materials to an analyzer for detecting therefrom the presence of, or calculating therefrom the concentration of, one or more individual component gases or subgroups within the gas mixture. 
 
     
     
         14 . An apparatus according to  claim 13  which provides an electrical response from exposure of the array to no gases other than the component gases of the multi-component mixture. 
     
     
         15 . An apparatus according to  claim 13  wherein one or more of the electro/chemical-active materials further comprises one or more additives to promote adhesion or to alter the conductance, resistance or selectivity thereof. 
     
     
         16 . An apparatus according to  claim 13  wherein the gas mixture comprises an emission from a combustion process. 
     
     
         17 . A vehicle for transportation, or a piece of equipment for construction, maintenance or an industrial operation, comprising an apparatus according to  claim 13 .