Pre-mix catalytic partial oxidation fuel reformer for staged and reheat gas turbine systems

Abstract

A gas turbine system includes a fuel reformer comprising: a fuel inlet; an oxygen inlet; a pre-mixing zone configured to mix the fuel and the oxygen in a pre-mixing device to form a gaseous pre-mix; wherein the pre-mixing device comprises a flow conditioning device configured to pre-condition the fuel stream, wherein the flow conditioning device is disposed upstream of the oxygen inlet; a diffuser disposed downstream of the flow conditioning device; a catalytic partial oxidation zone disposed downstream of the diffuser, wherein the catalytic partial oxidation zone comprises a catalyst composition configured to react the fuel and the oxygen to generate a syngas. The generated syngas is then mixed with rest of the fuel to form a hydrogen-enriched fuel mixture, which is then sent to the combustion chamber of a gas turbine to reduce the NOx emission and extend the lean blow out limit.

1 . A gas turbine system, comprising:
 a fuel inlet configured to receive a fuel stream;   an oxygen inlet configured to introduce a first oxygen-containing gas;   a fuel reformer system comprising:
 a pre-mixing zone configured to mix a first portion of the fuel stream and the oxygen-containing gas in a pre-mixing device to form a gaseous pre-mix; 
 a diffuser disposed downstream of and in fluid communication with the pre-mixing zone, wherein the diffuser is configured to provide a thermal shield between the pre-mixing zone and a catalytic partial oxidation zone; 
 a catalytic partial oxidation zone disposed downstream of and in fluid communication with the pre-mixing zone and configured to receive the gaseous pre-mix, wherein the catalytic partial oxidation zone comprises a catalyst composition configured to react the fuel and the oxygen to generate a syngas from the gaseous pre-mix; and 
 a dilution zone disposed downstream of and in fluid communication with the catalytic partial oxidation zone and configured to mix the syngas into a second portion of the fuel stream to form a fuel mixture; 
   a gas turbine pre-mixer configured to mix a second oxygen-containing gas from a gas turbine compressor with the fuel mixture; and   a gas turbine combustor configured to combust the fuel mixture.   
   
   
       2 . The system of  claim 1 , wherein the pre-mixing zone comprises a pre-mixing device comprising a plurality of swirler vanes configured to provide a swirl movement to the fuel stream first portion. 
   
   
       3 . The system of  claim 1 , further comprising a steam inlet configured to introduce steam to the pre-mixing device. 
   
   
       4 . The system of  claim 1 , further comprising a heat exchanger disposed downstream of and in fluid communication with the catalytic partial oxidation zone, wherein the heat exchanger is configured to simultaneously cool the syngas and pre-heat the first portion of the fuel stream. 
   
   
       5 . The system of  claim 1 , further comprising a water gas shift reactor disposed downstream of and in fluid communication with the catalytic partial oxidation zone, wherein the water gas shift reactor is configured to increase a hydrogen content of the syngas. 
   
   
       6 . The system of  claim 1 , wherein the first oxygen-containing gas is a portion of the second oxygen-containing gas. 
   
   
       7 . The system of  claim 6 , further comprising a control valve to control a volume flow rate of the first oxygen-containing gas according to an oxygen to carbon ratio of the catalytic partial oxidation zone. 
   
   
       8 . The system of  claim 1 , further comprising a control valve to control a volume flow rate of the first portion of the fuel stream. 
   
   
       9 . A method of operating a gas turbine system, comprising:
 introducing a first fuel portion of a fuel stream into a pre-mixing zone of a fuel reformer system;   introducing a first oxygen-containing gas to the first fuel portion in a flow conditioning device to facilitate pre-mixing of the first fuel portion and the first oxygen-containing gas to form a gaseous pre-mix   reacting the gaseous pre-mix to form a syngas through catalytic partial oxidation;   introducing the syngas into a second fuel portion of the fuel stream to form a fuel mixture;   mixing the fuel mixture with a second oxygen-containing gas in a gas turbine pre-mixer; and   combusting the fuel mixture in a gas turbine combustor.   
   
   
       10 . The method of  claim 9 , further comprising introducing steam into the pre-mixing zone. 
   
   
       11 . The method of  claim 10 , wherein the steam is combined with the first fuel portion. 
   
   
       12 . The method of  claim 11 , wherein the combination of the steam and the first fuel portion is combined with the first oxygen-containing gas. 
   
   
       13 . The method of  claim 9 , further comprising preheating the first fuel portion to a temperature of about 300° C. to about 500° C. 
   
   
       14 . The method of  claim 9 , further comprising cooling the syngas to a temperature of about 250° C. to about 450° C. 
   
   
       15 . The method of  claim 9 , further comprising increasing the hydrogen content of the syngas through a water gas shift reaction. 
   
   
       16 . The method of  claim 15 , wherein the cooling occurs after the catalytic partial oxidation and before the water gas shift reaction. 
   
   
       17 . A fuel reformer system, comprising:
 a fuel inlet configured to receive a fuel stream;   an oxygen inlet configured to introduce a first oxygen-containing gas;   a pre-mixing zone configured to mix a first portion of the fuel stream and the oxygen-containing gas in a pre-mixing device to form a gaseous pre-mix;   a diffuser disposed downstream of and in fluid communication with the pre-mixing zone, wherein the diffuser is configured to provide a thermal shield between the pre-mixing zone and a catalytic partial oxidation zone;   a catalytic partial oxidation zone disposed downstream of and in fluid communication with the pre-mixing zone and configured to receive the gaseous pre-mix, wherein the catalytic partial oxidation zone comprises a catalyst composition configured to react the fuel and the oxygen to generate a syngas from the gaseous pre-mix; and   a dilution zone disposed downstream of and in fluid communication with the catalytic partial oxidation zone and configured to mix the syngas into a second portion of the fuel stream to form a fuel mixture.