Method for controlling a flowrate of a recirculated exhaust gas

Abstract

A method for controlling an exhaust gas recirculation (EGR) system is provided. The EGR system may allow for the removal and the sequestration of at least one constituent within the exhaust before the recirculation occurs. The method may monitor the level of at least one constituent and adjust an EGR recirculation rate.

1 . A method of controlling an exhaust stream, wherein the exhaust stream is generated by a turbomachine; the method comprising:
 providing at least one exhaust gas recirculation (EGR) system comprising: at least one EGR flow conditioning device and at least one flow control device;   utilizing a mass flow control system, wherein utilizing the mass flow control comprises the steps of:
 receiving a target EGR fraction comprising the portion of the exhaust stream within an inlet fluid, wherein the inlet fluid enters the inlet section of the turbomachine; 
 determining a current EGR fraction; 
 determining whether the current EGR fraction is within a range of the target EGR fraction; and 
 adjusting an EGR rate of the exhaust stream if the current EGR fraction is outside of the range of the target EGR fraction. 
   
   
   
       2 . The method of  claim 1 , wherein the at least one constituent comprises at least one of: SOx, NOx, CO 2 , O 2 , water, chloride ions, acids, aldehydes, hydrocarbons, or combinations thereof. 
   
   
       3 . The method of  claim 1 , wherein the step of adjusting the EGR rate of the exhaust stream comprises at least one of: adjusting a speed of the EGR flow conditioning device; adjusting a pitch of at least one EGR device; modulating at least one flow control device; or combinations thereof. 
   
   
       4 . The method of  claim 1 , wherein the step of determining the current EGR fraction comprises receiving EGR rate data from at least one EGR feedback device; and wherein EGR rate data is used to determine the current EGR fraction. 
   
   
       5 . The method of  claim 4 , wherein the at least one EGR feedback device is located adjacent the inlet section. 
   
   
       6 . The method of  claim 1 , wherein the step of determining the current EGR fraction further comprises:
 receiving a plurality of turbomachine operating data; and   utilizing at least one energy balance for determining the current EGR fraction, wherein the at least one energy balance incorporates the turbomachine operating data.   
   
   
       7 . The method of  claim 6 , wherein the plurality of turbomachine operating data comprises at least one of the following data: compressor airflow; ambient temperature; compressor inlet temperature; exhaust stream temperature; humidity; or combinations thereof. 
   
   
       8 . The method of  claim 1 , further comprising integrating the EGR mass flow control system with at least one EGR constituent control system. 
   
   
       9 . The method of  claim 8 , wherein the step of utilizing the at least one EGR constituent control system comprises the steps of:
 receiving the target EGR fraction;   utilizing the target EGR fraction to determine a target level of at least one constituent;   determining a current level of the at least one constituent;   determining whether the current level of the at least one constituent is within a constituent range; and   adjusting an EGR rate of the exhaust stream if the at least one constituent is outside of the constituent range.   
   
   
       10 . A method of controlling an exhaust stream, wherein the exhaust stream is generated by a turbomachine; the method comprising:
 providing at least one exhaust gas recirculation (EGR) system comprising: at least one EGR flow conditioning device and at least one flow control device;   utilizing a mass flow control system, wherein the utilizing the mass flow control comprises the steps of:
 receiving a target level of at least one constituent; 
 determining a target EGR fraction; 
 determining a current EGR fraction; 
 determining whether the current EGR fraction is within a range of the target EGR fraction; and 
 adjusting an EGR rate of the exhaust stream if the current EGR fraction is outside of the range of the target EGR fraction. 
   
   
   
       11 . The method of  claim 10 , wherein the at least one constituent comprises at least one of: SOx, NOx, CO 2 , O 2 , water, chloride ions, acids, aldehydes, hydrocarbons, or combinations thereof. 
   
   
       12 . The method of  claim 10 , wherein the step of adjusting the EGR rate of the exhaust stream comprises at least one of: adjusting a speed of the EGR flow conditioning device; adjusting a pitch of at least one EGR device; modulating at least one flow control device; or combinations thereof. 
   
   
       13 . The method of  claim 10 , wherein the step of determining the current EGR fraction comprises receiving EGR rate data from at least one EGR feedback device; and wherein EGR rate data is used to determine the current EGR fraction. 
   
   
       14 . The method of  claim 13 , wherein the at least one EGR feedback device is located adjacent the inlet section. 
   
   
       15 . The method of  claim 10 , wherein the step of determining the current EGR fraction further comprises:
 receiving a plurality of turbomachine operating data; and   utilizing at least one energy balance for determining the current EGR fraction, wherein the at least one energy balance incorporates the turbomachine operating data.   
   
   
       16 . The method of  claim 15 , wherein the plurality of turbomachine operating data comprises at least one of the following data: compressor airflow; ambient temperature; compressor inlet temperature; exhaust stream temperature; humidity; or combinations thereof. 
   
   
       17 . The method of  claim 10  further comprising integrating the EGR mass flow control system with at least one EGR constituent control system. 
   
   
       18 . The method of  claim 17 , wherein the step of utilizing the at least one EGR constituent control system comprises the steps of:
 receiving the target level of at least one constituent;   determining a current level of the at least one constituent;   determining whether the current level of the at least one constituent is within a constituent range; and   adjusting an EGR rate of the exhaust stream if the at least one constituent is outside of the constituent range.