Inert gas purging system for an orc heat recovery boiler

Abstract

In one embodiment, a system includes a valve system switchable between a waste heat recovery position configured to direct incoming exhaust gas through an interior volume of an exhaust section of an engine and a bypass position configured to direct the incoming exhaust gas through a bypass duct to bypass a heat recovery boiler disposed within the interior volume. The system also includes an inert gas purging system configured to inject an inert gas into the interior volume to displace residual exhaust gas from the interior volume.

1 . A system comprising:
 a valve system switchable between a waste heat recovery position configured to direct incoming exhaust gas through an interior volume of an exhaust section of an engine and a bypass position configured to direct the incoming exhaust gas through a bypass duct to bypass a heat recovery boiler disposed within the interior volume; and   an inert gas purging system configured to inject an inert gas into the interior volume to displace residual exhaust gas from the interior volume.   
     
     
         2 . The system of  claim 1 , wherein the inert gas purging system comprises an inert gas valve system configured to selectively enable and disable a flow of the inert gas from an inert gas supply to the interior volume. 
     
     
         3 . The system of  claim 1 , wherein the inert gas purging system comprises flow nozzles configured to be mounted within the interior volume to inject the inert gas into the interior volume. 
     
     
         4 . The system of  claim 1 , comprising a controller configured to move the valve system to the bypass position and to activate the inert gas purging system in response to detection of a leak in the heat recovery boiler. 
     
     
         5 . The system of  claim 4 , comprising a sensor configured to detect an amount of an organic working fluid within the interior volume to detect the leak in the heat recovery boiler. 
     
     
         6 . The system of  claim 1 , wherein the heat recovery boiler is configured to circulate an organic working fluid from a waste heat recovery system. 
     
     
         7 . A system comprising:
 a heat recovery boiler configured to absorb heat directly from exhaust gas within an exhaust section of an engine to heat an organic working fluid when the organic working fluid is present within the heat recovery boiler;   an expander configured to expand the heated organic working fluid;   a condenser configured to condense the expanded organic working fluid;   a pump configured to direct the condensed organic working fluid to the heat recovery boiler;   a sensor configured to detect a leak of the organic working fluid from the heat recovery boiler; and   an inert gas purging system configured to inject inert gas into the exhaust section in response to detection of the leak.   
     
     
         8 . The system of  claim 7 , wherein the heat recovery boiler comprises a fin and tube heat exchanger. 
     
     
         9 . The system of  claim 7 , wherein the expander comprises an expander generator set configured to generate electricity through expansion of the heated organic working fluid. 
     
     
         10 . The system of  claim 7 , wherein the condenser comprises an air-cooled heat exchanger. 
     
     
         11 . The system of  claim 7 , comprising a controller configured to activate the inert gas purging system in response to detection of the leak. 
     
     
         12 . The system of  claim 11 , wherein controller is configured to stop the pump in response to detection of the leak. 
     
     
         13 . The system of  claim 7 , comprising a valve system configured to be mounted in the exhaust section and to be switchable between a waste heat recovery position configured to direct the exhaust gas through the interior volume and a bypass position configured to direct the exhaust gas through a bypass duct to bypass the heat recovery boiler. 
     
     
         14 . A method comprising:
 detecting a leak of an organic working fluid from a heat recovery boiler into an interior volume of an exhaust section of an engine;   setting a valve to a bypass position to direct incoming exhaust gas to bypass the interior volume of the exhaust section in response to detecting the leak; and   injecting an inert gas into the interior volume to displace residual exhaust gas from the interior volume in response to detecting the leak.   
     
     
         15 . The method of  claim 14 , wherein detecting a leak comprises detecting an increase in a level of hydrocarbons exiting the interior volume. 
     
     
         16 . The method of  claim 14 , wherein detecting a leak comprises receiving data indicative of the leak from a sensor disposed within an exhaust gas stack or within the interior volume. 
     
     
         17 . The method of  claim 14 , wherein setting a valve to a bypass position comprises moving the valve to open an inlet to a bypass duct and to close an inlet to the interior volume. 
     
     
         18 . The method of  claim 14 , wherein setting a valve to a bypass position comprises moving a system of valves to open an inlet to a bypass duct and to close an inlet to the interior volume. 
     
     
         19 . The method of  claim 14 , wherein injecting an inert gas into the interior volume comprises opening a valve connected to a supply of the inert gas to allow the inert gas to flow into the interior volume. 
     
     
         20 . The method of  claim 14 , comprising stopping a pump that circulates the organic working fluid through the heat recovery boiler in response to detecting the leak.