System and method of regenerating desulfurization beds in a fuel cell system

Abstract

A desulfurization system is disclosed that facilitates in situ or ex situ regeneration of hydrocarbon desulfurization beds. The desulfurization system can use a bed characterization limit, a predetermined sulfur threshold or other metric to determine when the hydrocarbon desulfurization bed should be regenerated. The desulfurization system can include heat and air intakes and an air/sulfur purge outlet to allow for the removal of sulfur from the hydrocarbon desulfurization bed. Alternatively, the regeneration of hydrocarbon desulfurization bed may be performed in situ by a service technician by using a prebuilt appliance that is connected to the inlet and outlets of the desulfurization appliance. The prebuilt appliance heats and purges hydrocarbon desulfurization bed, in substantially the same manner as described just above, and captures the sulfur outside of the desulfurization system.

What is claimed is: 
     
         1 . A desulfurization appliance for producing a substantially desulfurized fuel comprising:
 a hydrocarbon desulfurization bed having a fuel inlet, a refined fuel outlet, and an air/sulfur outlet and wherein said hydrocarbon desulfurization bed has a bed characterization limit;   a heat stream in thermal communication with said hydrocarbon desulfurization bed; and   a purge valve in fluid communication with said hydrocarbon desulfurization bed and said air/sulfur outlet, said purge valve configured to open when said bed characterization is exceeded.   
     
     
         2 . A desulfurization appliance according to  claim 1 , wherein said heat stream is provided by a heat source, and wherein said heat source is a thermal management module that is a component of a combined cooling, heating, and power system. 
     
     
         3 . A desulfurization appliance according to  claim 2 , wherein the desulfurization appliance is configured to provide the substantially desulfurized fuel as an input to a fuel cell system, and wherein said heat source is one or more of the components of said fuel cell system. 
     
     
         4 . A desulfurization appliance according to  claim 1 , further including an air stream in fluid communication with said hydrocarbon desulfurization bed when said bed characterization is exceeded. 
     
     
         5 . A desulfurization appliance according to  claim 1 , further including a control system including a sensor configured to monitor a sulfur content proximate said refined fuel outlet and wherein said hydrocarbon desulfurization bed has a bed characterization limit and said control system determines whether said bed characterization limit has been exceeded based upon said sulfur content. 
     
     
         6 . A desulfurization appliance according to  claim 5 , wherein said control system includes a sulfur compound sensor configured to detect a purge sulfur content proximate said air/sulfur outlet and to transmit a signal to said control system indicative of said purge sulfur content. 
     
     
         7 . A desulfurization appliance according to  claim 1 , wherein said control system is further configured to determine an air/purge sulfur content proximate said air/sulfur outlet, and wherein said heat stream is further configured to cease providing thermal energy to said hydrocarbon desulfurization bed when said air/purge sulfur content is below a predetermined amount, and wherein said purge valve is further configured to close when said air/purge sulfur content is below said predetermined amount. 
     
     
         8 . A desulfurization appliance for a fuel cell system, the desulfurization appliance being capable of self-regeneration of a hydrocarbon desulfurization bed contained therein, the desulfurization appliance comprising:
 a fuel inlet valve in fluid communication with the hydrocarbon desulfurization bed;   a refined fuel outlet valve in fluid communication with the hydrocarbon desulfurization bed and the fuel cell system;   a heat stream in thermal communication with the hydrocarbon desulfurization bed;   a purge valve in fluid communication with the hydrocarbon desulfurization bed and an air/sulfur outlet;   an air stream in fluid communication with the hydrocarbon desulfurization bed; and   a control system configured to:
 determine a sulfur content proximate said refined fuel outlet; 
 compare said sulfur content to a first predetermined sulfur amount and/or a bed characterization limit; 
 direct said fuel inlet valve to close, said refined fuel outlet valve to close, said purge valve to open, said heat stream to provide thermal energy, and said air stream to provide air, when said sulfur content exceeds said first predetermined sulfur amount and/or said bed characterization limit is reached. 
   
     
     
         9 . A desulfurization appliance according to  claim 8 , wherein said control system is further configured to determine an air/purge sulfur content proximate said air/sulfur outlet, and wherein said heat source is further configured to cease providing thermal energy to said hydrocarbon desulfurization bed when said air/purge sulfur content is below a second predetermined amount, and wherein said purge valve is further configured to close when said air/purge sulfur content is below said second predetermined amount. 
     
     
         10 . A desulfurization appliance according to  claim 8 , wherein said control system is further configured to direct said fuel inlet valve to open, said refined fuel outlet valve to open, said purge valve to close, said heat source to cease providing thermal energy, and said air source to cease providing air, after a predetermined amount of time. 
     
     
         11 . A desulfurization appliance according to  claim 8 , wherein said heat source is a component of the fuel cell system. 
     
     
         12 . A desulfurization appliance according to  claim 11 , further including a sulfur capture device in fluid communication with said air/purge outlet. 
     
     
         13 . A desulfurization appliance according to  claim 12 , wherein said sulfur capture device bubbles an exhaust gas received from said air/purge outlet through a fluid, wherein said exhaust gas includes sulfur and said fluid removes sulfur from said exhaust gas. 
     
     
         14 . A desulfurization appliance according to  claim 8 , wherein said heat source and said air source are portable external components configured to be connectable to the desulfurization appliance. 
     
     
         15 . A desulfurization appliance according to  claim 8 , wherein said control system includes a sulfur compound sensor configured to detect sulfur proximate said refined fuel outlet valve and to transmit a signal indicative of said sulfur content to said control system. 
     
     
         16 . A method of operating a fuel cell system comprising:
 providing a desulfurization appliance having a hydrocarbon desulfurization bed;   determining a sulfur content in a refined fuel exiting the hydrocarbon desulfurization bed;   comparing the sulfur content to a predetermined sulfur limit;   self-regenerating the hydrocarbon desulfurization bed when the sulfur content exceeds the predetermined sulfur limit.   
     
     
         17 . A method according to  claim 16 , wherein said self-regenerating includes:
 elevating the temperature of the hydrocarbon desulfurization bed;   directing air over the hydrocarbon desulfurization bed; and   collecting sulfur compounds in a sulfur capture system.   
     
     
         18 . A method according to  claim 17 , wherein said self-regenerating further includes monitoring said collecting. 
     
     
         19 . A method according to  claim 17 , further including providing a heat source, wherein said heat sources is a component of the fuel cell system and wherein said elevating the temperature is accomplished by the heat source. 
     
     
         20 . A method according to  claim 16 , further including:
 determining a second sulfur content during said self-regenerating;   comparing the second sulfur content with a second predetermined sulfur limit; and   restarting the desulfurization appliance when the second sulfur content drops below the second predetermined sulfur limit.