Solid oxide fuel system

Abstract

A system and method satisfies temperature and pressure requirements of solid oxide fuel cell system in a manner that increases the overall efficiency and decreases the overall weight of system. The system and method include a secondary blower for boosting air stream pressure level sufficient for operation of a reformer that is designed to minimize pressure drop; an integrated heat exchanger for recovering heat from exhaust and comprising multiple flow fields for ensuring inlet temperature requirements of a solid oxide fuel cell are met; and a thermal enclosure for separating hot zone components from cool zone components for increasing thermal efficiency of the system and better thermal management.

1 . A system comprising:
 a solid oxide fuel cell having a cathode flow field, an anode flow field, and an exhaust flow field, the cathode flow field and the anode flow field configured to direct exhaust from the cathode flow field and the anode flow field to the exhaust flow field;   a heat exchanger having a cathode heat exchanger flow field, an anode heat exchanger flow field, and a portion of the exhaust flow field;   a fuel reformer configured to generate a reformate stream;   a first blower configured to receive air from an air source and generate a first fluid stream at a first pressure level, wherein a first portion of the first fluid stream is directed to the cathode heat exchanger flow field and the cathode flow field; and   a second blower configured to receive a second portion of the first fluid stream and generate a second fluid stream at a second pressure level that is greater than the first pressure level, wherein a first portion of the second fluid stream is directed to the fuel reformer to generate the reformate stream, the reformate stream having at least a portion that is directed from the fuel reformer to the anode flow field.   
     
     
         2 . The system of  claim 1 , wherein the first pressure level is sufficient to overcome a pressure drop across the cathode heat exchanger flow field and the cathode flow field. 
     
     
         3 . The system of  claim 1 , wherein the second pressure level is sufficient to overcome a pressure drop across the fuel reformer, the anode heat exchanger flow field, and the anode flow field. 
     
     
         4 . The system of  claim 1 , wherein the fuel reformer further comprises:
 an atomizer housing having an inner surface and an upstream interior region;   a reactor housing connected to the atomizer housing and having a downstream interior region;   a spray port between the upstream interior region and the downstream interior region, the spray port comprising a mouth open to the upstream interior region, a chamfer downstream of the mouth, a throat portion downstream of the chamfer, and a spray orifice downstream of the throat portion and open to the downstream interior region, the mouth having a diameter larger than a diameter of the spray orifice;   an insert positioned in the upstream interior region comprising an outer surface, a first end, a second end, and a fuel conduit, the fuel conduit comprising a tip portion that extends beyond the second end and past the mouth, and is recessed relative to the spray orifice, the tip portion comprising a fuel outlet orifice; and   an air swirler positioned in the upstream interior region having an air flow field, wherein the air flow field extends between the outer surface of the insert and the inner surface of the atomizer housing for directing air through the upstream interior region, spray port, and into the downstream interior region.   
     
     
         5 . The system of  claim 4 , wherein the diameter of the spray orifice is less than about 5 mm, the chamfer is at an angle of less than about 60 degrees relative to the mouth, the tip portion extends beyond the second end by a distance of less than about 7 mm, the tip portion is recessed relative to the spray orifice by a distance of less than about 3 mm, the air swirler comprises vanes having an angle of less than about 30 degrees, and wherein fuel travels through the fuel conduit at a liquid flow rate of less than or equal to 1 kg/h, and air travels through the air flow field at an air-to-fuel mass ratio of about 4 to about 8. 
     
     
         6 . The system of  claim 4 , wherein the downstream interior region of the reactor housing further comprises a partial oxidation catalyst. 
     
     
         7 . The system of  claim 1 , wherein the exhaust flow field further comprises a catalytic burner. 
     
     
         8 . The system of  claim 7 , further comprising a thermal enclosure surrounding the heat exchanger, fuel reformer, solid oxide fuel cell, catalytic burner, and exhaust flow field, and wherein the first blower and the second blower are positioned outside the thermal enclosure. 
     
     
         9 . The system of  claim 1 , further comprising an air scoop to assist the first blower generate the first fluid stream at the first pressure level. 
     
     
         10 . The system of  claim 1  wherein the second blower is configured to operate at a variable speed. 
     
     
         11 . The system of  claim 1  wherein the second blower is positioned downstream of the first blower. 
     
     
         12 . The system of  claim 1  wherein the portion of the reformate stream that is directed to the anode flow field and the first portion of the first fluid stream that is directed to the cathode heat exchanger flow field and the cathode flow field are configured to collectively combust in a catalytic burner. 
     
     
         13 . The system of  claim 1  wherein the portion of the reformate stream that is directed to the anode flow field is cooled by mixing with another portion of the reformate stream that is directed through the anode heat exchanger flow field. 
     
     
         14 . The system of  claim 1  wherein the heat exchanger is constructed from a material selected from a group comprising of Haynes 214, Haynes 230, Hastelloy X, Inconel 600, Inconel 610, Inconel 718, and Inconel 713. 
     
     
         15 . A system comprising:
 a solid oxide fuel cell that includes an anode flow field and a cathode flow field;   an exhaust flow field configured to receive exhaust from the anode flow field and the cathode flow field, the exhaust flow field including a heat exchanger portion;   a heat exchanger integrated with at least three flow fields, the at least three flow fields including a first anode heat exchanger flow field, a cathode heat exchanger flow field, and the heat exchanger portion;   a fuel reformer configured to receive fuel from a fuel source and generate a reformate stream;   a first blower configured to receive air from an air source and generate a first fluid stream at a first pressure level, wherein a first portion of the first fluid stream is directed to the cathode heat exchanger flow field and the cathode flow field; and   a second blower configured to receive a second portion of the first fluid stream and generate a second fluid stream at a second pressure level that is greater than the first pressure level, wherein a first portion of the second fluid stream is directed to the fuel reformer to generate the reformate stream, the reformate stream having at least a portion that is directed from the fuel reformer to the anode flow field.   
     
     
         16 . The system of  claim 15  further comprising a second anode heat exchanger flow field wherein the reformate stream includes another portion that is directed to the second anode heat exchanger flow field. 
     
     
         17 . The system of  claim 15  wherein the second blower is configured to operate at a variable speed. 
     
     
         18 . The system of  claim 15  wherein the portion of the reformate stream that is directed to the anode flow field and the first portion of the first fluid stream that is directed to the cathode heat exchanger flow field and the cathode flow field are configured to collectively combust in a catalytic burner. 
     
     
         19 . The system of  claim 15  wherein the portion of the reformate stream that is directed to the anode flow field is cooled by mixing with another portion of the reformate stream that is directed through the anode heat exchanger flow field. 
     
     
         20 . The system of  claim 15  wherein the heat exchanger is constructed from a material selected from a group comprising of Haynes 214, Haynes 230, Hastelloy X, Inconel 600, Inconel 610, Inconel 718, and Inconel 713.