AI
Tuesday, September 29, 2015 10:50:53 PM
Nice find, and great question 
Not closely related, but does show that Alstom is involved deeply in fuel cells and thus it would be expected that Alstom would pay close attention to the recent MVTG fuel cell vehicle success!!
From the link:
The present disclosure relates to a fuel cell system and an operating method for a fuel cell system. Embodiments of the present disclosure are particularly, but not exclusively, concerned with fuel cell systems which include tubular solid oxide fuel cells (SOFCs) and operating methods for such fuel cell systems.
During operation of the illustrated fuel cell system, at the cathode side (air side) air is supplied to the cathodes 14 through an air inlet 16 and associated air plenum 17 and the air is heated via a heat exchanger 18 before it reaches the air plenum 17. The heated air passes over the cathodes 14 where oxygen is extracted and some waste heat is dissipated. The waste heat is recovered by the heat exchanger 18 as the oxygen-depleted air is exhausted through an air outlet 20, to thereby heat the air supplied through the air inlet 16. At the anode side (fuel side) of the fuel cell system, a suitable hydrocarbon fuel (for example natural gas containing methane) is injected into a steam reformer
Steam-reformed hydrocarbon fuel containing hydrogen and carbon monoxide is supplied from the external steam reformer 22 to a fuel plenum 24 which supplies the fuel to the internal anodes 12 of the fuel cells 10 through fuel injection passages 25. The steam-reformed fuel is reacted at the surface of each internal anode 12 such that the hydrogen and carbon monoxide is electrolytically oxidized by oxygen ions passing through the fuel cell surface (comprising cathode, electrolyte and anode layers). Exhaust products containing steam, carbon dioxide and unreacted hydrocarbon fuel are formed
A proportion of the exhaust products from the exhaust plenum 26 are recirculated to the external steam reformer 22 via an external ejector 28, which simultaneously injects fresh hydrocarbon fuel into the external steam reformer 22. The recirculated exhaust products provide the steam that is needed for the steam reforming process and the recirculated unreacted fuel increases fuel utilization and, hence, efficiency. The exhaust products that are not recirculated to the external steam reformer 22 may be used to heat the air supplied through the air inlet 16 or may alternatively be vented. The fuel cell stack is typically operated at a temperature in the order of 700 to 1000° C.
During operation of a fuel cell system, both endothermic and exothermic reactions take place and thermal management is, therefore, important. The conventional fuel cell systems described above do not provide optimal thermal management and it would, therefore, be desirable to provide a fuel cell system with improved thermal management.
---------------------------------
These types of solid oxide fuel cells are very large, bulky, heavy, run at very high temperatures, have seal problems and are costly to make due to the extreme temperatures encountered and the ceramics needed to build them, and they have a huge footprint, they are used in combined heat cycle applications, because they can only compete by producing steam from all the waste heat to run steam turbines to reach high enough efficiencies to compete with traditional combustion systems. With out that they do not produce enough direct electricity (the fuel cell part) to compete, too low of an efficiency.
Also the recycle hardware and reformer is an added cost as is the steam turbine and pumps, etc...High maintenance...
Not closely related, but does show that Alstom is involved deeply in fuel cells and thus it would be expected that Alstom would pay close attention to the recent MVTG fuel cell vehicle success!!
From the link:
The present disclosure relates to a fuel cell system and an operating method for a fuel cell system. Embodiments of the present disclosure are particularly, but not exclusively, concerned with fuel cell systems which include tubular solid oxide fuel cells (SOFCs) and operating methods for such fuel cell systems.
During operation of the illustrated fuel cell system, at the cathode side (air side) air is supplied to the cathodes 14 through an air inlet 16 and associated air plenum 17 and the air is heated via a heat exchanger 18 before it reaches the air plenum 17. The heated air passes over the cathodes 14 where oxygen is extracted and some waste heat is dissipated. The waste heat is recovered by the heat exchanger 18 as the oxygen-depleted air is exhausted through an air outlet 20, to thereby heat the air supplied through the air inlet 16. At the anode side (fuel side) of the fuel cell system, a suitable hydrocarbon fuel (for example natural gas containing methane) is injected into a steam reformer
Steam-reformed hydrocarbon fuel containing hydrogen and carbon monoxide is supplied from the external steam reformer 22 to a fuel plenum 24 which supplies the fuel to the internal anodes 12 of the fuel cells 10 through fuel injection passages 25. The steam-reformed fuel is reacted at the surface of each internal anode 12 such that the hydrogen and carbon monoxide is electrolytically oxidized by oxygen ions passing through the fuel cell surface (comprising cathode, electrolyte and anode layers). Exhaust products containing steam, carbon dioxide and unreacted hydrocarbon fuel are formed
A proportion of the exhaust products from the exhaust plenum 26 are recirculated to the external steam reformer 22 via an external ejector 28, which simultaneously injects fresh hydrocarbon fuel into the external steam reformer 22. The recirculated exhaust products provide the steam that is needed for the steam reforming process and the recirculated unreacted fuel increases fuel utilization and, hence, efficiency. The exhaust products that are not recirculated to the external steam reformer 22 may be used to heat the air supplied through the air inlet 16 or may alternatively be vented. The fuel cell stack is typically operated at a temperature in the order of 700 to 1000° C.
During operation of a fuel cell system, both endothermic and exothermic reactions take place and thermal management is, therefore, important. The conventional fuel cell systems described above do not provide optimal thermal management and it would, therefore, be desirable to provide a fuel cell system with improved thermal management.
---------------------------------
These types of solid oxide fuel cells are very large, bulky, heavy, run at very high temperatures, have seal problems and are costly to make due to the extreme temperatures encountered and the ceramics needed to build them, and they have a huge footprint, they are used in combined heat cycle applications, because they can only compete by producing steam from all the waste heat to run steam turbines to reach high enough efficiencies to compete with traditional combustion systems. With out that they do not produce enough direct electricity (the fuel cell part) to compete, too low of an efficiency.
Also the recycle hardware and reformer is an added cost as is the steam turbine and pumps, etc...High maintenance...
