Patent Application
20190345030
Fuel cells produce electricity based on an electrochemical reaction. Some fuel cells include a polymer electrolyte membrane (PEM) while others utilize a liquid electrolyte, such as phosphoric acid. In either configuration, the fuel cells utilize reactants for producing electricity. The reactants often are oxygen, which can be obtained from air, and hydrogen, which can be obtained by reforming a hydrocarbon gas in a reformer.
Over the years various advancements and improvements in reformers have become available. For example, it was necessary to be able to make reformers compact and economical enough to include them as part of a fuel cell power plant. Since then those skilled in the art have sought various ways to improve upon different aspects of reformers, such as their reliability and efficiency. The desire for further improvements continues as part of efforts to make fuel cells more economical for a wider range of applications.
An illustrative example reformer includes a housing having an inlet plenum, a reforming section, and an outlet. The inlet plenum includes a catalyst situated where a source fluid passing through the inlet plenum will be exposed to the catalyst prior to entering the reforming section.
In an example embodiment having one or more features of the reformer of the previous paragraph, the inlet plenum includes a mesh container and the catalyst is in the mesh container.
In an example embodiment having one or more features of the reformer of any of the previous paragraphs, the mesh container comprises a tube of mesh material.
In an example embodiment having one or more features of the reformer of any of the previous paragraphs, the tube comprises a cylinder having coaxial inner and outer mesh walls and the catalyst is situated between the inner and outer mesh walls.
In an example embodiment having one or more features of the reformer of any of the previous paragraphs, the catalyst comprises a pre-reformer catalyst.
In an example embodiment having one or more features of the reformer of any of the previous paragraphs, the catalyst comprises nickel.
An illustrative example method of reforming a source fluid includes directing the source fluid through an inlet plenum of a reformer, exposing at least some of the source fluid to a catalyst in the inlet plenum, and reforming the exposed source fluid after it exits the inlet plenum.
In an example embodiment having one or more features of the method of the previous paragraph, the catalyst comprises a pre-reformer catalyst.
In an example embodiment having one or more features of the method of any of the previous paragraphs, the catalyst comprises nickel.
In an example embodiment having one or more features of the method of any of the previous paragraphs, the catalyst in the inlet plenum is situated in a mesh container and exposing the source fluid to the catalyst comprises directing the source fluid into contact with the mesh container.
In an example embodiment having one or more features of the method of any of the previous paragraphs, exposing the source fluid to the catalyst comprises directing the source fluid at least partially through the mesh container.
In an example embodiment having one or more features of the method of any of the previous paragraphs, the source fluid comprises a hydrocarbon.
In an example embodiment having one or more features of the method of any of the previous paragraphs, the source fluid comprises at least one of natural gas, pure methane, ethane, propane or liquefied petroleum gas.
In an example embodiment having one or more features of the method of any of the previous paragraphs, the source fluid comprises natural gas.
Various features and advantages of at least one disclosed example embodiment will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
Natural gas enters the housing 22 through the inlet 24 and flows into an inlet plenum 28 prior to entering a reforming section 30 that includes catalyst tubes that operate in a known manner. Reformed gas exits the housing through the outlet 26. Other aspects of the reformer 20, such as a burner, are not shown as they are generally known in the art.
The inlet plenum 28 contains a catalyst 32 that is situated in the inlet plenum 28 where at least some of the natural gas in the inlet plenum is exposed to the catalyst 32 before the gas enters the reforming section 30. Exposing natural gas to the catalyst 32 in the inlet plenum 28 increases the efficiency of the reformer 20.
In some embodiments the catalyst 32 comprises nickel. An example embodiment includes a catalyst material used in pre-reforming devices that are designed to process propane. The catalyst 32 is such embodiments can be referred to as a pre-reformer catalyst.
Some embodiments include the catalyst 32 in a container within the inlet plenum 28.
In the example of
The example container 34 of
In another example arrangement the catalyst 32 occupies at least some of what otherwise would have been open space among the catalyst tubes 44 without being in a separate container 34. In one such embodiment the catalyst 32 effectively fills some of the space in the inlet plenum 28 in a manner that still allows the source fluid to flow through and among the catalyst tubes 44.
The pre-reforming catalyst 32 utilizes heat in the inlet plenum 28 and effectively converts what otherwise would be waste heat into useful heat that assists in reacting the incoming source fluid faster. This provides an improvement in reformer performance and better utilization of the source fluid.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.
