Abstract:
In present-day aircraft, common containers for storing of the raw materials required for on-board operation, such as oxygen and water, are used. Energy is produced by using generators and turbines. According to one exemplary embodiment of the present invention, an electrochemical reactor for producing energy, hydrogen, oxygen, and clear water is provided, which ensures the on-board supply. According to the invention, hereby released reaction heat is used as additional process heat in an SOSE- and FP-process. In addition, by use of the hydrogen produced in the process, an extra desulphurization unit is eliminated with the fuel processing of the fuel in the FP process. In this manner, large storage volumes and weight can be saved.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 60/598,243 filed Aug. 3, 2004, the disclosure of which is hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a supply system in aircraft. In particular, the present invention relates to an electrochemical reactor for producing energy, hydrogen, oxygen, and clear water from grey water, a hydrocarbon-containing fuel and air in an aircraft or spacecraft, an aircraft with an electrochemical reactor, as well as a method for operating a corresponding electrochemical reactor.  
         [0003]     In aircraft, supply systems are used for supplying the inner on-board region with oxygen and clear water and for supplying corresponding electrical consumers with electrical energy. Typically, the required raw materials, such as oxygen and clear or drinking water are stored in corresponding containers, which are loaded before beginning the flight. In this connection, the high weight of the supply containers as well as the partially enormous space requirements are disadvantageous, which are occupied by the large storage volumes.  
         [0004]     According to an exemplary embodiment of the present invention, an electrochemical reactor for producing energy, hydrogen, oxygen, and clear water from grey water, a hydrocarbon-containing fuel and air in an aircraft or spacecraft is provided. The electrochemical reactor hereby includes a fuel cell assembly, subsequently referred to as an SOSE assembly, and a fuel cell processor assembly, subsequently referred to as an FP assembly.  
         [0005]     This may allow for an improved provisioning of aircraft with energy and raw materials.  
         [0006]     Advantageously, an electrochemical reactor may be provided, which represents an autonomous system for on-board supply, so that large storage volumes and weight for storing required raw materials or also for producing energy can be reduced or even avoided.  
         [0007]     According to a further embodiment of the present invention, the process heat produced by the SOFC assembly is useable in the SOSE assembly for an electrolytic process and in the FP assembly for a reforming process. In addition, the proposed electrochemical reactor is designed, such that the hydrogen produced in the SOSE assembly can be used for a cyclical regeneration of individual SOFC anodes, so that advantageously, a separate desulphurization assembly is eliminated and any thermal load alternations can be driven without degradation losses.  
         [0008]     According to a further embodiment of the present invention, the electrochemical reactor includes further a control unit for controlling or regulating the processes running in the reactor, such that the energy produced by the SOFC assembly corresponds to the energy required by the SOSE assembly or by the FP assembly or by the on-board operation, whereby the load range, in which the processes are driven, is continuous, and whereby the processes yield altogether at least a part of the electrical energy, the oxygen, and the clear water required for the on-board operation.  
         [0009]     Advantageously, this is believed to make it possible, for example, that the thermal cycling of both high temperature systems SOSE and SOFT is stabilized, so that an extensive correction is eliminated. In addition, a corresponding regulation of the three assemblies (SOFC, SOSE, FP) makes possible that at each time point, the energy, oxygen, and clear water required for on-board operation maybe made available, and at the same time, no excess is produced or a possible loss is held to a minimal level.  
         [0010]     According to a further embodiment of the present invention, the SOFC assembly, the SOSE assembly, and the FP assembly are arranged in a thermally insulated casing.  
         [0011]     A heat loss to the environment may hereby be effectively avoided, so that a maximal utilization of the energy produced by the entire system is possible.  
         [0012]     According to a further embodiment of the present invention, the SOSE assembly or the SOFC assembly is formed at least partially from oxygen ion-conducting solid electrolytes.  
         [0013]     In this manner, additional stability of both assemblies maybe achieved. In addition, the use of solid electrolytes in the cells leads to a simplified manufacture and later manipulation of the cells.  
         [0014]     According to a further exemplary embodiment of the present invention, the SOSE assembly includes a first SOSE cell or a second SOSE cell. In addition, the SOFC assembly includes a first SOFC cell or a second SOFC cell and the FP assembly includes a first FP cell or a second FP cell. At least two of these cells are connected in parallel or in series to one another.  
         [0015]     Because of these parallel or serial connections or parallel-serial connections of different cells, an increased flexibility in design of the electrochemical reactor maybe achieved, whereby different configurations, adapted to the desired system specifications, are made possible. In addition, a modular-type connection of different cells or cell assemblies facilitates later maintenance or exchange of defective individual cells.  
         [0016]     According to a further advantageous embodiment of the present invention, the first SOSE cell is formed with at least a third SOSE cell as a multi-cellular electrolytic cell stack or the first SOFC cell is formed with at least a third SOFC cell as a multi-cellular fuel cell stack.  
         [0017]     This may lead to an increased flexibility with the assembly of the entire system, since the corresponding stacks already can be configured accordingly at the factory.  
         [0018]     According to a further exemplary embodiment of the present invention, the oxygen produced in the SOSE assembly can be supplied to a cathode of the SOFC assembly, to application in the on-board operation, to a PEM-fuel cell (polymer-electrolytic-fuel cell), or a downstream combustion process.  
         [0019]     By means of a corresponding redistribution of the produced oxygen by the control unit, advantageously, the supply of the corresponding module (SOFC assembly, PEM fuel cell, downstream combustion module, or also, however, an on-board operating module) may be ensured, so that a substantial self-sustaining operation of the electrochemical reactor and an always sufficient production of water, oxygen, hydrogen, and electrical energy is ensured.  
         [0020]     According to a further exemplary embodiment of the present invention, the carbon monoxide produced in the FP assembly can be supplied to an anode of the SOSE assembly.  
         [0021]     A lowering of the SOSE cell voltage may hereby be achieved.  
         [0022]     According to a further exemplary embodiment of the present invention, the hydrogen produced in the SOSE assembly can be supplied to an anode of the SOFC assembly, in particular, for increasing the conversion in the SOFC assembly or for regeneration of the SOFC anode, to a PEM-fuel cell, or a downstream combustion process.  
         [0023]     In addition to a method-technical optimizing of the processes running in the reactor, in particular, a decomposition of the degradation of the SOFC anode formed by sulfurous fractions in reformate may be ensured. Advantageously, the hydrogen is produced within the electrochemical reactor, so that a system-internal desulphurization of the SOFC anode can be performed and therewith, a desulphurization unit with the fuel preparation of the fuel in the FP assembly is eliminated.  
         [0024]     According to a further advantageous and exemplary embodiment of the present invention, the water produced in the SOFC assembly can be supplied to a cathode of the SOSE assembly, the FP assembly, or the application in the on-board operation.  
         [0025]     In this manner, supplying additional water from external water storage sources to the system may be avoided advantageously.  
         [0026]     According to a further embodiment of the present invention, individual cells or interconnections of cells are controllable or regulatable by the control unit in dependence on on-board requirements or the processes running in the reactor, in particular, also the regeneration processes.  
         [0027]     It may be is ensured that minimal total requirements of raw materials or energy result from a corresponding performance-related regulation of the reactor, so that, for example, individual subunits can be switched off, in order for a successive regeneration or purification process to be subdued. The purification process can operate, for example, as a desulphurization of an SOFC anode.  
         [0028]     According to a further exemplary embodiment of the present invention, individual cells or interconnections of cells can be dried after switching off by means of post-heating of a thermal storage capacity or the supplying of an inert gas.  
         [0029]     For this drying, no supply of system-external energy may be necessary, since the thermal storage capacity, for example, is a component of the electrochemical reactor.  
         [0030]     According to a further advantageous embodiment of the present invention, an aircraft is provided with an electrochemical reactor for production of energy, hydrogen, oxygen, and clear water from grey water, a hydrocarbon-containing fuel and air, including a fuel cell assembly, an electrolytic cell assembly, and a fuel processor assembly, whereby the process heat produced by the fuel cell assembly can be used in the electrolytic cell assembly for an electrolytic process and in the fuel processor assembly for a reforming process, and whereby the hydrogen produced in the electrolytic cell assembly can be used for regeneration of an anode of the fuel cell assembly.  
         [0031]     In this regard, an aircraft may be provided, which demonstrates an improved provisioning with energy and raw materials, so that large storage volumes and weight for storing required raw materials or also for production of energy can be reduced or completely avoided. In addition, the aircraft has an electrochemical reactor, which is designed, such that the hydrogen produced in the SOS assembly can be used for a cyclical regeneration of individual SOFC anodes, so that, advantageously, a separate desulphurization assembly is eliminated and any number of thermal load changes can be driven without degradation loss.  
         [0032]     According to a further exemplary embodiment of the present invention, a method for operating an electrochemical reactor with a fuel cell assembly, an electrolytic cell assembly, and a fuel cell processor assembly in an aircraft or a spacecraft is provided, in which the energy, hydrogen, oxygen, and clear water from grey water, a hydrocarbon-containing fuel and air is produced in an electrochemical reactor.  
         [0033]     This exemplary embodiment provides a method, through which it is believed that an improved supplying of aircraft or spacecraft with energy, hydrogen, oxygen, and clear water is ensured, so that large storage volumes and weight for storing necessary raw materials or also for production of energy can be reduced or completely avoided.  
         [0034]     According to a further exemplary embodiment of the present invention, the process heat produced by the fuel cell assembly is used in the electrolytic cell assembly for an electrolytic process and in the fuel processor assembly for a reforming process, whereby the hydrogen produced in the electrolytic cell assembly is use for regeneration of an anode of the fuel cell assembly.  
         [0035]     Therefore, with the method of the present invention the hydrogen produced in the SOSE assembly can be used for a cyclical regeneration of individual SOFC anodes, so that a separate desulphurization assembly may be eliminated and any number of thermal load changes can be driven without degradation loss.  
         [0036]     Further advantageous embodiments of the present invention are provided in the dependent claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0037]     Next, preferred embodiments of the present invention will be described with reference to the accompanying figures.  
         [0038]      FIG. 1  shows a schematic, method-technical representation of an electrochemical reactor according to an exemplary embodiment of the present invention;  
         [0039]      FIG. 2  shows a schematic representation of the electrochemical processes running in the electrochemical reactor and the corresponding supply circuits;  
         [0040]      FIG. 3  shows schematically an exemplary assembly of multiple SOFC cells and SOSE cells within an electrochemical reactor. 
     
    
     DETAILED DESCRIPTION  
       [0041]      FIG. 1  shows a schematic, method-technical representation of an electrochemical reactor according to an exemplary embodiment of the present invention. The electrochemical reactor comprises a fuel cell assembly (SOFC assembly)  23 , an electrolytic cell assembly (SOSE assembly)  21 , and a fuel processor assembly (FP assembly)  6 .  
         [0042]     In particular, the electrochemical reactor shown in  FIG. 1  operates as a modular, integrated electrochemical reactor for production of electrical energy, hydrogen, oxygen, and water for the use in aircraft. Fuel cell assemblies, such as, for example, a solid oxide fuel cell assembly, also can be used for water production in addition to current production, according to the present invention. Electrolytic cell assemblies, such as, for example, a solid oxide electrolytic cell, can produce hydrogen and oxygen in the embodiment as a “solid oxide steam electrolyzer.” 
         [0043]     SOFC and SOSE are known technical systems. With a suitable combination of these two systems, it is also possible to use the fuel produced from the fuel processor in a process-technical manner, such that with the production of electrical energy, hydrogen, oxygen, and water, the requirement can be performed according to a continuous load range, and therewith, the thermal cycling of both high temperature systems SOSE and SOFC is stabilized.  
         [0044]     Obtaining of water and oxygen, in particular, is important for air and space travel, since here, autonomous systems for on-board supply are required, in order to avoid large storage volumes and weight.  
         [0045]     The fuel processor  6  of the electrochemical reactor of the present invention is supplied via a mixing unit  3  with a hydrocarbon-containing fuel, such as, for example, kerosene  1 , and water, with which it can operate as a purified grey water  5 . Before fuel  1  and grey water  5  are supplied to the fuel processor  6 , a vaporization of the fuel  1  in a vaporizer  2  and a vaporization of the purified grey water  5  in a water vaporizer  4  takes place. The energy required for the vaporization of fuel  1  or grey water  5  can originate, for example, from the cathode exhaust from the cathode  21   a  of the electrolytic cell assembly or from the anode exhaust of the anode  23   a  of the fuel cell assembly.  
         [0046]     In the mixing unit  3 , fuel vapor and grey water vapor are mixed and supplied to the fuel processor  6 . In the FP  6 , the a reformate gas  7  is produced for the subsequent processes from the hydrocarbon-containing fuel  1  and the water  5 , which contains the primary components hydrogen, carbon monoxide, and water vapor.  
         [0047]     In the condenser  8 , a separation of the water of the hydrogen-water vapor-carbon monoxide gas mixture  7  takes place and the separated water  9  is intermediately stored in a container  43  or buffered and the remaining gas, hydrogen, and carbon monoxide are supplied  10  to a downstream molecular sieve  11  and there separated.  
         [0048]     The separated water  9  can be supplied, for example, via a suitable pump (not shown in  FIG. 1 ) to the intermediate storage unit  43  or, however, also via the pump  42 , which also is used for water emanating from the condensers  29  and  36  (the corresponding lines are not shown in  FIG. 1 ).  
         [0049]     The (if necessary, sulfurous) hydrogen  12  and the carbon monoxide  13  are heated subsequently in a heating apparatus  14  in separated chambers and thereafter condensed via a hydrogen condenser  18 , or a respective carbon monoxide condenser  17  and transported on.  
         [0050]     The condensed and eventually sulfurous hydrogen is supplied to an anode  23   a  of the SOFC assembly  22 . In addition to the hydrogen from the FP  6 , as will be described in greater detail subsequently, the anode site  23   a  of the SOFC  23  is supplied with hydrogen from the SOSE  21 . The distribution and production of the hydrogen flows for the SOFC  23  is regulated by the requirements of hydrogen, oxygen, water, and electrical energy.  
         [0051]     The oxygen for the SOFC cathode  23 b is taken from the atmospheric air or the cabin air  19  and compressed via a compressor  20  to the working pressure of the SOFC  23 .  
         [0052]     The hydrogen-water vapor-gas mixture in the anode exhaust flow of the SOFC  23  is separated in a downstream condenser  36  and the separated hydrogen is intermediately stored or buffered in a container  45 .  
         [0053]     The separated hydrogen  34  contains typically a known sulfur portion and is compressed for storage in a buffer for sulfurous hydrogen  45  by a hydrogen compressor  44 . Via a line  34 , the hydrogen can be supplied, for example, to a downstream combustion process.  
         [0054]     The water separated in the condenser  36  is supplied via the water pump  42  to the water intermediate storage unit or water buffer  43 . Alternatively, the water can be released via the water outlet  35 ; likewise, the separated hydrogen can be released via the hydrogen outlet  34 .  
         [0055]     The air in the cathode exhaust flow of the SOFC  22  is released via the air outlet  27 .  
         [0056]     The SOSE  21  is supplied on the cathode side  21  a with water vapor  15 , which was compressed accordingly in the water vapor compressor  16 . On the anode side  21 b, the SOSE  21  is supplied with carbon monoxide from the FP  6 , which is correspondingly compressed in the carbon monoxide compressor  17 . The water vapor for the cathode-side supply of the SOSE  21  emanates, according to an exemplary embodiment of the present invention, from the water container  43  and, therewith, a reactor-internal process. For this purpose, for example, an outlet  31  is provided, via which the water from the container  43  is supplied to the water compressor  16  in the form of water vapor. Alternatively, the water from the container  43  can be supplied also via the outlet  35  to the vaporizer  4 , after which it is then forwarded to the water compressor  16 .  
         [0057]     In the SOSE  21 , from the water vapor, hydrogen and oxygen are produced. According to the present invention, the oxidation of the carbon monoxide with the oxygen produced on the anode side to carbon dioxide causes a reduction of the cell voltage of the SOSE  21 .  
         [0058]     The SOSE can obtain additional water vapor from the vaporizer  4  for the FP  6 . The electrolytic flow relates to the SOSE  21  from the SOFC  23 . The distribution and production of the water vapor flows for the SOSE  21  is regulated by the requirements of hydrogen, oxygen, water, and electrical energy.  
         [0059]     The oxygen produced on the anode  21 b of the SOSE  21  and the carbon dioxide are supplied via the line  25  to the molecular sieve  30  and there separated. The separated oxygen is compressed via the oxygen compressor  40  and conducted to a container  41  for intermediate storage or buffering. Alternatively, the separated oxygen can be released via an oxygen outlet  33 .  
         [0060]     The carbon dioxide separated in the molecular sieve  30  can be released via a carbon dioxide outlet  32 .  
         [0061]     The cathode-side released hydrogen/water vapor mixture is conducted via the line  24  to the condenser  29 . The pure hydrogen separated in the condenser  29  is intermediately stored in a container  29  or buffered, after it was compressed accordingly by the hydrogen compressor  38 . Alternatively, the hydrogen released from the condenser  29  can be released via the hydrogen outlet  28 . The pure hydrogen intermediately stored in the hydrogen intermediate storage  39  can be heated subsequently, likewise, like the pure hydrogen originating directly from the condenser  29 , by a heating apparatus  37  to a corresponding reaction-friendly temperature, and thereafter, for example, for increasing the conversion, be conducted to the anode side  23   a  of the SOFC  23 . This takes place, for example, via line  12 , heating apparatus  14 , and hydrogen compressor  18 .  
         [0062]     Alternatively, the hydrogen produced internally in the reactor can be conducted to a downstream PEM-fuel cell (polymer-electrolytic-fuel cell) or a downstream combustion process.  
         [0063]     According to this, the produced oxygen and the produced water are intermediately stored or buffered in containers  41 ,  43  and are either used again in the entire process or supplied to the on-board supply for water or oxygen. The intermediately stored or buffered hydrogen (pure) can either be supplied gain to the SOFC  23  or can be used in another fuel cell process or combustion process.  
         [0064]     By means of a spatial integration of SOFC  23 , SOSE  21 , and FP  6  in a casing or housing, the reaction heat released in the SOFC  23  is used as additional process heat in the SOSE- and FP-processes.  
         [0065]     It should be noted that the water for the production of water vapor in the vaporizer  4  for the FP  6  and the SOSE  21  is purified grey water  5  from the on-board operation and/or water from the intermediate storage or buffer storage  43 .  
         [0066]     Advantageously, the heat output for the water vaporizer  4  and the kerosene vaporizer  2  is taken from the cathode exhaust of the SOSE  21  and the anode exhaust of the SOFC  23 , respectively, from the condensers  29 ,  36 .  
         [0067]     In addition, according to an exemplary embodiment of the present invention, the fuel cells  23  and electrolytic cells  21  are embodied in multi-cellular form as a fuel cell stack and electrolytic cell stack.  
         [0068]     By means of the integration of the three reactors FP  6 , SOSE  21 , and SOFC  23  in a thermally insulated casing or housing, the process heat produced by the SOFC  23  is used in the SOSE  21  and in the FP  6  for the respective electrolysis or reforming process. In this manner, with operation of the entire process, the energy loss, which, for example, exists by additional heat transfer units, may effectively be minimized.  
         [0069]     The reforming process, which runs in the FP, operates, for example, as the conversion from a hydrocarbon-containing fuel (such as, for example, kerosene) into a reformate gas, which contains hydrogen, carbon monoxide, and water vapor as primary components.  
         [0070]     These days, kerosene supplied for civil air travel contains, for example, approximately 300 ppm sulfur and it is known that the anode of the SOFC  23  can be contaminated by sulfur. In order to break down degradations formed by the sulfurous fractions in reformate on the SOFC anode  23   a , according to the present invention, the hydrogen produced in the SOSE or the intermediately stored or buffered hydrogen is supplied for regeneration to the SOFC anode  23   a . Since the hydrogen requirement for the regeneration of the SOFC anode  23   a  contaminated by sulfur depends on the remaining requirements of oxygen, water, electrical energy, and operating time, by means of the intermediate storage or buffering, always a sufficient amount of hydrogen is maintained. In this type of regeneration method, a desulphurization with the fuel preparation of the fuel in FP  6  is eliminated.  
         [0071]     The method-technical devices required for the entire process are designed according to generally known technical principles.  
         [0072]     According to a another embodiment of the present invention, multiple fuel cell stacks or electrolytic cell stacks or fuel processors are integrated in parallel or serial connection or parallel-serial connection. In addition, according to an exemplary embodiment of the present invention, it is provided that subsystems comprise multiple fuel cell stacks and electrolytic cell stacks, and fuel cell process assemblies can be interconnected in parallel- or serial connection or parallel-serial connection to a total system or subsystem. An individual subsystem can comprise an FP-SOSE-SOFC system or an FP-SOFC system or a SOSE-SOFC system or an FP system or SOFC system or SOSE system.  
         [0073]      FIG. 2  shows a schematic representation of the electrochemical processes running in the electrochemical reactor and the corresponding supply circuits. In the electrochemical reactor, a hydrocarbon-containing fuel CxHy, a part water, b part oxygen, and c part nitrogen are converted to d part clear water, e part oxygen, f part pure hydrogen, g part carbon dioxide, h part nitrogen, and energy. The energy acts on the one hand as thermal energy, which can be supplied for vaporizing of the hydrocarbon-containing fuel or for vaporizing of the process-supplied water or, however, also for an electrolytic process into the SOSE assembly or a reforming process in the FP assembly.  
         [0074]     On the other hand, the produced energy acts also in the SOFC assembly as produced electrical energy, which can be used on the one hand for on-board operation  203  or, however, also can be supplied to the SOSE  21  via a current supply  22  for the electrolytic cell process (see  FIG. 1 ).  
         [0075]     The water produced in the process be supplied on the one hand to the process again  202 , according to the present invention, or also can be used for the application in on-board operation  204 .  
         [0076]     The oxygen produced in the process can be used for the application in on-board operation  212  or is supplied to a downstream combustion process  211  or a PEM fuel cell  210 . In addition, the produced oxygen serves to increase the conversion of the SOFC  209 .  
         [0077]     The produced (pure) hydrogen is used, for example, for purifying the SOFC anode from sulfur  205 . In this type of regeneration method, desulphurization unit advantageously can be eliminated with the fuel preparation of the fuel for the FP. In addition, the produced hydrogen can be used for increasing the conversion of the SOFC  206  or, however, also supplied to a downstream combustion process  208  or a PEM fuel cell  207 .  
         [0078]     The carbon monoxide produced as an intermediate produce in FP, after it is separated by the molecular sieve  11  (see  FIG. 1 ), is useable for lowering the SOSE cell voltage  213 .  
         [0079]      FIG. 3  shows schematically an exemplary assembly of multiple SOFC cells and SOSE cells within an electrochemical reactor according to the present invention. The assembly includes hereby a first SOFC cell  301 , a second SOFC cell  302 , a third SOFC cell  303 , and a fourth SOFC cell  311 . First and third SOFC cells  301 ,  303  are hereby formed as a fuel cell stack. Second and fourth SOFC cells  302 ,  311  are serially connected to one another via a line system  310  and additionally via line systems  309  and  307 , are connected in parallel with the fuel cell stack  301 ,  303 .  
         [0080]     In addition, the assembly includes a first SOSE cell  304 , a second SOSE cell  306 , and a third SOSE cell  305 . First and third SOSE cells  304 ,  305  are hereby serially connected with one another via line system  308  and are connected in parallel with the second SOSE cell  306  via line systems  309 ,  307 . In addition, the SOSE cells  304 ,  305 ,  306  are connected with the SOFC cells  301 ,  302 ,  303 ,  304  via the line systems  309 ,  307 .  
         [0081]     The invention is not limited in its implementation to the exemplary embodiments shown in the figures. In addition, a plurality of variations are contemplated, which make use of the shown solution and inventive principle also with basically different embodiments.  
         [0082]     In addition, it should be noted that “including” does not exclude other elements or steps and “a” or “one” does not exclude a plurality. In addition, it should be noted that features or steps, which have been described with reference to one of the above-described exemplary embodiments, also can be used in combination with other features or steps of another above-described embodiment. Reference numerals in the claims are not to be viewed as limitations.