Patent Publication Number: US-2012045699-A1

Title: Fuel Cell Power and Water Generation

Description:
BACKGROUND 
     Many remote bases or other facilities utilize fuel cells for the generation of power. For example, in military applications, forward operating bases are often set up at remote locations not serviced by a fixed power grid. Fuel cells provide one means for supplying the necessary power to sustain the base operations. Similarly, in civilian applications such as disaster response scenarios, power generation is a critical consideration for response teams since permanent power grids are commonly unavailable. Like power, water is another integral component for sustaining operations at many remote locations. Many remote locations do not have the functional infrastructure to provide electricity or water, or the fuel necessary to generate the required electricity. 
     Due to the lack of suitable infrastructure at many of these locations, fuel and water must be transported to the forward operating bases or emergency response locations, often over great distances. Transporting these items via aircraft, trains, ships, trucks and/or other vehicles is a costly and often dangerous operation. In the military context, for example, fuel and water make up a significant portion of the cargo that is trucked to remote bases. The convoys associated with these shipments not only operate at a significant expense corresponding to fuel, vehicle maintenance, and manpower, but also expose personnel to hazards associated with operating in hostile environments. 
     It is with respect to these considerations and others that the disclosure made herein is presented. 
     SUMMARY 
     It should be appreciated that this Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to be used to limit the scope of the claimed subject matter. 
     Methods and systems described herein provide for the creation of power, water, and heat utilizing a fuel cell system. According to one aspect of the disclosure provided herein, fuel is received and utilized within a fuel cell to generate power and a fuel byproduct. Multiple fuel types may be used, such as natural gas, military logistics fuel (e.g. JP5, JP8 etc.), hydrogen, and others. Water is separated from the fuel byproduct to create a conditioned fuel byproduct and water. The conditioned fuel byproduct is burned or otherwise reacted to create heat or electricity. The power, water, and heat are provided for use within these and other systems, or for general consumption. 
     According to another aspect, a power and water generation system includes a fuel cell, a byproduct separation phase, and a burner phase. The byproduct separation phase is positioned downstream of the fuel cell and is configured to separate water from the fuel byproduct to create water and a conditioned fuel byproduct. The burner phase is positioned downstream of the byproduct separation phase and is configured to burn the conditioned fuel byproduct to create heat that can be used within the power and water generation system, or outside of the system. 
     According to yet another aspect, a power and water generation system includes a biofuel production subsystem, a fuel conditioner phase, a fuel cell, a byproduct separation phase, and a burner phase. The biofuel production subsystem utilizes water from the byproduct separation phase and other biofuel production ingredients to create a biofuel to be used by the fuel cell in the generation of power and ultimately water. The fuel conditioner phase prepares the biofuel for consumption by the fuel cell. The fuel cell converts the conditioned biofuel to power and a fuel byproduct. The byproduct separation phase is positioned between the fuel cell and the burner phase and is configured to remove water from the fuel byproduct and to provide the water to the biofuel production subsystem. The remaining mixture may be combusted in the burner phase to create heat that may be converted to mechanical energy or used in other processes or otherwise reacted to produce electricity. 
     The features, functions, and advantages that have been discussed can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing a comparison between a conventional power and water supply system to a fuel cell power and water generation system according to various embodiments presented herein; 
         FIG. 2  is a block diagram showing a fuel cell power and water generation system according to various embodiments presented herein; 
         FIG. 3  is block diagram showing fuel conditioner, byproduct separation, and burner phases of a fuel cell power and water generation system according to various embodiments presented herein; 
         FIG. 4  is a block diagram showing an illustrative fuel cell power and water generation system utilizing biofuel created with generated water according to various embodiments presented herein; and 
         FIG. 5  is a flow diagram illustrating a method for generating power and water with a fuel cell system according to various embodiments presented herein. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is directed to methods and systems for creating and capturing usable water during highly efficient electrical power generation. As discussed briefly above, transporting large quantities of fuel and water to forward operating bases and other remote locations is a costly, inefficient, and often dangerous process. Utilizing the concepts and technologies described herein, a fuel cell generation system is used not only to generate electrical power, but also to generate water that may be easily filtered for potable uses or to be routed in all or part into a biofuel creation process to generate the fuel used within the fuel cell for creating electricity. 
     Throughout this disclosure, the various embodiments will be described with respect to use with a military forward operating base, such as would be used by military forces on a temporary or semi-permanent basis at a remote location that does not have permanent infrastructure capable of providing power and water. However, it should be understood that the disclosure provided herein is equally applicable to any type of application in which it is desirable to generate power and water in an efficient manner that decreases the quantity fuel and water that is required to be transported to the use location from a remote source location. Similarly, because the concepts described below increase the efficiency of power and water generation, the various embodiments are also suitable for any implementations in which the transportation of resources is not an issue, but in which it is desirable to operate at a lower cost, with versatility as to the type of fuel used within the system, and at decreased noise levels, as will be described in detail below. 
     In the following detailed description, references are made to the accompanying drawings that form a part hereof, and which are shown by way of illustration, specific embodiments, or examples. Referring now to the drawings, in which like numerals represent like elements through the several figures, the efficient generation of electricity and water, among other functional byproducts such as the heated exhaust, will be described.  FIG. 1  shows a comparison between a conventional power and water supply system  102  to a fuel cell power and water generation system  110  in the context of supplying power  108  and water  106 / 114  to support the operations of a forward operating base or other operations according to various embodiments presented herein. 
     A conventional power and water supply system  102  typically includes a number of generators A-N that are used to supply power  108  to base operations. To operate the generators A-N, fuel  104  is shipped in from a remote source and stored in fuel bladders at the forward operating base. Because a conventional power generation system does not generate usable water, the water  106  is shipped from a remote source and stored in bladders for use at the base. 
     In contrast, referring to the bottom portion of  FIG. 1 , a fuel cell power and water generation system  110  as described herein utilizes one or more fuel cells to create and supply the power  108  to the base. The fuel cell utilizes fuel  104  to create the power  108 . As will be described further below, the fuel  104  may be a standard military fuel, such as JP-8 commonly used in military aircraft and other vehicles, a commercial fuel, such as propane or natural gas, or may be an alternative fuel  112 , such as a biofuel. The generation of power  108  by the fuel cell creates a byproduct, which is typically burned off in an afterburner to create a hot exhaust product that may be used to turn a turbine or to heat a product or process. 
     Utilizing the embodiments described below, the water  114  is separated from the byproduct of the fuel cell prior entry into the burner phase. This water  114  can be provided for various base operations, or all or part of the water  114  may be used for creation of a fuel  112 , including biofuels and other alternative fuels, to be used within the fuel cell power and water generation system  110 . According to various implementations, the water  114  created by the fuel cell power and water generation system  110  may be of quantities that meet or exceed the water consumption demand of the base, or at a minimum, will decrease the amount of water  106  required to be supplied to the base from a remote source. 
     Along with decreasing the water  106  quantities shipped to the base from the remote source, the fuel cell power and water generation system  110  allows for a decrease in the quantity of fuel  104  shipped to the base due to the increase in efficiency of the fuel cell power and water generation system  110  as compared to a comparable conventional generator system as described above. Moreover, the fuel cell power and water generation system  110  may be coupled to renewable energy sources such as solar and wind power sources to provide energy during daylight periods, further reducing the quantities of fuel  104  necessary to maintain base operations. The external fuel  104  requirements may be completely eliminated in various embodiments that utilize biofuel creation and utilization, particularly when used in combination with renewable energy sources, as described in greater detail below with respect to  FIG. 4 . 
     Turning now to  FIG. 2 , a fuel cell power and water generation system  110  will be described in further detail. According to one embodiment, the fuel cell power and water generation system  110  includes a fuel conditioning phase  202 , one or more fuel cells  204 , a byproduct separation phase  206 , and a burner phase  208 . In general, the fuel cell power and water generation system  110  receives fuel  104  as input and produces power  108 , water  114 , and a heated exhaust stream  216 . Fuel  104 , such as JP-8 or other military fuel, gasoline, hydrogen, butane, methanol, propane, or natural gas, is provided to the fuel conditioner phase  202  of the fuel cell power and water generation system  110 . The fuel conditioner phase  202  includes all applicable equipment and systems used to prepare the fuel  104  for efficient use by the fuel cell  204 . Specific examples of components of the fuel conditioner phase  202 , as well as of the byproduct separation phase  206  and the burner phase  208 , will be described below with respect to  FIG. 3 . 
     After conditioning, the conditioned fuel  210  is routed to the fuel cell  204 , where it is used to create electricity, or power  108 . The electrical power created by the fuel cell  204  may be direct current, but may be directed to an inverter to convert to alternating current for use with corresponding alternating current systems. It should be appreciated that although the fuel cell  204  is shown as a single generic unit for simplicity, any number and type of fuel cells  204  may be utilized within the fuel cell power and water generation system  110 . As an example, the fuel cell may include one or more solid oxide fuel cells (SOFCs). One advantage other than the operating efficiency and the corresponding cost savings associated with utilizing SOFCs to generate power within the fuel cell power and water generation system  110  as compared to utilizing the generators used in a conventional power and water supply system  102  is noise reduction. Power and water generation utilizing SOFCs rather than the traditional diesel/gas generators occurs at significantly reduced noise levels, reducing the potential for harm to nearby personnel. 
     One byproduct of the power generation process within the fuel cell  204  is a fuel byproduct  212  that contains water vapor. Traditionally, this mixture of unutilized broken down fuel and water is routed directly to an afterburner, where the resulting exhaust stream is burned with incoming air to produce heat energy that can be captured with a turbine or used for some other purpose. However, according to the disclosure provided herein, the fuel byproduct  212  is directed at least in part to the byproduct separation phase  206 , where the water vapor is separated from the unused fuel mixture of the fuel byproduct  212  to create the water  114 . After proper filtering and purification, this water  114  is potable and ready for consumption or other use by base personnel. It should be noted that a portion of the fuel byproduct  212 , or water  114 , may be routed back to the fuel conditioner phase  202  after leaving the fuel cell  204  for reconditioning and use within the fuel cell  204 . Alternatively, this reutilized fuel may be apportioned from the conditioned fuel byproduct  214  leaving the byproduct separation phase rather than from the fuel byproduct  212  after the fuel cell  204 . 
     After separating the water  114  from the fuel byproduct  212 , the remaining conditioned fuel byproduct  214  is burned within the burner phase  208  to create heated exhaust  216  or otherwise reacted to produce electricity. The heated exhaust  216  may be an exhaust stream that may be used in conjunction with a turbine or may be used to inject heat into a process. For example, the conditioner phase  202  and corresponding fuel conditioning process may include an endothermic process in which the heated exhaust  216  may be used. 
     Positioning the byproduct separation phase  206  in-line between the fuel cell  204  and the burner phase  208  has advantages over attempting to separate water  114  from the mixture after the burner phase  208 . First, the water  114  after the burner phase  208  would be significantly more polluted since the burning process would introduce contaminants such as soot. Second, because air is being mixed in during the combustion within the burner phase  208 , the water vapor is being diluted, which reduces the partial pressure of the water vapor. By separating the water vapor from the fuel byproduct  212  before the burner phase, then the partial pressure of the water vapor is much higher, allowing for a greater amount of water  114  to be separated efficiently from the mixture. 
     It should be understood that the block diagram of  FIG. 2  is a simplified representation of the various phases and components of a fuel cell power and water generation system  110  according to embodiments discussed herein. Some exemplary components of the fuel conditioner phase  202 , byproduct separation phase  206 , and burner phase  208  will be described below with respect to  FIG. 3 . However, the specific equipment utilized will depend on the particular implementation. Equipment and controls that are not germane to the concepts described herein have been omitted for clarity. For example, the fuel cell power and water generation system  110  includes power distribution and control hardware, various system controls, and other balance of plant hardware that has not been shown or described. 
     Referring to  FIG. 3 , the fuel conditioner phase  202 , byproduct separation phase  206 , and burner phase  208  will be described in further detail. According to one embodiment, the fuel conditioner phase  202  includes a reformer, such as a steam reformer, and sulfur remover  302 . The fuel reformation and sulfur removal breaks down the fuel  104  to various species that maximize the efficiency of the particular fuel cell  204  utilizing the fuel. The particular characteristics and operating parameters of the reformer and sulfur remover  302  depends on the type of fuel  104  being used and the characteristics of the fuel cell  104  processing the fuel. The fuel conditioner phase  202  may additionally include a recuperator to further increase the efficiency of the fuel processing prior to delivery of the fuel to the fuel cell  204 . 
     The byproduct separation phase  206  includes a separator  306  operative to separate the water vapor from the unutilized fuel and other byproducts within the fuel byproduct  212  from the fuel cell  204 . Additional filtering and purifying equipment  308  is utilized to further process the separated water to create the potable water  114  for use by base personnel and for base operations. The burner phase  208  utilizes an afterburner  310  to combust the conditioned fuel byproduct  214  and create heated exhaust  216 . The created heated exhaust stream  216  may be routed to a turbo-compressor  312  within the burner phase  208 , where the heated exhaust  216  is transformed to mechanical energy. A recuperator or heat exchanger  314  may again be used to increase the efficiency of the turbo-compressor  312  operation. As mentioned above, the fuel cell power and water generation system  110  and corresponding fuel conditioner  202 , byproduct separation  206 , and burner phases  208 , may include additional or fewer components than shown and described in the accompanying figures without departing from the scope of this disclosure. 
       FIG. 4  shows an alternative embodiment in which the fuel cell power and water generation system  110  includes a biofuel production subsystem  402 . As discussed above with respect to  FIG. 1 , the fuel cell power and water generation system  110  may be configured to utilize alternative fuels  112 , such as biofuels. The manufacturing process for creating a biofuel can occur at the forward operating base using seeds and/or ingredients  404  that are locally found, grown, or purchased. In doing so, the reliance on importing fuel to the forward operating base is diminished or eliminated. The creation of the biofuel typically requires water. According to one embodiment shown in  FIG. 4 , the water  114  that is created and captured by the fuel cell power and water generation system  110  is returned to the biofuel production subsystem  402  to be used in the fuel manufacturing process. Any surplus water  114  not used by the biofuel production subsystem  402  may be routed to other base operations. 
     Depending on the quantity of water  114  needed to produce the required quantity of fuel  112 , the fuel cell power and water generation system  110  could be a substantially stand alone, self-sustaining power and water generation process with respect to fuel and water requirements. The biofuel production subsystem would require the additional seeds and/or ingredients  404  to produce the fuel  112 , but would require very little to no fuel  104  and/or water  106  to be shipped to the base from a remote source. As the seeds and/or ingredients  404  may presumably be procured locally, the dangerous and costly convoys conventionally used to ship fuel and water from remote sources may be significantly reduced or eliminated. 
     Turning now to  FIG. 5 , an illustrative routine  500  for creating electrical power and water, while recapturing waste heat, will now be described in detail. It should be appreciated that more or fewer operations may be performed than shown in the  FIG. 5  and described herein. Moreover, these operations may also be performed in a different order than those described herein. The routine  500  begins at operation  502 , where the fuel is received. As discussed above, the fuel  104  may be standard military fuel such as JP-8 or commercial fuel such as gasoline, hydrogen, butane, methanol, propane, or natural gas. Alternatively, the fuel cell power and water generation system  110  may utilize alternative fuel  112 , such as a biofuel produced by a biofuel production subsystem  402  as described with respect to  FIG. 4 . 
     From operation  502 , the routine  500  continues to operation  504 , where the fuel  104  enters the fuel conditioner phase  202  of the fuel cell power and water generation system  110 . In the fuel conditioner phase  202 , operations such as reformation and sulfur removal prepare the fuel for efficient use by the fuel cell  204 , creating conditioned fuel  210 . At operation  506 , the conditioned fuel  210  enters the fuel cell  204 , where it reacts to create power  108  and a fuel byproduct  212  at operation  508 . The resulting electricity is routed to the use or storage locations at operation  510 . 
     The routine  500  continues from operation  510  to operation  512 , where the fuel byproduct  212  exiting the fuel cell  204  is provided to the byproduct separation phase  206  of the fuel cell power and water generation system  110 . The byproduct separation phase  206  may include any quantity and type of equipment suitable for reclaiming and processing the water  114  from the mixture leaving the fuel cell  204 . As discussed above, this equipment may include a separator  306  to separate and condense the water vapor, and filtering and processing equipment to make the water  114  potable and ready for use. The water  114  is processed and stored for use at operation  516 . 
     After separating the water  114  from the fuel mixture, the resulting conditioned fuel byproduct  214  is routed to the burner phase  208  of the fuel cell power and water generation system  110  at operation  518 . The conditioned fuel byproduct  214  is burned in the afterburner or reacted in another manner  310  at operation  520  to create the heated exhaust stream  216 . This exhaust stream is routed to the turbo-compressor  312  or other system at operation  522  to recoup the heat in the heated exhaust stream  216  as mechanical energy or to inject heat into another system or process, further increasing the efficiency of the fuel cell power and water generation system  110 , and the routine  500  ends. 
     It should be clear from the above disclosure that the fuel cell power and water generation system  110  described herein and encompassed by the claims below provides a significant improvement in operating efficiency over conventional systems, effectively reducing operating costs, reducing logistical costs associated with transporting fuel and water, and decreasing the casualty risks corresponding with the hazardous transportation of fuel and water to forward operating bases. The fuel cell power and water generation system  110  utilizes fuel cell technology to increase the flexibility of the system to accept various fuels  104  and to efficiently produce power  108 , reducing the fuel consumption rates of the base as compared to traditional generator sets. The use of fuel cell technology additionally reduces the hazardous noise levels associated with traditional diesel/gas generators. 
     The water reclamation aspects of the fuel cell power and water generation system  110  allow for the removal of water  114  from the fuel waste created during the production of power  108  by the fuel cell  204 . By separating the water  114  prior to the burner phase  208  of the fuel cell power and water generation system  110 , the water vapor has a higher partial pressure, which allows for increased water recovery efficiency. Separating the water vapor from the unutilized fuel mixture prior to burning the mixture additionally results in cleaner water  114  than would be available after the burner phase  208 , simplifying and assisting the water processing operations to create potable water. 
     When coupled with a biofuel production subsystem  402 , the fuel cell power and water generation system  110  may significantly reduce or eliminate the need for fuel  104  to be shipped to the forward operating base for power production and the water  114  recaptured during the byproduct separation phase  206  can be cycled into the biofuel production subsystem  402  to significantly reduce or eliminate the need for water  106  from a remote source for fuel production. Utilizing biofuel to fuel the fuel cell power and water generation system  110 , further combined with the use of renewable energy sources such as solar and wind power at the forward operating base, provides an extremely efficient, stand alone energy and water production system. 
     Finally, recaptured heated exhaust  216  from the burner phase  208  of the fuel cell power and water generation system  110  may be utilized to further increase the efficiency of the overall system. The heated exhaust  216  may be used to drive a turbo-compressor  312 , may be used in other components of the fuel cell power and water generation system  110 , or used in other base systems or processes. 
     The subject matter described above is provided by way of illustration only and should not be construed as limiting. Various modifications and changes may be made to the subject matter described herein without following the example embodiments and applications illustrated and described, and without departing from the true spirit and scope of the present invention, which is set forth in the following claims.