Abstract:
There is provided a hydrogen storage system having one or more hydrogen storage containers disposed in a confined area with a vent line extending from the one or more storage containers to a location outside of the confined area. One or more sensors are disposed in the confined area for detecting one or more pre-determined unsafe conditions relating to the storage of hydrogen in the contained area and at least one actuator is provided for actuating an operable valve of the vent line to release the hydrogen from the hydrogen storage container to a location outside the confined area at a pre-determined release rate in response to a signal from the sensor indicating an unsafe condition. A power system incorporating a hydrogen storage system as described above is also provided.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is directed to a system for storing hydrogen in a confined area and to power systems such as back-up power systems incorporating such hydrogen storage systems.  
         BACKGROUND OF THE INVENTION  
         [0002]    The storage of hydrogen requires great care due to the explosive properties of the gas. As hydrogen becomes a preferred choice as an alternative fuel to fossil fuels there is a need for systems for storing hydrogen in a safe manner at a confined location such as within a building. This is particularly desirable for use in conjunction with a hydrogen fueled power system, for instance a back-up power system, for a facility. Commercially feasible systems for storing and using hydrogen in this manner are not currently available.  
         SUMMARY OF THE INVENTION  
         [0003]    In one aspect the invention provides a hydrogen storage system comprising:  
           [0004]    a) at least one hydrogen storage container disposed in a confined area;  
           [0005]    b) a vent line extending from said at least one storage container to a location outside the confined area, said vent line having an operable valve;  
           [0006]    c) at least one sensor disposed in said confined area for detecting one or more predetermined unsafe conditions relating to the storage of hydrogen in the confined area; and  
           [0007]    at least one actuator in communication with said sensor for actuating said operable valve of said vent line to release hydrogen from said hydrogen storage container to a location outside of said confined area at a minimum pre-determined release rate in response to a signal received from said sensor relating to a sensed unsafe condition.  
           [0008]    In another aspect the invention provides a power system for providing back-up power to a facility comprising:  
           [0009]    a) a generating system disposed at the facility having at least one hydrogen generator and at least one hydrogen powered electrical generator.  
           [0010]    b) a storage system disposed at the facility having at least one storage container for receiving hydrogen from said hydrogen generator;  
           [0011]    c) a conduit for hydrogen from said at least one hydrogen generator to said storage system;  
           [0012]    d) a conduit for supplying hydrogen from said storage system to said at least one electrical generator;  
           [0013]    e) a sensor for sensing the supply of electric power from a primary electric power source;  
           [0014]    f) an actuator in communication with the sensor for actuating said at least electrical generator to generate electricity in response to a signal from said sensor indicating an interruption in the supply of electricity from said primary electric power source.  
           [0015]    In another aspect the invention provides a power system for a facility comprising:  
           [0016]    a) hydrogen generator for producing hydrogen;  
           [0017]    b) a hydrogen powered electrical generator for producing electricity;  
           [0018]    c) a storage system comprising at least one storage container for storing hydrogen produced by said hydrogen generator, said storage container being connected to said hydrogen powered electrical generator to produce electricity from hydrogen stored in said storage system; and a fuel station connected to said storage system, said fuel station comprising at least one fuel dispensing device. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a schematic view of a power system with a hydrogen storage system in accordance with the present invention.  
         [0020]    [0020]FIG. 2 is an elevation view of a generator room and a storage room for one embodiment of the system of FIG. 1.  
         [0021]    [0021]FIG. 3 is a plan view of the generator room for the system of FIG. 2.  
         [0022]    [0022]FIG. 4 is a plan view of the storage room for the system of FIG. 2.  
         [0023]    [0023]FIG. 5 is an elevation view of a fueling station for the system of FIG. 2.  
         [0024]    [0024]FIG. 6 is a front elevation view of a fuel dispensing device for the fueling station of FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]    A power system in accordance with the present invention is depicted generally at  10  in FIGS. 1-6. The system  10  includes a generation system  12  comprising at least one hydrogen generator  14  and at least one hydrogen fueled electrical generator  16 . The system  10  also includes a hydrogen storage system  18  comprising at least one hydrogen storage container  20 . The hydrogen generator  14  receives electrical power from a power source  22  and water from a water source  24  The hydrogen generator  14  then operates in known manner to produce hydrogen that is then transferred to the storage system  20 . The stored hydrogen may then be used to fuel the electrical generators  16  to produce back-up power for a facility or the hydrogen may be used for other purposes such as for fueling a hydrogen receiving device at a fuel station  200 .  
         [0026]    The generation system  12  of the preferred embodiment has a hydrogen generator  14  that is a CFA 450 Community Fueler Appliance (TM) manufactured by Stuart Energy Systems Corporation which is able to generate 450 scfh of hydrogen at up to 6,000 psig operating pressure and two hydrogen fueled electrical generators  16  that are Ford Power Products (FPP) hydrogen fueled, packaged internal combustion engine/generator sets (ICE) that will provide up to 135 kW of electrical output each complete with the necessary electrical equipment to produce electricity in a form compatible with the critical building circuits to be powered. Each of the above preferred electrical generator  16  requires 13,000 cfm of air to satisfy the integrated radiator&#39;s requirements and an additional 600 cfm for combustion air. Each electrical generator  16  also requires approximately 5250 scfh of hydrogen fuel at 75 psig when running at full load.  
         [0027]    The hydrogen storage system  18  of the preferred embodiment has a number of high pressure hydrogen storage containers  20  of sufficient total capacity to supply fuel to the electrical generator  16  to run for a desired period of time (eg. two hours) under desired power conditions. Preferably, the storage containers  20  are conventional cylinders for receiving compressed gas where each storage container  20  has a capacity of 1550 scf at a pressure of 5,000 psig. The storage containers  20  will be designed to restrict the flow from each cylinder to 10 scfs and the total from each bank to 50 scfs, maximum.  
         [0028]    The components of the system  10  are mostly disposed in a generator room  30  and a storage room  32 . The generator room  30  houses the hydrogen generator  14  and the electrical generators  16  and the storage room  32  houses the storage containers  20 . The embodiment depicted in FIGS. 2-6 demonstrates one arrangement for the rooms  30  and  32  however it will be appreciated that numerous alternate arrangements are possible while still meeting the objectives of the invention. Thus, in FIGS. 2-6, the roof  33  of the storage room  32  is constructed with sufficient structural strength to serve as a mezzanine area  35  over the generator room  30  where the electrical generators  16  are located. The hydrogen generator  14  will occupy most of the ground floor of the generator room  30 .  
         [0029]    A viewing room  34  is also depicted in the FIGS. 2-5 for viewing the generator room  30 . This is an optional element that is advantageous mainly to provide demonstrations of the operation of the system  10 . The viewing room  34  is equipped with observation windows  36  and access stairs  38  to the generator room  30 . The floor level in the viewing room  34  is above the floor level in the generator room  30  to provide optimum viewing. A master control panel  40  for the system  10  may be located in the viewing room  34  for ease of operation during facility demonstrations or it may be located at any convenient location outside the storage room  32 .  
         [0030]    Referring more specifically to the generator room  30 , a ventilation plenum  50  is provided for introducing make-up air ventilation into the room from outdoors. The ventilation plenum  50  preferably delivers approximately 30,000 cfm of unconditioned make-up air and is sized to ensure that the static pressure drop across the radiator fans  52  for the electrical generators  16  is not more than ½ inches of water column, total system. The ventilation plenum  50  preferably extends through the roof  53  and is capped with a Greenheck Model WIH (trademark) pre-fabricated louvered penthouse  54  complete with roof curb  56  and motorized dampers  58  (or equivalent).  
         [0031]    A generator room exhaust fan  60  is mounted on the roof  53  and the intake is preferably flush with the underside of the roof deck such that the fan  60  will remove any fugitive hydrogen emissions that may collect in the upper corners of the room. The generator room exhaust fan  60  provides 10,000 cfm of capacity at ½ inch static pressure, total system. The exhaust fan  60  is preferably a Greenheck TAUB (trademark) tube axial flow “upblast” belt drive fan complete with non-sparking impellers and integrated butterfly dampers (or equivalent). The fan  60  is fitted with an appropriately classified electric motor.  
         [0032]    The generator room exhaust fan  60  is preferably a start/stop model which is thermostatically controlled to attempt to maintain the room temperature below a desired level (eg. 77° F.). The exhaust fan  60  is also activated by the control system PLC  62  such that the exhaust fan  60  runs for a desired period of time (eg. at least 5 minutes) every hour for general room exhausting. In addition, the fan  60  may be controlled by other devices that are integrated into the system  10 .  
         [0033]    A discharge pipe  64  is connected to the hydrogen generator  14  for the venting of excess oxygen and water vapour created by the hydrogen generator  14  during its operation. The discharge pipe  64  extends through the inside of the ventilation plenum  50  and discharges at the roof  53  through the curb box  56  of the pre-fabricated penthouse  54 . The pipe  64  is sized to ensure that the hydrogen generator  14  is not exposed to a pre-determined excessive back pressure (eg. greater than or equal to 4″ water column).  
         [0034]    A second discharge pipe  68  is connected to the hydrogen generator  14  for venting excess, low-pressure hydrogen and water vapour. The second discharge pipe  68  preferably extends to the ceiling of the generator room  30  and then is routed through the roof  53  through the curb box  56  of the penthouse  54 . The pipe  68  is sized to ensure that the hydrogen generator  14  is not exposed to a pre-determined excessive back pressure (eg. greater than or equal to 4″ water column).  
         [0035]    A supply line  70  extends from the hydrogen generator  14  to the storage containers  20  in the storage room  32  to transfer hydrogen at a desired pressure (eg. 5000 psig). This is described in more detail with reference to the storage room  32  structure.  
         [0036]    The electrical generators  16  are placed on a mezzanine in the generator room  30  as depicted in FIGS. 2 and 3. As discussed above, alternate room arrangements are also contemplated.  
         [0037]    Combustion air for the electrical generators  16  is preferably sourced from within the general space  72  of the generator room  30 . The exhausts  74  for the engines  76  of the electrical generators  16  are preferably discharged through the roof  53  via two separate pipes  78  and  80  complete with critical grade mufflers  82  and gravity-activated caps  84 .  
         [0038]    The electrical generators  16  are oriented such that their radiators  90  will discharge through two separate suitably sized exhaust plenums  92  disposed in the wall. The exhaust plenums  92  are preferably equipped with outlet dampers  94  and re-circulation air discharge dampers  96  to re-circulate air from the electrical generators  16  back into the generator room  30  under cold weather conditions. The outlets  94  and  96  of the plenums  92  may be fitted with discharge air louvers  98 , complete with drains. The louvers  98  are preferably sized to fill the entire wall area above the mezzanine floor. Any louver area not required for exhaust purposes may be fitted with blanking panels  100 .  
         [0039]    Hydrogen fuel for the electrical generators  16  may be provided at a desired pressure (eg. 75 psig) from a pressure regulator station  102  disposed inside the storage room  32 . A single supply line  104  from the storage room  32  extends through the mezzanine floor and branches to a connection point on each engine for the electrical generators  16 .  
         [0040]    The generator room  30  is preferably equipped with a thermostatically controlled space heating device  106  that will maintain the temperature in the generator room  30  above a desired level (eg. 68° F.).  
         [0041]    The generator room  30  may be equipped with a large access door  108  sized such that the large equipment that will be located in the generator room  30  and any equipment necessary to service that equipment is able to gain access through this door  108 .  
         [0042]    Referring now to the storage room  32 , a sufficient number of storage containers  20  are provided to supply enough hydrogen to allow the electrical generator  16  to run for a desired minimum time period (eg. 2 hours) under desired power conditions. In the embodiment depicted in the figures, fifteen containers  20  arranged in three banks  110  are provided. Each container  20  preferably has a capacity of 1550 scf at a pressure of 5,000 psig. The storage containers  20  are designed to restrict the flow from each container  20  to 10 scfs and the total from each bank  110  to 50 scfs, maximum.  
         [0043]    The containers  20  are racked horizontally with the bottom  112  of the containers  20  located along a louvered wall and the manifold tubing  114  located facing an opposing wall. The cylinder rack is covered by a sheet metal enclosure  116  that is designed to collect and direct any hydrogen leaks in the containers  20  or manifold piping upward to the opening  118  in the enclosure&#39;s roof. The primary hydrogen and temperature sensors  120  are mounted in this opening. This minimizes the detection time of a leak or fire in the storage bank arrangement.  
         [0044]    Make-up air intake louvers  130  are located at the lower portion of the outside wall area of the storage room. A louvered, exterior access door  132 , opening outward is also located along this wall. Preferably, none of the louvers  130  and  132  shall have back draft dampers. The louvers  130  and  132  deliver a desired amount (eg. 18,000 cfm) of unconditioned make-up air to the storage room  32  and are sized to ensure that the static pressure drop across the two fans  134  described below is not more than a desired amount (eg. ¼ inches of water column, total system). The louvers  130  and  132  are preferably designed to nominally deliver 250 cubic feet per minute of make-up air per square foot of louver and will require 75 square feet of louvered wall, including the exterior access door  132 .  
         [0045]    Storage room exhaust fans  134  are preferably mounted on the roof. The intake for the fans  134  is located in the storage room  32  ceiling at a location that will remove any hydrogen accumulation from the room. The exhaust intake  136  connects to an exhaust air plenum  138  that is preferably constructed of two hour rated dry wall, acoustically lined (or equivalent).  
         [0046]    The storage room exhaust fans  134  preferably provide 9,000 cfm of capacity each with a total capacity of 18,000 cfm at ¼ inch static pressure, total system. The fans are preferably two identical Greenheck TAUB (trademark) tube axial flow “upblast” belt drive fans complete with non-sparking impellers and integrated butterfly dampers (or equivalent). The fans  134  are fitted with an appropriately classified electric motor.  
         [0047]    The storage room exhaust fans  134  are start/stop models and are activated by the control system PLC  62  such that at least one of the fans  134  runs for a desired period of time (eg. at least 2 minutes every 60 minutes) for general room exhaust. The fan  134  that is activated for this function is preferably alternated such that the running hours of each fan  134  is accumulated approximately equally. In addition, the fans  134  will be controlled by other devices that are integrated into the system  10 .  
         [0048]    A pressure relief valve  140  is provided in the fuel line  142  between the outlet  144  of the pressure reducing station and the inlet  146  to the electrical generator fuel line  148 . Each bank of storage containers  20  also requires a high-pressure relief vent line  150 ,  152  and  154 . The hydrogen generator  14  also includes a vent line  156  to vent fugitive oxygen and hydrogen emissions and the associated water vapour. This venting will require the installation of four lines constructed of high-pressure steel tubing suitably sized and compatible fittings and valves plus the two lines  64  and  68  described in the generator room  30  section above for the low pressure hydrogen and oxygen and associated water vapour.  
         [0049]    The high-pressure relief vent line from the hydrogen generator  14  is an integral part of the hydrogen generator design. Its primary purpose is to maintain adequate back-pressure on the outlet of the hydrogen compressors to ensure proper operation. If an overpressure situation occurs in the storage supply line from the hydrogen generator  14 , the overpressure relief line is discharged into a “blow down” pressure vessel  160 . This vessel  160  is of adequate strength and size to effectively accept the low flow, high-pressure hydrogen from the storage supply line and reduce it to low pressure. The blow down pressure vessel  160  is equipped with a relief valve  162  that allows the low pressure hydrogen and associated water vapour to vent to atmosphere via the hydrogen/water vapour vent line  64  and  68  described in the generator room  30  section above. All other hydrogen relief lines preferably exit the storage room at a desired level (eg. about 7.0 ft) above grade.  
         [0050]    The high-pressure hydrogen relief system preferably consists of one pressure relief valve for the hydrogen generator fuel line and three pressure relief valves, one for each of the three banks of storage containers. The hydrogen generator fuel line relief valve is set to relieve at a desired pressure (eg. at 83 psig (110% of design pressure)). The storage relief valves are also set to relieve at a desired pressure (eg. 5,500 psig (110% of design pressure)).  
         [0051]    In addition, the high-pressure lines from the three banks of storage are teed and piped to 3 Class 1, Zone 2 rated electrically actuated/pneumatically operated ball valves  166 . These valves provide a closed-loop storage dump capability that is controlled by the system  10  complete with a manual override capability.  
         [0052]    The outlets of all four vent lines are connected to a common vent stack  168 . The vent stack  168  is installed at the point where all of the high-pressure vent lines exit the storage room (eg. about 7.0′ above grade). The vent stack  168  is affixed to the exterior wall of the building and extends to a sufficient height (eg. approximately 20.0 ft above grade) where it terminates in an elbow  170  that directs the hydrogen away from the building and is covered with a gravity actuated rain cap  172 .  
         [0053]    The Safety Control System (SCS)  174  employs several strategies to ensure that the release of hydrogen into either the generator room  30  or the storage room  32  is avoided. In the unlikely event that a major hydrogen leak occurs, the SCS uses several redundant sensors  174  and associated closed-loop control devices  176  to mitigate the event. The mitigation strategy includes the manual or automatic dumping of a desired amount (eg. at least 95%) of all hydrogen in storage to atmosphere in a desired time period (eg. in less than 5 minutes).  
         [0054]    In addition, manually actuated/electrically operated Emergency Stop Devices (ESDs)  180  and Emergency Dump Devices (EDDs)  182  complemented with visual/audible alarm beacons  184  are located in the viewing room, the generator room  30  and outdoors adjacent to the exterior access door to the storage room  32 . The cabinet  188  located adjacent to the exterior storage room door that houses the EDD,  182  also contains a pressure gauge  190  that directly measures the pressure in each of the three banks of storage containers. The gauge allows emergency personnel or qualified operations personnel to ensure that each bank of the storage containers is fully relieved of pressure when the EDD  182  is activated. The EDD  182  can be by-passed by a manual valve  192  located in the same cabinet.  
         [0055]    The generator room  30  and the storage room  32  are also equipped with a network of temperature sensors  194  and fusible links  196  to manage the operation of all equipment and safety devices under all fault situations.  
         [0056]    Referring to FIG. 6, a fuel station  200  is shown having at least one hydrogen fuel dispensing device  202 . The fuel dispensing device is connected to the storage containers  20  by a supply line  204 . The dispensing device includes a nozzle  206  and a control device  208  for dispensing hydrogen fuel at a pre-determined pressure to a receiving apparatus such as a vehicle.  
         [0057]    The hydrogen-fueled back-up power system thus provides an advantageous alternative to diesel, and other forms of fuel, for back-up electrical power systems. Such a system has industrial, institutional and commercial uses primarily although other uses may become feasible in future. An advantage of the system is that the stored hydrogen can be utilized for other purposes as well provided that the storage maintains a minimum desired amount for providing the back up power system functionality. For instance, the hydrogen may be used for onsite vehicle fueling.  
         [0058]    It is to be understood that what has been described is a preferred embodiment to the invention. If the invention nonetheless is susceptible to certain changes and alternative embodiments fully comprehended by the spirit of the invention as described above, and the scope of the claims set out below.