Abstract:
The invention is an apparatus and method for producing two chemical products, hypochlorite for use as a sanitizing solution and hydrogen as a fuel source for vehicles, and a system to create a hydrogen fuel network therefrom.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. application Ser. No. 10/810,551, filed Mar. 29, 2004, currently pending, the entire disclosure of which is incorporated herein be reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention is in the field of hydrogen and hypochlorite production and distribution.  
       BACKGROUND OF THE INVENTION  
       [0003]     Hydrogen is widely used for industrial purposes and its production is concentrated in large facilities, in a small number of geographic locations. Hydrogen and hydrogen production is not widely distributed geographically. Geographic distribution of hydrogen is essential for the development of transportation or distributed power generation applications.  
         [0004]     Hydrogen is a difficult substance to transport from location to location due to its chemical properties. At room temperature its density is very low and must be compressed or chilled to achieve a useable energy density. Hydrogen is highly combustible and explosive. It is a gas at atmospheric pressure, and becomes a liquid only at extremely high pressures. Hydrogen can embrittle steel and other metals, making it difficult to handle.  
         [0005]     Transportation via rail or truck is also inefficient as the amount of energy used in transportation can make up a large percentage of the energy available from the hydrogen itself. Hydrogen is dangerous to transport due to the requirement to store it at high pressures along with the explosiveness of the gas.  
         [0006]     Local production of hydrogen, mostly for transportation, is used on a very small scale, generally as pilot projects. Without sufficient demand for local hydrogen production the growth of these stations will be limited. Without sufficient supply of local hydrogen the adoption of hydrogen fueled devices and local power generation applications will be limited.  
         [0007]     Current hydrogen vehicles have limited range and typically require large fuel tanks to store compressed hydrogen. Hydrogen can be stored either as a gas, as a liquid, or in a solid state storage. Gas storage requires energy to compress the gas for storage in a high-pressure vessel, and typically requires relatively large tanks. Because of the increased pressure, gas storage may pose a greater threat of leakage and the possibility of an explosion. Liquefaction of hydrogen consumes a significant amount of energy. Hydrogen can also be stored using solid state hydrogen storage technology, such as metal hydride solid hydrogen storage. A metal hydride is formed when hydrogen reacts with the metal ions in a storage alloy, in an exothermic reaction. When heat is applied to the system, the reverse reaction occurs, and hydrogen is released from the metal hydride alloy for use.  
         [0008]     Hydrogen is typically used to generate power for transportation needs either by using a process of combustion with oxygen to generate mechanical energy and heat, or fuel cell technologies, where typically protons, but not electrons, are diffused through a membrane, generating an electrical current and heat.  
         [0009]     There is a need to provide a geographically distributed network of hydrogen production, storage, and dispensing to facilitate the development of a hydrogen fuel infrastructure network and a distributed hydrogen power generation network. Hydrogen fuel stations need to be abundant and accessible.  
         [0010]     One of the most geographically distributed industries is the water and wastewater treatment industry. A large number of these treatment plants use hypochlorite in their processes, or could use it as a substitute for other products. As shown by the art of this field, hypochlorite can be produced on-site at individual water or wastewater treatment plants through an electrolytic process that evolves hydrogen as a waste by-product.  
         [0011]     Chlorine in the form of hypochlorite, typically sodium hypochlorite, has been used in the field of water treatment for over a century. Hypochlorite is an alternative to the use of chlorine gas for disinfecting water. Prior to the use of hypochlorite, chlorine gas was primarily used as a chlorine source for disinfecting water. The transportation of chlorine gas is a safety concern, so sodium hypochlorite is now often used as an alternative source of chlorine, as it is relatively safe to transport.  
         [0012]     On-site sodium hypochlorite generation has been used as a relatively safe and cost efficient way of providing chlorine for water treatment applications. Sodium hypochlorite is made by reacting sodium chloride and water in the presence of a DC current according to the following equation 1: 
 
NaCl+H 2 O+2e − →NaOCl+H 2  
 
         [0013]     Previous systems of on-site sodium hypochlorite generation have vented away the H 2  produced into the atmosphere.  
         [0014]     U.S. Pat. No. 6,468,412 illustrates a hypochlorite production system. The system includes an electrolyzer that requires a source of brine which may be either a synthetic source such as a salt saturator or a natural source such as sea water. The brine is metered by a pump into the electrolyzer containing electrolytic cell where electrolysis occurs. The electrolytic cell contains cathodes and anodes. A separate softened water supply may be provided to the electrolyzer to optimize the brine concentration within. The resultant hypochlorite solution is transferred past product outlet and travels through solution line to storage tank.  
         [0015]     Hydrogen gas, produced in addition to hypochlorite in the electrolyzer, passes with the hypochlorite solution through solution line into the storage tank where it separates from the liquid product. In other embodiments some separation may occur in the electrolyzer itself with a gas vent connected to the top of the electrolyzer allowing for the venting of hydrogen gas directly from the electrolyzer into the atmosphere. An air blower may also be connected to the storage tank to provide a forced flow of air to purge the hydrogen in the storage tank into atmosphere. In further embodiments a fan may be attached to individual electrolyzers. In the prior art, hydrogen is thus not collected for future use.  
         [0016]     There is a need to provide a way to collect and use the hydrogen produced during hypochlorite production such as to remove or minimize the disadvantages mentioned above.  
       SUMMARY OF THE INVENTION  
       [0017]     The invention relates to apparatus and method for producing hypochlorite for use as a sanitizing solution in water and waste-water treatment and hydrogen as a fuel source for vehicles, as part of a hydrogen infrastructure. By producing and collecting hydrogen as part of water and waste-water treatment, a network of fueling stations can be provided near inhabited areas to supply hydrogen to vehicles without the problems typically associated with mass hydrogen fuel transportation and production.  
         [0018]     The proximity of treatment plants to population centers make these locations ideal for producing hydrogen locally, to address local demand without the costs and dangers associated with hydrogen transportation. When a number of treatment plants have been adapted to conform to the invention, a wide area network of hydrogen production, storage, and dispensing can be created. Given the existing technologies available for use in the water and wastewater treatment industry that produce hydrogen as a waste gas, one can intuitively see the inventive and valuable nature of this invention as a means of creating a hydrogen production, storage, and dispensing network through the capture of what was formerly considered a waste gas currently produced at a large number of water or wastewater treatment plants.  
         [0019]     An apparatus for producing hypochlorite and hydrogen from brine to enable the transfer of hydrogen to another location comprising: 
        an electrolyzer that generates hypochlorite and hydrogen, which received brine from a source of brine, and, using electricity from a source of electrical energy, evolves hydrogen and hypochlorite from the brine by passing a electrical current through the brine, the electrolyzer having an electrolyzer outlet for transporting hypochlorite in solution with spent brine, and generated hydrogen;     a separator that receives the hypochlorite in solution with spent brine, and generated hydrogen from the electrolyser, and separates spent brine in solution with hypochlorite from hydrogen;     a hydrogen conduit coupled to the separator that transports hydrogen separated by the separator to a hydrogen storage system; and     a hydrogen transfer device coupled to the hydrogen storage system for transferring hydrogen from the hydrogen storage system.        
 
         [0024]     A method for producing hypochlorite and hydrogen comprising the steps of: 
        producing hypochlorite and hydrogen in an electrolyzer from brine received from a source of brine, using electricity from a source of electrical energy, evolves hydrogen and hypochlorite from the brine by passing a electrical current through the brine;     separating in a separator spent brine and hypochlorite in solution, and generated hydrogen received from the electrolyzer;     directing generated hypochlorite from the separator to a hypochlorite storage,     directing generated hydrogen from the separator to a hydrogen storage, and     filling a storage tank in or on a vehicle with hydrogen from the hydrogen storage.        
 
         [0030]     A distribution network for production, storage, and dispensing hydrogen gas, comprising: 
        a plurality of water treatment devices, each device having: 
            an electrolyzer that generates hypochlorite and hydrogen, which received brine from a source of brine, and, using electricity from a source of electrical energy, evolves hydrogen and hypochlorite from the brine by passing a electrical current through the brine;     a separator that receives the hypochlorite in solution with spent brine and generated hydrogen from the electrolyzer, and separates spent brine in solution with hypochlorite from hydrogen;     a hydrogen conduit coupled to the separator that transports hydrogen separated by the separator to a hydrogen storage system; and     a hydrogen transfer device coupled to the hydrogen storage system for transferring hydrogen from the hydrogen storage system;    
            wherein the hydrogen transfer device is designed to transfer hydrogen from the hydrogen storage system to a storage tank in or on a vehicle;     wherein at least one of the water treatment devices is located at a first water or waste water treatment facility; and     wherein at least one of the water treatment devices is located at a second water or waste water treatment facility located a distance away from the first water or waste water treatment facility.        
 
         [0039]     Other features of the invention will be evident from the disclosure of several embodiments that follows. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0040]     Embodiments of the invention will be described by way of example and with reference to the drawings in which:  
         [0041]      FIG. 1  is a schematic diagram of an embodiment of the invention.  
         [0042]      FIG. 2  is a schematic diagram of an embodiment of the invention.  
         [0043]      FIG. 3  is a schematic diagram detailing one embodiment of the hydrogen storage system aspect of the invention.  
         [0044]      FIG. 4  is a schematic diagram of an embodiment of the invention.  
         [0045]      FIG. 5  is a schematic diagram of an apparatus for the production, separation, and storage of hypochlorite and hydrogen according to an embodiment of the invention.  
         [0046]      FIG. 6  is a schematic diagram of an apparatus for the production, separation, and storage of hypochlorite and hydrogen integrating a fuel cell according to an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0047]     The present invention is generally directed to an integrated system for generating both a disinfecting agent, and the production of gaseous hydrogen for use in vehicles or other devices requiring a high energy density power supply. Many of the specific details of certain embodiments of the invention are set forth in the following description and in FIGS.  1  to  6  to provide a thorough understanding of such embodiments. One who is skilled in the art will understand, however, that the present invention may have additional embodiments, or that the present invention may be practiced without several of the details described in the following description.  
         [0048]      FIG. 1  is a schematic diagram of an apparatus for the production, separation, and distribution of hypochlorite and hydrogen according to an embodiment of the invention. The apparatus comprises a brine electrolyzer  103 , a hydrogen separator  105 , a hydrogen storage system  107 , and a hydrogen transfer device  110 . Brine is provided to the electrolyzer  103  by a brine source  101 , and the electrolysis process occurring within the electrolyzer is powered using an electricity source  102 . The electrolyzer  103  has an electrolyzer outlet  104 .  
         [0049]     The electrolysis process is well known, and produces hypochlorite in solution with spent brine, and hydrogen. The hypochlorite in solution with spent brine, and the hydrogen in gaseous form, flow out of the electrolyzer  103  through the electrolyzer outlet  104  to the separator  105 .  
         [0050]     In the separator  105 , typically a large tank, the hydrogen gas is drawn from the top of the tank as it bubbles out of the spent brine solution, and flows along a hydrogen conduit  106  to a hydrogen storage system  107 .  
         [0051]     As needed, the hydrogen storage system  107  is coupled to a hydrogen transfer device  110 . The hydrogen transfer device  110  may be a simple flow control valve and mechanical coupling device designed to safely couple with a hydrogen storage tank in or on a vehicle. It is conceived that the hydrogen stored in the hydrogen storage tank in the vehicle is used to power the vehicle, or is transported elsewhere for further use. An example of a further use might be to fuel other vehicles, or to provide fuel for a electrical power generator.  
         [0052]     From the separator  105 , the hypochlorite in solution with spent brine flows along a spent brine conduit  108  to a hypochlorite storage  109 . The hypochlorite in solution with spent brine may be further processed, or used as is, to sanitize water or waste water in accordance with know methods for treating water or waste water, or may be sold commercially.  
         [0053]      FIG. 2  is a schematic diagram of an apparatus for the production, separation, and distribution of hypochlorite and hydrogen according to an embodiment of the invention. The apparatus comprises a brine electrolyzer/separator assembly  203 , a hydrogen storage system  207 , and a hydrogen transfer device  210 . Brine is provided to the brine electrolyzer/separator assembly  203  by a brine source  201 , and the electrolysis process occurring within the brine electrolyzer/separator assembly is powered using an electricity source  202 .  
         [0054]     In the brine electrolyzer/separator assembly  203 , electrolysis occurs and separation is permitted to happen all within one assembly. Hypochlorite in solution with spent brine, and the hydrogen in gaseous form, flow out of the electrolyzer/separator assembly  203  through hydrogen and spent brine conduits  206   208  to the hydrogen storage system  207  and the hypochlorite storage  208 .  
         [0055]     As needed, the hydrogen storage system  207  is coupled to a hydrogen transfer device  210 . The hydrogen transfer device  210  is designed to safely couple with a hydrogen storage tank in or on a vehicle.  
         [0056]      FIG. 3  elaborates on a hydrogen storage system  307  which may be used as part of an apparatus for the production, separation, and distribution of hypochlorite and hydrogen according to an embodiment of the invention. Hydrogen from the hydrogen conduit  306  may be compressed and purified by a hydrogen compressor and purifier  311 , and subsequently stored in at least one hydrogen storage vessel  312 .  
         [0057]     The hydrogen stored in the one or more hydrogen storage vessels  312  may be controllably transferred to a storage tank in or on a vehicle using the hydrogen transfer device  310 . Alternatively, the hydrogen can also be stored using solid state hydrogen storage technology, such as metal hydride solid hydrogen storage (not shown).  
         [0058]      FIG. 4  is a schematic diagram of an apparatus for the production, separation, and distribution of hypochlorite and hydrogen according to an embodiment of the invention. The apparatus comprises an electrolyzer  403 , a hydrogen storage system  407 , and a hydrogen transfer device  414 . Brine is provided to the electrolyzer  403  by a brine source  401 , and the electrolysis process occurring within the electrolyzer  403  is powered using an electricity source  402 . The electrolyzer  403  has an electrolyzer outlet  404 .  
         [0059]     Electrolysis occurs within the electrolyzer  403 , and hypochlorite in solution with spent brine and the hydrogen in gaseous form flow out of the electrolyzer  403  through the electrolyzer outlet  404  to the separator  405 . Some hydrogen may bubble out of the spent brine solution in the electrolyzer  403 , and is carried away using a first duct  415  to a hydrogen purification subsystem  417 .  
         [0060]     Hydrogen is separated from the hypochlorite in solution with the spent brine in the separator  405 , and flows through a second duct  416  to the hydrogen purification subsystem  417 . The hydrogen is purified in the hydrogen purification subsystem  417  to remove any non-combustible gases, such as atmospheric air, nitrogen, or carbon dioxide, using known methods.  
         [0061]     Instead of using a separate hypochlorite storage, the separator  405  may act as a storage for the hypochlorite in solution with the spent brine, so that the spent brine conduit  408  directs the hypochlorite in solution with the spent brine directly away for use in water or waste water treatment.  
         [0062]     After the hydrogen is purified by the hydrogen purification subsystem  417 , the hydrogen flows through the hydrogen conduit  406  to the hydrogen storage system  407 .  
         [0063]     One or more dedicated water electrolyzers  413  are also fed by the electricity source  402 , and electrolyze water to produce hydrogen using known techniques. The evolved hydrogen may be directly stored in the hydrogen storage system  407  along with hydrogen from the hydrogen purification subsystem  417 . Alternatively, the evolved hydrogen from the one or more dedicated water electrolyzers  413  may be directed to the hydrogen purification subsystem  417 . The oxygen evolved from one or more dedicated water electrolyzers  413  could be vented or captured for subsequent use (not shown).  
         [0064]     As needed, the stored hydrogen in the hydrogen storage subsystem  417  maybe be controllably transferred to a storage tank in or on a vehicle using a fueling device  414 , which in this embodiment comprises the hydrogen transfer system.  
         [0065]      FIG. 5  is a schematic diagram of an apparatus for the production, separation, and storage of hypochlorite and hydrogen  500  according to an embodiment of the invention. The apparatus  500  comprises a brine electrolyzer  503 , a hypochlorite storage and hydrogen separation vessel  504 , and a hydrogen storage system  515 . The internal details and operation of the electrolyzer  503 , the hypochlorite storage and hydrogen separation vessel  504 , and the hydrogen storage system  515  are well known to a person skilled in the relevant art.  
         [0066]     Operation of the apparatus  500  may require water to be delivered to a water deionizer  501 . The source of the water may be either potable or non-potable. The flow rate of the water may be dictated by various factors and may include but not be limited to the level of hypochlorite in the storage vessel  503  or the dosing rate of the metering pump  514 . Once the water has been softened to a sufficient level it is delivered to salt saturator  502  where salt is added to the water to create a brine solution that is input into the electrolyzer  503 . Within the electrolyzer  503  a direct current is applied to cause the brine solution to evolve into hypochlorite and hydrogen in accordance with Equation 1 above. Electrical connections and power conversion devices are not shown but implied.  
         [0067]     In the electrolysis process, hypochlorite and hydrogen are evolved and flow as a two-phase mixture out of the electrolyzer  503  into the hypochlorite storage vessel  504  where phase separation into liquid hypochlorite solution  505  and gaseous hydrogen  506  occurs. Some separation may occur within the electrolyzer  503  itself and any separated hydrogen may be vented out of individual electrolyzers via a vent line  519  directly into the hypochlorite storage vessel  504  to increase the efficiency of any downstream electrolyzers. Additionally, dedicated phase separators and condensers may be employed to purify the hydrogen but are not shown on the diagram. A gas outlet valve  507  allows for evolved hydrogen to be vented to atmosphere in the case of a failure of the hydrogen storage system or the hydrogen fuel cell. A fan that is not shown may be used to purge the system of hydrogen under any alarm conditions in conjunction with the opening of the outlet valve  507 . Check valve  508  prevents the backflow of hydrogen back into the storage vessel  504 .  
         [0068]     When the hydrogen gas has been sufficiently purified it may pass through vacuum regulator  516  to compressor  509 . The compressor  506  transfers the hydrogen to storage or directly into a proton exchange membrane fuel cell. Pressure sensor  518  monitors the pressure in the storage system and may be used in controlling the operation of the system. Control valve  510  is used to dictate the direction of gas flow either into the hydrogen storage system  515  or through pressure regulator  517  and then to a proton exchange membrane fuel cell (not shown). A plurality of vessels  511  may be utilized in storing the hydrogen. Safety relief valve  512  is attached at the manifold of the pressure vessels to expulse any excess pressure and prevent vessel rupture. Burst discs (not shown) may also be included on the pressure vessels. The flow of hydrogen from the pressure vessels  512  to a proton exchange membrane fuel cell may be controlled by a pressure regulator  513 .  
         [0069]      FIG. 6  is a schematic diagram of an apparatus  600  for the production, separation, and storage of hypochlorite and hydrogen integrating fuel cell  600  according to an embodiment of the invention. The apparatus  600  comprises a brine electrolyzer or plurality of electrolyzers  604 , a hypochlorite storage and hydrogen separation vessel  607 , a hydrogen storage system  616 , and a proton exchange membrane fuel cell  637 . The internal details and operation of electrolyzer  604 , hypochlorite storage and hydrogen separation vessel  607 , hydrogen storage system  616 , and proton exchange membrane fuel cell  637  are well known to a person skilled in the relevant art.  
         [0070]     Operation of the apparatus  600  requires a source of water to be delivered to a water deionizer  601  as with the other preferred embodiment discussed. The source of the water may be either potable or non-potable. Softened water from the water deionizer  601  is supplied to salt saturator  603  to create a brine solution. Softened water may similarly distributed to proton exchange membrane fuel cell  637  through valve  602  and supply line  629  to cool the fuel cell  637  and also to electrolyzer  604  through water line  634  to dilute the brine concentration in the electrolyzer  604  if necessary. Brine created in the salt saturator  603  is metered into electrolyzer  604  where a direct current is applied to the solution in order to evolve hypochlorite and hydrogen. A series of electrolyzers  604  is shown in  FIG. 8  with each having an optional hydrogen gas port  639  to remove hydrogen that has separated from the solution in each cell therefore by-passing any downstream electrolyzers  604 . The separated hydrogen flows through hydrogen gas line  606  into hypochlorite storage and hydrogen separation vessel  607 . The solution mixture of hypochlorite, entrained hydrogen, and brine exits the final electrolyzer  604  in the series and flows through solution line  605  to the hypochlorite storage and hydrogen separation vessel  607 .  
         [0071]     Within the hypochlorite storage and hydrogen separation vessel  607 , two distinct phases are present: the liquid hypochlorite phase  608  and the gaseous hydrogen phase  609 . The liquid hypochlorite phase  608  is metered as a disinfecting agent into a water system by metering pump  633  but could also be transferred to another storage device to be transported to an off-site (disinfection) system, or sold commercially. A gas outlet valve  610  is attached to the top of the vessel  607  allowing for evolved hydrogen to be vented to atmosphere in the event of a failure of the hydrogen storage system  616  or the fuel cell  637 . A fan (not shown) may be connected to the vessel  607  to purge any evolved hydrogen into the atmosphere through gas outlet valve  610  during an alarm condition.  
         [0072]     Successive hydrogen purification mechanisms (not shown) may be used in addition to the primary separation vessel  607 . When the hydrogen gas has been sufficiently purified it will pass through vacuum regulator  612  to compressor  613 . An optional check valve  611  will prevent the backflow of hydrogen. The compressor  613  provides the necessary pressure to store the hydrogen as compressed gas or feed the gas directly to the fuel cell  637 . Pressure sensor  614  monitors the pressure in the hydrogen storage system  616  and may be used in the control scheme of the entire system. Control valve  615  is used to direct the flow of hydrogen to either the hydrogen storage system  616  or the fuel cell  637  or proportionally to both. A plurality of pressure vessels  617  may be employed based on the demands of the system  600 . A safety relief valve  638  is attached at the manifold of the pressure vessels  617  to expulse any excess pressure and prevent a vessel  617  rupture. Pressure regulator  618  may be used to control the flow of hydrogen from the pressure vessels  617  to the fuel cell  637 . Likewise pressure regulator  620  may be used to control the flow of hydrogen from the compressor  613  to the fuel cell  637 .  
         [0073]     Isolation control valves  619  and  635  allow for the selection of either the stored or direct source of hydrogen for the fuel cell  637 . Hydrogen fuel flows into the humidification module  622  of the fuel cell  637  through hydrogen inlet  621 . The chosen oxidizer flows into the humidification module  622  of the fuel cell  637  through oxidizer inlet  631 . Softened water from deionizer  601  is transferred to the fuel cell  637  for humidification and cooling through water supply line  629 . The water is removed from the fuel cell  637  via water waste line  630 . Humidified hydrogen and oxidizer are transferred into the electrochemically active module  623  where the electrochemical reaction creates a potential difference between positive electrode  624  and negative electrode  625 . The potential difference across the electrodes  624   625  produces a DC which is accepted by power handling module  627  where it could be applied directly to a load (not shown) or converted to AC current by power-conditioning module  628  and then applied to a load.  
         [0074]     Unused hydrogen from the electrochemical reaction may be re-circulated back through the system  600  via hydrogen return line  626  or it may be exhausted to atmosphere through a gas outlet valve that is not shown. Check valve  636  prevents the backflow of hydrogen. Oxidizer that is not reacted is exhausted to atmosphere through the oxidizer outlet  632 .  
         [0075]     It will be appreciated that the above description relates to the preferred embodiments by way of example only. Many variations on the system and method for delivering the invention without departing from the spirit of same will be clear to those knowledgeable in the field, and such variations are within the scope of the invention as described and claimed, whether or not expressly described.