WO2022124881A1

WO2022124881A1 - A hydrogen generator for fuel cell application, a method and a system thereof

Info

Publication number: WO2022124881A1
Application number: PCT/MY2020/050205
Authority: WO
Inventors: Mohd Izmir Bin YAMIN
Original assignee: Nanomalaysia Berhad; Pulsar Uav Sdn Bhd
Priority date: 2020-12-09
Filing date: 2020-12-22
Publication date: 2022-06-16

Abstract

The present invention provides a hydrogen generator (200) for fuel cell application for generating hydrogen gas its method and a system thereof. The hydrogen generator (200) is used within fuel cell system particularly for Proton Exchange Membrane Fuel Cell application. The hydrogen generator provides for on demand hydrogen gas as an alternative fuel supply in generating electrical energy. The hydrogen generator comprises a drying chamber (290) that further comprises a hydrophobic polymer membrane (292) and a water collection unit (291). The hydrophobic polymer membrane (292) is positioned on a top compartment of the drying chamber (290) for preventing water, liquid impurities and particulates to enter the plurality of fuel cells and the water collection unit (291) collects condensed water in the drying chamber (290).

Description

A HYDROGEN GENERATOR FOR FUEL CELL APPLICATION, A METHOD AND A SYSTEM THEREOF

FIELD OF INVENTION

The present invention provides a hydrogen generator for generating hydrogen for fuel cell application and a method of generating hydrogen from the hydrogen generator and a system thereof. In particular, the hydrogen generator provides for an on demand hydrogen gas as an alternative fuel supply for generating electrical energy to be used in various applications.

BACKGROUND ART

Hydrogen fuel has drawn a lot of interest in recent years particularly in its potential in powering various electrical and mechanical systems. Hydrogen generator does not only power large apparatus for transportation such as vehicles as it also powers smaller portable devices such as mobile computers including, laptops, GPS and unmanned aerial vehicle. Hydrogen fuel is environmentally friendly source of fuel. Particularly when fuel cells react with hydrogen fuel, the by-product is water which is a safe alternative to combustible fuel that emits harmful by-products to the environment.

Hydrogen is the simplest existing element of chemicals only containing a proton and an electron. Hydrogen does not occur naturally as a gas and due to its simplest form is always combined with other elements forming a compound. Hence, technologies have been developed to generate hydrogen in its purest form to be able to utilize hydrogen in its gaseous form for powering various applications.

The advancement of technologies for obtaining high purity hydrogen is an object of interest in fuel cell technology whereby fuel cell combines hydrogen and oxygen for electrical generation. Hence, numerous technologies have been applied in efficient generation of hydrogen gases for various applications as described in the following prior arts.

United States Patent No. US 7858068 B2, hereinafter referred to as US’068 B2 Patent, entitled “Method of storing and generating hydrogen for fuel cell applications” having a filing date 17 April 2007, Applicant: NANOTEK INSTRUMENTS GROUP LLC, discloses hydrogen gas storage and supply method wherein hydrogen is stored as part of a metal hydride or chemical hydride and hydrogen is generated when the hydride is brought to contact and react with a liquid reactant such as water or alcohol. The US’068 B2 patent discloses the utilization of a reaction-controlling agent such as an acid or a metal salt, to accelerate or delay the reaction between a hydride and a liquid reactant, which makes it possible to produce an adequate amount of hydrogen using an inexpensive and environmentally benign acid such as citric acid.

United States Patent Application Publication No. US 20070138006 A1 (hereinafter referred to as US’006 A1 application) entitled “System and Method for Generating Hydrogen Gas” having a filing date 19 December 2006, Applicant: CENESTRA LLC, discloses a hydrogen gas generation system using an electrolysis process for use in a mobile vehicle with an on-board hydrogen generator for generating hydrogen gas. The US’006 A1 application discloses the storage of the hydrogen produced by the electrolysis process in an on-board hydrogen storage tank, whereby the hydrogen flows into a vehicle propulsion system to provide power to propel the vehicle. The US’006 A1 application further discloses an on-board electrical generation system that provides some of the electricity for the electrolysis process which traps hydrogen gas using a membrane system. The US’006 A1 application further discloses the utilization of renewable sources of energy and/or regenerative energy for generating hydrogen gas for consumption in the vehicle's propulsion system.

United States Patent No. US 6932847 B2 hereinafter referred to as US’847 B2 Patent, entitled “Portable hydrogen generator” having a filing date 06 July 2001 , Applicant: SILICON VALLEY BANK INC and BALLARD UNMANNED SYSTEMS INC, discloses a hydrogen generator System having a first container, a second container, a catalyst system and a pumping system, for pumping fuel from one of the containers through the catalyst system. The US’847 B2 patent discloses that both container can be a fuel container or a spent fuel container, and the catalyst chamber has a hydrogen generator catalyst for reacting with a fuel, such as metal hydride and/or sodium borohydride solution to create hydrogen. The US’847 B2 Patent further discloses a hydrogen generator system with a transportation cart having a frame, a back, at least one support band and a number of wheels, whereby the back can be provided with support struts, vertical braces and bands to act as a heat sink. International Patent Application Publication No. WO 2019050959 A1 (hereinafter referred to as WO’959 A1 Publication) entitled “Compact efficient hydrogen reactor” having a filing date 5 September 2017 (Applicant: INTELLIGENT ENERGY INC.) discloses devices, systems and methods, and aspects thereof, of producing power using a Proton Exchange Membrane, PEM fuel cell power system fed with on demand hydrogen. The WO’959 A1 Publication discloses generation of hydrogen by the hydrolysis of fuel pellets in a rotatable reactor containment insert while controlling the addition of pressurized liquid into said containment insert, then rotating at least the reactor during liquid feed to generate hydrogen by the hydrolysis of fuel pellets in the reactor; to provide hydrogen via fluid communication to the anode side of an open cathode PEM fuel cell stack whereby said fuel cell stack generates electricity.

As outlined above, various systems have been developed to generate pure hydrogen for fuel cell technology. There is need for improvement in producing high purity hydrogen gas that provides ease of operation and maintenance and is light weight for portability. Presently, hydrogen fuel supplied to fuel cell technology systems are compressed hydrogen gas which is difficult to store and transport. There is need for a scalable hydrogen generator that is able to accommodate various run time or operational time and further accommodate a hydrolysis reaction within the hydrogen generator that can contain reaction that powers up to 10kW in a system. Hence, the present invention provides an improved hydrogen generator that is light weight for portability while not compromising on its capacity to generate high purity hydrogen and safely store the hydrogen gas generated from the hydrogen generator for use on demand.

SUMMARY OF INVENTION

The present invention provides a hydrogen generator for generating hydrogen for fuel cell application and a method of generating hydrogen from the hydrogen generator and a system thereof. In particular, the hydrogen generator provides for an on demand hydrogen gas as an alternative fuel supply for generating electrical energy in various applications.

One aspect of the present invention provides a hydrogen generator (200) for a fuel cell comprising an enclosure (226) for housing the hydrogen generator, a piping section (266) for receiving a connecting tubing for allowing flow of hydrogen gas to a plurality of fuel cells through the connecting tube, a reaction chamber (252) for generating hydrogen gas and water vapour resulting from an immediate reaction of a chemical hydride compound that is in contact with water present in the reaction chamber and a catalyst producing an alkaline solution, a cooling and gas storage chamber (258) for cooling hydrogen gas generated from the reaction chamber which flows through by removing heat from hydrogen gas which flows through a coiled tubing within the cooling and gas storage chamber; a drying chamber (290) for storing drying agents for reducing humidity of the generated hydrogen gas before flowing to the plurality of fuel cells, a plurality of acrylic plates (234, 236, 238) forming an acrylic sandwich separating the reaction chamber (252) from the cooling and gas storage chamber (258), a plurality of acrylic plates (260, 262, 264) forming an acrylic sandwich separating the cooling and gas storage chamber (258) from the piping section (266), a plurality of acrylic plates (246, 248, 250) forming an acrylic sandwich for closing the reaction chamber (252), a first gas outlet channel (224) for allowing movement of gas from the cooling and gas storage chamber to the plurality of fuel cells, the gas outlet channel further comprising a barb to ensure tight attachment of the connecting tubing, a second gas outlet channel (232) for allowing gas to move from the reaction chamber to the cooling and gas storage chamber; and a syringe barrel (230) for separating the reaction chamber (252) from the cooling and gas storage chamber (258) for allowing fuel to directly flow to the reaction chamber (252). The reaction chamber (252) further comprises a catalyst bed (244) comprising catalyst positioned at a bottom part of the reaction chamber (252) that is lowered or elevated for initiating a reaction to generate hydrogen gas and water vapour; a plurality of mobile magnets (242) affixed to an outer wall of the enclosure (226) is further extended and held by solenoid actuators for lowering or elevating the catalyst bed to be in contact with metal hydride solution and a refuelling channel port (204) for providing direct access to the reaction chamber through the cooling and gas storage chamber (258). Further, the coiled tubing within the cooling and gas storage chamber for cooling the generated hydrogen gas received from the reaction chamber is 6 mm in diameter and the drying chamber comprises a hydrophobic polymer membrane positioned on a top compartment of the drying chamber (290) for preventing water, liquid impurities and particulates to enter the plurality of fuel cells and a water collection unit (291 ) connected to a bottom compartment of the drying chamber (290) for collecting condensed water in the drying chamber (290).

Another aspect of the present invention provides a hydrogen generator wherein the catalyst bed (244) comprises a catalyst that is ruthenium based, platinum based, cobalt based or nickel based or a combination thereof.

Yet another aspect of the present invention provides a hydrogen generator according to claim 1 , wherein the plurality of acrylic plates (234, 238, 246, 250, 260, 264) have an outer layer of thickness of at least 2mm.

Another aspect of the present invention provides a hydrogen generator, wherein the plurality of acrylic plates (236, 248, 262) have an inner layer of thickness of at least 3mm.

Yet another aspect of the present invention provides a hydrogen generator, wherein the chemical hydride crystal salt is selected from a group comprising of NaBH₄, LiH, NaH, AIH₃, KH, CaH₂, AI(BH4)₃, LiBH₄ or LiAIH₄.

Another aspect of the present invention provides a hydrogen generator wherein the coiled tubing from the cooling and gas storage chamber is made from polyurethane.

Yet another aspect of the present invention provides a hydrogen generator wherein the cooling and gas storage chamber comprises a pressure controller that detects an increase in pressure preferably between at least 300 to 400 kPa (3 to 4 bars).

Another aspect of the present invention provides a hydrogen generator wherein the drying agent is preferably calcium chloride or silica gel desiccant. Yet another aspect of the present invention provides a hydrogen generator wherein the hydrophobic polymer membrane is preferably polytetrafluoroethylene, PTFE.

Another aspect of the present invention provides a hydrogen generator wherein the hydrophobic polymer membrane is preferably polypropylene, PP.

Yet another aspect of the present invention provides a hydrogen generator wherein the hydrophobic polymer membrane is preferably polycarbonate track etched, PTCE.

Another aspect of the present invention provides a hydrogen generator wherein the hydrophobic polymer membrane is preferably hydrophobic ceramic membrane.

Yet another aspect of the present invention provides a hydrogen generator wherein the hydrophobic polymer membrane is preferably non-sterile cellulose acetate membrane.

Another aspect of the present invention provides a hydrogen generator wherein the hydrophobic polymer membrane is preferably non-sterile cellulose nitrate membrane.

The present invention consists of features and a combination of parts hereinafter fully described and illustrated in the accompanying drawings, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

To further clarify various aspects of some embodiments of the present invention, a more particular description of the invention will be rendered by references to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the accompanying drawings in which:

Figure 1.0 is a diagram illustrating the hydrogen generator applied to a Proton Exchange Membrane Fuel Cell, PEMFC system.

Figure 2.0a is a diagram illustrating a top view of the hydrogen generator of the present invention.

Figure 2.0b is a diagram illustrating an orthogonal view of the hydrogen generator of the present invention.

Figure 2.0c is a diagram illustrating a side view of the body of the hydrogen generator of the present invention.

Figure 2.0d is a diagram illustrating a general overview of the hydrogen generator of the present invention.

Figure 2.0e is a diagram illustrating an exploded view of the hydrogen generator of the present invention.

Figure 2. Of is a diagram illustrating a cross sectional view of the hydrogen generator of the present invention.

Figure 2.0g is a diagram illustrating a cooling and gas storage chamber having cooling coils.

Figure 2.0h(a) is a diagram illustrating a first configuration type of introducing a catalyst to a metal hydride solution. Figure 2.0h(b) is a diagram illustrating a second configuration type of introducing the catalyst to a metal hydride solution.

Figure 2.0i is a diagram illustrating a scalable hydrogen generator in terms of length of cylinder and height of a reaction chamber.

Figure 2.0j (a) is a diagram illustrating an enclosure of the scalable hydrogen generator.

Figure 2.0j (b) is a diagram illustrating a latch unit that sandwiches to cylindrical sections together.

Figure 2.0k is a diagram illustrating a drying chamber of the scalable hydrogen generator.

Figure 3.0 is a flowchart illustrating a method for producing hydrogen gas in the hydrogen generator of the present invention.

Figure 4.0 is a graph illustrating a relationship between run time duration to the amount of water in relation to fuel cell power.

Figure 4.1 is a graph illustrating a relationship between run time duration to fuel cell power for an amount of 500 grams of water.

Figure 4.2 is a graph illustrating the relationship between run time duration to fuel cell power for an amount of 1000 grams of water.

Table 1.0 illustrates the runtime reaction in relation to a range from 500 g to 10000g of water.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention provides a hydrogen generator for generating hydrogen for fuel cell application and a method of generating hydrogen from the hydrogen generator and a system thereof. In particular, the hydrogen generator provides for an on demand hydrogen gas as an alternative fuel supply for generating electrical energy in various applications. Hereinafter, this specification will describe the present invention according to the preferred embodiments. It is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned without departing from the scope of the appended claims.

The present invention provides a hydrogen generator that is applicable for powering of various electrical or mechanical systems. In particular, the hydrogen generator is used to supply hydrogen fuel to a Proton Exchange Membrane Fuel Cell, PEMFC providing an alternative to current hydrogen fuel supply that involves compressed hydrogen gas that poses problems with regards to storage and transportation. The present invention provides for ease of operation and maintenance of the hydrogen generator which is lightweight.

Reference is first made to Figure 1.0. Figure 1.0 shows a diagram illustrating the hydrogen generator of the present invention within a PEMFC system. The system (100) for generating hydrogen from a hydrogen generator comprises a liquid fuel connection from a fuel reservoir (104) to a first solenoid valve (106) and a hydrogen generator (200) for passing liquid fuel activated by a level sensor (102). The system further comprises a hydrogen gas connection from the hydrogen generator (200) to a gas cooler (112), a gas dryer (114), a pressure regulator (118), a flow meter (120), a second solenoid valve (124) and Proton Exchange Membrane Fuel Cell (126) for passing hydrogen gas produced from the hydrogen generator (200). The hydrogen gas connection also includes removal of excess hydrogen gas by a third solenoid valve (128). The system comprises an electrical connection for passing electrical current through a series of electronic circuits from the Proton Exchange Membrane Fuel Cell (126), a DC-DC Converter (130), a power module (132) that either activates a hybrid card (138) directly or by path of powering a graphene ultracapacitor (134) power device that activates a junction module (136). The hybrid card further activates a thyristor (140) producing an electrical load (142) that either initiates a mechanical output (144) or regenerates energy (146) to further activate the junction module (136) to repower the hybrid card (138). Condensed water retrieved from Proton Exchange Membrane Fuel Cell (126) is recycled into the hydrogen generator (200) which reduces mass of the energy requirement of the system. The system comprises a control means having a microcontroller (148) connection for control and operation of the level sensor (102), the first solenoid valve (106), the power module (132), the flow meter (120), the second solenoid valve (124), a thermo couple (108), a hygro meter (116), a pressure regulator (118), a control (150), a pressure transducer (122) and a Liquid Crystal Display, LCD, (152). The hydrogen generator is connected to a by-product container (110) that receives by-products such as excess impurities during generation of hydrogen gas in the hydrogen generator.

In describing further on the hydrogen generator (200), reference is made to Figure 2.0a, Figure 2.0b, Figure 2.0c, Figure 2.0d, Figure 2.0e and Figure 2. Of where the components of the hydrogen generator is illustrated.

Figure 2.0a is a diagram illustrating a top view of the hydrogen generator of the present invention. From the top view of the hydrogen generator, a refuelling port screw cap (220) is shown. Figure 2.0b is an orthogonal view of the hydrogen generator and Figure 2.0c is a side view of the hydrogen generator where the enclosure (226) that houses the hydrogen generator and a tubing access channel (268) is shown. The enclosure (226) is made of acrylic. However, the material of the enclosure is not limited to acrylic and may include any lightweight material that is able to withstand the power generated during operation of the hydrogen generator. The structure of the enclosure is preferably cylindrical. However, the shape of the enclosure is not limited to a cylindrical form and may take any form that provides for portability of the hydrogen generator.

A general overview of the hydrogen generator (200) of the present invention is further illustrated in Figure 2.0d. Figure 2.0d shows various general parts of the hydrogen generator that provides the functionality of the hydrogen generator. A drying chamber (290) as further illustrated in Figure 2.0k is configured by connecting a tubing (216) to the hydrogen generator for flow of hydrogen gas to fuel cell upon demand. The drying chamber (290) is filled with drying agents (294) such as calcium chloride or silica gel desiccant to enable drying of gas when hydrogen gas (295) passes through to remove the presence of gas moisture in the tubing. The drying chamber further comprises a hydrophobic polymer membrane (292) sandwiched in between a compartment at the bottom part of the drying chamber having drying agents and a compartment at a top part of the drying chamber having hydrogen gas bubbles. The drying chamber is further connected to a water collection unit (291) at the bottom of the drying chamber that collects condensed water (293). The hydrogen generator comprises a channel (214) for generated hydrogen gas to flow through to a cooling and gas storage chamber (258) from the reaction chamber (252) which is further illustrated in Figure 2. Of. The hydrogen generator (200) comprises a refuelling channel port (204) for providing direct access to the reaction chamber through the cooling and gas storage chamber (258). The cooling and gas storage chamber comprises water (206) for maintaining a cooling environment for cooling the hydrogen gas that is received. The cooling and gas storage chamber (258) also comprises a cooling coil (208) as further illustrated in Figure 2.0g where the generated hydrogen gas from the reactor chamber (252) passes through the cooling coil for additional cooling duration before releasing of the generated hydrogen gas into the water (206) of the cooling and gas storage chamber (258). The cooling coil (208) is a 6mm plastic tube that circulates three rounds around the cooling and gas storage chamber (258) forming a spiral structure. The hydrogen generator comprises at least three O-ring gaskets (2958) that are positioned above and below the cooling and gas storage chamber (258) and below the reaction chamber (252) for tight sealing to avoid leakage or solution from the hydrogen generator. The hydrogen generator comprises a metal hydride solution (218) positioned at a bottom part of the reaction chamber (252) that comprises a catalyst needed in the hydrolysis reaction to produce hydrogen gas which is further described in Figure 2. Of.

Figure 2.0e is a diagram illustrating an exploded view of the hydrogen generator of the present invention. As illustrated in Figure 2.0e, representation of the compartments is shown from the refuelling port screw cap to an enclosure. Figure 2. Of is a diagram illustrating a cross sectional view of the hydrogen generator of the present invention showing the interior of the components of the hydrogen generator.

The hydrogen generator (200) of Figure 2.0e and Figure 2. Of comprises various parts that make up the hydrogen generator.

A first embodiment of the hydrogen generator (200) comprises an enclosure (226), a piping section (266), a reaction chamber (252), a cooling and gas storage chamber (258), and a tubing access channel (268). The enclosure (226) is used for housing the hydrogen generator (200). The piping section (266) is used for receiving a connecting tubing. The reaction chamber (252) is used for generating hydrogen gas and water vapour. The hydrogen gas and water vapor are resulted from an immediate reaction of a metal hydride with water and a catalyst, producing an alkaline solution. The cooling and gas storage chamber (258) is used for cooling hydrogen gas generated from the reaction chamber (252). Heat is removed when the hydrogen gas flows through a coiled tubing within the cooling and gas storage chamber (258). The tubing access channel (268) is used for connecting a tubing to the piping section (266). The tubing access channel (268) also provides access of hydrogen gas generated in the hydrogen generator (200) to fuel cells. The metal hydride solution or chemical hydride compound is selected from a group comprising of NaBH4. The metal hydride solution or chemical hydride compound is not limited to NaBH₄ and may be selected from the group comprising LiH, NaH, AIH₃, KH, CaH₂, AI(BH4)₃, LiBH₄ or LiAIH₄.

The hydrogen generator (200) further comprises a plurality of acrylic plates (234, 236, 238) forming an acrylic sandwich separating the reaction chamber (252) from the cooling and gas storage chamber (258), a plurality of acrylic plates (260, 262, 264) forming an acrylic sandwich separating the cooling and gas storage chamber (258) from the piping section (266) and a plurality of acrylic plates (246, 248, 250) forming an acrylic sandwich for closing the reaction chamber (252). The plurality of acrylic plates (234, 238, 246, 250, 260, 264) have an outer layer of thickness of at least 2mm. The plurality of acrylic plates (236, 248, 262) have an inner layer of thickness of at least 3mm. The hydrogen generator includes a screen display (269) for displaying onsite information of the reaction. The onsite information displayed includes reaction rate, tags and numbers.

The hydrogen generator (200) comprises a first gas outlet channel (224) and a second gas outlet channel (232). The first gas outlet channel (224) allows movement of gas from the cooling and gas storage chamber to a plurality of fuel cell. The first gas outlet channel (224) further comprises a barb to ensure tight attachment of the connecting tubing. The second gas outlet channel (232) allows gas to move from the reaction chamber (252) to the cooling and gas storage chamber (258). A syringe barrel (230) separates the reaction chamber (252) from the cooling and gas storage chamber (258) for allowing fuel to directly flow to the reaction chamber (252). The reaction chamber (252) comprises a metal hydride solution positioned at a bottom part of the reaction chamber (252). A catalyst bed (244) will be introduced into the reaction chamber (252) for contact with the metal hydride solution. The catalyst bed (244) contains a metal framework that supports the catalyst. The catalyst bed is lowered or elevated for initiating a reaction to generate hydrogen gas and water vapour. A plurality of mobile magnets (242) is affixed to an outer wall of the enclosure (226) for lowering or elevating the catalyst bed as further -illustrated in Figure 2.0h(a). The reaction chamber further includes a refuelling channel port (204) for providing direct access to the reaction chamber through the cooling and gas storage chamber (258).

The cooling and gas storage chamber (258) is illustrated in Figure 2.0g. The hydrogen generator is designed and configured to passively flow the generated hydrogen gas (278) to the fuel cell by pressure difference between the cooling and gas storage chamber and the fuel cell. By utilising the pressure difference between the cooling chamber and the fuel cell active pumps are not required for transporting the generated hydrogen gas to the required chambers. The cooling and gas storage chamber comprises a pressure controller that detects increase in pressure where the preferred pressure for hydrogen build up is between 300 to 400 kPa (3 to 4 bars).

A detailed illustration of the cooling and gas storage chamber (258) is shown in Figure 2.0g, where the cooling and gas storage chamber comprises a plurality of cooling coils (208) that is submerged in water (206) or a cooling gel. The cooling coil is made of 6mm polyurethane tube or copper pipe. The cooling and gas storage chamber (258) cools down and stores the generated hydrogen gas. Heat generated from the hydrogen gas having a temperature range of between 40 °C to 50°C is transferred from the gas as it travels through the cooling coil into the liquid water or cooling gel that surrounds the coil. The cooling and gas storage chamber (258) includes exit points for the travelling generated hydrogen. A first exit point (274) is where the hydrogen gas exits from the reactor chamber (252) into the cooling and gas storage chamber (258). A second exit point (276) is when the generated hydrogen gas exits from the cooling coil into the liquid water or cooling gel. The heat from the water will radiate through the walls of the cooling and gas storage chamber (258). The wall of the cooling and gas storage chamber (258) is preferably painted black to absorb the heat. A heat sink is attached on the exterior of the cooling and gas storage chamber (258) for absorption of heat from the generated hydrogen gas. The cooling and gas storage chamber (258) allows for the reduction of pressure steam therefore eliminating the need for thick wall canister high pressure buffer tank which is heavy. The cooling and gas storage chamber (258) of the present invention acts as a low pressure buffer tank allowing for lighter materials to be selected as material for the hydrogen generator (200). Cooling that occurs in the cooling and gas storage chamber (258) is an important aspect of the present invention as it reduces the entropy of hydrogen and further ensures that no steam or water vapour flows to the fuel cell which will affect fuel cell performance. Hydrogen gas that is not cooled will cause a percentage of 60% drop in fuel cell performance.

Reference is made to Figure 2.0h (a) and Figure 2. Oh (b) on the type of configuration of catalyst being introduced to the metal hydride solution in the reaction chamber (252). There are two configurations type of introducing the catalyst to the metal hydride solution (218) in the reaction chamber (252). Figure 2.0h (a) shows a first configuration type (252a) that allows the reaction to take place by a large circular surface with catalyst on a 4mm thick metal support or a catalyst bed (244) that is lowered down using a plurality of solenoids (280) having mobile magnets (242) extended from the solenoids that switches on or off for lifting up from or lowering down to the metal hydride solution (218). The solenoid in the first configuration type (252a) that have mobile magnets that retract the catalyst from the metal hydride solution to a stow position where the catalyst bed (244) is elevated to a position out of contact with the metal hydride solution. The stow position is effected when a controller of the hydrogen generator detects sufficient amount of gas. In an event where the controller detects insufficient amount of gas, the solenoids extends and causes the catalyst bed to be in contact with the chemical hydride solution. Figure 2. Oh (b) shows a second configuration type (252b) where the mobile magnets are replaced with extended cylindrical pieces (288) comprising the catalyst held by the solenoid (280) which are lowered or lifted for contact with the metal hydride solution (218). The cylindrical pieces comprising the catalyst that are held by solenoids (280) will be retracted when sufficient amount of gas is detected. In the event where insufficient amounts of gas are detected, the cylindrical pieces (288) comprising the catalyst will be motioned to dip and be in contact with the metal hydride solution (218) to initiate hydrolysis reaction.

A hydrogen generator (200) of the first embodiment further comprises a refuelling port screw cap (220) closes an end of the refuelling channel port (204) for allowing access to a fuel section of the hydrogen generator for refuelling means. The refuelling port screw cap (220) further comprises a plunger attached to an end of the refuelling port screw cap to prevent backflow of fuel during refuelling. The hydrogen generator (200) further comprises a cover (222) that houses the electronics of the hydrogen generator (200). When refuelling through the refuelling channel port (204) is completed, a first knurl bolt (228) locks with the refuelling port screw cap. A second knurl bolt (256) and a knurl nut (254) locks the syringe barrel (230) to secure it in place, allowing an access to the reaction chamber (252) from the refuelling channel port (204).

A second embodiment of the present invention provides a scalable hydrogen generator. The scalable hydrogen generator (200) comprises an enclosure (226) that is scalable, a piping section (266), a reaction chamber (252), a cooling and gas storage chamber (258), and a tubing access channel (268). The enclosure (226) is used for housing the hydrogen generator (200). The piping section (266) is used for receiving a connecting tubing. The reaction chamber (252) is used for generating hydrogen gas and water vapour. The hydrogen gas and water vapor are resulted from an immediate reaction of a metal hydride with water and a catalyst, producing an alkaline solution. The cooling and gas storage chamber (258) is used for cooling hydrogen gas generated from the reaction chamber (252). Heat is removed when the hydrogen gas flows through a coiled tubing within the cooling and gas storage chamber (258). The tubing access channel (268) is used for connecting a tubing to the piping section (266). The tubing access channel (268) also provides access of hydrogen gas generated in the hydrogen generator (200) to fuel cells. The metal hydride solution or chemical hydride compound is selected from a group comprising of NaBH4. The enclosure (226) of the hydrogen generator is scalable and connected to a plurality of gasket seal plates that are configured in an arrangement having spacings to suit the Proton Exchange Membrane Fuel Cell, PEMFC that generates a higher power between 200W to 10kW. The enclosure can be scaled up using a longer cylinder, L and increased in height of the reaction chamber section, C as illustrated in Figure 2.0i.

The enclosure of the present invention is further illustrated in Figure 2.0j (a) and Figure 2.0j(b). The enclosure comprises a cooling chamber section (2942) that is scaled up by using cylinders, a reaction chamber section (2948) that is scaled up using cylinders and connected to the cooling chamber section (2942) by a latch unit (2944) and a plurality of o-ring gaskets (2958) attached on a machine nylon disc block (2960) and a bottom plate section (2952) positioned below the hydrogen generator (200) that acts as a barrier for the liquid present in the reaction chamber (252) from the outside of the hydrogen generator (200). A latch unit (2944) sandwiches two cylinders namely the cooling chamber section (2942) and the reaction chamber section (2948) together which is an upper and bottom part to either provide the necessary linkages or to create an end plate. The cylinders are held tightly together by a latch unit (2944) and silicone o-ring gaskets (2958) that are placed on a machine nylon disc block (2960). The sizing of the hydrogen generator varies according to duration of run time and rate of hydrogen generation to cater for different power rating of fuel cells. The hydrogen generator further comprises a driver motor (2940) for engaging in clockwise or counter-clockwise rotation when a catalyst is to be lowered to be in contact with the metal hydride solution for the hydrolysis reaction or to be retracted from the metal hydride solution to stop the hydrolysis process. Further a latch unit (2944) is placed to hold two cylinders in place with sufficient tightness to withstand pressure and liquid leakages in the presence of sealing rubber- silicone gaskets. The latch unit (2944) causes the generator to be modular for purposes of modifying to different lengths of the reactor. A lead screw (2950) is placed in the reactor as a means to transmit linear translational downward and upward motion (2956) of the catalyst bed (2946), mounted on a specialized nut to allow for transverse motion while the lead screw is rotated by the driver motor. A bottom plate section (2952) attached to the reaction chamber section by gasket seals (2954) is included at the bottom of the reactor for isolating the reaction chamber liquid from the outside of the reactor.

The hydrogen generator further comprises a plurality of acrylic plates (234, 236, 238) forming an acrylic sandwich separating the reaction chamber (252) from the cooling and gas storage chamber (258), a plurality of acrylic plates (260, 262, 264) forming an acrylic sandwich separating the cooling and gas storage chamber (258) from the piping section (266) and a plurality of acrylic plates (246, 248, 250) forming an acrylic sandwich for closing the reaction chamber (252). The plurality of acrylic plates (234, 238, 246, 250, 260, 264) have an outer layer of thickness of at least 2mm. The plurality of acrylic plates (236, 248, 262) have an inner layer of thickness of at least 3mm. The hydrogen generator includes a screen display (269) for displaying onsite information of the reaction. The onsite information displayed includes reaction rate, tags and numbers.

The hydrogen generator comprises a first gas outlet channel (224) and a second gas outlet channel (232). The first gas outlet channel (224) allows movement of gas from the cooling and gas storage chamber to a plurality of fuel cells further comprising a barb to ensure tight attachment of the connecting tubing. The second gas outlet channel (232) allows gas to move from the reaction chamber to the cooling and gas storage chamber. A syringe barrel (230) separates the reaction chamber (252) from the cooling and gas storage chamber (258) for allowing fuel to directly flow to the reaction chamber (252).

Reference is made to Figure 2. Oh (a) and Figure 2. Oh (b) on introduction of the catalyst to the metal hydride solution in the reaction chamber (252). There are two configurations of introducing the catalyst to the metal hydride solution (218) in the reaction chamber (252) of the second embodiment. For the hydrogen generator having a scalable enclosure the reaction chamber (252) the two configuration types are used interchangeably. Figure 2. Oh (a) shows a first configuration type (252a) that allows the reaction to take place by a large circular surface with catalyst on a 4mm thick metal framework as support or a catalyst bed (244) that is lowered down using solenoid (280) having mobile magnets (242) extended from the solenoids that switches on or off for lifting up from or lowering down to the metal hydride solution (218). The solenoid in the first configuration type (252a) that have mobile magnets retract the catalyst from the chemical hydride solution to a stow position where the catalyst bed (280) is removed or placed in a position so as to not be in contact with the chemical hydride solution. The stow position is effected when a controller of the hydrogen generator detects sufficient amount of gas. On the other hand, in an event where the controller detects insufficient amount of gas, the solenoids extends and causes the catalyst bed to be in contact with the chemical hydride solution. The first configuration type (252a) comprises a catalyst that is a disc shape metallic porous substrate coated with catalytic particles.

Figure 2. Oh (b) shows a second configuration type (252b) where the mobile magnets are replaced with extended cylindrical pieces (288) comprising the catalyst held by the solenoid (280) which are lowered or lifted for contact with the metal hydride solution (218). The second configuration type (252b) comprises a plurality of cylinder shape metallic porous substrate coated with catalytic particle having a small diameter arranged vertically and equally spaced apart. The cylindrical pieces comprising the catalyst that are held by solenoids (280) will be retracted when sufficient amount of gas is detected. In the event where insufficient amounts of gas are detected, the cylindrical pieces (288) comprising the catalyst will be motioned to dip and be in contact with the metal hydride solution (218) to initiate hydrolysis reaction. More units of the catalyst in cylindrical pieces will be added depending on run time and rate of power.

The number of catalyst required can be determined by the equation provided below:

» ⁴⁸ thickness of catalyst

- r ~ radius of catalyst

- ~ density of substrate

" hading efficiency

“ ^cacperf. ” fate of hydrogen generation catalyst performance

The enclosure (226) further comprises a plurality of gasket seals (2954) configured in an arrangement at the bottom edge ends of the cooling chamber section (2942) and the reaction chamber section (2948) that secures the cooling chamber section (2942) to the reaction section (2948), further securing the reaction chamber section (2948) to the bottom plate section (2952).

The relationship of reaction in terms of run duration and water amount and fuel power cell is shown in the graph in Figure 4.0. Further Figure 4.1 shows a graph illustrating the relationship between runtime in minutes for fuel cell power of 200, 1000, 5000 and

10000 Watts for 500 grams of water. Figure 4.2 shows a graph illustrating the relationship between runtime in minutes for fuel cell power of 200, 1000, 5000 and

10000 Watts for 1000 grams of water. A table showing the runtime reaction in relation to amount of water is recorded in Table 1.0. From the table the enclosure (226) is able to accommodate hydrogen production at a rate of between 2.7 to 130 standard liter per minute, SLPM and an amount of water of up to 10000 grams.

A third embodiment of the present invention illustrated in Figure 2.0k provides a hydrogen generator connected to a drying chamber which is an external extension of the hydrogen generator. The hydrogen generator (200) comprises an enclosure (226), a piping section (266), a reaction chamber (252), a cooling and gas storage chamber (258), and a tubing access channel (268). The enclosure (226) is used for housing the hydrogen generator (200). The piping section (266) is used for receiving a connecting tubing. The reaction chamber (252) is used for generating hydrogen gas and water vapour. The hydrogen gas and water vapor are resulted from an immediate reaction of a metal hydride with water and a catalyst, producing an alkaline solution. The cooling and gas storage chamber (258) is used for cooling hydrogen gas generated from the reaction chamber (252). Heat is removed when the hydrogen gas flows through a coiled tubing within the cooling and gas storage chamber (258). The tubing access channel (268) is used for connecting a tubing to the piping section (266). The tubing access channel (268) also provides access of hydrogen gas generated in the hydrogen generator (200) to fuel cells. The metal hydride solution or chemical hydride compound is selected from a group comprising of NaBH4. The hydrogen generator further comprises a drying chamber (290) for storing drying agents for reducing humidity of the generated hydrogen gas prior to flowing to the plurality of fuel cells. The drying chamber comprises drying agents (294) such as calcium chloride (CaCh) or silica gel desiccant that reduces humidity. The drying chamber is connected by piping that connects the drying chamber to the fuel cells and to the reactor. The drying chamber further comprises a hydrophobic polymer membrane (292) to prevent water, liquid impurities and particulates to pass through and allowing only hydrogen gas (295) to pass through the hydrophobic polymer membrane. The hydrophobic polymer membrane (292) is strategically placed in the drying chamber (290) as an added measure for preventing water, liquid impurities and particulates from entering the fuels cells. This measure is to ensure that the fuel cell is able to operate at optimum condition and increase the efficiency of the fuel cells. Some examples of hydrophobic polymer membrane but not limited to these materials are polytetrafluoroethylene, PTFE, polypropylene, PP, polycarbonate track etch, PTCE, hydrophobic ceramic membrane, non-sterile cellulose acetate and non-sterile cellulose nitrate. The drying chamber (290) is further connected to a water collection unit (291) at a bottom part of the drying chamber that collects condensed water (293).

The reaction chamber (252) comprises a metal hydride solution positioned at a bottom part of the reaction chamber (252). A catalyst bed (244) will be introduced into the reaction chamber for contact with the metal hydride solution. The catalyst bed contains a metal framework that supports the catalyst . The catalyst means is lowered or elevated for initiating a reaction to generate hydrogen gas and water vapour. A plurality of mobile magnets (242) affixed to an outer wall of the enclosure (226) for lowering or elevating the catalyst bed (244) as further described in Figure 2. Oh (a). The reaction chamber further includes a refuelling channel port (204) for providing direct access to the reaction chamber through the cooling and gas storage chamber (258).

The various parts of the hydrogen generator and its function provides for a method (300) for generating hydrogen gas in the hydrogen generator. The step begins with compressing a chemical hydride crystal salt in a tablet form to produce a packed chemical hydride cartridge (302). The packed hydride cartridge comprises Sodium Borohydride, NaBH₄ that is used in generating hydrogen gas at a maximum purity of 99.5% which is also a source of fuel as it comprises hydrogen stored in its solid state. The packed chemical hydride which is Sodium Borohydride, NaBF used in the present invention is in a crystal salt form and compressed to form a cylinder shape tablet pill. The packed chemical hydride cartridge is inserted into a reaction chamber through a refuelling channel port of the hydrogen generator (304) and deionized water is added into the reaction chamber of up to 180 ml (306). A refuelling port screw cap is required for fastening to ensure no leakage occurs when the hydrogen generator is operating. The packed chemical hydride cartridge comes into contact with the deionized water (308). A catalyst bed is introduced by lowering using mobile magnets whereby the catalyst comprises a supported catalyst and unsupported catalyst (310). The supported catalyst comprises selecting a compound from cobalt and nickel based catalyst preferably of Cobalt Boride on Nickel Foam or Molybdenum Carbide on Nickel Foam. The unsupported catalyst comprises selecting a compound of Cobalt Boride Powder or Molybdenum Carbide Powder. The cobalt and nickel based catalyst is not limited to Cobalt Boride on Nickel Foam or Molybdenum Carbide on Nickel Foam and may include Cobalt and Nickel catalyst selected from any cobalt and nickel based catalyst. The catalyst is not limited to cobalt or nickel based catalyst and may include catalyst that are ruthenium based and platinum based. During cleaning process and maintenance, the supported catalyst can be cleaned while the catalyst is in the reactor chamber by the refuelling channel port without losing materials. For the unsupported catalyst, a neodymium magnet will be required to be in place to clean the catalyst. The use of the catalyst is to reduce the activation energy of the hydrolysis reaction for generating hydrogen gas. The presence of nickel in the catalyst bed causes the mobile magnets to attract the nickel framework substrate enabling lowering and elevation of the catalyst bed for halting or proceeding with the hydrolysis reaction.

Hydrolysis reaction is initiated from contact of the packed chemical hydride cartridge with deionized water in the presence of the catalyst to produce hydrogen gas (312) and hydrogen gas bubbles (314). Initiating hydrolysis reaction further initiates alkalinity of the deionized water when the hydrogen gas has a gravimetric hydrogen density of 10.8 wt%. The pH of the deionized water at 10.5 has a half-life to liberate hydrogen gas fuel within a 58 minute duration. An increased alkaline level to pH 14.0 creates stability in terms of half-life of the hydrogen gas fuel to about 400 days with the use of Sodium Hydroxide. The hydrolysis process which is an exothermic process occurs in the reaction chamber when the chemical hydride in salt form, the catalyst, the deionized water and sodium hydroxide are in contact. The hydrogen generation rate generated from the reaction produces at rates of 30000 to 40000 ml/min-g of catalyst. Produced gas can be seen through a canister containing tiny gas bubbles indicating levels of hydrogen gas. To ensure that the hydrogen gas produced is pure, gas chromatography is carried out to ensure the absence of poisonous gases such as carbon monoxide, nitrous dioxide, hydrogen sulphide and other contaminant gases. Hydrogen gas is accumulated in the reaction chamber up to a pressure of 400 kPa (4 bars) that flows upwards into a cooling and gas storage chamber (316) where cooling of hydrogen gas takes place for cooling the hydrogen gas from 45°C to at least 25°C by passing through a cooling coil (318). The cooling coil is a 6mm plastic tube that circulates three rounds around the cooling and gas storage chamber forming a spiral structure. Cooling is important as it creates a low temperature environment within the hydrogen generator allowing for the hydrogen generator to be made of light weight material such as polymeric plastic material. The hydrogen gas is then released to the Proton Exchange Membrane Fuel Cell upon demand by opening of solenoid valve (320). Releasing of hydrogen gas to Proton Exchange Membrane Fuel Cell comprises introducing a hydrophobic polymer membrane that allows for hydrogen gas penetration and prevents water or other liquid impurities from transmitting through the membrane.

Throughout this specification, unless the context requires otherwise, the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated step or element or integer or group of steps or elements or integers, but not the exclusion of any other step or element or integer or group of steps, elements or integers. Thus, in the context of this specification, the term “comprising” is used in an inclusive sense and thus should be understood as meaning “including principally, but not necessarily solely”.

Claims

23 CLAIMS

1 . A hydrogen generator (200) for a fuel cell comprising: an enclosure (226) for housing the hydrogen generator; a piping section (266) for receiving a connecting tubing for allowing flow of hydrogen gas to a plurality of fuel cells through the connecting tube; a reaction chamber (252) for generating hydrogen gas and water vapour resulting from an immediate reaction of a chemical hydride compound that is in contact with water present in the reaction chamber and a catalyst producing an alkaline solution; a cooling and gas storage chamber (258) for cooling hydrogen gas generated from the reaction chamber which flows through by removing heat from hydrogen gas which flows through a coiled tubing (208) of 6mm in diameter within the cooling and gas storage chamber; a drying chamber (290) for storing drying agents for reducing humidity of the generated hydrogen gas before flowing to the plurality of fuel cells; a plurality of acrylic plates (234, 236, 238) forming an acrylic sandwich separating the reaction chamber (252) from the cooling and gas storage chamber (258); a plurality of acrylic plates (260, 262, 264) forming an acrylic sandwich separating the cooling and gas storage chamber (258) from the piping section (266); a plurality of acrylic plates (246, 248, 250) forming an acrylic sandwich for closing the reaction chamber (252); a first gas outlet channel (224) for allowing movement of gas from the cooling and gas storage chamber to the plurality of fuel cells, the gas outlet channel further comprising a barb to ensure tight attachment of the connecting tubing; a second gas outlet channel (232) for allowing gas to move from the reaction chamber to the cooling and gas storage chamber; and a syringe barrel (230) for separating the reaction chamber (252) from the cooling and gas storage chamber (258) for allowing fuel to directly flow to the reaction chamber (252); characterized in that : the reaction chamber (252) further comprises: a catalyst bed (244) comprising catalyst positioned at a bottom part of the reaction chamber (252) that is lowered or elevated for initiating a reaction to generate hydrogen gas and water vapour; a plurality of mobile magnets (242) affixed to an outer wall of the enclosure (226) is further extended and held by solenoid actuators for lowering or elevating the catalyst bed to be in contact with metal hydride solution; and a refuelling channel port (204) for providing direct access to the reaction chamber through the cooling and gas storage chamber (258); further characterized in that: the drying chamber (290) comprises: a hydrophobic polymer membrane (292) positioned on a top compartment of the drying chamber (290) for preventing water, liquid impurities and particulates to enter the plurality of fuel cells; and a water collection unit (291 ) connected to a bottom compartment of the drying chamber (290) for collecting condensed water in the drying chamber (290).

2. The hydrogen generator (200) according to claim 1 , wherein the catalyst bed (244) comprises a catalyst that is ruthenium based, platinum based, cobalt based or nickel based or a combination thereof.

3. The hydrogen generator (200) according to claim 1 , wherein the plurality of acrylic plates (234, 238, 246, 250, 260, 264) have an outer layer of thickness of at least 2mm.

4. The hydrogen generator (200) according to claim 1 , wherein the plurality of acrylic plates (236, 248, 262) have an inner layer of thickness of at least 3mm.

5. The hydrogen generator (200) according to claim 1 , wherein the chemical hydride compound is selected from a group comprising of NaBH₄, LiH, NaH, AIH3, KH, CaH₂, AI(BH4)₃, LiBH₄ or LiAIH₄.

6. The hydrogen generator (200) according to claim 1 , wherein the coiled tubing (208) from the cooling and gas storage chamber (258) is made from polyurethane.

7. The hydrogen generator (200) according to claim 1 , wherein the cooling and gas storage chamber (258) comprises a pressure controller that detects an increase in pressure preferably between at least 300 to 400 kPa (3 to 4 bars).

8. The hydrogen generator (200) according to claim 1 , wherein the drying agent is preferably calcium chloride or silica gel desiccant.

9. The hydrogen generator (200) according to claim 1 , wherein the hydrophobic polymer membrane (292) is preferably polytetrafluoroethylene, PTFE.

10. The hydrogen generator (200) according to claim 1 , wherein the hydrophobic polymer membrane (292) is preferably polypropylene, PP.

11 . The hydrogen generator (200) according to claim 1 , wherein the hydrophobic polymer membrane (292) is preferably polycarbonate track etched, PTCE.

12. The hydrogen generator (200) according to claim 1 , wherein the hydrophobic polymer membrane (292) is preferably hydrophobic ceramic membrane.

13. The hydrogen generator (200) according to claim 1 , wherein the hydrophobic polymer membrane (292) is preferably non-sterile cellulose acetate membrane.

14. The hydrogen generator (200) according to claim 1 , wherein the hydrophobic polymer membrane (292) is preferably non-sterile cellulose nitrate membrane.