GB2505202A

GB2505202A - A hydrogen generation unit

Info

Publication number: GB2505202A
Application number: GB1214911.8A
Authority: GB
Inventors: Mark Robert Nailis
Original assignee: INOVA POWER Ltd
Current assignee: INOVA POWER Ltd
Priority date: 2012-08-21
Filing date: 2012-08-21
Publication date: 2014-02-26
Also published as: GB201214911D0

Abstract

A hydrogen generator unit 1 is disclosed which includes two chambers 2, 3 in a cartridge unit which are separated by a hydrogen-permeable membrane 4, wherein a reactant such as aluminium, aluminium oxide, calcium, magnesium, sodium, borides, potassium, zinc, titanium or sodium silicide is reacted with water to generate hydrogen in a first chamber which then passes across the membrane to the second chamber. The water can be drawn into the first chamber by a mechanically-created vacuum in the second chamber. The generator unit further includes an arrangement for the connection and continued hydrogen supply to a separate power conversion unit. Also disclosed are methods of generating hydrogen.

Description

HYDROGEN GENERATOR UNIT AND METHOD OF GENERATING HYDROGEN

Technical field of invention

The present invention relates to Hydrogen generator units, suitable for use in standalone energy systems or for use in on-vehicle systems in conjunction with either a fuel cell or an internal combustion engine. Moreover, the invention relates to methods of using the aforesaid systems for generating Hydrogen gas.

Background to the invention

Hydrogen is a well known energy vector which has many practical uses within chemical and energy industrial sectors. These practical uses require Hydrogen to be generated from chemical compounds which are in Hydrogen via one or more process steps, for example steam methane reformation of hydrocarbon fuels or via electrolysis of water. Hydrogen generated from aforesaid one or more process steps can be utilized to fuel numerous applications: (i) for fuel for micro energy systems (e.g. battery replacements); (H) for emergency power supply systems; and (Hi) for vehicle propulsion.

In portable applications, one or more additional process steps are required in addition to a step of Hydrogen generation, wherein the one or more additional steps concern Hydrogen storage and supply logistics. As the lightest know element, Hydrogen often requires extensive external equipment and energy input to achieve practical energy densities appropriate for use in transportation or in portable systems markets for Hydrogen units. Often bulky, high-pressure tanks limit the application of Hydrogen in vehicle propulsion systems. Other methods of Hydrogen supply, via Hydrogen pipelines, require significant infrastructure, currently restricted to a few geographical locations globally.

In an alternative approach for achieving high densities of Hydrogen storage, Hydrogen is often stored within a metal hydride wherein Hydrogen molecules are disassociated into individual hydrogen atoms that are able to absorb or dissolve into a metal phase. In a yet further approach, Hydrogen is stored cryogenically as liquid Hydrogen, or at a high pressure in gaseous form, for example in vehicle applications.

In the case of contemporary fuel cell or Hydrogen internal combustion powered vehicles, Hydrogen is commonly stored at pressures of up to 70MPA, for example within specially prepared composite Aluminium and Carbon fibre tanks. High pressure storage is required primarily to give comparable energy densities to that of existing hydrocarbon liquid or gaseous fuels.

It is known to employ metallic composite materials to generate Hydrogen through reaction with water. In a United States patent no. US3957483 issued on 18 May 1976 to M. Suzuki, it is disclosed how a Magnesium composition is utilized for producing Hydrogen. This document elucidates that the presence of one or more elements selected from the group consisting of Sodium Chloride (NaCI), Potassium Chloride (KCI) and various similar metal salts leads to an increase in a quantity of Hydrogen gas generated. This type of solution allows for somewhat more convenient handling of the composite prior to use in a reaction to generate Hydrogen gas.

Similarly, in a United States patent no. US 6506360, there is described a system which utilizes a reaction of Aluminum with water in the presence of Sodium Hydroxide as a catalyst. The system uses a pressure and a temperature of the reaction to control a degree of immersion of a fuel cartridge in water and consequently to control a vigor and a duration of the reaction. The fuel cartridge exemplified has a volume of about 1 liter, contains about 500 ml of Magnesium composition, and is submersed in 10 liters of water for allowing for 2 hours of Hydrogen gas generation which is sufficient for cooking food on a burner plate. A control of the temperature of the water and a degree of immersion of the fuel cartridge in the water can become complicated if utilization in any type of portable solution is intended.

In a published international PCT patent application no. WO 0174710, there is described a manner in which a Hydrogen generation system employs a wicking material to control a contact between a mixture of fuel contained in a fuel tank and a hydrolysing catalyst supply of Hydrogen. The system is portable but requires a complex feedback mechanism for automatically maintaining a constant pressure for Hydrogen-generating reactions.

In addition, Hydrogen and fuel cell systems have also been developed for use onboard electric vehicles for range extension purposes. Such systems provide a way of charging batteries during vehicle operation, thus extending the range of such vehicles. The storage of Hydrogen in such vehicle application therefore requires extensive ancillary equipment which increases vehicle weights.

Summary of the invention

The present invention seeks to provide a Hydrogen generator unit for improving storage and generation of Hydrogen gas on demand.

According to a first aspect of the present invention, there is provided a Hydrogen generator unit as claimed in appended claim 1: there is provided a Hydrogen generator unit for generating low-pressure Hydrogen from water, characterized in that the generator unit includes: a structural housing and replacement cartridge which contains separate reaction chambers for: the extraction of Hydrogen generated from water in an exothermic reaction from a chemical reactant, and an expandable Hydrogen buffer storage unit for the temporary storage of the Hydrogen generated.

Separation of the two chambers in the cartridge is via a hydrophobic membrane. In the system, via an mechanical generated vacuum, the Hydrogen generator is able to start and stop the production of Hydrogen on demand. The stop and start process is achieved through the use of the vacuum to control the level of water within the reaction chamber and associated pressure in the Hydrogen storage buffer.

Optionally, the Hydrogen generator unit is implemented, such that the cartridge-based system is operable to receive replaceable cartridges for providing reactants for the extraction chemical process. More optionally, the replaceable cartridges include reactants comprising at least one of: Aluminium Oxide, Calcium, Magnesium, Sodium, Borides, Titanium, Sodium Silicide and Potassium.

Optionally, the Hydrogen generator unit is implemented so that the cartridge system includes at least two cartridge sections, preferably three or more sections, for allowing for re-fuelling mechanism of the system once the energy material in each cartridge section has been used.

Optionally, the Hydrogen generator unit is implemented to provide hydrogen for a fuel cell system so that the fuel cell is operable to generate clean water by way of a chemical reaction within the fuel cell, wherein said generator unit is adapted so that said water is re-circulated for use in the extraction chemical process for generating low-pressure Hydrogen.

Optionally, the Hydrogen generator unit is implemented so that the fuel cell is operable to generate clean water by way of a chemical reaction within the fuel cell, wherein said generator unit is adapted so that said water is extracted for drinking or agriculture use.

According to the second aspect of the invention the Hydrogen Generator is incorporated within a fuel cell system balance of plant, allowing for automated control of the start and stop of Hydrogen generation. This is achieved by the creation of a controlling vacuum in the Hydrogen feed line. The vacuum being created by the actions of fuel cell balance of plant, flow controller, which feed Hydrogen to the fuel cell system.

Optionally the vacuum in the Hydrogen feed line is created by the actions of balance of plant needed to operate an Internal combustion engine. The Hydrogen generator unit is controlled via the creation of a vacuum in the expandable Hydrogen storage unit as a result of start stop of an internal combustion engine fuel injection system.

According to a third aspect of the invention, the Hydrogen generator incorporates a separate pressure cartridge to provide a means for providing a neutralising agent during shut down conditions. The separate cartridge is connected to the water feed of the Hydrogen generator's cartridge reaction chamber. The separate cartridge incorporating Carbon Dioxide as a means for providing a chemical neutralisation process for used reactants.

Optionally, the separate cartridge incorporates an extract of an internal combustion engine exhaust gas stream as a means for providing a chemical neutralisation process for used reactants.

Description of the diagrams

Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein: FIG. la is an exploded part view of the Hydrogen generator unit, viewed from underneath; FIG. lb is an exploded part view of the Hydrogen generator unit, viewed from above; FIG. 2a is a sectional view along the line A-A shown detailed on FIG 2b; FIG. 2b is a partial side of the Hydrogen generator unit with its side housing removed; FIG. 2c is a protected top view of the Hydrogen generator unit; FIG. 3 is a view of a simplified section of the Hydrogen generator to illustrate hydrogen a production cycle occurring within the Hydrogen generator; FIG. 3a is a view of a start position of the Hydrogen generator after loading of the cartridge; FIG. 3b is a view of a start of Hydrogen production in the Hydrogen generator; FIG. 3c is a view of a temporary storage of Hydrogen gas generated and an end of an initial reaction cycle; and FIG. 4 is a view of a simplified multiple cartridge loading system for the Hydrogen generator.

In the accompanying diagrams, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

Description of embodiments of the invention

Referring to FIG Ia, there are shown individual parts of a Hydrogen generator unit from an upward viewing position from ground, and, in FIG Ib, there is shown the parts of the Hydrogen generator unit I from a higher viewing position looking towards the ground. The Hydrogen generator unit comprises two major components, namely a structural outer housing 6 and a replaceable cartridge. The cartridge is separable into 3 parts, namely a part I is an expandable Hydrogen storage unit, a part 2 is a lower cartridge housing unit with four supports posts, a part 3 is an upper cartridge housing which sits above the housing unit 2 and is movable in the horizontal along the four support posts and a part 4 which is a hydrophobic separator membrane. The expandable Hydrogen storage unit is manufactured from a non-porous Hydrogen barrier material and is joined to the lower housing unit 2 and upper cartridge housings, as shown in FIG 2a as a section view on the line A-A section on FIG 2b.

The part 4, namely the hydrophobic separator membrane, is located inside the expandable Hydrogen storage unit I and in between the upper cartridge housing 3 and the lower cartridge housing 2 in such as way to allow a flow of Hydrogen but preventing any crossing of any liquid, in this case water. Moreover, there are also shown in FIG Ia and FIG lb an outer housing side panel II, a lower water feed valve 8 and its housing 7, a micro gas valve 10 and a connecting Hydrogen outlet pipe 9.

In FIG 2b, there are shown by location a manner in which the replaceable cartridge is positioned once loaded in to the Hydrogen generator I. Loading of the replacement cartridge requires the outer housing side panel II to be removed, and the replacement cartridge to be manual or automatic loaded via a central fixing, namely as shown in FIG 2c and FIG 4 respectfully.

A composite material is employed as a source to generate Hydrogen gas when in contact with water, wherein water acts as a Hydrogen source during an associated reaction. The composite material is loaded into a space between the replacements lower housing 2 and the hydrophobic separator membrane 4. The composite material is preferably manufactured from Aluminum Oxide but can also be manufactured from other compounds such as Calcium, Magnesium, Sodium, Borides, Potassium Titanium, and others known to the person technically skilled in the art. The following formulae provide examples of chemical processes that are employed to generate Hydrogen and heat from an exothermic reaction with water: 2NaSi (s) + 5H20 (I) -* Na2Si2O5 (aq.) + 5H2 + Heat (-175 kJ/mol).

In this case the reaction above, there is produced rapidly five moles of Hydrogen from a reduction of five moles of water and only two moles of NaSi by way of an exothermic reaction. As Sodium Suicide is pyrophoric, the cartridge system containing this powder is beneficially sealed using an air tight membrane prior to use to prevent any incident of fire resulting from contact with air.

Operation of the Hydrogen generator I is shown in FIG 3, which is a simplified cross-sectional view on line A-A as shown on FIG 2b.

A replacement cartridge is loaded into the Hydrogen generator housing 6 by being positioned centrally and fixing into place in a small recess between a base of the replacement cartridge lower housing 2 and with the water feed valve housing 7. This action pierces a plastic film seal covering a water intake hole in the replacement cartridge's lower housing 2. The loading of the cartridge is shown in FIG 3a. The position of the composite material, within the replacement cartridge, is indicated by the solid black rectangle 12. During loading, both the water feed valve 8 and the lower Hydrogen micro valve 10 are closed. This is to prevent air or water from entering the replacement cartridge which has had all air initially removed via a vacuum during manufacture. The upper housing 3 of the replacement cartridge is pulled up vertically and fixed to a fixing point in the Hydrogen generator's outer housing 6. The outer housing 6 is connected to the outer Hydrogen pipe 9 and to the Hydrogen micro valve 10. The action of fixing the upper housing 2 to the Hydrogen generator outer housing 6 stretches the expandable Hydrogen storage unit I and creates a vacuum within the replacement cartridge. This vacuum is sufficient to pump water from the water reservoir 14 up into the lower chamber of the replacement cartridge's lower housing 2. The vacuum is sufficient to pump enough water to cover the position of the composite power 12, as illustrated in FIG 3b. The water is prevented from entering the upper chamber of the expanded Hydrogen storage unit I by the position of the hydrophobic separator membrane 4. The Hydrogen reaction cleaves Hydrogen atoms from corresponding water molecules, wherein the Hydrogen atoms are buoyant and are of a sufficiently small size to enable them to pass through the membrane to the upper chamber of the replacement cartridge and to fill the expandable Hydrogen storage unit. The chemical reaction between the composite material and the water in the lower chamber continues until all water has been reacted and corresponding Hydrogen produced. A build-up of pressure in the expandable storage unit I is measured by a pressure sensor in the hydrogen micro valve 10. The lower valve in the Hydrogen micro valve 10 remains closed until pressure reaches a set point. At the set point, the lower valve will open and allow Hydrogen generated and stored in the expandable Hydrogen storage unit I to pass either to a separate storage unit or to an energy conversion device 13, as illustrated in Fig 3c. The release of this Hydrogen creates a new partial vacuum which is sufficient to pump more water into the lower chamber, thereby re-initiating the Hydrogen producing reaction, as illustrated in FIG 2b. Continued production of Hydrogen will occur in such a batch process until all the reactant in the composite material has been used. The pressure difference between the reaction chambers in the cartridge can therefore be used to achieve a start-and-stop functionality of Hydrogen generation.

In Fig 4, there is shown a simplified automated mechanism to replace multiple cartridges in a fuel cell system. The system utilizes power generated from a parasitic load of the energy conversion device 13 implemented as a fuel cell, or from any other suitable power conversion device. Each replacement cartridge is loaded and ejected after a prefixed number of operating cycles. Replacement cartridges are positioned above one another in a magazine belt 16 and are loaded by an upward movement of the belt. This secures the replacement cartridge to a fixed point connected to the Hydrogen micro valve 10 and connects and water supply to the cartridge via a two-way water valve 17. The replacement cartridge is then moved down by action of a downward movement of the magazine belt 16, wherein the movement has an effect of stretching the expandable Hydrogen storage unit I and pumping water into the reaction chamber as previously shown in FIG 3a. Extractionof the replacement cartridge is achieved by the partial movement of the magazine belt 16 downwards and tan action of an ejection piston controlled by a solenoid 15. Such action positions the spent replacement cartridge under a gas cylinder 18 containing a neutralizing agent for the left over reactant used in the generation of Hydrogen. The agent is injected through the water connection point in the lower housing of the reaction cartridge.

Furthermore, the applications of the Hydrogen generator unit I encompass from in an order of 1W to 500W output systems for portable electronic devices, to in an order of 500W to 10kW output for bigger systems. Additionally, the cartridge loaded with 1 kg (the typical size of a single cartridge) of fuel element/composite material is capable of producing 1500 litres of Hydrogen or 134g of Hydrogen. Alternatively, 10 kg (10 nominal cartridges) of the composite material will therefore generate 1.34kg of Hydrogen, equating to 45 kWhr of power. Converted to electricity through a fuel cell, this hydrogen (assuming an industry standard fuel cell operating with an energy efficiency of 50%) is capable of producing 22.5 kWhr of electricity. The element/composite therefore would be comparable to an industry standard 24 kWhr Lithium Ion battery pack. Such a pack when used to power an electric vehicle would give a range of 100 miles and therefore is highly desired by within the motor industry.

Simple manual cartridge replacement loaded into a magazine arrangement feed from a separate on board water supply would therefore provide an additional 100 mile range.

Hydrogen is also suitable for use within a fuel cell energy system. The injection of Hydrogen gas into an internal combustion engine cleans up exhaust emissions from the engine by more than 25% compared to conventional ICEs; considerable output soot reduction and NOX reduction is potentially feasible to achieve by employing the present invention.

In Fig. 4, there is also illustrated a water collection arrangement which extracts water generated by the fuel cell 12 and recycles this water into a separate water storage tank 13. Prior to starting the reaction, it is necessary to remove air in the cartridge unit I to avoid explosive mixtures of Hydrogen and air arising.

The utilization of an aforementioned replacement cartridge setup for the present invention allows for a very compact and user-friendly solution for numerous applications such as portable units, vehicle Hydrogen generation units, or even for stationary units which need a safe and easy disposal of residual waste from the Hydrogen reaction within the cartridges. The residue in the cartridges is often of alkaline nature with a pH value in the range of 8 to 14, but most often with a pH value in a range of 9 to 11. This residue, namely a waste product, is today a major drawback for Hydrogen generator systems, but the cartridge system can be designed to supply the unit I with a right amount of composite material for implementing the invention. It allows for safe disposal or return of the cartridge for safe disposal or treatment by acids or other pH lowering methods; the residue can be used, for example, to treat acidic Sulfurous gaseous emissions from coal-burning facilities, for example coal-burning power stations. An alternative embodiment uses Carbon dioxide (C02) for scrubbing of the residue composite material in a used cartridge Ito lower the pH. A Carbon dioxide unit is then connected to the cartridge via the lower water feed valve 8 or the Hydrogen micro valve 10 allowing Carbon dioxide to be in contact with the residue composite material and lower the pH of the residue.

Beneficially, the cartridge I is capable of being cleaned and refilled, therefore rendering recycling possible. The cleaning of the cartridge is shown in FIG 4. A separate cylinder 14 containing a neutralizing agent is connected to the lower housing of the spent cartridge and injected in to the lower chamber of the replacement cartridge. The cartridge unit could also be used in a large number of applications where Hydrogen gas is to be produced such as laboratory hydrogen, miniature propulsion units, marine applications, off-grid power generation, oxygen generation units, and water generation units Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "consisting of", "have", "is" used to describe and claim the present invention are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.

Claims

CLAIMS1. A Hydrogen generator unit including a replacement cartridge unit for generating low-pressure Hydrogen from water, characterized in that the generator unit includes two reaction chambers which are adapted to employ an extracting chemical process to generate low-pressure Hydrogen from water in an exothermic reaction in a cartridge-based system, wherein the cartridge-based system has a membrane separating the two reaction chambers, and wherein the cartridge unit has a start-and-stop functionality.
2. A Hydrogen generator unit as claimed in claim 1, wherein the Hydrogen generation start-and-stop is controlled by means of a mechanically-generated vacuum within a two chamber replacement cartridge.
3. A Hydrogen generator unit as claimed in claim 1 or 2, wherein the Hydrogen generation start-and-stop is controlled by means of a pressure difference between the two chambers of the replacement cartridge.
4. A Hydrogen generator unit as claimed in any one of claim 1, 2 or 3, wherein the Hydrogen generation start-and-stop is controlled by the supply of water to the composite material in at least one of the reaction chambers.
5. A Hydrogen generator unit as claimed in any one of the preceding claims, wherein the replacement cartridge has associated therewith an expandable Hydrogen storage unit to compress the generated Hydrogen in a continuous cycle.
6. A Hydrogen generator unit as claimed in any one of the preceding claims, wherein a fuel cell is operable to generate clean water by way of a chemical reaction within the fuel cell, wherein said water generator unit is adapted so that said water is recirculated for use in the extraction chemical process for generating low-pressure Hydrogen.
7. A Hydrogen generator unit as claimed in any one of the preceding claims, wherein the Hydrogen generator unit is adapted for use in an on-vehicle system.
8. A Hydrogen generator unit as claimed in any one of the preceding claims, wherein the cartridge-based system is operable to receive replaceable cartridges for providing reactants for the extraction chemical process.
9. A hydrogen generator unit as claimed in any one of the preceding claims, wherein the replaceable cartridges include reactants comprising at least one of: Aluminium, Aluminium Oxide, Calcium, Magnesium, Sodium, Borides, Potassium, Zinc, Titanium, or Sodium Silicide.
10. A Hydrogen generator unit as claimed in any one of the preceding claims, wherein the cartridge-based system has separate sections for storing an energy material used to extract Hydrogen gas from water.
11. A Hydrogen generator unit as claimed in any one of the preceding claims, wherein the cartridge system includes at least two cartridge sections for allowing for re-fuelling mechanism of the system once the energy material in each cartridge section has been used.
12. A Hydrogen generator unit as claimed in claim 11, wherein the cartridge system includes three or more sections.
13. A method of generating using a Hydrogen generator unit including a compression unit for generating low-pressure Hydrogen from water, characterized in that said method includes: providing a replacement cartridge unit including one or more composite materials, and which is connected to a water storing means, said replacement cartridge unit being operable to generate Hydrogen; characterized in that said method further includes supporting, using said replacement cartridge's lower housing, an exothermic reaction involving the one or more composite materials and water supplied from the water storing means to generate the Hydrogen, wherein one or more composite elements are enclosed in the replacement cartridge's lower housing unit which is adapted to be disposed of or recycled after use in the Hydrogen generator unit.
14. A method as claimed in claim 13, further including using a cassette arrangement for automatically loading and extracting the replacement cartridge unit without user intervention or contact with chemicals included in the Hydrogen generator.
15. A method as claimed in any one of claim 13 or 14, wherein providing a fuel cell or power conversion device for receiving generated Hydrogen from the replacement cartridge's expandable Hydrogen storage unit via a Hydrogen micro valve.
16. A method of generating Hydrogen from a hydrogen generator unit, wherein the method includes employing a replacement cartridge unit which includes two separate chambers which can be connected to a water storing means (13), and also temporary store and arrangement to compress generated Hydrogen.