System and process for generating hydrogen

Abstract

A system is capable to safely generate a continuous controlled hydrogen flow. The passive auto sufficient hydrogen system is very valuable for example for emergency power back up, propulsion application, battery charging or powering portable devices. Also, a chemical process generates hydrogen using alkali metals, alkaline earth metals, hydrides of alkali metals or hydrides of alkaline earth metals to obtain primary by products from water. Then, the primary byproducts react with a metal reactant to obtain additional hydrogen.

Claims

1. A system for generating hydrogen from water comprising: (a) a structural material to support: a primary reactant in a solid state selected from the group consisting of alkali metals, alkaline-earth metals, alkali-alkaline earth metal alloys, hydrides of alkali metals, and hydrides of alkaline earth metals, and; a boost reactant in a solid state selected from the group consisting of tin, iron, zinc, manganese, aluminum, berylium, magnesium or alloy between them; (b) a moderator material which is in contact with the structural material, wherein the moderator material is a phase-change material (PCM) selected from the group consisting of salt hydrates, metals, salts, and eutectic mixtures, or a material able to release primary or secondary by-products when temperature is increased selected from the group consisting of nanostructured materials, and zeolites; and (c) a diffuser material wherein the system is configured such that water is diffused before reacting with the primary reactant and such that the hydrogen obtained is permeated.

2. A process for generating hydrogen from water in a chain reaction, comprising: (a) reacting liquid water at room temperature with a primary reactant in a solid state selected from the group consisting of alkali metals, alkaline-earth metals, alkali-alkaline earth metal alloys, hydrides of alkali metals, and hydrides of alkaline earth metals in solid state, to obtain the corresponding hydroxide as primary by products in presence of a phase-change material (PCM) selected from the group consisting of salt hydrates, metals, salts, and eutectic mixtures, or a material able to release primary or secondary by-products when temperature is increased selected from the group consisting of nanostructured materials, and zeolites; (b) reacting the hydroxide obtained in said a) with water and with a boost reactant in a solid state selected from the group consisting of tin, iron, zinc, manganese, aluminum, berylium, magnesium or alloy between them in solid state to obtain additional hydrogen and an oxide as secondary by-products; (c) separating hydrogen from residual reaction product; and (d) collecting the hydrogen.

3. The system for generating hydrogen from water according to claim 1, wherein the moderator material comprises barium salts.

4. A process for generating hydrogen from water in a chain reaction, comprising (a) reacting liquid water at room temperature with a primary reactant in a solid state selected from the group consisting of alkali metals, alkaline-earth metals, alkali-alkaline earth metal alloys, hydrides of alkali metals, and hydrides of alkaline earth metals in solid state, to obtain the corresponding hydroxide as primary by products in presence of a phase-change material (PCM) selected from the group consisting of salt hydrates, metals, salts, and eutectic mixtures, or a material able to release primary or secondary by-products when temperature is increased selected from the group consisting of nanostructured materials, and zeolites; (b) reacting the hydroxide obtained in said a) with water and with a boost reactant in a solid state selected from the group consisting of silicon, tin, iron, zinc, manganese, aluminum, berylium, magnesium or alloy between them in solid state to obtain additional hydrogen and an oxide as secondary by-products; (c) separating hydrogen from residual reaction product; and (d) collecting the hydrogen, wherein the moderator material comprises barium salts.

5. The system of claim 1, wherein the primary reactant further comprises a potassium/sodium alloy.

6. The system of claim 1, wherein the primary reactant further comprises a 5/95 Li/Na alloy.

7. The process for generating hydrogen from water in a chain reaction according to claim 2, wherein the primary reactant further comprises, a potassium/sodium alloy.

8. The process for generating hydrogen from water in a chain reaction according to claim 2, wherein the primary reactant further comprises a 5/95 Li/Na alloy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a flow diagram of the system of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(2) As mentioned above, another aspect of the present invention relates to a system for generating hydrogen from water comprising: (a) a structural material to support:

(3) a primary reactant in solid state selected from: alkali metals, alkaline-earth metals, alkali-alkaline earth metal alloys, hydrides of alkali metals or hydrides of alkaline earth metals and;

(4) a boost reactant in solid state selected from: silicon, tin, iron, zinc, manganese, aluminium, iron, berylium, magnesium or alloy between them;

(5) (b) a moderator material which is in contact with the structural material

(6) (c) a diffuser material wherein the water is diffused before reacting with the primary reactant and wherein the hydrogen obtained is permeated.

(7) In a preferred embodiment the structural material is selected from inorganic solid metal, oxide, salt, graphite, sulphur and steel. Alkali metal hydroxides and alkaline earth metal hydroxides are known to be strongly corrosive. Therefore, in a particular embodiment the structural material is steel.

(8) In a preferred embodiment the moderator material is selected from a phase change material (PCM) like salt hydrates, metals, salts, eutectics compound or any material able to release primary or secondary by-products when temperature increase like nanostructured materials, inorganic sorbent material, zeolites and so on. In a preferred embodiment the moderator is barium salts.

(9) Diffuser material can be any porous material with diffusion properties like synthetized steels, metal membranes between others. Diffuser material is inert or compatible with reactants, by-products, water and hydrogen.

(10) As mentioned above, an aspect of the present invention relates to a process for generating hydrogen from water in a chain reaction which comprises the steps of:

(11) (a) reacting water with primary reactant selected from: alkali metals, alkaline-earth metals, alkali-alkaline earth metal alloys, hydrides of alkali metals or hydrides of alkaline earth metals in solid state, to obtain the corresponding hydroxide as primary by products;

(12) (b) reacting the hydroxide obtained in the step a) with water and with a metal selected from: silicon, tin, zinc, manganese, aluminium, iron, berylium, magnesium or alloy between them in solid state to obtain additional hydrogen and an oxide as secondary by products;

(13) (c) separating hydrogen from residual reaction product

(14) (d) collecting the hydrogen.

(15) In a preferred embodiment the alkali and alkaline earth metal is selected from: Li, Na, K and Mg, preferred suitable metal reagents are Na and Li, and a particularly preferred is Na due that has a relatively low melting point and is abundant. An especially interesting alloy is 5/95 Li/Na alloy which has an energetic intensity that is higher than that of Na alone and a melting point (=89° C.) that is 10° C. lower than that of Na, Other useful alloys comprise, for example, potassium and sodium such as 56/44 Na/K alloy the melts at 6.8° C., or lithium and strontium such as 12/88 Li/Sr alloy that melts at 132° C.

(16) The efficiency of the process of the invention is at least of 90%.

Example

(17) The example is prepared as follows:

(18) Reactants and Material

(19) reactants: sodium metal; ferrosilicon; structural material: steel foil moderator: CuSO.sub.4+BaCl.sub.2+NH.sub.4Cl; mesh: Steel SS304 mesh The reactions developments were the following:
Na+H.sub.2O.fwdarw.NaOH+½H.sub.2  1.
3Fe+4H.sub.2O.fwdarw.Fe.sub.3O.sub.4+4H.sub.2
2NaOH+Si+H.sub.2O.fwdarw.Na.sub.2SiO.sub.3+2H.sub.2  2.

(20) Reaction of the Phase Change Material
BaCl.sub.2+NaOH.fwdarw.Ba(OH).sub.2+NaCl (it is removing hydroxides from reaction media)
Ba(OH).sub.2.8H.sub.2O(s)+2NH.sub.4Cl(s).fwdarw.2NH.sub.3(g)+10H.sub.2O(l)+BaCl.sub.2(s) (very endothermic)
CuSO.sub.4+4NH.sub.3+H.sub.2O.fwdarw.[Cu(NH.sub.3).sub.4]SO.sub.4. H.sub.2O (secuestrating NH.sub.3)
the total weight of the different elements were the following:

(21) 50 g Na metal

(22) 50 g Si metal

(23) 200 g Fe metal

(24) 75 g BaCl.sub.2

(25) 35 g NH.sub.4Cl

(26) 210 g CuSO.sub.4

(27) Steel foil: 90 g

(28) Steel SS304 mesh: 14 g

(29) TOTAL WEIGTH: 724 g

(30) Hydrogen generated (weight): 13 g H.sub.2

(31) Hydrogen generated (volume): 145.6 SL

(32) Energy stored: 433.33 Wh

(33) Gravimetric energy density: 724 Wh/Kg

(34) Minimum water needed for reaction: 125 g