Method of controlling rate of hydrogen release from metastable hydrogen carriers

Patent metadata

Field	Value
Publication number	US-11165083-B1
Application number	US-201916283454-A
Country	US
Kind code	B1
Filing date	Feb 22, 2019
Priority date	Aug 26, 2016
Publication date	Nov 2, 2021
Grant date	Nov 2, 2021

Abstract

According to an embodiment of the present disclosure, a method of controlling a rate of hydrogen release from a decomposition reaction of a hydrogen carrier includes: relating the rate to a temperature and a composition of the metastable hydrogen carrier; determining the composition of the metastable hydrogen carrier; and adjusting the temperature according to the relating of the rate and the determining of the composition.

First claim

What is claimed is:

1. A method for controlling a rate of hydrogen release from a metastable hydrogen carrier according to a rate relation, the method comprising:
determining a target rate of hydrogen release r i at t i in one of a first or second act, t representing time and i being an integer;
determining a composition x i of the metastable hydrogen carrier at t i in another one of the first or second act;
determining a required temperature at t i according to the rate relation in a third act;
adjusting a temperature of the metastable hydrogen carrier to the required temperature in a fourth act; and
repeating the first through the fourth acts for a subsequent t i+1 ,
wherein the rate relation determines the required temperature according to the target rate of hydrogen release and the composition of the metastable hydrogen carrier,
wherein the composition of the metastable hydrogen carrier is an amount of hydrogen already released by the metastable hydrogen carrier divided by a total amount of hydrogen in the metastable hydrogen carrier in a pristine condition,
wherein the metastable hydrogen carrier comprises a metastable metal hydride comprising alpha aluminum hydride (α-AlH 3 ) surrounded/encapsulated by a surface oxide and/or hydroxide passivation layer, and
wherein hydrogen is released by decomposing the metastable hydrogen carrier in an endothermic or thermal neutral reaction.

2. The method of claim 1 , wherein the determining the target rate of hydrogen release comprises determining a desired load of a power system, the power system utilizing the hydrogen from the metastable hydrogen carrier as a fuel.

3. The method of claim 2 , wherein the determining the desired load of the power system comprises measuring a current draw of a fuel cell.

4. The method of claim 1 , wherein the determining the composition of the metastable hydrogen carrier at t i+1 in the repeating of the first through the fourth acts for the subsequent t i+1 comprises:
calculating a product of the rate of hydrogen release r i and (t i+1 −t i ); and
adding the product and x i to obtain x i+1 .

5. The method of claim 2 , wherein the rate relation is determined by:

T
=

[

-

R

E
a

⁢

⁢

ln
(

r

r

0
⁢
0

+

A
0

(

x
-

x
0

)

2

+
B

)

]

-
1

,

Equation
⁢

⁢
2

wherein in Equation 2, r represents the target rate, T represents the required temperature, R is the gas constant, E a represents activation energy in unit of KJ/mol, r 00 and A 0 each represent a pre-exponential constant, B represents a temperature independent constant, and x 0 is an initial composition of the metastable hydrogen carrier, and
wherein E a , r 00 , A 0 , x 0 and B are determined utilizing numerical fits to isothermal cumulative or fractional decomposition curves over a range of temperatures.

6. The method of claim 5 , further comprising:
determining an initial composition of the metastable hydrogen carrier prior to the first act at t 1 ; and
utilizing the initial composition of the metastable hydrogen carrier as the composition of the metastable hydrogen carrier at t 1 in the determining of the composition of the metastable hydrogen carrier in the other one of the first or second act.

7. The method of claim 6 , wherein the determining of the initial composition of the metastable hydrogen carrier comprises:
heating the metastable hydrogen carrier by applying a chosen temperature profile;
measuring a rate of hydrogen release corresponding to the chosen temperature profile; and
determining the initial composition of the metastable hydrogen carrier according to Equation 2.

8. The method of claim 7 , wherein the chosen temperature profile is a constant temperature step, a plurality of constant temperature steps, a linear ramp, a sine wave, or a combination thereof.

9. The method of claim 2 , wherein the rate relation is determined by:

T
=

[

-

R

E
a

⁢

ln
(

r

Assignees

• Hrl Lab Llc

Inventors

• Graetz Jason A
• Vajo John J

Classifications

• Y02T90/40

  Application of hydrogen technology to transportation, e.g. using fuel cells · CPC title

• Y02E60/36

  Hydrogen production from non-carbon containing sources, e.g. by water electrolysis · CPC title

• H01M8/04425

  at auxiliary devices, e.g. reformers, compressors, burners · CPC title

• C01B3/04 Primary

  by decomposition of inorganic compounds (reversible storage of hydrogen C01B3/0018) · CPC title

• Y02E60/50

  Fuel cells · CPC title