# US 11,999,620 B2 · Sorbent-enhanced processes for the reaction of fuel to produce hydrogen and related systems

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- Number: US 11,999,620 B2
- Document ID: US11999620B2
- Status: Granted
- Kind: B2
- Application number: 17/090,235
- Filed: 2020-11-05
- Published: 2021-05-13
- Granted: 2024-06-04
- Earliest claimed: 2019-11-07
- Assignees: Massachusetts Institute of Technology
- Applicants: Massachusetts Institute of Technology
- Inventors: Trevor Alan Hatton; Takuya Harada; Cameron G. Halliday
- Web page: https://patentgrep.com/patent/US11999620B2

## CPC

- C01B 3/38: using catalysts
- C01B 3/48: followed by reaction of water vapour with carbon monoxide
- B01D 53/62: Carbon oxides
- B01D 53/80: Semi-solid phase processes, i.e. by using slurries
- B01D 53/96: Regeneration, reactivation or recycling of reactants
- C01B 3/34: by reaction of hydrocarbons with gasifying agents
- C01B 3/384: with external heating of the catalyst
- C01B 3/56: by contacting with solids; Regeneration of used solids
- C01B 35/128: {containing plural metal or metal and ammonium}
- B01D 2251/302: of lithium
- B01D 2251/304: of sodium
- B01D 2251/60: Inorganic bases or salts
- B01D 2257/504: Carbon dioxide
- C01B 2203/0233: the reforming step being a steam reforming step
- C01B 2203/0283: containing a CO-shift step, i.e. a water gas shift step
- C01B 2203/0415: Purification by absorption in liquids
- C01B 2203/0475: the impurity being carbon dioxide
- C01B 2203/0811: by combustion of fuel
- C01B 2203/1241: Natural gas or methane
- C01B 2203/86: Carbon dioxide sequestration
- Y02C 20/40: of CO2
- Y02P 20/133: Renewable energy sources, e.g. sunlight
- Y02P 30/00: Technologies relating to oil refining and petrochemical industry
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Methods of using sorbents to enhance the production of hydrogen from fuel, and related systems, are generally described. In some embodiments, the production of hydrogen from the fuel involves a reforming reaction and/or a gasification reaction combined with a water-gas shift reaction.

## Claims

### Claim 1

A method, comprising:
exposing a molten sorbent comprising a salt in molten form to an environment containing a mixture of gaseous fuel and steam such that at least part of the mixture interacts with the molten sorbent and reacts to form hydrogen gas,
wherein the salt in molten form comprises boron and oxygen.

### Claim 2 (depends on 1)

The method of claim 1, wherein the salt in molten form comprises an alkali metal borate, AxB1-xO1.5-x, where A is an alkali metal, B is Boron, O is Oxygen, and x is a number such that 0<x<1.

### Claim 3 (depends on 2)

The method of claim 2, wherein the alkali metal comprises lithium (Li), sodium (Na), potassium (K), and/or a mixture of alkali metals.

### Claim 4 (depends on 3)

The method of claim 3, wherein the alkali metal comprises Li0.5Na0.5.

### Claim 5 (depends on 1)

The method of claim 1, wherein the gaseous fuel comprises natural gas, methane (CH4), and/or a hydrocarbon of the form CnH2n+2, where n is an integer number.

### Claim 6 (depends on 1)

The method of claim 1, wherein the mixture further comprises oxygen, nitrogen, and/or sulfur.

### Claim 7 (depends on 1)

The method of claim 1, wherein the steam is mixed with the gaseous fuel in a ratio of steam-to-carbon (S/C), where S/C is at least ½.

### Claim 8 (depends on 1)

The method of claim 1, wherein the environment is at a temperature of above 200° C.

### Claim 9 (depends on 1)

The method of claim 1, wherein the environment is at a pressure of above 1 bar.

### Claim 10 (depends on 1)

The method of claim 1, wherein the mixture reacts within a reactor, and a temperature of the reactor is maintained, at least in part, by an exothermic reaction between the molten sorbent and carbon dioxide.

### Claim 11 (depends on 1)

The method of claim 1, wherein the mixture reacts within a reactor, and a temperature of the reactor is maintained, at least in part, by an external energy supply.

### Claim 12 (depends on 11)

The method of claim 11, wherein the external energy supply comprises combustion of a fuel to generate heat.

### Claim 13 (depends on 11)

The method of claim 11, wherein the external energy supply comprises concentration of solar energy to generate steam.

### Claim 14 (depends on 2)

The method of claim 2, further comprising:
releasing the captured carbon dioxide in a gas phase to a second environment to upconcentrate the carbon dioxide and regenerate the molten sorbent.

### Claim 15 (depends on 14)

The method of claim 14, wherein the release is driven by a change in partial pressure, or a change in temperature, or both a change in partial pressure and a change in temperature, in the second environment.

### Claim 16 (depends on 1)

The method of claim 1, wherein the molten sorbent is mixed with a catalyst.

### Claim 17 (depends on 1)

The method of claim 1, wherein the salt in molten form further comprises an alkali metal.

### Claim 18 (depends on 1)

The method of claim 1, wherein the salt in molten form further comprises a plurality of alkali metals.

### Claim 19

A method, comprising:
reacting a fuel and water to produce hydrogen gas and carbon dioxide; and
exposing the carbon dioxide to a molten sorbent comprising a salt in molten form such that the molten sorbent captures at least a portion of the carbon dioxide.

### Claim 20 (depends on 19)

The method of claim 19, wherein the reacting and the exposing are conducted in a single vessel.

### Claim 21 (depends on 19)

The method of claim 19, wherein the reacting is conducted in a first vessel, and the exposing is conducted in a second vessel separate from the first vessel.

### Claim 22 (depends on 21)

The method of claim 21, wherein an inlet stream containing the hydrogen gas and the carbon dioxide is transported from the first vessel to the second vessel, and further comprising recycling a recycle stream, from the second vessel to the first vessel, wherein the recycle stream is enriched in hydrogen relative to the inlet stream and depleted in carbon dioxide relative to the inlet stream.

### Claim 23 (depends on 19)

The method of claim 19, wherein the salt in molten form comprises boron and oxygen.

### Claim 24 (depends on 23)

The method of claim 23, wherein the salt in molten form further comprises an alkali metal.

### Claim 25 (depends on 23)

The method of claim 23, wherein the salt in molten form further comprises a plurality of alkali metals.