# US 2021/0276864 A1 · System for generating h2s in an alkaline medium and method of using the same

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- Number: US 2021/0276864 A1
- Document ID: US20210276864A1
- Status: Published application
- Kind: A1
- Application number: 17/324,449
- Filed: 2021-05-19
- Published: 2021-09-09
- Earliest claimed: 2015-12-27
- Assignees: Clean Resources Pte. Ltd
- Applicants: Clean Resources Pte. Ltd.
- Inventors: Abraham Fouad Jalbout
- Web page: https://patentgrep.com/patent/US20210276864A1

## CPC

- C01B 3/04: by decomposition of inorganic compounds (reversible storage of hydrogen C01B3/0018)
- B01J 3/04: Pressure vessels, e.g. autoclaves
- B01J 7/02: by wet methods
- B01J 8/0005: {Catalytic processes under superatmospheric pressure (non-catalytic processes B01J3/00)}
- B01J 8/20: with liquid as a fluidising medium
- B01J 19/0013: {Controlling the temperature of the process}
- B01J 19/0066: {Stirrers (mixing per se B01F)}
- B01J 19/06: Solidifying liquids (making microcapsules B01J13/02)
- B01J 19/1862: {placed in series}
- C01B 17/161: {Preparation from elemental sulfur}
- C01B 17/165: {Preparation from sulfides, oxysulfides or polysulfides}
- C01D 5/00: Sulfates or sulfites of sodium, potassium or alkali metals in general {(sulfites in general C01B17/62)}
- B01J 2208/0007: Pressure measurement
- B01J 2208/00141: Coils
- B01J 2208/00176: outside the reactor
- B01J 2208/00212: Plates; Jackets; Cylinders
- B01J 2208/00283: involving reactant liquids
- B01J 2208/00592: Controlling the pH
- B01J 2219/00074: by indirect heating or cooling employing heat exchange fluids
- Y02E 60/36: Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C01D: COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides C01B17/22; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia and cyanogen, containing nitrogen and other non-metals C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; phosphides C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Method of producing hydrogen sulfide in an alkaline environment. A mixture having a sodium salt, elemental sulfur (S) and water is added to a reactor for the purpose of generating hydrogen sulfide (H2S) gas as the main product and sodium sulfate (Na2SO4) as a byproduct.

## Claims

### Claim 1

A method for producing hydrogen sulfide (H2S) gas, the method comprising:
placing elemental sulfur and a sodium salt solution comprising a sodium salt in water in a reaction vessel;
reacting the elemental sulfur with the sodium salt solution to form hydrogen sulfide (H2S) and sodium sulfate (Na2SO4);
removing the formed Na2SO4 from the reaction vessel;
crystallizing the Na2SO4 using a crystallizer;
reducing the crystallized Na2SO4 to produce Na2S;
forming a Na2S solution with the produced Na2S;
placing elemental sulfur and the Na2S solution in the reaction vessel; and
reacting the elemental sulfur with the Na2S solution to form hydrogen sulfide and sodium sulfate.

### Claim 2 (depends on 1)

The method of claim 1, wherein the reaction vessel is pressurized to a pressure ranging from about 500 psi to about 1500 psi and heated to a temperature ranging from about room temperature to about 400° C.

### Claim 3 (depends on 1)

The method of claim 1, wherein the reaction vessel is pressurized to a pressure ranging from about 500 psi to about 700 psi and heated to a temperature ranging from about 200° C. to about 300° C.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
pressuring the reaction vessel to a pressure of about 600 psi; or
heating the reaction vessel to a temperature ranging from about 230° C. to about 240° C.

### Claim 5 (depends on 1)

The method of claim 1, further comprising agitating the elemental sulfur and the sodium salt solution in the reaction vessel.

### Claim 6 (depends on 1)

The method of claim 1, wherein the crystallized Na2SO4 is reduced to produce Na2S by a carbothermal reduction system.

### Claim 7 (depends on 1)

The method of claim 1, further comprising reacting the formed hydrogen sulfide with an aqueous copper sulfate solution to form CuS for determining the effective yield of H2S.

### Claim 8 (depends on 1)

The method of claim 1, wherein the sodium salt is any one of sodium hydroxide (NaOH), sodium carbonate (Na2CO3), sodium hydrogen sulfide (NaHS), and sodium sulfide (Na2S).

### Claim 9 (depends on 8)

The method of claim 8, wherein the sodium salt is NaOH or Na2S.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
decomposing the hydrogen sulfide to produce hydrogen and elemental sulfur;
placing the produced elemental sulfur and a sodium salt solution comprising a sodium salt in water in the reaction vessel; and
reacting the produced elemental sulfur with the sodium salt solution to form hydrogen sulfide (H2S) and sodium sulfate (Na2SO4).

### Claim 11

A system for producing hydrogen sulfide (H2S) gas and sodium sulfate (Na2SO4), the system comprising:
a reaction vessel;
a sulfur feed source fluidically coupled with the reaction vessel;
a sodium salt solution feed source fluidically coupled with the reaction vessel;
a storage container fluidically coupled with the reaction vessel for storage of produced H2S gas;
a heat exchanger fluidically coupled with the reaction vessel for cooling a solution containing the Na2SO4 produced in the reaction vessel;
a crystallizer fluidically coupled with the heat exchanger for crystallizing the Na2SO4;
a Na2SO4 reduction system for reducing the crystallized Na2SO4 to form liquid Na2S; and
a container fluidically coupled with the reduction system for forming an aqueous Na2S solution, the container also being fluidically coupled with the reaction vessel.

### Claim 12 (depends on 11)

The system of claim 11, wherein the reaction vessel is configured to be pressurized to a pressure ranging from about 500 psi to about 1500 psi and heated to a temperature ranging from about room temperature to about 400° C.

### Claim 13 (depends on 11)

The system of claim 11, wherein the reaction vessel is configured to be pressurized to a pressure ranging from about 500 psi to about 700 psi and heated to a temperature ranging from about 200° C. to about 300° C.

### Claim 14 (depends on 11)

The system of claim 11, wherein the reaction vessel is heated by an internal heating element.

### Claim 15 (depends on 11)

The system of claim 11, wherein the reaction vessel is configured for agitation or stirring of the contents within the reaction vessel.

### Claim 16 (depends on 11)

The system of claim 11, wherein the Na2SO4 reduction system is a carbothermal reduction system.

### Claim 17 (depends on 11)

The system of claim 11, further comprising:
a first pump between the sulfur feed source and the reaction vessel; and
a second pump between the sodium salt solution feed source and the reaction vessel.

### Claim 18 (depends on 11)

The system of claim 11, further comprising an H2S decomposition reactor fluidically coupled with the storage container for decomposing the H2S to produce hydrogen and elemental sulfur.

### Claim 19 (depends on 18)

The system of claim 18, further comprising:
a hydrogen storage container fluidically coupled with the decomposition reactor for storing the produced hydrogen; and
a sulfur storage container coupled with the decomposition reactor for storing of the produced elemental sulfur and producing an aqueous sulfur solution therein.

### Claim 20 (depends on 19)

The system of claim 19, wherein the sulfur storage container is fluidically coupled with the reaction vessel.