# US 10,369,513 B2 · Methods for methane purification

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- Number: US 10,369,513 B2
- Document ID: US10369513B2
- Status: Granted
- Kind: B2
- Application number: 15/696,946
- Filed: 2017-09-06
- Published: 2018-03-22
- Granted: 2019-08-06
- Earliest claimed: 2008-10-17
- Applicants: Alchem Environmental IP LLC
- Inventors: John R. Pease; John F. Blatnick
- Web page: https://patentgrep.com/patent/US10369513B2

## CPC

- B01D 53/18: Absorbing units; Liquid distributors therefor (B01D3/16, B01D3/26, B01D3/30 take precedence; packing elements B01J19/30, B01J19/32)
- B01D 53/1462: {Removing mixtures of hydrogen sulfide and carbon dioxide}
- B01F 23/10: Mixing gases with gases
- B01F 23/21322: {Internal mixer atomization, i.e. liquid and gas are mixed and atomized in a jet nozzle before spraying}
- B01F 23/2323: {by circulating the flow in guiding constructions or conduits}
- B01F 25/3121: {with additional mixing means other than injector mixers, e.g. screens, baffles or rotating elements}
- B01F 25/31243: {Eductor or eductor-type venturi, i.e. the main flow being injected through the venturi with high speed in the form of a jet}
- B01F 25/422: between stacked plates, e.g. grooved or perforated plates
- B01F 25/4231: {using baffles}
- B01F 25/4331: {Mixers with bended, curved, coiled, wounded mixing tubes or comprising elements for bending the flow}
- B01F 25/4338: {Mixers with a succession of converging-diverging cross-sections, i.e. undulating cross-section}
- B01F 25/4524: {the components being pressed through foam-like inserts or through a bed of loose bodies, e.g. balls}
- C01B 17/021: {Separation of sulfur from gases}
- C01B 32/50: Carbon dioxide
- C07C 7/11: by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
- C10L 3/103: {Sulfur containing contaminants}
- C10L 3/104: {Carbon dioxide}
- A01G 31/00: Soilless cultivation, e.g. hydroponics (growth substrates therefor A01G24/00; cultivation of seaweed A01G33/00)
- B01F 25/312512: {Profiled, grooved, ribbed throat, or being provided with baffles}
- C10L 2290/541: Absorption of impurities during preparation or upgrading of a fuel
- Y02C 20/40: of CO2
- Y02P 20/582: Recycling of unreacted starting or intermediate materials
- 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)
- B01F: MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING (mixing paints B44D3/06)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
- A01G: HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING (picking of fruits, vegetables, hops or the like A01D46/00; propagating unicellular algae C12N1/12)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Ancillary embodiments and modifications to a homogenizer unit (“PPH”), and methods of use directed to purification of biogas or other raw methane streams. The apparatus includes a homogenizer body, one or more stream inlets (for the raw methane), one or more chilled water inlets, a mixing zone where the water stream is commingled with the raw methane stream, and a venturi immediately downstream from the mixing zone such that the commingled streams are pulled into the venturi resulting in homogenization. The PPH components are insulated to maintain the chilled water of the various streams at a cooled, below ambient temperature, increasing dissolution of the contaminant gases into the chilled water, and producing a purified methane stream including little or no H2S and CO2.

## Claims

### Claim 1

A method for purifying a methane containing stream, the method comprising:
introducing a raw methane stream into a mixing zone through an inlet, the raw methane stream including methane and one or more contaminants selected from the group consisting of carbon dioxide, ammonia, hydrogen sulfide and combinations thereof;
introducing a water stream into the mixing zone through a separate water inlet such that the water stream is commingled with the raw methane stream upon both streams entering the mixing zone;
passing the commingled streams through a venturi so as to homogenize the streams such that one or more contaminants within the raw methane stream are dispersed within the water stream, forming a contaminant isolation stream including the one or more contaminants and a purified methane stream;
wherein the water stream is chilled to below ambient temperature to increase dissolution of the one or more contaminants therein.

### Claim 2 (depends on 1)

A method as recited in claim 1, wherein the raw methane stream includes carbon dioxide, the carbon dioxide dissolving into the chilled water stream, so as to remove the carbon dioxide from the raw methane stream, the method further comprising capturing the carbon dioxide and conveying it one or more storage tanks for use as a plant metabolite.

### Claim 3 (depends on 1)

A method as recited in claim 1, wherein the raw methane stream includes hydrogen sulfide, the hydrogen sulfide dissolving into the chilled water stream, so as to remove the hydrogen sulfide from the raw methane stream, the dissolved hydrogen sulfide forming hydrogen gas and precipitated elemental sulfur, the method further comprising collecting the precipitated sulfur for use as a value added product.

### Claim 4 (depends on 1)

A method as recited in claim 1, wherein an ante-chamber is provided, the raw methane stream being introduced into the antechamber before introduction into the mixing zone, the ante-chamber comprising a packing material therein for retarding flow of the raw methane stream through the ante-chamber.

### Claim 5 (depends on 1)

A method as recited in claim 1, wherein a retention chamber is provided downstream from an outlet of the venturi so as to extend a residence time of the contaminant isolation stream and the purified methane stream.

### Claim 6 (depends on 5)

A method as recited in claim 5, wherein the inlets, the venturi, and the retention chamber are insulated.

### Claim 7

A method for purifying a biogas stream containing methane using a PPH, the method comprising:
introducing a raw biogas stream into a mixing zone through an inlet of the PPH, the raw biogas stream including methane, carbon dioxide, and hydrogen sulfide;
introducing a chilled water stream into the mixing zone through a separate water inlet such that the water stream is commingled with the raw biogas stream upon both streams entering the mixing zone;
passing the commingled streams through a venturi of the PPH so as to homogenize the streams such that the carbon dioxide and hydrogen sulfide are dissolved into the chilled water stream and removed from the raw biogas stream, forming a purified methane stream and an aqueous contaminant isolation stream;
wherein the water stream is chilled to below ambient temperature to increase dissolution of the carbon dioxide and hydrogen sulfide therein.

### Claim 8 (depends on 7)

A method as recited in claim 7, wherein the chilled water is oxygenated, and the raw biogas stream further comprises ammonia, wherein the hydrogen sulfide is converted to water and elemental sulfur in the presence of the chilled oxygenated water, and the carbon dioxide and ammonia are converted to ammonium carbonate in the presence of the chilled oxygenated water.

### Claim 9 (depends on 8)

A method as recited in claim 8, further comprising introducing oxygen into a chilled water stream to produce the chilled oxygenated water stream prior to its introduction into the mixing zone, the introduction of the oxygen into the chilled water stream being accomplished within an upstream PPH.

### Claim 10 (depends on 9)

A method as recited in claim 9, wherein oxygen is dissolved within the chilled oxygenated water stream at a concentration from about 8 ppm to about 12 ppm.

### Claim 11 (depends on 9)

A method as recited in claim 9, wherein oxygen is dissolved within the chilled oxygenated water stream at a concentration above that that would be provided by sparging.

### Claim 12 (depends on 8)

A method as recited in claim 8, wherein the hydrogen sulfide that is converted to hydrogen and elemental sulfur in the oxygenated water results from the hydrogen sulfide dissolving in the water to form dissolved hydrogen and the elemental sulfur, the dissolved hydrogen reacting with oxygen in the chilled oxygenated water to produce the water and elemental sulfur that the hydrogen sulfide is converted to.

### Claim 13 (depends on 8)

A method as recited in claim 8, wherein the carbon dioxide is converted to carbonic acid in the chilled oxygenated water, the ammonia reacting with the carbonic acid in the chilled oxygenated water to produce the ammonium carbonate that the carbon dioxide and ammonia are converted to.

### Claim 14 (depends on 7)

A method as recited in claim 7, wherein the raw biogas stream further includes water vapor, the water vapor condensing to form liquid water that is removed from the raw biogas stream, and which enters the aqueous contaminant isolation stream.

### Claim 15 (depends on 7)

A method as recited in claim 7, wherein the raw biogas stream further includes volatile organic compounds (VOCs) including free fatty acids (FFAs), the method further comprising contacting the FFAs with an oleophilic mesh or a chilled metal surface to remove them from the raw biogas stream.

### Claim 16 (depends on 7)

A method as recited in claim 7, wherein the raw biogas stream further includes particulate matter (PM), wherein the PM settles with elemental sulfur in the aqueous contaminant isolation stream.

### Claim 17 (depends on 7)

A method as recited in claim 7, wherein the chilled water stream is chilled to a temperature within a range of 60° F. to 75° F.

### Claim 18 (depends on 7)

A method as recited in claim 7, wherein the purified methane stream is conveyed to an internal combustion engine or burner for use as fuel.