# US 9,005,335 B2 · Hybrid parallel / serial process for carbon dioxide capture from combustion exhaust gas using a sweep-based membrane separation step

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- Number: US 9,005,335 B2
- Document ID: US9005335B2
- Status: Granted
- Kind: B2
- Application number: 13/665,620
- Filed: 2012-10-31
- Published: 2013-03-07
- Granted: 2015-04-14
- Earliest claimed: 2011-05-25
- Assignees: Membrane Technology and Research, Inc.
- Applicants: Membrane Technology and Research, Inc
- Inventors: Richard W. Baker; Xiaotong Wei; Timothy C Merkel
- Web page: https://patentgrep.com/patent/US9005335B2

## CPC

- B01D 53/22: by diffusion (manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00)
- B01D 53/62: Carbon oxides
- F02C 3/34: with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle
- F23C 9/00: Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber (fluidised bed combustion apparatus with means for recirculation of particles entrained from the bed F23C10/02; fluidised bed combustion apparatus with devices for removal and partial reintroduction of material from the bed F23C10/26)
- B01D 2256/22: Carbon dioxide
- B01D 2257/102: Nitrogen
- B01D 2257/104: Oxygen
- B01D 2257/504: Carbon dioxide
- B01D 2258/0283: Flue gases
- F23J 2215/50: Carbon dioxide
- F23L 2900/07001: Injecting synthetic air, i.e. a combustion supporting mixture made of pure oxygen and an inert gas, e.g. nitrogen or recycled fumes
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02C 20/40: of CO2
- Y02E 20/32: Direct CO2 mitigation
- 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)
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F23C: METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN {A CARRIER GAS OR} AIR (burners F23D)
- F23J: REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES (combustion apparatus for consuming smoke or fumes, e.g. exhaust gases, F23G7/06)
- F23L: SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ({air-supply arrangements for fluent fuels F23C;} firebridges with means for feeding air or steam F23M3/04; baffles or shields with air supply passages F23M9/04); VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS {(dampers and throat restrictors for open fire-places F24; air inlet valves for open fire fronts F24)}; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A gas separation process for treating an exhaust gas stream from a combustion processes. The invention involves routing a first portion of the exhaust stream to a carbon dioxide capture step, and flowing a second portion of the exhaust stream and at least a portion of an off-gas stream from the carbon dioxide capture step across the feed side of a membrane, while flowing a sweep gas stream, usually air, across the permeate side, and then passing the resulting permeate sweep stream back to the combustor.

## Claims

### Claim 1

A process for controlling carbon dioxide exhaust from a combustion process, comprising:
(a) performing a combustion process by combusting a mixture of a fuel and air, oxygen-enriched air, or oxygen, thereby creating an exhaust stream comprising carbon dioxide and nitrogen;
(b) performing a carbon dioxide capture step to remove a portion of carbon dioxide in concentrated form from a first portion of the exhaust stream, thereby creating an off-gas stream from the capture step that is less concentrated in carbon dioxide than the exhaust stream;
(c) providing a membrane having a feed side and a permeate side, and being selectively permeable to carbon dioxide over nitrogen and to carbon dioxide over oxygen;
(d) passing a second portion of the exhaust stream and at least a portion of the capture step off-gas stream across the feed side;
(e) passing air, oxygen-enriched air, or oxygen as a sweep stream across the permeate side;
(f) withdrawing from the feed side a carbon-dioxide depleted vent stream;
(g) withdrawing from the permeate side a permeate stream comprising oxygen and carbon dioxide;
(h) passing the permeate stream to step (a) as at least part of the air, oxygen-enriched air, or oxygen used in step (a).

### Claim 2 (depends on 1)

The process of claim 1, wherein the at least a portion of the capture step off-gas stream that is passed to step (d) comprises between about 3 vol % to about 20 vol % carbon dioxide.

### Claim 3 (depends on 1)

The process of claim 1, wherein the exhaust stream emanates from a gas turbine.

### Claim 4 (depends on 1)

The process of claim 1, wherein the exhaust stream emanates from a steam turbine.

### Claim 5 (depends on 1)

The process of claim 1, wherein the exhaust stream comprises between about 10 vol % to about 25 vol % carbon dioxide.

### Claim 6 (depends on 1)

The process of claim 1, wherein the first portion of the exhaust stream that is sent to step (b) comprises between about 10 vol % and about '75 vol % of the total exhaust stream.

### Claim 7 (depends on 6)

cess of claim 6, wherein the first portion of the exhaust stream that is sent to step (b) comprises between about 20 vol % and about 65 vol % of the total exhaust stream.

### Claim 8 (depends on 7)

The process of claim 7, wherein the first portion of the exhaust stream that is sent to step (b) comprises between about 40 vol % and about 60 vol % of the exhaust stream.

### Claim 9 (depends on 1)

The process of claim 1, wherein the carbon dioxide capture step comprises at least one process selected from the group consisting of absorption, adsorption, liquefaction, and membrane separation.

### Claim 10 (depends on 9)

The process of claim 9, wherein the carbon dioxide capture step is an absorbent-based capture step.

### Claim 11 (depends on 10)

The process of claim 10, wherein the absorbent-based capture step comprises a chemical absorption process.

### Claim 12 (depends on 11)

The process of claim 11, wherein the chemical absorption process is an amine-based absorption process.

### Claim 13 (depends on 11)

The process of claim 11, wherein the chemical absorption process is a potassium carbonate scrubbing process.

### Claim 14 (depends on 10)

The process of claim 10, wherein the absorption-based carbon dioxide capture step comprises a physical absorption process.

### Claim 15 (depends on 1)

The process of claim 1, wherein the sweep stream follows a sweep flow direction across the permeate side, the off-gas stream follows a feed flow direction across the feed side, and the sweep flow direction is substantially countercurrent to the feed flow direction.

### Claim 16 (depends on 1)

The process of claim 1, wherein the membrane exhibits a carbon dioxide permeance of at least 500 gpu under process operating conditions.

### Claim 17 (depends on 1)

The process of claim 1, wherein the membrane exhibits a selectivity in favor of carbon dioxide over nitrogen of at least 10 under process operating conditions.

### Claim 18 (depends on 1)

The process of claim 1, wherein the vent stream comprises 3 vol % carbon dioxide or less.