Carbon dioxide capture / removal from point sources

Abstract

A method for carbon dioxide capture includes feeding a gas stream from a point source to a mixer, the gas stream being contaminated with carbon dioxide, feeding atmospheric air to the mixer; using the mixer to create a mixture of the gas stream and the atmospheric air; and feeding the mixture to an electrochemically driven carbon dioxide separator (EDCS) based, direct-air- capture (DAC) cell which captures carbon dioxide from the mixture.

Description

CARBON DIOXIDE CAPTURE / REMOVAL FROM POINT SOURCESFIELD OF THE INVENTION

[0001] The present invention relates to carbon dioxide capture / removal from point sources and the atmosphere.BACKGROUND OF THE INVENTION

[0002] Carbon dioxide is the primary greenhouse gas emitted through human activities. Carbon capture is a way to reduce the emission of greenhouse gases. Carbon capture technologies may capture carbon dioxide from the atmosphere or a point source. The U.S. Environmental Protection Agency (EPA) defines point source pollution as “any single identifiable source of pollution from which pollutants are discharged, such as a pipe, ditch, ship or factory smokestack”.

[0003] According to the Intergovernmental Panel on Climate Change (IPCC), it is desired to reduce or eliminate existing carbon dioxide emissions caused by human contributions in order to keep global temperature rise under 1.5° C. or 2° C. Data provided by the IPCC show that approximately 10 gigatons of net CO2per year (10 Gt CO2 / yr) need to be removed and safely sequestered from the atmosphere by the year 2050 to keep global temperature rise under 1.5° C.

[0004] In carbon dioxide removal systems known as “direct air carbon capture and storage (DACCS)”, CO2is extracted directly from the air. The CO2 may be stored in geological formations deep underground or converted to other compounds and substances.

[0005] Accordingly, in the prior art, DAC is used at point sources to reduce the carbon dioxide emission at the point source.SUMMARY

[0006] The present invention seeks to provide an innovative method of carbon dioxide capture / removal from point sources, as is described herein below.

[0007] Instead of removing carbon dioxide from the polluting point source before the carbon dioxide enters the atmosphere, in the present invention, the contaminated air exits the point source, is mixed with atmospheric air and then undergoes carbon dioxide capture / removal by means of an electrochemically driven carbon dioxide separator(EDCS). This is counterintuitive: in the prior art, the goal is to remove carbon dioxide from the point source contaminated air before any contaminants exit the point source. The invention surprisingly mixes the contaminated air with atmospheric air to arrive at a mixture from which carbon dioxide is removed more efficiently by the EDCS.

[0008] There is provided in accordance with a non-limiting embodiment of the invention, a method for carbon dioxide capture including feeding a gas stream from a point source to a mixer, the gas stream being contaminated with carbon dioxide, feeding atmospheric air to the mixer; using the mixer to create a mixture of the gas stream and the atmospheric air; and feeding the mixture to an electrochemically driven carbon dioxide separator (EDCS) based, direct-air-capture (DAC) cell which captures carbon dioxide from the mixture.BRIEF DESCRIPTION OF DRAWINGS

[0009] The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

[0010] Fig. 1 is a block diagram of a method of carbon dioxide capture / removal from a point source, in accordance with a non-limiting embodiment of the present invention.

[0011] Fig. 2 is a graphical illustration of removed CO2 levels as a function of time, wherein each plot represents different inlet levels of CO2.DETAILED DESCRIPTION

[0012] Reference is now made to Fig. 1, which illustrates a method of carbon dioxide capture / removal from a point source, in accordance with a non-limiting embodiment of the present invention.

[0013] A point source 1 expels a gas stream 2, which contains oxygen, nitrogen and other gases, and is contaminated with a high percentage of 0.05-30% carbon dioxide.

[0014] The gas stream 2 is fed together with atmospheric air to a mixer 4. The flow of atmospheric air may be enhanced by an air mover 3, such as a blower. The atmospheric air generally contains about 400 ppm of carbon dioxide, and of course contains oxygen, nitrogen and other gases.

[0015] After mixing, the mixture is then fed to an electrochemically driven carbon dioxide separator (EDCS) based, direct-air-capture (DAC) cell 5. One suitable, nonlimiting example is the EDCS described in US Patent Application 2021 / 0036350 toYushan Yan et al. This EDCS is an electrochemical pump (ECP) for separating carbon dioxide from a carbon dioxide-containing gas. The ECP includes a cell, which has a membrane and two electrodes that are capable of acting as an anode or a cathode. Each of the electrodes independently comprises a charge-storage compound that reacts to form hydroxide when acting as cathode and reacts to consume hydroxide or produce protons when acting as anode. The membrane is adjacent to and separates the two electrodes. A carbon dioxide-containing gas contacts the electrode acting as cathode and the carbon dioxide reacts with the hydroxide ions to form bicarbonate ions, carbonate ions, or bicarbonate and carbonate ions; the bicarbonate ions, carbonate ions, or bicarbonate and carbonate ions are transported to the electrode serving as anode through the membrane; and the bicarbonate ions, carbonate ions, or bicarbonate and carbonate ions react at the electrode acting as anode to form carbon dioxide and water. The ECP also has means for reversing the direction of current flow and simultaneously alternating the electrode with which the carbon dioxide-containing gas is contacted, thereby allowing each electrode to act, in turn, as anode and as cathode.

[0016] The electrochemical cell is connected to a power source which applies an electrical current / potential to the cell.

[0017] Reference is now made to Fig. 2, which illustrates removed CO2 levels as a function of time, wherein each plot represents different inlet levels of CO2.

Claims

CLAIMS1. A method for carbon dioxide capture comprising: feeding a gas stream that has exited from a point source to a mixer, said gas stream being contaminated with carbon dioxide, said point source being a source of pollution from which pollutants are discharged; feeding atmospheric air to said mixer; using said mixer to create a mixture of said gas stream and said atmospheric air; and feeding said mixture to an electrochemically driven carbon dioxide separator (EDCS) based, direct-air-capture (DAC) cell which captures carbon dioxide from said mixture.

2. The method according to claim 1, wherein feeding the atmospheric air to said mixer is enhanced by an air mover that enhances flow of the atmospheric air.

3. The method according to claim 1, wherein said gas stream is contaminated with 0.05- 30% carbon dioxide.

4. The method according to claim 1, wherein the atmospheric air contains 400 ppm of carbon dioxide.

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