Closed-cycle use of hydrogen and oxygen for carbon capture and emissions reduction

Abstract

Embodiments of the present disclosure provide for a processing system and methods for carbon capture and emissions reduction associated with industrial processes. The processing system includes an electrolysis plant, a first kiln, a second kiln, and a carbon capture system. The electrolysis plant configured to generate oxygen and hydrogen from a first amount of water. The first kiln is configured to receive the oxygen generated by the electrolysis plant and to produce a second amount of water, a commercial product, and flue gas via an oxy-combustion reaction. The second kiln is configured to receive the hydrogen generated by the electrolysis plant and to produce a third amount of water, the commercial product, and an exhaust gas via a combustion reaction. The carbon capture system is configured to receive flue gas from the first kiln.

Description

CLOSED-CYCLE USE OF HYDROGEN AND OXYGEN FOR CARBON CAPTURE AND EMISSIONS REDUCTIONBACKGROUNDField

[0001] Embodiments of the present disclosure generally relate to apparatus and method for closed-cycled use of hydrogen and oxygen for carbon capture and emissions reduction.Description of the Related Art

[0002] Electrolysis of water using renewable energy is gaining interest in both research and commercial setting and has become available as a commercial service for refining chemicals and manufacturing steel, among other applications. In the cement and lime industry, electrolysis of water is entering a pilot / research and development stages. In general, electrolysis of water involves splitting the water molecule into hydrogen and oxygen. Both hydrogen and oxygen can be used for generating heat. Electrolysis, however, has been criticized for generating ten times more oxygen than hydrogen, resulting in the discarding of the oxygen and only making use of the hydrogen.

[0003] Industries which use kilns, crackers, or other heat generation apparatus for commercial processes often power such apparatus with fossil fuels. The burning of fossil fuels creates noxious emissions which can be environmentally deleterious. As such, there is a need in the art for improved processing systems, apparatus, and methods for carbon capture and emissions reduction associated with industrial processes. More specifically, there is a need in the art for closed-cycle use of hydrogen and oxygen for carbon capture and emissions reduction.SUMMARY

[0004] In one embodiment, a processing system is disclosed. The processing system includes an electrolysis plant, a first kiln, a second kiln, and a carbon capture system. The electrolysis plant configured to generate oxygen and hydrogen from a first amount of water. The first kiln is configured to receivethe oxygen generated by the electrolysis plant and to produce a second amount of water, a commercial product, and flue gas via an oxy-combustion reaction. The second kiln is configured to receive the hydrogen generated by the electrolysis plant and to produce a third amount of water, the commercial product, and an exhaust gas via a combustion reaction. The carbon capture system is configured to receive flue gas from the first kiln.

[0005] In another embodiment, a lime production system is disclosed. The lime production system includes an electrolysis plant, a limestone source, a first kiln, a second kiln, and a carbon capture system. The electrolysis plant is configured to generate oxygen and hydrogen from a first amount of water. The first kiln is configured to receive the oxygen generated by the electrolysis plant and limestone from the limestone source, and to produce a second amount of water, lime, and flue gas via an oxy-combustion reaction. The second kiln is configured to receive the hydrogen generated by the electrolysis plant and limestone from the limestone source, and to produce a third amount of water, lime, and an exhaust gas via a combustion reaction. The carbon capture system which is configured to receive flue gas from the first kiln.

[0006] In yet another embodiment, a method of processing and carbon capture is disclosed. The method includes generating oxygen and hydrogen at an electrolysis plant from a first amount of water. A commercial product, a second amount of water, and a flue gas are formed at a first kiln using an oxy- combustion reaction fueled by the oxygen from the electrolysis plant. A commercial product, an exhaust gas, and a third amount of water is formed at a second kiln using a combustion reaction fueled by the hydrogen from the electrolysis plant. The second amount of water and the third amount of water are recycled to the electrolysis plant.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is tobe noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, may admit to other equally effective embodiments.

[0008] Figure 1 is a schematic of a closed cycle system, according to embodiments.

[0009] Figure 2 is a schematic of a carbon capture system, according to embodiments.

[0010] Figure 3 is a flow diagram of a method of industrial processing and carbon capture, according to embodiments

[0011] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.DETAILED DESCRIPTION

[0012] The present disclosure relates to systems, apparatus, and methods for closed-cycle use of hydrogen and oxygen for carbon capture and emissions reduction.

[0013] Figure 1 is a closed cycle system 100. The closed cycle system 100 may include a system and associated apparatus which can be implemented to perform a closed-cycle use of hydrogen and oxygen for carbon capture and emissions reduction in commercial and industrial processes. The closed cycle system 100 includes a plurality of heat generation apparatuses 101 , an electrolysis plant 102, and a carbon capture system 103. The heat generation apparatuses 101 may include a plurality of kilns (e.g., a first kiln 101 A and a second kiln 101 B). The first kiln 101 A includes a carbonated kiln and the second kiln 101 B includes a hydrogen fired kiln. The first kiln 101 A and second kiln 101 B may be utilized for any number of suitable industrial processes. Within the aggregate industry, specifically the cement and lime industry, there is an opportunity to utilize oxygen produced by the electrolysis plant 102, ratherthan atmospheric air, in the first kiln 101 A. In some embodiments, the heat generated by the first kiln 101 A and the second kiln 101 B is used to produce an industrial or commercial product, such as lime, phosphate, or other dry products. Limestone used to form the lime is provided to the first kiln 101 A and the second kiln 101 B from a processing material source 106 (e.g., a limestone source). The lime (or other commercial or industrial product) produced by the first kiln 101 A and second kiln 101 B is collected in a product reservoir 111.

[0014] In some embodiments, renewable energy sources 105, such as solar, wind, hydro, geothermal, or the like, are utilized to generate electricity which is then utilized to power an electrolysis plant 102. The electrolysis plant 102 receives water from a water source 104, such as an on-site water well, or from any other suitable water source. The electricity generated from the renewable energy sources 105 powers the electrolysis plant 102 to generate two outputs: hydrogen and oxygen. In one embodiment, the oxygen and hydrogen are separated from one another upon generation by the electrolysis plant. The oxygen is delivered to the first kiln 101 A and the hydrogen is delivered to the second kiln 101 B.

[0015] The oxygen generated from the electrolysis plant 102 is delivered to the first kiln 101 A and used in combination with hydrocarbons, such as coal or other conventional fuel sources, to fire the first kiln 101 A and increase heat generation. The hydrocarbons are provided to the first kiln 101 A by a hydrocarbon source 107. The heat in the first kiln 101 A is generated using an oxy-combustion reaction. The products of the oxy-combustion reaction include a flue gas and water. The first kiln 101 A may be sealed, thus confining the oxy- combustion reaction to the oxygen from the electrolysis plant 102 and the hydrocarbons. The flue gas, in one embodiment, includes pure or nearly pure carbon dioxide (CO2). As used herein, nearly pure CO2 is contemplated to include a gaseous feedstock which is about 75% or greater CO2, 85% or greater CO2, 95% or greater CO2, 99% or greater CO2, or 99.5% or greater CO2. The use of the oxygen in the oxy-combustion reaction enables an inert atmosphere in which nitrogen can be removed from the combustion area, resulting in pureC02exhaust. The flue gas can approach near 100% pure CO2, which significantly reduces the cost of carbon capture and compression within the carbon capture system 103. In some embodiments, a portion of the pure or nearly pure CO2 is recirculated within the first kiln 101 A. The pure or nearly pure CO2 which is recirculated within the first kiln 101 A in order to control the combustion temperature within the first kiln 101 A, as well as to reduce nitrogen oxide formation. The water formed from the oxy-combustion reaction may be recycled to the electrolysis plant 102.

[0016] The hydrogen generated from the electrolysis plant 102 is delivered to the second kiln 101 B and utilized in combination with atmospheric air to fire the second kiln 101 B and increase heat generation. The atmospheric air is provided to the second kiln 101 B by an air source 108 as an oxygen source for the combustion of the hydrogen within the second kiln 101 B. The products of the heat generation in the second kiln 101 B include an exhaust gas and water. The exhaust gas includes deoxygenated air and CO2. In some embodiments, the CO2 from the second kiln 101 B may also be delivered to the carbon capture system 103. In order to increase the purity of the CO2 generated in the second kiln 101 B, the second kiln 101 B may be designed such that the heat of the combustion reaction between the atmospheric air and the hydrogen is outside of a rotating drum where the raw material is being processed. The CO2 formed within the rotating drum from the processing of the raw materials (e.g., the limestone) will be near 100% pure CO2. A portion of the water formed from the oxy-combustion reaction may be recycled to the electrolysis plant 102.

[0017] In some embodiments, the water produced from the first kiln 101 A and the second kiln 101 B, in combination, may provide a sufficient amount of water to the electrolysis plant 102 in order to remove the need to draw water from the water source 104, as the total production of water from the first kiln 101 A and the second kiln 101 B is greater than the water consumed by the electrolysis plant 102. As a result, the closed cycle system 100 is less resource demanding than conventional industrial processing plants.

[0018] Figure 2 is a schematic of a carbon capture system 103. The flue gas from the first kiln 101 A is delivered to the carbon capture system 103. In one embodiment, the carbon capture system 103 is an amine based system. The carbon capture system 103 includes a pretreatment module 220, an absorption unit 222, a heat exchanger 224, a desorption unit 226, and a reboiler 228. The reboiler 228 includes a CO2 lean solvent and provides the CO2 lean solvent to the carbon capture system 103. In particular, the reboiler provides the CO2 lean solvent to the heat exchanger 224 via the desorption unit 226. The CO2 lean solvent may be provided to the reboiler via a solvent source 230.

[0019] The flue gas from the first kiln 101 A is provided to the pretreatment module 220. In some embodiments, the CO2 from the second kiln 101 B may also be delivered to the pretreatment module 220. The flue gas is cooled (quenched) and treated to remove contaminants, such as acidic gases, particulates, etc., that would degrade the solvent in the absorption unit 222. The treated flue gas is then provided to the absorption unit 222.

[0020] The heat exchanger 224 provides the CO2 lean solvent to the absorption unit 222. The heat exchanger 224 heats the CO2 lean solvent from the reboiler 228 prior to supplying the CO2 lean solvent to the absorption unit 222. The absorption unit 222 continuously absorbs the CC from the flue gas using the CO2 lean solvent. A CO2 rich solvent exits the bottom of the absorption unit 222 and is transferred to the desorption unit 226 via the heat exchanger 224. CO2 lean flue gas 110 exits via the top of the absorption unit 222.

[0021] In some embodiments, water is provided to the heat exchanger 224 from the water source 104, the first kiln 101 A, the second kiln 101 B, or a combination thereof. Power is provided to the heat exchanger 224 from the renewable energy source 105.

[0022] The heat exchanger 224 heats the CO2 rich solvent prior to supplying the CO2 rich solvent to the desorption unit 226. The desorption unit 226 strips the CO2 from the CO2 rich solvent that is provided from the absorption unit 222to reform the CO2 lean solvent. A stream of pure CO2 109 exits the top of the desorption unit 226 and it collected at the CO2 reservoir. The CO2 lean solvent is recycled through the reboiler 228 and back to the absorption unit 222 via the heat exchanger 224. By recycling the CO2 lean solvent, the carbon capture system 103 is less resource demanding.

[0023] Figure 3 is a flow diagram of a method 300 of industrial processing and carbon capture. The method 300 is used with the closed cycle system 100. At operation 301 , oxygen and hydrogen are formed at an electrolysis plant 102. Water for the electrolysis plant 102 is initially provided from a water source 104. After the initial amount of water is provided, as will be discussed in further detail below, the closed cycle system 100 may use recycled water to sustain operations without the water source 104.

[0024] At operation 302, a commercial product is formed in a first kiln 101 A using an oxy-combustion reaction. The oxy-combustion reaction is fueled by the oxygen from the electrolysis plant 102. The oxy-combustion reaction create a pure or near pure carbon dioxide (CO2). A raw material for processing (e.g., limestone for lime production) is provided from a processing material source 106. A portion of the CO2 formed by the oxy-combustion reaction may be recirculated within the first kiln in order to control the combustion temperature within the first kiln 101 A and to reduce nitrogen oxide formation. The oxy- combustion reaction further forms water.

[0025] At operation 303, the commercial product is formed in a second kiln 101 B using a conventional combustion reaction. A raw material for processing (e.g., limestone for lime production) is provided from a processing material source 106. The conventional combustion reaction is fueled by the hydrogen from the electrolysis plant 102. In some embodiments, the second kiln 101 B may be designed to isolate the heat of the combustion reaction between the atmospheric air and the hydrogen outside of a rotating drum where the raw material is being processed. The CO2 formed within the rotating drum from the processing of the raw materials (e.g., the limestone) will be near 100% pure CO2. The conventional combustion reaction further forms water.

[0026] At operation 304, water formed from the first kiln 101 A and the second kiln 101 B is recycled to the electrolysis plant 102. The water produced from the first kiln 101 A and the second kiln 101 B, in combination, may provide a sufficient amount of water to the electrolysis plant 102 in order to remove the need to draw water from the water source 104, as the total production of water from the first kiln 101 A and the second kiln 101 B is greater than the water consumed by the electrolysis plant 102. As a result, the closed cycle system 100 is less resource demanding than conventional industrial processing plants.

[0027] At operation 305, the CO2 formed from the first kiln 101 A is captured by a carbon capture system 103. In some embodiments, the CO2 formed in the second kiln 101 B is captured by the carbon capture system 103. In some embodiments, the carbon capture system 103 may be an amine carbon capture system. In other embodiments, the carbon capture system may include a membrane carbon capture system, a cryogenic capture system, or an ammonia capture system. The water from the first kiln 101 A and the second kiln 101 B may be used by a heat exchanger 224 of the carbon capture system 103.

[0028] In summation, embodiments described herein make use of the oxygen “waste product” of water electrolysis in a two-part system. The first kiln makes thermal heat with highly-concentrated carbon dioxide emissions, which therefore lends itself to carbon capture and storage applications. The second kiln makes thermal heat with no carbon dioxide emissions.

[0029] The closed cycle system 100 generates greater thermal heat than conventional techniques by using both hydrogen and fossil-fuels as fuel sources and using both oxygen and atmospheric air as oxygen sources. By keeping these two combustions separate and cross-paired from conventional implementations, embodiments of this disclosure generate a concentrated CO2 exhaust stream more suitable for carbon capture. Further, by recovering the water resulting from combustion, embodiments described herein enable electrolysis to consume less water than it normally would. As a result, the two parts of this system (oxygen stream and hydrogen stream) to be owned by separate legal entities, which allows maximization of federal tax credits.

[0030] It is contemplated that embodiments of the present disclosure provide for various improvements over conventional methods, devices or materials.Lower carbon emissions, higher efficiency in use of the electricity from the electrolysis, increased revenue from tax credits, greater thermal heat than conventional systems, less make-up water consumption, and capture of CO2 at high concentrations while still burning fossil fuels are all aspects of embodiments described herein.

[0031] As such, thermal heat generation systems such as kilns, district heat plants, ore processing plants, and other similar systems of heat generation and application for imparting physical and chemical changes to industrial products may benefit from the embodiments described herein.

[0032] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:1 . A processing system, comprising: an electrolysis plant configured to generate oxygen and hydrogen from a first amount of water; a first kiln configured to receive the oxygen generated by the electrolysis plant and configured to produce a second amount of water, a commercial product, and flue gas via an oxy-combustion reaction; a second kiln configured to receive the hydrogen generated by the electrolysis plant and configured to produce a third amount of water, the commercial product, and an exhaust gas via a combustion reaction; and a carbon capture system which is configured to receive flue gas from the first kiln.

2. The processing system of claim 1 , wherein the flue gas includes a carbon dioxide.

3. The processing system of claim 2, wherein the carbon capture system is configured to capture the carbon dioxide from the first kiln.

4. The processing system of claim 1 , wherein the exhaust gas comprises deoxygenated air and carbon dioxide, and wherein the carbon capture system is configured to capture the carbon dioxide from the second kiln.

5. The processing system of claim 1 , wherein the second amount of water produced from the first kiln and the third amount of water produced from the second kiln is greater than the first amount of water.

6. A lime production system, comprising: an electrolysis plant configured to generate oxygen and hydrogen from a first amount of water; a limestone source,a first kiln configured to receive the oxygen generated by the electrolysis plant and limestone from the limestone source, and configured to produce a second amount of water, lime, and flue gas via an oxy-combustion reaction; a second kiln configured to receive the hydrogen generated by the electrolysis plant and limestone from the limestone source, and configured to produce a third amount of water, lime, and an exhaust gas via a combustion reaction; and a carbon capture system which is configured to receive flue gas from the first kiln.

7. The lime production system of claim 6, wherein the carbon capture system is configured to capture a carbon dioxide from the flue gas of the first kiln.

8. The lime production system of claim 7, wherein the first kiln is configured to recycle the carbon dioxide from the flue gas within the first kiln to control the oxy-combustion reaction.

9. The lime production system of claim 6, wherein the carbon capture system is configured to capture a carbon dioxide from the exhaust gas of the second kiln.

10. The lime production system of claim 6, wherein the second amount of water produced from the first kiln and the third amount of water produced from the second kiln is greater than the first amount of water.

11. A method of processing and carbon capture, comprising: generating oxygen and hydrogen at an electrolysis plant from a first amount of water; forming a commercial product, a second amount of water, and a flue gas at a first kiln using an oxy-combustion reaction fueled by the oxygen from the electrolysis plant;forming a commercial product, an exhaust gas, and a third amount of water at a second kiln using a combustion reaction fueled by the hydrogen from the electrolysis plant; and recycling the second amount of water and the third amount of water to the electrolysis plant.

12. The method of claim 11 , further comprising: capturing carbon dioxide from the flue gas of the first kiln utilizing a carbon capture system.

13. The method of claim 11 , further comprising: capturing carbon dioxide from the exhaust gas of the second kiln utilizing a carbon capture system.

14. The method of claim 11 , further comprising: recycling carbon dioxide from the flue gas within the first kiln to control the oxy-combustion reaction.

15. The method of claim 11 , wherein the combination of the second amount of water and the third amount of water is greater than the first amount of water.

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