METHODS AND SYSTEMS FOR GREENHOUSE GAS CAPTURE AND SEQUESTRATION UTILIZING DIRECT AIR CAPTURE

Abstract

Integrating direct air capture techniques in a novel manner with a novel process for using subterranean coal formations to filter CO.sub.2 from mixed gas streams thereby reducing the energy input and cost of removing CO.sub.2 from the atmosphere.

Claims

1. A method utilizing direct air capture to move CO2 into a fluid stream, the method comprising: freezing gas CO2 into a solid; positioning the solid CO2 into a constrained container; warming the solid CO2; increasing a pressure within the constrained container; utilizing the pressure increase within the constrained container to inject the CO2 into a water stream under pressure.

2. The method of claim 1, further comprising: dissolving the CO2 into the water stream at a desired concentration.

3. The method of claim 2, wherein the desired concentration is between one and fifteen percent.

4. The method of claim 2, wherein the water with the dissolved CO2 is injected into a subterranean formation.

5. The method of claim 4, wherein the injection of the dissolved CO2 into the subterranean formation radially pushes methane away from a face of a coal seam.

6. The method of claim 4, wherein the constrained container includes an inlet, the inlet configured to receive the frozen CO2.

7. The method of claim 6, wherein the frozen CO2 has a phase change within the constrained container to create compressed high-pressure CO2 of nearly pure CO2 within the constrained container.

8. The method of claim 7, wherein the compressed high-pressure CO2 is injected into fluid piping, wherein the fluid piping receives first fluids, the first fluids being water.

9. The method of claim 8, wherein the CO2 dissolves in the first fluids before being injected into the subterranean formation.

10. The method of claim 1, wherein a percentage of the injected CO2 into the water stream is controlled to match a sequestration action of a sequestration medium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present disclosure is best understood from the following description and accompanying figures. Various features are not drawn to scale. Dimensions of features may be arbitrarily increased or reduced for clarity of discussion.

[0020] FIG. 1 depicts a method utilizing DAC (direct air capture) to inject or dissolve CO.sub.2 into a fluid stream, according to an embodiment.

[0021] FIG. 2 depicts a system leveraging Cryogenic DAC (direct air capture) to utilize frozen CO.sub.2 that it implemented for sequestering carbon within a coal seam, according to an embodiment.

[0022] Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present disclosure. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted to facilitate a less obstructed view of these various embodiments of the present disclosure.

DETAILED DESCRIPTION

[0023] The following disclosure provides many different examples for implementing different features of various embodiments. Specific examples of components and arrangements are described to simplify the disclosure. These examples are not limiting. The disclosure may repeat reference numerals or letters in the examples. This repetition is for simplicity and clarity and does not dictate a relationship between the embodiments or configurations.

[0024] FIG. 1 depicts method 100 utilizing DAC (direct air capture) to inject or dissolve CO.sub.2 into a fluid stream, according to an embodiment. Utilizing DAC to dissolve CO.sub.2 into a mixed gas stream may reduce the energy input to forming the mixed gas stream, enabled by utilizing subterranean coal formations to filter the CO.sub.2 from the mixed gas stream. Embodiments may utilize DAC technologies to extract CO.sub.2 directly from the atmosphere. The CO.sub.2 can be permanently stored in geological formations, thereby achieving carbon dioxide removal (CDR). In embodiments, the medium to extract the CO.sub.2 directly from the atmosphere may be positioned remotely from the geological formations where the CO.sub.2 is subsequently sequestered. A major advantage of DAC is its flexibility, wherein a DAC plant can be situated in any location with low-carbon energy and a CO2 storage resource or CO2 use opportunity. Yet, there may be limits to this flexibility. To date, DAC plants have been successfully operated in various climatic conditions in Europe and North America.

[0025] A specific embodiment may utilize Cryogenic DAC to create solid CO.sub.2 that is implemented for sequestering carbon within a coal seam, according to an embodiment. The operations of the method depicted in FIG. 1 are intended to be illustrative. In some embodiments, the method may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of the method are illustrated in FIG. 1 and described below is not intended to be limiting.

[0026] At operation 110, cryogenic DAC may freeze gas CO.sub.2 into a solid. Cryogenic DAC may use cold energy, thereby minimizing the thermal energy needed for the process while isolating CO.sub.2 from other gases. In other embodiments, different methods may be utilized to freeze gas CO.sub.2 into a solid. For example, gas CO.sub.2 may be frozen into a solid utilizing altitude, or gas CO.sub.2 may be created utilizing bi-products of compression plants. For example, in a compression gas-processing plant, gas may be successively compressed requiring energy. As the gas is decompressed, the air is cooledwhich can be utilized to create the solid CO.sub.2.

[0027] At operation 120, the solid CO.sub.2 may be positioned with a constrained container, and the solid CO.sub.2 may be warmed. For example, the solid CO.sub.2 may be warmed due to natural atmospheric temperatures.

[0028] At operation 130, due to the phase change of the solid CO.sub.2 into a gas via sublimation, the pressure within the constrained container may increase. This will result in a compressed, high-pressure gas stream of nearly pure CO.sub.2.

[0029] At operation 140, the trapped pressure within the constrained container may be utilized to inject the CO.sub.2 gas into a water stream under pressure.

[0030] At operation 150, the CO.sub.2 gas may be dissolved into water. In embodiments, the CO.sub.2 may be dissolved within water at a desired concentration, which may be between one and fifteen percent. In embodiments, the amount of CO.sub.2 that may be dissolved within water or medium may be any percentage less than 100%. The desired concentration of the dissolved CO.sub.2 may allow for enough CO.sub.2 to be adsorbed by the coal seam at a desired pressure without damaging the subterranean formation. However, one skilled in the art may appreciate that the CO.sub.2 may be directly captured from the air and injected into the fluid stream in any known method.

[0031] At operation 160, the water with dissolved CO.sub.2 may be injected into the coal seam. This may cause the CO.sub.2 to be absorbed within the coal seam and radially push methane away from the face of a coal seam.

[0032] FIG. 2 depicts a system 200 leveraging Cryogenic DAC (direct air capture) to utilize solid CO.sub.2 that it implemented for sequestering carbon within a coal seam, according to an embodiment. As depicted in FIG. 2, system 200 may include a contained chamber 210, fluid piping 220, wellbore 230, and gas sequestration medium 240.

[0033] Constrained container 210 may be any type of container with a fixed volume. In embodiments, constrained container 210 may be a tank, storage container, etc. Constrained container 210 may be configured to selectively seal CO.sub.2 within the fixed volume. Constrained container 210 may be configured to receive frozen gas CO.sub.2 in a solid state and allow the solid CO.sub.2 to sublimate into a gas. Responsive to the phase change of the CO.sub.2 with constrained container 210, the pressure within constrained container 210 may increase. This will result in a compressed, high-pressure gas stream of nearly pure CO.sub.2 within constrained container 210. In embodiments, constrained container 210 may include an outlet 212 that is configured to allow the pressurized CO.sub.2 within constrained container 210 to be injected into fluid piping 220. In further embodiments, constrained container 214 may include an inlet, that is configured to receive fluid piping 220, as well as water supplied from fluid piping.

[0034] Fluid piping 220 may be tubing configured to transport fluids downhole, such as a fluid stream mixture formed of water of dissolved CO.sub.2 from constrained container 210. Fluid piping 220 may include a first inlet configured to receive first fluids, such as water, and a second inlet that is configured to receive the pressurized CO.sub.2 from constrained container 210. The fluid stream mixture may subsequently travel downhole and into gas sequestration medium 240. In other embodiments, fluid piping 220 may be configured to run directly through constrained container 210, to allow the fluid within fluid piping 220 to receive and dissolve the pressurized CO.sub.2 within constrained container 210. This may allow the CO.sub.2 to be dissolved within a water stream in fluid piping 220 to create a fluid stream mixture, wherein the fluid stream mixture may be created before being injected into wellbore 230 or gas sequestration medium 240. This may allow most of the CO.sub.2 to be dissolved before being injected into wellbore 230 or gas sequestration medium 240. In further embodiments, the percentage of the pressurized CO.sub.2 gas within constrained container 210 that is injected into fluid piping 220 may be increased, slowed, or halted to match the duty cycle of the source or to match the sequestration action of greenhouse gas sequestration medium 150. The concentration of CO.sub.2 within the fluid piping 220 and fluid stream mixture traveling within piping 220 may be controlled by adjusting the flow rate of CO.sub.2 within constrained container 210 or of the water traveling within fluid piping 220. Accordingly, there may be a plurality of ways to impact the amount of CO.sub.2 gas that is dissolved in the fluid stream mixture.

[0035] Wellbore 230 may be a hole that is drilled to aid in the exploration and recovery of natural resources, including oil, gas, or water. Wellbore 230 may include greenhouse gas sequestration medium 240 may be a coal seam, whereas greenhouse gas sequestration medium 240 may include a plurality of coal seams at different depths within a single wellbore or multiple wellbores. In an embodiment, the fluid mixture stream within fluid piping 220 may be injected into the coal seam and be used to recover methane from within the porous structure of the coal seam. Without being bound by theory, coal has a greater affinity for CO.sub.2 and nitrogen than for methane. When water having CO.sub.2, such as within the fluid mixture stream, is injected into the coal seam, methane may be liberated and extracted. More specifically, when a fluid mixture stream is injected into greenhouse gas sequestration medium 240, the CO.sub.2 is absorbed by the coal seam, pushing methane ahead within the fracture. The rate and length of the injection, and the location of the production wells, can be chosen to facilitate or eliminate the production of methane from the coal seam. In specific embodiments, appreciative production of methane from the coal seam may be eliminated by halting the injection before the methane reaches a production well, thereby leaving room in the coal for the methane to continue to reside. Further, greenhouse gas sequestration medium 240 could be any target production zone, and the injected solution may be used to enhance the recovery of a variety of hydrocarbons, such as enhanced oil recovery from a mudrock or sandstone reservoir. After sequestration, water containing one or more salts and absorbed hydrocarbon gases, such as natural gas, is transported to the surface through wellbore 230 as produced water stream 250. In other embodiments, the displaced gas may be in a free state depending on the pressure. Produced water stream 250 may be separated in separator 260 into gaseous hydrocarbon stream 270 and separated water stream 280.

[0036] The foregoing outlines features of several embodiments so that a person of ordinary skill in the art may better understand the aspects of the present disclosure. Such features may be replaced by any one of numerous equivalent alternatives, only some of which are disclosed herein. One of ordinary skill in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. One of ordinary skill in the art will also understand that such equivalent constructions do not depart from the scope of the present disclosure and that they may make various changes, substitutions, and alterations to the devices disclosed herein without departing from the scope of the present disclosure.