Systems, Methods and Devices for Geologic Storage of CO2 from Modular Point Sources

Abstract

Methods, systems and devices for the subsurface storage of CO.sub.2 from a modular industrial point source. In an embodiment the CO.sub.2 is from a modular cement plant. In an embodiment the CO.sub.2 from a point source is dissolved in saline/brine solution and pumped into a subterranean storage space.

Claims

1-28. (canceled)

29. A system for geologic storage of CO.sub.2, the system comprising: a CO.sub.2 enrichment unit; the CO.sub.2 enrichment unit comprising: an inlet for receiving a flow of a brine solution; an inlet for receiving a flow of gaseous CO.sub.2; and, an outlet for removing an outflow from the enrichment unit; wherein the outlet is in fluid communication with a borehole in the earth; wherein the CO.sub.2 enrichment unit is configured whereby the flow of gaseous CO.sub.2 is in direct contact within the flow of the brine solution; and, wherein the outflow comprises a CO.sub.2-rich brine, and the outflow is not a super critical fluid.

30. The system of claim 29, wherein the borehole extends less than 1,000 m below a surface of the earth into a reservoir.

31. The system of claim 29, comprising a second borehole in the earth extending into a reservoir, wherein the reservoir contains the brine solution, and the second borehole is in fluid communication with the inlet for receiving the flow of the brine solution.

32. The system of claim 29, wherein the CO.sub.2-rich brine comprises H.sub.2CO.sub.3 (carbonic acid).

33. The system of claim 29, wherein the CO.sub.2-rich brine comprises one or more of the species H.sub.+, HCO.sub.3.sup.1− and CO.sub.3.sup.2−.

34. The system of claim 29, wherein the enrichment unit is a semi-open system.

35. The system of claim 29, wherein the enrichment unit is a semi-open system comprising one or more of a bubbler, a mixer, a falling brine solution, a brine sprayer, a CO.sub.2 gas blanket, and a counter flow system.

36. The system of claim 29, wherein the inlet is for receiving a flow of the brine solution from a reservoir in the earth.

37. The system of claim 29, wherein the CO.sub.2 is generated from a source.

38. The system of claim 29, wherein the source of CO.sub.2 is a cement plant.

39. The system of claim 29, wherein the enrichment unit is a semi-open system.

40. A method for geologic storage of CO.sub.2 generated from a source, the method comprising: flowing a brine solution from a brine source into a semi-open CO.sub.2 enrichment system; flowing a gaseous CO.sub.2 from the source into the semi-open CO.sub.2 enrichment system; bringing the gaseous CO.sub.2 into direct contact with the brine solution; whereby a CO.sub.2-rich brine is formed; removing the CO.sub.2-rich brine from the brine semi-open CO.sub.2 enrichment system; and injecting the CO.sub.2-rich brine into a reservoir below the surface of the earth.

41. The method of claim 40, wherein the CO.sub.2-rich brine is a liquid, and is not a super critical fluid.

42. The system of claim 40, wherein the borehole extends less than 1,000 m below a surface of the earth.

43. The system of claim 40, wherein the brine solution is pumped from the reservoir, through a second borehole in the reservoir.

44. The methods of claim 40, wherein the CO.sub.2-rich brine comprises H.sub.2CO.sub.3 (carbonic acid) and/or one or more of the species H.sub.+, HCO.sub.3.sup.1− and CO.sub.3.sup.2−.

45. The methods of claim 40, wherein the source of CO.sub.2 is a cement plant.

46. A method for geologic storage of CO.sub.2 from modular point source emissions comprising: pumping brine water from a permeable reservoir; dissolving a CO.sub.2 stream in brine water; and injecting the CO.sub.2 into a storage aquifer to store the CO.sub.2.

47. The method of claim 46, wherein the CO.sub.2 is not a supercritical fluid.

48. The method of claim 46, wherein the shallowest point of the aquifer is less than 800 m below a surface of the earth.

Description

BRIEF DESCRIPTION

[0030] FIG. 1A is a schematic of an embodiment of a system and methods of dissolving CO.sub.2 in saline for subsurface storage in accordance with the present inventions.

[0031] FIG. 1B is a schematic of an embodiment of a system and methods of dissolving CO.sub.2 in saline for subsurface storage in accordance with the present inventions.

[0032] FIG. 2A is a phase diagram showing the solubility of CO.sub.2 in water with temperature and pressure.

[0033] FIG. 2B is a graph showing the density of CO.sub.2 as a function of pressure.

[0034] FIG. 3 is a graph showing the solubility of CO.sub.2 in water for different salinity levels.

[0035] FIG. 4 is a graph showing injection rate vs. permeability of the reservoir (denoted by Kh, or permeability(k)×height/thickness (h)) in accordance with the present inventions.

[0036] FIG. 5 is a schematic of an embodiment of a system and methods of dissolving CO.sub.2 in saline for subsurface storage using an embodiment of a CO.sub.2 enrichment reactor where an undersaturated solution of water is passed and flows counter flow to a stream of CO.sub.2 in accordance with the present inventions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The present invention relates to technical and economic systems, methods and devices for the storage of CO.sub.2 from a point source of CO.sub.2

[0038] An embodiment of the present inventions relates to methods, systems and devices for the subsurface storage of CO.sub.2 from an industrial point source that produces about 10 tons(“t”) of CO.sub.2/day, about 50 t of CO.sub.2/day, about 100 t of CO.sub.2/day, about 200 t of CO.sub.2/day, about 400 t of CO.sub.2/day, from about 10 t to about 500 t of CO.sub.2/day, from about 10 t to about 300 t of CO.sub.2/day, from about 50 t to about 250 t of CO.sub.2/day, from about 20 t to about 200 t of CO.sub.2/day, less than 300 t of CO.sub.2/day, less than 200 t of CO.sub.2/day, less than 100 t of CO.sub.2/day, less than 50 t of CO.sub.2/day, and larger and smaller amounts, as well as, all amounts within these ranges. Although discussed as tons/day, it is understood that this could be average tons/day based on a weekly, monthly, annually, project or run basis. The CO.sub.2 is dissolved in a brine or saline solution and then injected into a subsurface storage space, without the need to, and without using a SCF, i.e., without having to form, keep and maintain the CO.sub.2 as a SCF. Thus, in embodiments of the present inventions, the CO.sub.2 is dissolved in a brine or saline solution and then injected into a subsurface storage space in a formation in the ground, without forming, keeping and maintaining the CO.sub.2 as a SCF.

[0039] An embodiment of the present inventions relates to methods, systems and devices for the subsurface storage of CO.sub.2 from a modular industrial point source, for example a cement plant, having for example the daily production of CO.sub.2 as discussed above. The CO.sub.2 from this point source is dissolved in saline/brine solution and pumped into a subterranean storage space, e.g., a formation or reservoir within the earth. For example, the modular industrial point source can be one of the cement facilities set forth in US Application Publication No. 2022/0024818, the entire disclosure of which is incorporated herein by reference.

[0040] An embodiment of the present inventions relates to eliminating the need to use a supercritical fluid to store CO.sub.2 in subsurface storage space. A particular embodiment of the present invention relates to storing CO.sub.2 from a high purity modular point source of CO.sub.2 from a cement facility.

[0041] The invention relates to a method of storing CO.sub.2 in the subsurface. In an embodiment the method has three steps. The first step involves pumping of reservoir brine from a deep underground undrinkable aquifer, the second step involves dissolution of a high purity stream of CO.sub.2 gas into reservoir brine, the third and final step involves re-injection of a reservoir brine into the deep underground aquifer permanently storing CO.sub.2.

[0042] Thus, turning to FIG. 1A, there is shown a schematic of a method and system for subsurface CO.sub.2 without using a SCF. The CO.sub.2 subsurface storage system 100, has a CO.sub.2 enrichment unit 101 that is located on the surface 102 of the earth 103. It being understood that the unit 101 can be subsurface, or above the surface. The surface 102 can be dry land, or the surface of a sea bed.

[0043] A subsurface brine reservoir 104 is located below the surface 102 in the earth 104. The brine reservoir can be about 100 m below the surface 102, about 200 m below the surface 102, about 300 m below the surface 102, from 50 m to 1,000 m below the surface 102, from 100 m to 790 m below the surface 102, less than 1,000 m below the surface 102, less than 800 m below the surface 102, less than 700 m below the surface 102, less than 500 m below the surface 102, less than 300 m below the surface 102, and deeper and shallower depths.

[0044] The brine in the brine reservoir 104 can have a salinity of from about 0.3 molar to about 5 molar, from about 0.5 molar to about 4 molar, from about 1 molar to about 3 molar, about 0.6 molar, more than 0.4 molar, more than 0.5 molar, more than 0.6 molar, more than 0.7 molar, and greater and smaller concentrations.

[0045] The brine 105b from brine reservoir 104 flows into well (e.g., cased or uncased borehole) 105 as shown by arrow 105a. The brine 105b flows through tubulars (e.g., pipe) 106 from the surface 102 into the enrichment unit 101, as shown by arrow 106a. CO.sub.2 gas 107b is flowed into enrichment unit 101 by line (e.g., pipe) 107, as shown by arrow 107a. The CO.sub.2 gas is from a point source or sources, as discussed in this Specification (but not shown in the drawing).

[0046] The unit 101 has an outflow 108b shown by arrow 108a into line 108 (e.g., pipe) that is then flowed into well 109 (e.g., cased or uncased borehole). The outflow 108a flows through well 109 where is it flowed (e.g., injected) back into reservoir 104, as shown by arrow 109a.

[0047] The outflow 108b has the CO.sub.2 gas dissolved in the brine solution, and thus is a CO.sub.2 rich brine, which is made up of H.sub.2CO.sub.3 (carbonic acid), which is present in equilibrium, as discussed in greater detail below, as species H.sub.+, HCO.sub.3.sup.1− and CO.sub.3.sup.2−.

[0048] Turning to FIG. 1B the system 100b, is the embodiment of FIG. 1A (like numbers have like meaning) that has a horizontal well section 110 (preferably cased and perforated) that provides for flows (e.g., 110a) of outflow 108b into the reservoir 104.

[0049] The unit 101 has a housing 120 and has a means 121 within the housing to dissolve the CO.sub.2 gas into the brine solution. The system 100 has a removal pump 150 for pumping the brine solution out of the reservoir and into the unit 101. The system has an injunction pump 151 for pumping the outflow (e.g., CO.sub.2 rich brine) into the reservoir.

[0050] In this manner, the outflow 108 is returned to (e.g., injected into) the reservoir 104, where the dissolved CO.sub.2 gas is captured and held in the reservoir 104.

[0051] The parameters, e.g., pressure and temperature, under which the outflow 108 is flowed (e.g., injected) into the reservoir 104 are such that the outflow 108 is not a SCF. Preferably, the flow rate and the pressure of the outflow is such that the pressure in the formation that holds reservoir 104 is kept below (i.e., does not exceed) the closure pressure of the formation holding the reservoir 104; and thus, the formation is not hydraulically fractured, i.e., no new fractures are formed in the formation holding the reservoir.

[0052] The focus of the present specification is toward any modular high purity point source of CO.sub.2 emissions, these include process and energy emissions. An example of such a modular point source of CO.sub.2 emissions are modular cement plants. Modular plants include any manufacturing or processing facility where its pre-built components, or systems, can be transported to a location of use, by truck, rail, ship or air, and then assembled at the location into an operation plant. These would include any type of recycling, processing and manufacturing facilities.

[0053] It should be understood that although the focus of the present Specification is on these modular point sources of emission, the present inventions find applicability in fixed point source, and for larger fixed sources such as coal fired electrical generation, steel making, carbon black manufacture and others.

[0054] In general, for embodiments of the present systems and methods the CO.sub.2 gas is dissolved into the brine solution, using a means to dissolve the CO.sub.2 gas into the brine. In an embodiment the means to dissolve the CO.sub.2 gas into the brine is an enrichment unit. Preferably the enrichment unit is a semi-open system, e.g., CO.sub.2 gas is brought into contact with the brine through bubbling, mixing, falling liquids or liquid sprays, surface interactions, counter flows, laminar flows, gas blankets, and other forms of having the gas in direct contact with the liquid. The mixing of the CO.sub.2 with the brine may also be done by any other known and preferably commercially available systems for dissolving gases into liquids such as dissolving the gas into the brine within the injection well there by removing the need for a separate unit.

[0055] In an embodiment of such a semi-open enrichment system, the system has an inflow of CO.sub.2 gas through a brine solution. The flowing brine solution is open to, and in direct contact with CO.sub.2 gas. The CO.sub.2 may also be injected or flowed into the flow of brine co-currently, e.g., bubbled into the brine in the injection well.

[0056] The mole percent of carbon dioxide gas in water in equilibrium with atmospheric air (˜2.37%) is almost 60 times the mole percent of carbon dioxide gas in atmospheric air (˜0.04%) while that of each of the other atmospheric gases is less than they are in atmospheric air. Thus, if CO.sub.2 gas is input in a semi-open system where water (brine) that is undersaturated in CO.sub.2 is continuously being fed into the system and the brine saturated with CO.sub.2 is being removed from the system, CO.sub.2 is net removed from the gas phase and dissolved into the liquid phase. The entrapment of the CO.sub.2 into the brine to form a CO.sub.2 rich brine can be referred to as the CO.sub.2 enrichment stage in the process, i.e., the brine is enriched with CO.sub.2.

[0057] Turning to FIG. 5 there is shown an embodiment of a CO.sub.2 enrichment unit 500 for performing an enrichment stage. The semi-open enrichment unit 500 has a housing 504 that forms a chamber 505. The unit 500 has an inflow line 506, which flows (e.g., pumps) the brine solution from the reservoir that is depleted in CO.sub.2 into the chamber 505. The unit 500 has an outflow line 508 that takes away CO.sub.2 rich (e.g., saturated) brine solution from the chamber 505 for injection back into the reservoir. The brine solution 530 is flowed through the bottom of the chamber 505 and has a surface 533, which provides a surface area for contact and exchange with the CO.sub.2 blanket 520. CO.sub.2 gas 501a, 502a, 503a, is added to the chamber 505, from a point source or sources, through lines (e.g., pipes) 501, 502, 503. The CO.sub.2 gas forms a CO.sub.2 blanket 502 that has a surface 523, which provides a surface area for contact and exchange with the surface 533 of the flowing brine solution 530. The exchange of the CO.sub.2 gas into the brine solution occurs across surface 523-533. In this manner the brine solution 531 is depleted in CO.sub.2; and the brine solution 532 is rich in CO.sub.2.

[0058] In embodiments the unit 500 is a part of the system 100 of FIGS. 1A and 1B.

[0059] In an embodiment, a system, such as the embodiment of FIGS. 1, 2 and 5 receives a high purity stream of CO.sub.2 from the modular point source. In the dissolution process, carbon dioxide is dissolved into the water. Water used in this process is extracted from the injection reservoir.

[0060] The effect on the operating conditions in the semi-open enrichment systems can be any of those shown in FIGS. 2A, 2B and FIG. 3. In particular, any of the conditions shown FIG. 3 can be used, and any of the non-supercritical fluid conditions of FIGS. 2A and 2B can be used. In particular, the effect of salinity of the brine water and temperature on solubility is shown in these figures.

[0061] In an embodiment of the present CO.sub.2 capture systems, including the semi-open systems, a water recycle pump pumps the water, e.g., a brine solution from the reservoir, in a continuous loop extracting water undersaturated with CO.sub.2 then injecting CO.sub.2 enriched water into the reservoir.

[0062] The injectivity of a single-phase fluid within a reservoir is given by the equation below:

[00001]$\Delta p=\frac{Q{\mu }_w}{4\pi kb}\left(\ln \left(\frac{4kt}{{\mathrm{\varphi \mu }}_w{c}_t{r}^2}\right)-0.5772\right)$

[0063] Here Q is volumetric flow rate (m.sup.3/s), t is time, μ.sub.w is the viscosity of water, k is permeability of the reservoir, b is thickness of the reservoir, r is the radius of the well, Ct is 5×10.sup.−9 Pa.sup.−1, and ϕ is porosity. In general, a rule of thumb places a thermotical limit of a preferred injection pressure buildup to ˜150% of initial reservoir pressure. In general, a primary variable influencing the pressure build up is the permeability of the reservoir.

[0064] FIG. 4 shows the relationship between the maximum injection rate allowed to maintain safe injection pressures (<150%) and Kh (permeability×Thickness of the reservoir). The dotted black line shows an injection of 1 Mt of CO.sub.2/year (0.048 m.sup.3s.sup.−1), the amount required for an average coal fired power plant. The maximum acceptable injection rate for safe injection is plotted vs. Kh; for CO.sub.2 dissolved in water, line 603 (black line), super-critical CO.sub.2 via a vertical well, line 602 (redline) and scCO.sub.2 via. a 1 km long horizontal well, line 601. Shaded regions show the range of permeability values for different types of formations: Hyaloclastites 610, Flow top 611, Flow interior 612, Interbed 613.

[0065] This present invention includes drilling of both vertical and horizontal wells for storage of water. It is understood that one or more existing wells that are not producing, e.g., depleted, abandoned or otherwise not being used, e.g., dry hole, can be used, and used in conjunction with, a newly drilled well. Horizontal wells as shown in FIG. 4 the graph above will increase the surface area and injectivity by up to two orders of magnitude.

[0066] Injection rates above the safe injection threshold presented in FIG. 4 lead to fracturing of the host rock and can potentially compromise the integrity of the wells. As a result it is important to consistently inject below this threshold, e.g., the closure pressure of the formation.

[0067] Unlike the injection of supercritical CO.sub.2 which needs to be injected >800 m below the surface, the injection of CO.sub.2 saturated water can be injected at much shallower depths into saine aquifers. These can be anywhere preferably from 100 m to >800 m in depth. Selection of aquifers will depend on local geology, brine composition and also the proximity of other potentially freshwater aquifers.

EXAMPLES

[0068] The following examples provided illustrate various embodiments of the present systems, apparatus, and methods. These examples are for illustrative purposes, may be prophetic, and should not be viewed as, and do not otherwise limit the scope of the present inventions.

Example 1

[0069] A system of the type shown in FIG. 1A or 1B having a semi-open enrichment unit of the type shown in operation to dissolve CO2 in a brine. The CO.sub.2 enrichment reactor, the undersaturated solution of water (i.e., having little to no CO.sub.2) is passed and flows counter flow or co-current to a stream of CO.sub.2, here the water is saturated with CO.sub.2 and the saturated water is re-injected into the aquifer. Constant removal of the saturated water, ensures constant depletion of CO.sub.2 from the chamber, and thus ensures constant dissolution of the CO.sub.2 into the water. In a prefer embodiment the water is a saline solution, and in a more preferred embodiment the water is a brine solution.

[0070] If the enrichment chamber has an atmosphere of CO.sub.2 ˜2 MPa, the solubility of CO.sub.2 in the brine would be ˜3 kg/100 kg of water. FIG. 2, there is shown a graph of the solubility of CO.sub.2 in water (having various salinities) vs temperature). Based on these values, the dissolution of ˜100 t of CO.sub.2 in a brine would require a 30,000 t of water. 30,000 t/day equates to an injection rate of ˜3.85×10-4 m3 per second. This injection rate enables a preferred injection in reservoirs with a permeability (K) >0.01 Darcy.

[0071] While dissolution of CO.sub.2 in water and re-injection stores less CO.sub.2, per pound of fluid injected, when compared to SCF injection, there are several key benefits that provide significant advantages over SCF injection. For example, CO.sub.2 when dissolved in water is present as a bicarbonate ion, and as such the water with CO.sub.2 is more-dense than the original reservoir water and upon injection this fluid will sink to the bottom of a reservoir and CO.sub.2 will be trapped in the pore of this reservoir dissolved in water. In the presence of reactive alkali minerals, over time this slightly acidic solution could dissolve these minerals and form carbonate minerals following the equation below:

mM+2CO.sub.2(g)+H.sub.2O.fwdarw.sS+2HCO.sub.3.sup.−+aA+bB+cSiO.sub.2(aq)

[0072] Here, M is a silicate mineral, S a carbonate mineral and A and B are cations. When the pH recovers high enough, cations and bicarbonate ions in the fluid react to precipitate 2+2+2+ carbonates storing CO.sub.2 as Ca/Mg/Fe carbonate. Thus, CO.sub.2 could be stored in brine water or in the form of a mineral. In contrast when injecting CO.sub.2 as a supercritical fluid CO.sub.2 (SCF) is more buoyant, as a result it will rise to the top of a reservoir. So, a strong seal/caprock is required further more supercritical CO.sub.2 can only be injected >800 m depth such that temperature and pressure are sufficient to maintain that CO.sub.2 remains at a density such that it is in a supercritical phase and leakage remains less of an issue. CO.sub.2 dissolved in water side steps these technical challenges, with the prior SCF approach, so that drilling or storage efforts do not have a minimum depth instead drilling only needs to be deep enough so that it avoids potential contamination of any drinking aquifers. The shallow depth requirement also reduces the cost in drilling the wells. In embodiments the depth could be as low as 200 m to 400 m deep instead of 800 m. This would greatly reduce the the drilling costs. Furthermore, given CO.sub.2 is no longer in a plume of low density super critical fluid that needs to be monitored long term to avoid leakage, monitoring costs drop dramatically when CO.sub.2 is dissolved in water. Such that CO.sub.2 might not even need to be monitored if the reservoir has already been declared as isolated from any human drinking water. Furthermore, given the fluid will be denser—it's will sink and not rise. These key difference in storage relate to large cost savings when conducting a large-scale CO.sub.2 storage project and regulatory approvals. This makes an ideal solution for modular sources of emission.

[0073] CO.sub.2 saturated water creates a slightly acidic solution, in another embodiment injection of this solution may be used as an extraction technique to dissolve or leach specific alkali minerals in reservoirs by injecting the acidic solution and extracting or leaching key minerals and bringing this mineral rich fluid back to the surface where they are separated and the fluid is saturated with CO.sub.2 and re-injected.

[0074] It is noted that there is no requirement to provide or address the theory underlying the novel and groundbreaking performance or other beneficial features and properties that are the subject of, or associated with, embodiments of the present inventions. Nevertheless, various theories are provided in this specification to further advance the art in this important area, and in particular in the important area of cement and materials manufacture, calcining, pyrolysis, cost controls and minimizing greenhouse gasses. These theories put forth in this specification, and unless expressly stated otherwise, in no way limit, restrict or narrow the scope of protection to be afforded the claimed inventions. These theories many not be required or practiced to utilize the present inventions. It is further understood that the present inventions may lead to new, and heretofore unknown theories to explain the operation, function and features of embodiments of the methods, articles, materials, devices and system of the present inventions; and such later developed theories shall not limit the scope of protection afforded the present inventions.

[0075] The various embodiments of the processes, methods, assemblies, activities and operations set forth in this specification may be used in the above identified fields and in various other fields. Further, the various embodiments set forth in this specification may be used with each other in different and various combinations. Thus, for example, the configurations provided in the various embodiments of this specification may be used with each other. For example, the components of an embodiment having A, A′ and B and the components of an embodiment having A″, C and D can be used with each other in various combination, e.g., A, C, D, and A. A″ C and D, etc., in accordance with the teaching of this Specification. The scope of protection afforded the present inventions should not be limited to a particular embodiment, configuration or arrangement that is set forth in a particular embodiment, example, or in an embodiment in a particular Figure.

[0076] The invention may be embodied in other forms than those specifically disclosed herein without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.