Method for permanently sequestering carbon dioxide through geological minerals and jointly improving geothermal grade

Abstract

The invention discloses a method for permanently sealing and storing carbon dioxide by geological minerals and jointly improving geothermal grade. The method comprises the following steps: selecting injection and screening stratum conditions, rapidly mineralizing and fixing carbon dioxide, and coupling heat release and reaction rate to improve the geothermal grade. The method for permanently and stably sealing and storing carbon dioxide and jointly improving the geothermal grade has good geological stability and good economic benefits, and can be used as a compensation means for compensating energy consumption and economic cost in the carbon dioxide sealing and storing process. According to the method, geological minerals are used as geological carbon sequestration for sequestration of carbon dioxide, and injection and strata screening conditions are used as regulation and control factors, so that the leakage risk of conventional carbon dioxide sequestration is well solved, the economic feasibility of geological carbon dioxide sequestration is further improved, and the method is of great significance in carbon sequestration, emission reduction and increase of carbon sequestration ways.

Description

Technical Field

[0001] The present invention relates to the fields of carbon emission reduction, geological engineering and environmental protection engineering, and in particular to a method for permanently sealing carbon dioxide with geological minerals and jointly improving geothermal grade. Background Art

[0002] Industrial development has emitted a large amount of greenhouse gases and over the years, it is warming the atmosphere, oceans and land, triggering global climate change, which has now caused huge human and economic losses, and urgently requires the reduction of carbon dioxide emissions into the atmosphere. However, the actual natural carbon sink is far lower than the carbon emissions, especially in developing countries like China. Developed countries have already formed a huge amount of carbon emissions to the atmosphere due to early development. Although carbon emissions are currently decreasing, they all have high requirements for carbon dioxide capture and storage to achieve the goal of carbon neutrality. The development of artificial carbon sinks has the current carbon dioxide geological storage technology, but it will be affected by geological conditions and their changes such as earthquakes, causing the artificially stored carbon dioxide to return to the atmosphere again.

[0003] Carbon dioxide reacts with geological minerals to form carbonate rocks, which is the so-called geological mineral carbonization process. The top of the rock layer is an impermeable, non-reactive cap rock. The overall geological environment involved is very stable and environmentally friendly. Even under natural acidic and high-temperature geothermal conditions, the stored carbon dioxide will not return to the atmosphere as in the aforementioned artificial geological storage. The geological mineral carbonization process is an exothermic process. By selecting the carbon dioxide injection conditions and the geological conditions of the formation, the geothermal grade of the original formation is improved, and then this part of the geological energy is utilized, which is of great significance to the economic efficiency of the geological storage project of carbon dioxide by geological mineral carbonization. Therefore, this geological mineral carbonization method of using geological minerals to store carbon dioxide and improve geothermal grade will economically support carbon emission reduction work and is an environmentally friendly and economical technology. Summary of the invention

[0004] The purpose of the present invention is to provide a method for permanently and stably sealing carbon dioxide with geological minerals and simultaneously improving geothermal grade. The method proposed in the present invention can quickly, stably and permanently fix carbon dioxide in minerals, extract energy from the reaction and use it to improve geothermal grade, better achieve carbon dioxide sealing while fully utilizing geological energy, and solve the stability and economy problems of conventional geological sealing.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0007] (1) Selecting injection and screening formation conditions: Different injection conditions and formation conditions bring different geological mineral carbonization effects. Selecting corresponding injection conditions under different formation conditions can improve energy utilization. The formation conditions include: underground depth 0 to 3000m, formation temperature 10°C to 300°C, formation flow pressure 0.1 to 30MPa, formation porosity 0.01% to 50%, formation permeability 1×10 -20 ~1×10 -10 m 2 , the volume of formation minerals is 1~1×10 20 m 3 , the injection conditions of carbon dioxide include: carbon dioxide temperature 20℃~300℃, carbon dioxide pressure 0.1~40MPa, injection time 1~7300 days;

[0008] (2) Rapid mineralization and fixation of carbon dioxide, coupling heat release with reaction rate to improve geothermal grade: Inject carbon dioxide into the geological mineral selected in step (1). After seepage and mass transfer, the mineral reacts with carbon dioxide to quickly generate stable carbonates. The mineral carbonization reaction is an exothermic process. The appropriate temperature of carbon dioxide is regulated to maximize the reaction rate. The exothermic process of the mineral carbonization reaction is coupled with the reaction rate to improve the geothermal grade.

[0009] The effect of heat release of mineral carbonization reaction on reaction rate is: when the regional formation temperature is less than or equal to the optimal mineral carbonization reaction temperature, heat release accelerates the reaction rate; when the regional formation temperature is greater than the optimal mineral carbonization reaction temperature, heat release slows down the reaction rate; the effect of reaction rate on heat release rate is: the faster the reaction rate, the faster the heat release rate.

[0010] The method proposed by the present invention for improving geothermal grade by permanently storing carbon dioxide with geological minerals comprises the following steps: selecting injection and screening formation conditions, fast mineralization and fixation of carbon dioxide, and coupling heat release with reaction rate to improve geothermal grade. In step (1), different carbonization effects of geological minerals represent different carbon dioxide storage rates and geothermal grade improvement ranges, and energy utilization is the effect of process heat release on the carbonization effect of geological minerals; the seepage and mass transfer in step (2) create conditions for carbon dioxide to react with the surface of geological minerals, and the generated carbonate can stably fix carbon dioxide underground. The heat release rate in step (2) depends on the reaction rate and will also affect the reaction rate. The coupling of the two can improve geothermal grade.

[0011] The present invention constructs technical routes such as mineralization and fixation of carbon dioxide, process heat release to improve geothermal grade, and optimal injection conditions for different formation conditions, which improves energy efficiency, can fix carbon dioxide on a large scale and improve geothermal grade, and improve energy utilization efficiency.

[0012] Preferably, the geological minerals in step (1) include peridotite, serpentinite, basalt, wollastonite and anorthite.

[0013] Preferably, the formation conditions in step (1) meet the following conditions: underground depth 1000m, formation temperature 37°C to 185°C, formation flow pressure 10MPa, formation porosity 10%, formation permeability 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

[0014] Preferably, the injection conditions of the carbon dioxide into the geological minerals in step (2) include: carbon dioxide temperature of 37°C to 185°C, carbon dioxide pressure of 15MPa, and injection time of 730 days. The energy required for controlling the temperature of carbon dioxide before injection can come from ventilation flue gas from nearby power plants, high-temperature geothermal energy, associated gas from oil fields after combustion, and solar collectors.

[0015] Preferably, the geothermal temperature in step (2) ranges from 20°C to 500°C.

[0016] More preferably, the geothermal grade described in step (2) includes low-temperature geothermal, medium-temperature geothermal, and high-temperature geothermal.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: drilling and injecting carbon dioxide into geological minerals will quickly produce carbonates in suitable geological structures to achieve permanent and stable storage of carbon dioxide, and at the same time, the reaction process will generate recoverable heat to increase the formation temperature; in actual operation, there is an optimal reaction temperature for mineral carbonization, and energy utilization can be improved by selecting injection and screening formation conditions. The method of permanently and stably storing carbon dioxide and improving geothermal grade proposed in the present invention has good geological stability and good economic benefits, and can be used as a means of compensating for energy consumption and economic costs in the process of carbon dioxide storage. The present invention uses geological minerals as geological carbon sinks for storing carbon dioxide, and injecting and screening formation conditions as regulating factors, which well solves the leakage risk of conventional carbon dioxide storage, and further improves the economic feasibility of geological storage of carbon dioxide, which is of great significance to carbon fixation and emission reduction, and increasing carbon sinks. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below with reference to the examples. These examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually carried out according to conventional conditions in the art or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are deemed to be raw materials and reagents that can be obtained through commercial channels such as conventional markets. The present invention proposes that the reactions can be carried out continuously until the relevant geological minerals in the selected area are exhausted, and the required energy comes from the ventilation flue gas of nearby power plants, high-temperature geothermal energy, associated gas from oil fields after combustion, and solar collectors.

[0019] Example 1

[0020] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0021] (1) Injection and screening of formation conditions: Under the conditions of injection temperature of 90°C, pressure of 15 MPa, injection time of 730 days, underground depth of 1000 m, formation temperature of 90°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

[0022] (2) Rapid mineralization and fixation of carbon dioxide: Carbon dioxide is injected into the geological mineral peridotite. After seepage and mass transfer through porous rocks, the peridotite reacts with carbon dioxide to form stable carbonate precipitates.

[0023] (3) Coupling heat release and reaction rate to improve geothermal grade: Every kilogram of peridotite reacts with carbon dioxide to produce carbonates and releases 760 kJ of heat. When the formation temperature is below 185°C, the heat release will increase the reaction rate, and when the formation temperature is above 185°C, the heat release will reduce the reaction rate.

[0024] The implementation effect is: geological mineralization stores 70,000 tons of carbon dioxide and the geothermal temperature increases by 22°C.

[0025] Example 2

[0026] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0027] (1) Injection and screening of formation conditions: Under the conditions of injection temperature of 100°C, pressure of 15 MPa, injection time of 730 days, underground depth of 1000 m, formation temperature of 100°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6m 3 .

[0028] (2) Rapid mineralization and fixation of carbon dioxide: Carbon dioxide is injected into the geological mineral peridotite. After seepage and mass transfer through porous rocks, the peridotite reacts with carbon dioxide to form stable carbonate precipitates.

[0029] (3) Coupling heat release and reaction rate to improve geothermal grade: Every kilogram of peridotite reacts with carbon dioxide to produce carbonates and releases 760 kJ of heat. When the formation temperature is below 185°C, the heat release will increase the reaction rate, and when the formation temperature is above 185°C, the heat release will reduce the reaction rate.

[0030] The implementation results are: geological mineralization has stored 230,000 tons of carbon dioxide and the geothermal temperature has increased by 82°C.

[0031] Example 3

[0032] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0033] (1) Injection and screening of formation conditions: Under the conditions of injection temperature of 110°C, pressure of 15 MPa, injection time of 730 days, underground depth of 1000 m, formation temperature of 110°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

[0034] (2) Rapid mineralization and fixation of carbon dioxide: Carbon dioxide is injected into the geological mineral peridotite. After seepage and mass transfer through porous rocks, the peridotite reacts with carbon dioxide to form stable carbonate precipitates.

[0035] (3) Coupling heat release and reaction rate to improve geothermal grade: Every kilogram of peridotite reacts with carbon dioxide to produce carbonates and releases 760 kJ of heat. When the formation temperature is below 185°C, the heat release will increase the reaction rate, and when the formation temperature is above 185°C, the heat release will reduce the reaction rate.

[0036] The implementation results are: 340,000 tons of carbon dioxide are stored by geological mineralization and the geothermal temperature is increased by 119°C.

[0037] Example 4

[0038] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0039] (1) Injection and screening of formation conditions: Under the conditions of injection temperature of 120°C, pressure of 15 MPa, injection time of 730 days, underground depth of 1000 m, formation temperature of 120°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

[0040] (2) Rapid mineralization and fixation of carbon dioxide: Carbon dioxide is injected into the geological mineral peridotite. After seepage and mass transfer through porous rocks, the peridotite reacts with carbon dioxide to form stable carbonate precipitates.

[0041] (3) Coupling heat release and reaction rate to improve geothermal grade: Every kilogram of peridotite reacts with carbon dioxide to produce carbonates and releases 760 kJ of heat. When the formation temperature is below 185°C, the heat release will increase the reaction rate, and when the formation temperature is above 185°C, the heat release will reduce the reaction rate.

[0042] The implementation effect is: geological mineralization stores 360,000 tons of carbon dioxide and the geothermal temperature increases by 125°C.

[0043] Example 5

[0044] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0045] (1) Injection and screening of formation conditions: Under the conditions of injection temperature of 130°C, pressure of 15 MPa, injection time of 730 days, underground depth of 1000 m, formation temperature of 130°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

[0046] (2) Rapid mineralization and fixation of carbon dioxide: Carbon dioxide is injected into the geological mineral peridotite. After seepage and mass transfer through porous rocks, the peridotite reacts with carbon dioxide to form stable carbonate precipitates.

[0047] (3) Coupling heat release and reaction rate to improve geothermal grade: Every kilogram of peridotite reacts with carbon dioxide to produce carbonates and releases 760 kJ of heat. When the formation temperature is below 185°C, the heat release will increase the reaction rate, and when the formation temperature is above 185°C, the heat release will reduce the reaction rate.

[0048] The implementation results are: 350,000 tons of carbon dioxide are stored by geological mineralization and the geothermal temperature is increased by 122°C.

[0049] Example 6

[0050] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0051] (1) Injection and screening of formation conditions: Under the conditions of injection temperature of 150°C, pressure of 15 MPa, injection time of 730 days, underground depth of 1000 m, formation temperature of 150°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

[0052] (2) Rapid mineralization and fixation of carbon dioxide: Carbon dioxide is injected into the geological mineral peridotite. After seepage and mass transfer through porous rocks, the peridotite reacts with carbon dioxide to form stable carbonate precipitates.

[0053] (3) Coupling heat release and reaction rate to improve geothermal grade: Every kilogram of peridotite reacts with carbon dioxide to produce carbonates and releases 760 kJ of heat. When the formation temperature is below 185°C, the heat release will increase the reaction rate, and when the formation temperature is above 185°C, the heat release will reduce the reaction rate.

[0054] The implementation results are: 320,000 tons of carbon dioxide are stored by geological mineralization and the geothermal temperature is increased by 109°C.

[0055] Example 7

[0056] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0057] (1) Injection and screening of formation conditions: Under the conditions of injection temperature of 37°C, pressure of 15 MPa, injection time of 730 days, underground depth of 1000 m, formation temperature of 185°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

[0058] (2) Rapid mineralization and fixation of carbon dioxide: Carbon dioxide is injected into the geological mineral peridotite. After seepage and mass transfer through porous rocks, the peridotite reacts with carbon dioxide to form stable carbonate precipitates.

[0059] (3) Coupling heat release and reaction rate to improve geothermal grade: Every kilogram of peridotite reacts with carbon dioxide to produce carbonates and releases 760 kJ of heat. When the formation temperature is below 185°C, the heat release will increase the reaction rate, and when the formation temperature is above 185°C, the heat release will reduce the reaction rate.

[0060] The implementation effect is: geological mineralization stores 250,000 tons of carbon dioxide and the geothermal temperature increases by 63°C.

[0061] Example 8

[0062] A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal quality comprises the following steps:

[0063] (1) Injection and screening of formation conditions: Under the conditions of injection temperature of 107°C, pressure of 15 MPa, injection time of 730 days, underground depth of 1000 m, formation temperature of 37°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

[0064] (2) Rapid mineralization and fixation of carbon dioxide: Carbon dioxide is injected into the geological mineral peridotite. After seepage and mass transfer through porous rocks, the peridotite reacts with carbon dioxide to form stable carbonate precipitates.

[0065] (3) Coupling heat release and reaction rate to improve geothermal grade: Every kilogram of peridotite reacts with carbon dioxide to produce carbonates and releases 760 kJ of heat. When the formation temperature is below 185°C, the heat release will increase the reaction rate, and when the formation temperature is above 185°C, the heat release will reduce the reaction rate.

[0066] The implementation effect is: geological mineralization stores 300,000 tons of carbon dioxide and the geothermal temperature increases by 90°C.

[0067] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for permanently storing carbon dioxide with geological minerals and jointly improving geothermal grade, characterized in that: The steps include: (1) Selecting injection and screening formation conditions: Different injection conditions and formation conditions bring different geological mineral carbonization effects. Selecting corresponding injection conditions under different formation conditions can improve energy utilization. The formation conditions include: underground depth 0 to 3000m, formation temperature 10°C to 300°C, formation flow pressure 0.1 to 30MPa, formation porosity 0.01% to 50%, formation permeability 1×10 -20 ~1×10 -10 m 2 , the volume of formation minerals is 1~1×10 20 m 3 , the injection conditions of carbon dioxide include: carbon dioxide temperature 20℃~300℃, carbon dioxide pressure 0.1~40MPa, injection time 1~7300 days; (2) Rapid mineralization and fixation of carbon dioxide, coupling heat release with reaction rate to improve geothermal grade: Inject carbon dioxide into the geological mineral selected in step (1). After seepage and mass transfer, the mineral reacts with carbon dioxide to quickly generate stable carbonates. The mineral carbonization reaction is an exothermic process. The appropriate temperature of carbon dioxide is regulated to maximize the reaction rate. The exothermic process of the mineral carbonization reaction is coupled with the reaction rate to improve the geothermal grade.

2. The method according to claim 1, characterized in that The geological minerals described in step (1) include peridotite, serpentinite, basalt, wollastonite and anorthite.

3. The method according to claim 1, characterized in that The formation conditions in step (1) include: underground depth of 1000 m, formation temperature of 37°C to 185°C, formation flow pressure of 10 MPa, formation porosity of 10%, and formation permeability of 1×10 -13 m 2 , the volume of formation minerals is 1×10 6 m 3 .

4. The method according to claim 1, characterized in that: The injection conditions of injecting carbon dioxide into geological minerals in step (2) include: carbon dioxide temperature of 37° C. to 185° C., carbon dioxide pressure of 15 MPa, and injection time of 730 days.

5. The method according to claim 1, characterized in that: The geothermal temperature in step (2) ranges from 20°C to 500°C.

6. The method according to claim 1 or 7, characterized in that: The geothermal grades described in step (2) include low-temperature geothermal, medium-temperature geothermal, and high-temperature geothermal.