Integrated device and method for continuously capturing, storing and separating flue gas in underground rock stratum

Abstract

An integrated device and a method for continuously capturing, storing and separating a flue gas in an underground rock stratum are provided. An injection well, a monitoring well and an emission well are arranged in sequence at locations from near to far from a flue gas emission source. The injection well, the monitoring well and the emission well are respectively drilled to different depths in a storage rock stratum. A horizontal injection channel is arranged at bottom end of the injection well. During migrating the flue gas in the storage rock stratum, CO.sub.2 and sulfur nitride are absorbed by a rock porous medium and gradually enriched, and meanwhile, the CO.sub.2 and sulfur nitride, after chemically reacting with water, minerals and biomass in a rock, are gradually mineralized to achieve storage; and separated N.sub.2 is gradually migrated upwards to the emission well to achieve separation.

Claims

1. An integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum, comprising: an injection well, a monitoring well and an emission well, which are arranged in sequence at locations from near to far from a flue gas emission source, so as to form a well pattern, the injection well comprising at least one injection well, the monitoring well comprising at least two monitoring wells, and the emission well comprising at least four emission wells, and a pore aperture diameter of each emission well being greater than that of each monitoring well and less than that of each injection well; a well pattern mode promoting the flue gas to migrate in an underground rock porous medium for a distance to undergo a physical and chemical reaction process of differential adsorption, dissolution mineralization and biomass reaction, and in combination with a way of injecting an amount of water or saline or biomass water with a concentration into a storage rock stratum in real time by the monitoring wells, effective capture and storage of CO.sub.2 and sulfur nitride and separation and emission of N.sub.2 in the flue gas are completed; a distance from the injection well to the flue gas emission source being less than 1 km, a distance from the monitoring wells to the flue gas emission source being 2-5 km, and a distance from the emission wells to the flue gas emission source being 5-10 km; the injection well, the monitoring wells and the emission wells being respectively drilled to different depths in a storage rock stratum; a horizontal injection channel being arranged at a bottom end of the injection well; a length of the horizontal injection channel being between the injection well and the emission wells, and the horizontal injection channel not being in communication with the monitoring wells; a backpressure valve being arranged at a wellhead location of each of the monitoring wells and the emission wells; the flue gas being pressed into the injection well, an injection pressure of the flue gas being less than or equal to 10 MPa, and enters-entering the storage rock stratum along the horizontal injection channel; CO.sub.2 and sulfur nitride in the flue gas being dynamically captured and stored during migrating of the flue gas in the storage rock stratum, and N.sub.2 being separated and then migrated upwards to the emission well to be emitted; and an end hole location of the injection well being located at a lower middle region of the storage rock stratum, an end hole location of each monitoring well being located at a middle region of the storage rock stratum, and an end hole location of each emission well being located at an upper middle region of the storage rock stratum.

2. The integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum according to claim 1, wherein the horizontal injection channel is formed by implementing hydraulic fracturing or a directional horizontal well at the bottom end of the injection well.

3. The integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum according to claim 1, wherein each of a roof and a floor of the storage rock stratum has a lithology of an impermeable caprock.

4. A method for capturing, storing and separating flue gas implemented by the integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum according to claim 1, the method comprising the following steps: (1) drilling and completing the injection well, the monitoring wells and the emission wells; (2) implementing a perforation operation at a storage rock stratum section at a lower portion in the injection well to form a flue gas injection hole, and making the horizontal injection channel at the bottom end of the injection well; (3) after dust removal and cooling, pressing the flue gas into the injection well, to enter the storage rock stratum through the flue gas injection hole and the horizontal injection channel, wherein an injection pressure of the flue gas is less than or equal to 10 MPa; and (4) during migrating the flue gas in the storage rock stratum, adsorbing CO.sub.2 and sulfur nitride by a rock porous medium, and enriching the CO.sub.2 and sulfur nitride into the rock porous medium to achieve capture of the CO.sub.2; meanwhile, mineralizing the CO.sub.2 and sulfur nitride after the CO.sub.2 and sulfur nitride chemically react with water, minerals and biology bacteria in a rock to achieve storage of the CO.sub.2, and migrating separated N.sub.2 upwards to the emission well to achieve separation of the CO.sub.2.

5. The method for capturing, storing and separating flue gas implemented by the integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum according to claim 4, wherein a method for making the horizontal injection channel is to implement hydraulic fracturing at the bottom end of the injection well to form an injection fracture surface, or to implement a directional horizontal well at the bottom end of the injection well, and to carry out staged pinnate fracturing inside the directional horizontal well, so as to form a horizontal injection channel.

6. The method for capturing, storing and separating flue gas implemented by the integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum according to claim 4, wherein an open pressure of each backpressure valve of each emission well is set to be 0.3-0.4 MPa, and wherein when a pressure of N.sub.2 in each emission well reaches the open pressure, each backpressure valve of each emission well is opened to emit N.sub.2 into atmosphere.

7. The method for capturing, storing and separating flue gas implemented by the integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum according to claim 4, wherein during pressing the flue gas, characteristic changes of gas component, concentration and pressure in the storage rock stratum are monitored in real time by at least one of the backpressure valves of the monitoring wells; and according to the changes of the gas component and concentration, water is injected into the storage rock stratum through at least one of the monitoring wells to promote the capture and storage of CO.sub.2 and sulfur nitride and the separation of N.sub.2 in the flue gas.

8. The method for capturing, storing and separating flue gas implemented by the integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum according to claim 4, wherein the horizontal injection channel is formed by implementing hydraulic fracturing or a directional horizontal well at the bottom end of the injection well.

9. The method for capturing, storing and separating flue gas implemented by the integrated device for continuously capturing, storing and separating a flue gas in an underground rock stratum according to claim 4, wherein each of a roof and a floor of the storage rock stratum has a lithology of an impermeable caprock.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a plan view of an integrated well pattern technique for continuously capturing-storing-separating a small-scale flue gas in an underground rock stratum;

(2) FIG. 2 is a front view of an integrated well pattern technique for continuously capturing-storing-separating a small-scale flue gas in an underground rock stratum;

(3) FIG. 3 is a plan view of an integrated well pattern technique for continuously capturing-storing-separating a large-scale flue gas in an underground rock stratum;

(4) FIG. 4 is a front view of an integrated well pattern technique for continuously capturing-storing-separating a large-scale flue gas in an underground rock stratum.

(5) In the drawings: 1-flue gas outlet; 2-injection well; 3-monitoring well; 4-emission well; 5-storage rock stratum; 6-backpressure valve; 7-upper caprock; 8-lower caprock; 9-flue gas injection hole; 10-horizontal injection fracture surface; 11-gas compressor; 12-600,000 KW generator set; 13-1 million KW generator set; 14-directional horizontal well.

DETAILED DESCRIPTION

(6) In order to make the technical problems to be solved by the present disclosure, technical solutions and beneficial effects more clearly, the present disclosure is further described in detail with reference with the embodiments and accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present disclosure, rather than limiting. The technical solution of the present disclosure is described in detail below in conjunction with the embodiments and accompanying drawings, but the scope of protection is not limited.

Embodiment 1

(7) The amount of coal consumed by a power plant with a 600,000 KW generator set is about 4,000 tons per day, and a concentration of CO.sub.2 in a flue gas is 15%, so the power plant with 600,000 KW generator set emits 4107 m.sup.3 of flue gas per day, which belongs to small-scale flue gas emission level. Referring to FIG. 1 and FIG. 2, an integrated device and method for continuously capturing, storing and separating a flue gas in an underground rock stratum provided in this embodiment are used to separate and store the flue gas, specifically as follows:

(8) (1) An injection well 2 is arranged at a linear distance of 0.2 km from a flue gas outlet 1 of a 600,000 KW generator set 12. Two monitoring wells 3 are arranged at a linear distance of 3 km from the flue gas outlet 1, and four emission wells 4 are arranged at a linear distance of 6 km from the flue gas outlet 1, as shown in FIG. 1. Pore aperture diameters of openings of the injection well 2, the monitoring well 3 and the emission well 4 on the ground are 350 mm, 80 mm and 120 mm, respectively.

(9) (2) Drilling operation is as follows: referring to FIG. 2, the injection well 2, the monitoring well 3 and the emission well 4 are drilled to a lower middle region, a middle region and an upper middle region of a storage rock stratum 5, respectively, and the completion work of well is completed. Finally, backpressure valves 6 are installed at wellhead locations of the monitoring well 3 and the emission well 4, respectively. A roof of the storage rock stratum 5 is an impermeable upper caprock 7, and a floor of the storage rock stratum 5 is an impermeable lower caprock 8.

(10) (3) A perforation operation is implemented in a storage rock stratum section at a lower portion in the injection well 2 to form a flue gas injection hole 9. Further, hydraulic fracturing is controlled and implemented at a bottom end of the injection well 2 to form a horizontal injection fracture surface 10. An extension radius of the horizontal injection fracture surface 10 is controlled within a middle position between the injection well 2 and the emission well 4, and the horizontal injection fracture surface 10 does not communicate with the monitoring well 3 during the horizontal extension.

(11) (4) The flue gas continuously produced by the flue gas outlet 1, is removed dust and cooled, and then is pressed into the injection well 2 by a gas compressor 11 on the ground after the pressure is increased to 5 MPa, and then the flue gas enters the storage rock stratum 5 through the flue gas injection hole 9 and the horizontal injection fracture surface 10.

(12) (5) During long-distance migration of the flue gas in the storage rock stratum 5, CO.sub.2 and sulfur nitride are gradually enriched and captured in a rock porous medium due to the characteristics that the adsorption of CO.sub.2 and sulfur nitride by the rock porous medium is greater than that of N.sub.2. Meanwhile, the CO.sub.2 and sulfur nitride, after chemically reacting with water and minerals in a rock, are gradually mineralized and stored. At the same time, the remaining N.sub.2 is gradually sorted upwards and migrated to the emission well 4 to achieve separation.

(13) (6) An open pressure of the backpressure valve 6 arranged at the emission well 4 is 0.3 MPa, after the N.sub.2 pressure in the emission well 4 reaches the open pressure, the N.sub.2 is emitted to atmosphere through the backpressure valve 6 of the emission well 4.

(14) (7) During injecting the flue gas, characteristic changes of gas component, concentration and pressure in the storage rock stratum 5 are monitored in real time by the backpressure valve of the monitoring well 3. According to real-time change data of the gas component and concentration, a certain amount of water or saline or biomass water with a certain concentration is injected into the storage rock stratum 5 through the monitoring well 3, so as to promote the capture and storage of CO.sub.2 and sulfur nitride and the separation of N.sub.2 in the flue gas.

Embodiment 2

(15) The amount of coal consumed by a power plant with two 1 million KW generator sets is about 16,000 tons per day, and a concentration of CO.sub.2 in a flue gas is 15%, so the power plant with the two 1 million KW generator sets emits 1.6108 m.sup.3 of flue gas per day, which belongs to medium and large-scale flue gas emission level. Referring to FIG. 3 and FIG. 4, a an integrated device and method for continuously capturing, storing and separating a flue gas in an underground rock stratum provided in this embodiment are used to separate and store the flue gas, specifically as follows:

(16) (1) An injection well 2 is arranged at a linear distance of 0.3 km from a flue gas outlet 1 of each of the two 1 million KW generator sets 13. A monitoring well 3 is arranged at a linear distance of 4 km from each flue gas outlet 1, and meanwhile, one monitoring well 3 is arranged at a distance of 4 km from each of both sides of the two 1 million KW generator sets 13. Two emission wells 4 are arranged at a linear distance of 8 km from each of the two 1 million KW generator sets 13, and an emission well 4 is arranged at a distance of 8 km from each of both sides of the two 1 million KW generator sets 13. That is, two injection wells 2, four monitoring wells 3 and six emission wells 4 are arranged in total, as shown in FIG. 3. Pore aperture diameters of openings of the injection well 2, the monitoring well 3 and the emission well 4 on the ground are 450 mm, 90 mm and 150 mm, respectively.

(17) (2) Drilling operation is as follows: referring to FIG. 2, the injection well 2, the monitoring well 3 and the emission well 4 are drilled to a lower middle region, a middle region and an upper middle region of a storage rock stratum 5, respectively, and the completion work of well is completed. Finally, backpressure valves 6 are installed at wellhead locations of the monitoring well 3 and the emission well 4, respectively. A roof of the storage rock stratum 5 is an impermeable upper caprock 7, and a floor of the storage rock stratum 5 is an impermeable lower caprock 8.

(18) (3) A perforation operation is implemented in a storage rock stratum section at a lower portion in the injection well 2 to form a flue gas injection hole 9. Further, a directional horizontal well is implemented at a bottom end of the injection well 2, and the interior of the directional horizontal well is subjected to staged pinnate fracturing to form a horizontal well injection channel. A length of the directional horizontal well 14 is controlled within a middle position between the injection well 2 and the emission well 4, and the directional horizontal well 14 does not communicate with the monitoring well 3.

(19) (4) The flue gas continuously produced by the flue gas outlet 1, is removed dust and cooled, and then is pressed into the two injection wells 2 by a gas compressor 11 on the ground after the pressure is increased to 8 MPa, and then the flue gas enters the storage rock stratum 5 through the flue gas injection hole 9 and the horizontal well injection channel.

(20) (5) During long-distance migration of the flue gas in the storage rock stratum 5, CO.sub.2 and sulfur nitride are gradually enriched and captured in a rock porous medium due to the characteristics that the adsorption of CO.sub.2 and sulfur nitride by the rock porous medium is greater than that of N.sub.2. Meanwhile, the CO.sub.2 and sulfur nitride, after chemically reacting with water and minerals in a rock, are gradually mineralized and stored. At the same time, the remaining N.sub.2 is gradually sorted upwards and migrated to the emission well 4 to achieve separation (Referring to FIG. 4).

(21) (6) An open pressure of the backpressure valve 6 arranged at the emission well 4 is 0.4 MPa, after the N.sub.2 pressure in the emission well 4 reaches the open pressure, the N.sub.2 is emitted to atmosphere through the backpressure valve 6 of the emission well 4.

(22) (7) During injecting the flue gas, characteristic changes of gas component, concentration and pressure in the storage rock stratum 5 are monitored in real time by the backpressure valve of the monitoring well 3. According to real-time change data of the gas component and concentration, a certain amount of water or saline or biomass water with a certain concentration is injected into the storage rock stratum 5 through the monitoring well 3 in real time, so as to promote the capture and storage of CO.sub.2 and sulfur nitride and the separation of N.sub.2 in the flue gas.

(23) The above is a further detailed description of the present disclosure in conjunction with specific preferred embodiments, and cannot be considered that the specific embodiments of the present disclosure are limited thereto. For those of ordinary skill in the art, several simple deductions or substitutions can be made without departing from the present disclosure, which should all be regarded as belonging to the scope of protection determined by the claims submitted in the present disclosure.