CN106130406B - Stratum itself low-temperature receiver type hot dry rock thermoelectric heat generation system and method - Google Patents

Abstract

The invention relates to a self-cooling source type hot dry rock thermoelectric power generation system. The system includes: an underground thermoelectric power generation module, a negative lead wire, and a positive lead wire; within the overlying strata of the hot dry rock; the part of the downhole thermoelectric power generation module within the overlying stratum of the hot dry rock is in direct contact with the part of the wellbore completed by the casing cementing method, forming a low-temperature cold end of the stratum’s own cold source type hot dry rock thermoelectric power generation; The electric energy generated by the downhole thermoelectric generation module is supplied to the ground load through the positive wire and the negative wire; the downhole thermoelectric power generation module, the positive wire, the ground load and the negative wire are sequentially connected to form a closed circuit. The invention only needs one geothermal well drilled through the hot dry rock reservoir, and does not need to build an artificial heat storage. The thermoelectric module arranged in the well is used to realize the on-site power generation of the hot dry rock reservoir, and the heat energy extracted by the cold end of the thermoelectric power generation system can be used for Heating, breeding, bathing and other applications.

Description

Formation self-cooling source type hot dry rock thermoelectric power generation system and method

technical field

The present invention relates to the field of geothermal power generation, in particular to a system and method for thermoelectric power generation of hot dry rock with self-cooling source of formation.

technical background

Geothermal energy is a huge natural resource stored in the interior of the earth. It has large reserves and is clean and pollution-free. It has long been concerned by countries all over the world. The development and utilization of geothermal resources can achieve energy saving, emission reduction, and environmental protection, and is considered to be an effective means to solve smog. At present, hot water and steam geothermal resources are mainly developed and utilized, which are often used in heating, breeding and power generation. In contrast, the development of hot dry rock has just emerged, but its reserves are much higher than the hot water and steam geothermal resources that have been widely used. Power generation is considered to be the most important application field of hot dry rock.

Hot dry rock power generation mainly forms artificial heat storage through hydraulic fracturing, and then injects water or carbon dioxide and other working fluids through injection wells, and after energy exchange with artificial heat storage, high-temperature water or steam is produced from production wells and sent to conventional geothermal energy. The power generating device generates power. This method requires at least one injection well and one production well, the reservoir needs to be artificially fractured, and the circulating working medium water or carbon dioxide needs to be continuously injected during operation. The technology is expensive to build and run.

With the advancement of material technology, thermoelectric power generation technology is gradually emerging. When different temperatures are applied to both ends of a conductor or semiconductor, due to the Seebeck effect, an electromotive force is generated between the high temperature part and the low temperature part. Utilizing this phenomenon, thermal energy can be directly converted into electrical energy using a thermoelectric power generation element. This thermoelectric power generation technology has been widely used in new energy fields such as automobile exhaust waste heat power generation, industrial waste heat power generation, and solar power generation.

Aiming at the problems existing in traditional hot dry rock power generation, considering the long-term and stable heat source supply of hot dry rock, combined with thermoelectric power generation technology, a system and method for hot dry rock thermoelectric power generation with its own cold source in the formation are proposed, which can not only save a lot of construction costs And operating costs, but also to ensure a stable power supply.

Contents of the invention

In order to solve the above technical problems, the present invention provides a self-cooling source type hot dry rock thermoelectric power generation system and method.

To achieve the above object, the present invention adopts the following scheme:

The formation self-cooling source type hot dry rock thermoelectric power generation system includes: an downhole thermoelectric power generation module, a negative electrode wire, and a positive electrode wire; part of the overlying strata of the hot dry rock; the part of the downhole thermoelectric power generation module within the range of the hot dry rock reservoir is in direct contact with the exposed hot dry rock reservoir, and the exposed hot dry rock reservoir forms the stratum itself. The high-temperature hot end of the source-type hot dry rock thermoelectric power generation; the downhole thermoelectric power generation module part within the range of the overlying hot dry rock is directly in contact with the wellbore part completed by casing cementing, forming the formation's own cold source type hot dry rock thermoelectricity The low-temperature cold end of power generation; the electric energy generated by the downhole thermoelectric power generation module is supplied to the ground load through the positive lead and the negative lead; the downhole thermoelectric power generation module, the positive lead, the ground load and the negative lead are connected in sequence to form a closed circuit.

Compared with the prior art, the beneficial effects of the present invention are:

1. Only one geothermal well drilled through the hot dry rock reservoir is required.

2. There is no need to build artificial heat storage.

3. Realize on-site power generation in hot dry rock reservoirs by using thermoelectric modules arranged underground.

4. The heat energy extracted by the cold end cycle of the thermoelectric power generation system can be used for heating, breeding, bathing and other applications other than power generation.

Description of drawings

Fig. 1 is a structural schematic diagram of the formation self-cooling source type hot dry rock thermoelectric power generation system;

Fig. 2 is a schematic structural diagram of the downhole thermoelectric power generation module of the formation self-cooling source type hot dry rock thermoelectric power generation system;

Fig. 3 is a schematic diagram of the longitudinal section structure development of the downhole thermoelectric power generation module of the formation's own cold source type hot dry rock thermoelectric power generation system;

In the figure: 10, hot dry rock reservoir; 11, overlying formation of hot dry rock; 8, shaft; 33, downhole thermoelectric power generation module; 61, negative lead wire; 62, positive lead wire; 71, ground load; 203, cold end insulation 204. Metal conductor group at cold end; 205. Semiconductor group for thermoelectric power generation; 206. Metal conductor group at hot end; 207. Insulated heating member at hot end; 212. Negative pole of downhole thermoelectric power generation module; 213. Positive pole of downhole thermoelectric power generation module .

detailed description

As shown in Figure 1, the hot dry rock reservoir 10 is a high-temperature rock mass with a buried depth of several thousand meters, a temperature greater than 200°C, and no fluid inside or only a small amount of underground fluid; the overlying formation 11 of the hot dry rock is dry From the hot rock reservoir above 10 to the sedimentary rock or soil covering the surface, the temperature of the formation gradually decreases from bottom to top, which is lower than the temperature of the hot dry rock reservoir; Pass through the hot dry rock overlying formation 11 and the hot dry rock reservoir 10; the wellbore 8 within the range of the hot dry rock overlying formation 11 is completed by casing cementing, and the wellbore 8 within the range of the hot dry rock reservoir 10 Some of them are completed by open hole completion. The shaft 8 provides access for the downhole thermoelectric power generation module 33 , the negative lead wire 61 and the positive lead wire 62 .

As shown in Figure 1, the formation self-cooling source type hot dry rock thermoelectric power generation system includes: an downhole thermoelectric power generation module 33, a negative electrode lead 61, and a positive electrode lead 62; Part of the module 33 is within the range of the hot dry rock reservoir 10, and part of it is within the range of the overlying strata 11 of the hot dry rock reservoir; part of the downhole thermoelectric power generation module 33 within the range of the hot dry rock reservoir 10 is directly connected to the exposed hot dry rock reservoir 10 Contact, the exposed hot dry rock reservoir 10 forms the high-temperature hot end of the formation’s own cold source type hot dry rock thermoelectric power generation; the downhole thermoelectric power generation module 33 part within the range of the overlying hot dry rock formation 11 is directly connected with the casing cementing method The completed wellbore 8 is partly in contact, forming the low-temperature cold end of the formation's own cold source type hot dry rock thermoelectric power generation; the electric energy generated by the downhole thermoelectric power generation module 33 is supplied to the ground load 71 through the positive lead wire 62 and the negative lead wire 61; the downhole thermoelectric power generation The module 33, the positive wire 62, the ground load 71 and the negative wire 61 are connected in sequence to form a closed circuit.

As shown in Figure 2, the downhole thermoelectric power generation module 33 includes: cold-end insulating and heat-radiating components 203, cold-end metal conductor groups 204, thermoelectric power generation semiconductor groups 205, hot-end metal conductor groups 206, hot-end insulating and heating components 207, underground The thermoelectric power generation module negative electrode 212, the downhole thermoelectric power generation module positive pole 213; the hot end insulation heating member 207 is in a circular structure, and the hot end insulation heating member 207 is located at the bottom of the entire downhole thermoelectric generation module 33, and is connected with the exposed hot dry rock reservoir layer 10 in direct contact; the hot-end metal conductor group 206 is located on the top surface of the hot-end insulating and heating member 207 and is in close contact with the hot-end insulating and heating member 207; The thermal component 203 is in direct contact with the part of the wellbore 8 completed by casing cementing within the range of the hot dry rock overlying formation 11; the cold-end metal conductor group 204 is located under the cold-end insulating heat-radiating member 203 and is insulated from the cold-end. The thermal components 203 are in close contact; the thermoelectric power generation semiconductor group 205 is located above the hot end metal conductor group 206 and below the cold end metal conductor group 204; the thermoelectric power generation semiconductor group 205 is composed of several groups of N-type semiconductors and P-type semiconductors alternately Arranged in pairs; one end of the thermoelectric power generation semiconductor group 205 composed of several groups of N-type semiconductors and P-type semiconductors alternately and in pairs is placed in the high-temperature hot end, and the other end is placed in the low-temperature cold end; placed in the high-temperature hot end The N-type semiconductor is the N-type semiconductor hot end, and the P-type semiconductor is the P-type semiconductor hot end; the N-type semiconductor placed in the low-temperature cold end is the N-type semiconductor cold end, and the P-type semiconductor is the P-type semiconductor cold end; The hot-end metal conductor group 206 is made up of a plurality of conductors, and is used for connecting the N-type semiconductor hot end and the P-type semiconductor hot end in the thermoelectric power generation semiconductor group 205 placed in the high-temperature hot end; the cold-end metal conductor group 204 is composed of a plurality of conductors, and is used to connect the N-type semiconductor cold end and the P-type semiconductor cold end in the thermoelectric power generation semiconductor group 205 placed in the low-temperature cold end; in the thermoelectric power generation semiconductor group 205, the first group of thermoelectric The N-type semiconductor cold end of the power generation semiconductor group is externally connected to the negative electrode 212 of the downhole thermoelectric power generation module through a wire; Conductor connection; the P-type semiconductor cold end of the first group of thermoelectric power generation semiconductor groups is connected to the N-type semiconductor cold end of the second group of thermoelectric power generation semiconductor groups through the first conductor of the cold end metal conductor group 204; the second group of thermoelectric power generation semiconductors The N-type semiconductor hot end and the P-type semiconductor hot end of the group are connected by the second conductor in the hot-end metal conductor group 206; The N-type semiconductor cold end is connected by the second conductor of the cold-end metal conductor group 204; according to this circular connection, the N-type semiconductor and the P-type semiconductor are connected into a series structure; the P-type semiconductor cold end of the last group of thermoelectric power generation semiconductor groups The positive electrode 213 of the downhole thermoelectric power generation module is externally connected through the wire; the positive electrode wire 6 2. The downhole part is connected to the positive pole 213 of the downhole thermoelectric power generation module 33, and the ground part of the positive lead wire 62 is connected to the ground load 71; The negative pole 212 is connected, and the ground part of the negative pole wire 61 is connected with the ground load 71 .

One N-type semiconductor and one P-type semiconductor constitute a group of thermoelectric semiconductor groups; the number of groups of N-type semiconductors and P-type semiconductors can be 1 group, 10 groups, 100 groups, or any number of groups.

The method for thermoelectric power generation of hot dry rock with its own cold source in the formation adopts the above-mentioned hot dry rock thermoelectric power generation system with its own cold source in the formation, and the steps are as follows:

Step 1: According to the selected well position of the hot dry rock, use a drilling rig to drill through the overlying formation 11 of the hot dry rock to the top of the hot dry rock reservoir 10, run the casing, inject cement and cement the well; then replace the drill bit with a small size to drill through the hot dry rock Reservoir 10 reaches the predetermined depth, and the open hole is completed and completed;

Step 2: Connect the positive wire 62 and the negative wire 61 to the negative pole 212 of the downhole thermoelectric power generation module and the positive pole 213 of the downhole thermoelectric power generation module respectively, and lower them into the shaft 8 after being assembled on the ground. within the range of layer 10, partly placed within the range of overlying formation 11 of hot dry rock;

Step 3: The positive wire 62 and the negative wire 61 are respectively connected to the ground load 71 , and the electric energy generated by the downhole thermoelectric power generation module 33 is supplied to the ground load 71 through the positive wire 62 and the negative wire 61 .

Claims (4)

1. A formation self-cooling source type hot dry rock thermoelectric power generation system, comprising: a downhole thermoelectric power generation module, a negative electrode lead, and a positive electrode lead; Within the range of hot dry rock reservoirs, some are within the range of overlying hot dry rock reservoirs; part of the downhole thermoelectric power generation module within the range of hot dry rock reservoirs is in direct contact with the exposed hot dry rock reservoirs, and the exposed hot dry rock reservoirs form The high-temperature hot end of the formation's own cold source type hot dry rock thermoelectric power generation; the part of the downhole thermoelectric power generation module within the range of the overlying hot dry rock is directly in contact with the wellbore part completed by casing cementing, forming the formation's own cold source type dry The low-temperature cold end of the hot rock thermoelectric power generation; the downhole thermoelectric power generation module, the positive lead, the ground load and the negative lead are sequentially connected to form a closed circuit; The downhole thermoelectric power generation module includes: a cold-end insulating heat-radiating component, a cold-end metal conductor group, a thermoelectric power generation semiconductor group, a hot-end metal conductor group, a hot-end insulating heating member, a negative pole of the downhole thermoelectric power generation module, and a positive pole of the downhole thermoelectric power generation module The hot-end insulating and heating member has a circular structure, and the hot-end insulating and heating member is located at the bottom of the entire downhole thermoelectric power generation module, and is in direct contact with the exposed hot dry rock reservoir; the hot-end metal conductor group is located on the top of the hot-end insulating and heating member surface and is in close contact with the hot-end insulating heat-receiving member; the cold-end insulating heat-radiating member has a circular structure, and the cold-end insulating and heat-radiating member is in the range of the hot dry rock overlying stratum and is completed by casing cementing. The wellbore part is in direct contact; the cold-end metal conductor group is located under the cold-end insulating heat-dissipating member and is in close contact with the cold-end insulating heat-radiating member; the thermoelectric power generation semiconductor group is located above the hot-end metal conductor group and below the cold-end metal conductor group . 2. The formation self-cold source type hot dry rock thermoelectric power generation system according to claim 1, characterized in that, the thermoelectric power generation semiconductor group is arranged alternately and in pairs by several groups of N-type semiconductors and P-type semiconductors; One end of the group is placed in the high-temperature hot end, and the other end is placed in the low-temperature cold end; the N-type semiconductor placed in the high-temperature hot end is the N-type semiconductor hot end, and the P-type semiconductor is the P-type semiconductor hot end; The N-type semiconductor in the end is the N-type semiconductor cold end, and the P-type semiconductor is the P-type semiconductor cold end; the hot end metal conductor group is composed of multiple conductors, which are used to connect the thermoelectric power generation semiconductor placed in the high-temperature hot end The N-type semiconductor hot end and the P-type semiconductor hot end in the group; the cold-end metal conductor group is composed of a plurality of conductors, and is used to connect the N-type semiconductor cold end in the thermoelectric power generation semiconductor group placed in the low-temperature cold end and P-type semiconductor cold end; in the thermoelectric power generation semiconductor group, the N-type semiconductor cold end of the first group of thermoelectric power generation semiconductor group is externally connected to the negative pole of the downhole thermoelectric power generation module through a wire; the N-type semiconductor heat of the first group of thermoelectric power generation semiconductor group is The hot end of the P-type semiconductor and the P-type semiconductor are connected through the first conductor in the hot-end metal conductor group; The first conductor of the terminal metal conductor group is connected; the N-type semiconductor hot end and the P-type semiconductor hot end of the second group of thermoelectric power generation semiconductor groups are connected through the second conductor in the hot-end metal conductor group; the second group of thermoelectric power generation semiconductors The P-type semiconductor cold end of the first group is connected with the N-type semiconductor cold end of the third group of thermoelectric power generation semiconductor groups through the second conductor of the cold-end metal conductor group; in this way, the N-type semiconductor and the P-type semiconductor are connected in series Structure; the P-type semiconductor cold end of the last group of thermoelectric power generation semiconductor groups is externally connected to the positive pole of the downhole thermoelectric power generation module through a wire; The load is connected; the downhole part of the negative wire is connected with the negative pole of the downhole thermoelectric power generation module in the downhole thermoelectric power generation module, and the ground part of the negative wire is connected with the ground load. 3. The formation self-cold source type hot dry rock thermoelectric power generation system according to claim 2, wherein an N-type semiconductor and a P-type semiconductor constitute a group of thermoelectric power generation semiconductor groups; the several groups of N-type semiconductors and P-type semiconductors can be 1 group, 10 groups, 100 groups, or any other multiple groups. 4. A method for thermoelectric power generation of stratum self-cold source type hot dry rock, adopting the stratum self-cold source type hot dry rock thermoelectric power generation system according to claim 3, characterized in that, the steps are as follows: Step 1: According to the selected hot dry rock well position, use a drilling rig to drill through the overlying strata of the hot dry rock to the top of the hot dry rock reservoir, run the casing, inject cement and cement the well; then replace the small-sized drill bit to drill through the hot dry rock reservoir To the predetermined depth, the open hole is completed and the well is completed; Step 2: Connect the positive wire and the negative wire to the negative pole of the downhole thermoelectric power generation module and the positive pole of the downhole thermoelectric power generation module respectively. Within the overlying strata of hot dry rock; Step 3: The positive wire and the negative wire are respectively connected to the ground load, and the electric energy generated by the downhole thermoelectric power generation module is supplied to the ground load through the positive wire and the negative wire.