Open-pit coal mine dump photovoltaic and pumped storage system and energy storage control method

Abstract

The present disclosure relates to the technical field of open coal mine and pumped storage comprehensive utilization, and proposes an open coal mine dump photovoltaic and pumped storage system and energy storage control method. The system comprises an upper reservoir, a lower reservoir and a floating bidirectional hydroelectric power generation system. An underground concrete reservoir is constructed at the top of the dump as the upper reservoir. A green layer is arranged on the upper reservoir. The lower reservoir is constructed at the bottom of the mining field with the edge of the dump as the boundary. The lower reservoir is provided with a floating bidirectional hydroelectric power generation system. The upper reservoir and the lower reservoir are connected by a water conveying pipeline system. The position or depth of the lower reservoir is changed according to the shape change of the dump. A comprehensive utilization mode of dump photovoltaic, pumped storage and ecological management is proposed. The production type open coal mine dump photovoltaic is matched with the construction of pumped storage power station. The space of the dump is fully utilized to reduce the occupied area. The water resources in the mine pit are comprehensively utilized, which is beneficial to broaden the application range of pumped storage.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of open-pit coal mines and pumped storage comprehensive utilization, in particular to an open-pit coal mine dump photovoltaic and pumped storage system and an energy storage control method. BACKGROUND

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] In terms of energy storage installation, pumped storage has always been the dominant technology. Pumped storage was initially mainly used to adjust the seasonal imbalance of conventional hydropower station generation. To adapt to the rapid development of new energy, pumped storage has reached a peak, and with the development of the new energy industry and the increase in the proportion of power generation, the value of energy storage for the safety and flexibility of the power system has gradually been recognized, and a development pattern of new energy development and ecological protection has emerged. Under the guidance of the policy, each open-pit coal mine actively carries out preliminary preparation work for new energy projects such as dump photovoltaic.

[0004] Currently, three modes of abandoned mine pumped storage power station construction and their technical paths are proposed, including "open-pit mine full-surface mode", "subsidence mine half-surface mode", and "abandoned mine full-underground mode". The main idea is to use abandoned mine pits or abandoned mine tunnels as lower reservoirs, and use the higher surrounding terrain to build dams for upper reservoirs. Through high and low water storage areas, water pipelines, and bidirectional water turbines, the functions of pumped storage and drainage power generation are realized. The inventors found in the research that the current energy storage development based on open-pit coal mines is mainly aimed at abandoned open-pit coal mines, but research on the construction of dump photovoltaic supporting pumped storage in production-type open-pit coal mines has not been carried out. Production-type open-pit coal mines are mines in the mining stage, and the mining slope and dump of the mine site change at any time, which cannot provide a stable topographic structure for the construction of an energy storage system. SUMMARY

[0005] To solve the above problems, the present disclosure proposes an open-pit coal mine dump photovoltaic and pumped storage system and an energy storage control method, and proposes a comprehensive utilization mode of dump photovoltaic, pumped storage, and ecological governance. The construction of a pumped storage power station in a production-type open-pit coal mine dump photovoltaic is proposed, which fully utilizes the space of the dump to reduce the occupied area, comprehensively utilizes the water resources in the mine pit, is beneficial to broaden the application range of pumped storage, makes the station site closer to the load center and new energy base, promotes the safe and stable operation of the new energy power grid, ensures the rapid transformation of coal mining from oil mining to electricity mining, and also promotes the repair and governance of the ecological environment in the mining area.

[0006] To achieve the above purpose, the present disclosure adopts the following technical solutions:

[0007] One or more embodiments provide a photovoltaic and pumped storage system for an open-pit coal mine spoil heap, comprising: an upper reservoir, a lower reservoir, and a floating bidirectional hydropower generation system. An underground concrete reservoir is constructed at the top of the spoil heap as the upper reservoir, and a greening layer is built on top of the upper reservoir. A lower reservoir is constructed at the bottom of the mining area, with the edge of the spoil heap as the boundary. The lower reservoir is equipped with a floating bidirectional hydropower generation system. The upper and lower reservoirs are connected by a water pipeline system. The position or depth of the lower reservoir is changed according to the shape of the spoil heap.

[0008] One or more embodiments provide an energy storage control method for a photovoltaic and pumped storage system in an open-pit coal mine spoil heap, comprising the following steps:

[0009] When the photovoltaic power generation exceeds the electricity demand of the power load point and cannot be fully absorbed, water is transported from the lower reservoir to the upper reservoir of the spoil heap through a floating bidirectional hydropower system for energy storage.

[0010] When the photovoltaic power generation is less than the electricity demand at the power load point, water is transported from the upper reservoir to the bidirectional hydropower system through a water pipeline under the action of potential energy to generate electricity, thereby supplementing the power supply.

[0011] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0012] In this disclosure, by setting up a floating bidirectional hydropower generation system and a lower reservoir that changes with the spoil heap, it is possible to realize the operation of the energy storage system while constructing a spoil heap in a production open-pit coal mine. As the spoil heap is continuously piled up and the area of ​​the spoil heap changes, the lower reservoir can be moved along with it. At the same time, the floating bidirectional hydropower generation system can be moved, which can realize the stable operation of the pumped storage system.

[0013] The advantages of this disclosure, as well as its additional advantages, will be described in detail in the following specific embodiments. Attached Figure Description

[0014] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute a limitation thereof.

[0015] Figure 1 This is a block diagram of the photovoltaic and pumped storage system for an open-pit coal mine spoil heap according to Embodiment 1 of this disclosure;

[0016] Figure 2 This is a schematic diagram of the upper reservoir structure of Embodiment 1 of this disclosure;

[0017] Figure 3 This is a schematic diagram of the lower reservoir structure according to Embodiment 1 of this disclosure;

[0018] Figure 4 is an example north open-pit coal mine mining and dumping site topographic map of embodiment 1 of the present disclosure;

[0019] Figure 5 is an example north open-pit coal mine mining and dumping site cross-sectional view of embodiment 1 of the present disclosure. DETAILED DESCRIPTION

[0020] The present disclosure will be further described below in conjunction with the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the present disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0022] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit exemplary embodiments according to the present disclosure. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of a feature, step, operation, device, component, and / or combinations thereof. It should be noted that the various embodiments and features in the present disclosure can be combined with each other without conflict, and the embodiments will be described in detail below in conjunction with the accompanying drawings.

[0023] Embodiment 1

[0024] In the technical solutions disclosed in one or more embodiments, as shown in Figures 1-5 A photovoltaic and pumped storage system for an open-pit coal mine dump site includes an upper reservoir, a lower reservoir, and a floating bidirectional hydroelectric power generation system. An underground concrete reservoir is constructed at the top of the dump site as the upper reservoir. A green layer is provided on the upper reservoir. A lower reservoir is constructed at the bottom of the mining site with the edge of the dump site as the boundary. The lower reservoir is provided with a floating bidirectional hydroelectric power generation system. The upper reservoir and the lower reservoir are connected by a water pipeline system. The position or depth of the lower reservoir is changed according to the shape change of the dump site.

[0025] In this embodiment, by providing a floating bidirectional hydroelectric power generation system and a lower reservoir that changes with the dump site, the operation of the energy storage system can be realized while the dump site is constructed in the production-type open-pit coal mine. As the dump site is continuously filled with dump, the area of the dump site changes, and the lower reservoir is maintained to move, so that the lower reservoir can move, and the floating bidirectional hydroelectric power generation system can move to realize stable operation of the pumped storage system.

[0026] Further, a photovoltaic power station is arranged on the top of the dam. Specifically, the photovoltaic power station can be arranged on the upper part of the reservoir.

[0027] In some embodiments, the reservoir on the dump includes a plurality of underground water pools connected by pipelines; and a certain thickness of soil can be arranged on the reservoir on the dump.

[0028] Further, a spraying system is arranged on the reservoir and the green layer on the reservoir.

[0029] The dump of the open-pit coal mine is a huge artificial loose heap body. According to the mining design plan, the dump of the open-pit coal mine is divided into multiple layers for dumping, and the height of each layer is about 15-20 meters. Due to different dumping times, there is a different degree of settlement, and the settlement degree of the top layer of the dump is larger. Therefore, the underground water pool of the dump should have a stable structure against settlement and the volume should not be too large. In this embodiment, according to the design scale of pumped storage and the storage time, a plurality of small underground water pools are constructed, which are connected by pipelines, can increase the total volume of the upper reservoir, and the structure of multiple water pools can increase the stability of the water pool structure.

[0030] Optionally, the upper part of the underground water pool of the dump can be covered with 1-1.5m of soil, which can play a role in frost prevention and heat preservation. The upper part can be constructed with photovoltaic equipment, effectively utilizing the land space resources of the dump, greening on the topsoil, and realizing the comprehensive utilization mode of photovoltaic power + pumped storage + ecological management of the dump.

[0031] The photovoltaic equipment of the photovoltaic power station and the green layer can be arranged alternately. The photovoltaic equipment is connected to the booster station, and the photovoltaic power is connected to the power grid through the booster station to realize the grid connection of the photovoltaic equipment.

[0032] In some embodiments, according to the actual situation of the production open-pit coal mine, the position and volume of the lower reservoir are arranged, and the lower reservoir is moved according to the change of the dump.

[0033] In a specific implementation, the lower reservoir can be provided with a telescopic water delivery pipeline, and the water delivery pipeline is arranged along the steps of the dump and extends to the upper reservoir. The bidirectional hydroelectric power generation system is connected to the water delivery pipeline through a hose. The bidirectional hydroelectric power generation system is connected to the power grid of the power system to realize the grid connection of the pumped hydroelectric power.

[0034] The lower the water head used by the production open-pit coal mine pumped storage power station, the larger the water storage space of the upper water pool required. Although the space of the dump site is sufficient to meet the requirement of constructing the upper water pool, the investment and operation cost will be increased. The water head used by the pumped storage power station is too high, and the lower water pool needs to be constructed at the bottom of the mining site. There is no large space for the lower water pool, and the mining production is greatly affected. The position and volume of the lower water pool are set according to the actual situation of the production open-pit coal mine, and the water head used is reasonably determined. The water pipeline is arranged along the steps of the dump site, which can be realized by reasonably setting the expansion joints. The adverse factors caused by the settlement of the dump steps to the pressure pipeline are considered. The lower water reservoir is set at a proper position in the lower part of the mining site. The water at the bottom of the pit can be supplemented to the lower water reservoir at any time. The lower water reservoir is moved and set in time according to the mining and stripping advancing situation. In addition, the water level of the lower water reservoir changes greatly in different seasons. The floating type bidirectional hydraulic power generation system is set in the lower water reservoir, and the water pipeline system adopts a soft connection mode to adapt to the change of the water level and facilitate the movement and setting.

[0035] In some embodiments, the water pipeline system is used to connect the upper water reservoir and the lower water reservoir. The water pipeline system includes a buried pipeline, a valve arranged on the buried pipeline, a pressure stabilizer and other components. An insulation layer is arranged outside the pipeline to meet the needs of water pumping and power generation by drainage in winter.

[0036] The construction of the pumped storage power station by using the photovoltaic of the dump site of the production open-pit coal mine meets the requirements of the national and autonomous region new energy development planning. The photovoltaic project is constructed on the dump site, and the pumped storage power station is constructed to make full use of the land resources. The ecological management effect of the dump site is achieved. The ecological environment and social benefits are remarkable, and the system has good popularization and application prospect.

[0037] From the relative position of the pumped storage power station and the mining and dumping site of the production open-pit coal mine, the upper water pool is constructed by using the underground space of the dump site, the photovoltaic components are constructed on the upper soil, and the ecological management is performed. The lower water pool is constructed by using the existing buffer water pool of the mining site. The system does not involve land acquisition and new land occupation. The land space is fully utilized, the construction cost is low, and the economic benefit is good.

[0038] To illustrate the effect of the system, a specific application is carried out, and the system is applied to the Beilvtian coal mine.

[0039] The existing mining site of the Beilvtian coal mine occupies an area of 4613 mu. Eight mining steps are designed, and the elevation is from 860m to 720m. There are nine dump steps in the inner dump site, and the elevation is from 724m to 896m. There are four dump steps in the upper part of the inner dump site, and the elevation is from 932m to 1020m. The outer dump site has been discarded to the boundary (region A in the figure). The available area at the 1020m level is 3528 mu, and a 100MW photovoltaic project can be planned and constructed.

[0040] The runoff in the North Open-Pit Coal Mine mainly consists of groundwater and rainfall. Groundwater primarily originates from atmospheric precipitation infiltration. The elevation within the mining area is below the weak aquifer level. This stratum is mainly medium-fine sandstone, with a unit yield of 0.041–0.344 L / s·m. The average annual precipitation in this region is 380.5 mm, with an average monthly rainfall of 100 mm during the rainy season. Normal rainfall runoff is decreasing year by year, with July, August, and September accounting for approximately 84% of the annual runoff. Calculations indicate that the average open-pit coal mine drainage volume is 1.2 million m³. 3 / a.

[0041] To mitigate the impact of water runoff from the mining area on mining operations, a 100,000-200,000 m³ mining channel has been constructed at level 740 of the mining area. 3 The buffer water collection pool is equipped with submersible pumps at the water collection surfaces at various low points in the mining area to drain the accumulated water to the buffer water collection pool. Then, through open drainage pumps and submersible pumps, the water is transported through pipelines to the drainage water purification treatment workshop. After purification treatment, the drainage water is sent to the self-owned power plant or used for land reclamation, greening, and dust suppression.

[0042] The elevation of the buffer reservoir in the North Open-pit Coal Mine is 740m, and the volume of the buffer reservoir is 100,000-200,000 m³. 3 The elevation of the water storage pond at the boundary spoil heap is 1010m, and the preliminary plan proposes to construct 10 ponds with a depth of 1500m each. 3 The underground water storage tanks (each tank measures 15*20*5m) cover an area of ​​3000㎡, with a total volume of 15,000m³. 3 The water supply pipeline flow rate is based on 1m³ / h. 3 Considering / s, the unit efficiency is taken as 0.7.

[0043] Based on the rapid calculation method for the installed power of small hydroelectric generators:

[0044] P=HQng, S=V / Q / 3600, E=TN

[0045] In the formula: P is the installed power (kW), H is the head difference between the upper and lower reservoirs (m), and Q is the flow rate of water in the pipeline (m³). 3 / s), η is the generator efficiency, g is the gravitational acceleration, S is time (h), and V is the total capacity of the spoil heap reservoir (m³). 3 E represents power generation (kW·h), T represents time (h), and N represents installed capacity (kW).

[0046] According to the construction conditions of Beilvtian coal mine, combined with the overall layout requirements of pumped storage power station and the actual situation of mining and drainage field, different volumes of upper water pool and pipe flow are selected to further develop the installed capacity of the power station. Considering the actual situation of the production of the mining field of the open-pit coal mine, the lower part of the mining field cannot be provided with a large-volume buffer water storage pool, which is generally 100-120 thousand cubic meters. The construction scale and installed capacity of pumped storage are not very large. Therefore, the capacity of the upper water pool of the dumping site is estimated to be 150 thousand m 3 and 180 thousand m 3 to provide reference for related research.

[0047] Table 1 Installed capacity estimation table of design scheme of construction of pumped storage power station in production open-pit coal mine

[0048]

[0049] According to the preliminary research scheme of the project, it is initially planned to construct an installed power of 1.85 MW, which can store energy for the 4 MW dumping site wind power project planned to be constructed in Beilvtian coal mine, the continuous full-load hours are about 4 h, the single continuous power generation capacity is 7400 kw.h, and the annual power generation capacity can reach 2.44 million kw.h. According to the time pricing policy of Mengdong power grid, pumped storage is pumped during valley period and drained for power generation during peak period, and the price difference between peak and valley periods is 0.36 yuan kw.h, which can bring an annual income of 870,000 yuan.

[0050] In the long run, a 100 MW dumping site photovoltaic + pumped storage + ecological governance project can be constructed in the dumping site without new land occupation. A buffer water storage pool with a total capacity of more than 200 thousand m 3 is arranged in the lower part of the existing mining field, and a dumping site underground water storage pool with a total capacity of 180 thousand m 3 is constructed. In theory, a pumped storage power station with an installed capacity of 20 MW can be constructed, the energy storage scale can reach 20% of the total installed capacity, and the energy storage time is more than 4 hours. The single continuous power generation capacity is 80,000 kw.h, and the annual power generation capacity can reach 24 million kw.h. The annual consumption of standard coal can be reduced by 9,600 tons, and the annual emission of carbon dioxide and sulfur dioxide can be reduced by 24,000 tons and 720 tons respectively. According to the time pricing policy of Mengdong power grid, pumped storage is pumped during valley period and drained for power generation during peak period, and the price difference between peak and valley periods is 0.18 yuan kw.h, which can bring an annual income of 4.32 million yuan.

[0051] In this embodiment, the project is explored by taking Beilvtian coal mine as an example. The results show that the scheme can realize the maximum pumped storage installed capacity of 20 MW, the single continuous power generation capacity is 80,000 kw.h, and the annual power generation capacity can reach 24 million kw.h, which can bring economic benefits and effectively guarantee the safe and stable operation of regional new energy power grid.

[0052] Example 2

[0053] Based on example 1, the energy storage control method of the open-pit coal mine dump photovoltaic and pumped storage system provided in example 1 is provided in this embodiment, including the following steps:

[0054] When the photovoltaic power generation capacity is greater than the power load point demand power and cannot be fully consumed, the water is transported from the lower reservoir to the upper reservoir in the dump through the pipeline by the floating bidirectional hydroelectric power generation system for energy storage;

[0055] When the photovoltaic power generation capacity is less than the power load point demand power, the water is transported from the upper reservoir to the bidirectional hydroelectric power generation system through the water conveying pipeline under the action of potential energy for power generation, realizing power supplement, ensuring the stability of the power system, and improving the power quality and reliability.

[0056] Further, when the upper reservoir is full of water, the water in the upper reservoir is irrigated to the vegetation by connecting the spraying system.

[0057] The above only describes the preferred embodiments of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

[0058] The above describes the specific embodiments of the present disclosure in combination with the accompanying drawings, but is not intended to limit the protection scope of the present disclosure. Those skilled in the art should understand that various modifications or changes made on the basis of the technical solutions of the present disclosure without creative labor are still within the protection scope of the present disclosure.

Claims

1. A photovoltaic and pumped storage system for an open-pit coal mine spoil heap, characterized in that, include: The upper reservoir, lower reservoir, and floating bidirectional hydroelectric power generation system are constructed. An underground concrete reservoir is built at the top of the spoil heap as the upper reservoir, which is covered with a green layer. The lower reservoir is built at the bottom of the mining area, with the edge of the spoil heap as the boundary. The lower reservoir is equipped with a floating bidirectional hydroelectric power generation system. The upper and lower reservoirs are connected by a water pipeline system. The position or depth of the lower reservoir is changed according to the shape of the spoil heap. A photovoltaic power station is also set up on the top spoil heap at the boundary. The spoil heap reservoir includes multiple underground water storage tanks connected by pipelines; Based on the actual conditions of the production-type open-pit coal mine, the location and volume of the lower reservoir are determined, and the lower reservoir is moved according to the changes in the spoil heap; The lower reservoir is equipped with a retractable water conveyance pipeline, which extends along the steps of the spoil heap to the upper reservoir. A two-way hydroelectric power generation system is connected to the water conveyance pipeline via a flexible hose.

2. The photovoltaic and pumped storage system for an open-pit coal mine spoil heap as described in claim 1, characterized in that: The photovoltaic equipment in the photovoltaic power station is interspersed with the green layer; Alternatively, the photovoltaic equipment in the photovoltaic power station can be connected to a booster station, which then connects the photovoltaic power to the power grid, thus achieving grid connection of the photovoltaic equipment.

3. The photovoltaic and pumped storage system for an open-pit coal mine spoil heap as described in claim 1, characterized in that: The reservoir is covered with soil of a set thickness on the spoil heap for insulation and to install a green layer.

4. The photovoltaic and pumped storage system for an open-pit coal mine spoil heap as described in claim 1, characterized in that: The bidirectional hydropower system is connected to the power grid, enabling the electricity generated by pumping water to be fed into the grid.

5. The photovoltaic and pumped storage system for an open-pit coal mine spoil heap as described in claim 1, characterized in that: The water transmission pipeline system is used to connect the upper and lower reservoirs. The water transmission pipeline system includes buried pipelines, valves and pressure regulator components installed on the buried pipelines, and the pipelines are provided with an insulation layer.

6. The energy storage control method for a photovoltaic and pumped storage system for an open-pit coal mine spoil heap as described in any one of claims 1-5, characterized in that, Includes the following steps: When the photovoltaic power generation exceeds the electricity demand of the power load point and cannot be fully absorbed, water is transported from the lower reservoir to the upper reservoir of the spoil heap through a floating bidirectional hydropower system for energy storage. When the photovoltaic power generation is less than the electricity demand at the power load point, water is transported from the upper reservoir to the bidirectional hydropower system through a water pipeline under the action of potential energy to generate electricity, thereby supplementing the power supply.

7. The energy storage control method as described in claim 6, characterized in that: When the upper reservoir is full, the water is used to irrigate the vegetation through a sprinkler system.

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