Coal-fired unit for peak regulation coupling energy storage

Abstract

A peak regulation coupling energy storage coal-fired unit comprises a main steam system, a first steam turbine, a second steam turbine and a water storage energy storage system, an outlet of the main steam system is communicated with a high-pressure cylinder of the first steam turbine, the high-pressure cylinder of the first steam turbine is provided with an energy storage branch, and the energy storage branch is communicated with the second steam turbine; the water storage and energy storage system comprises a water storage pump, a high-level reservoir, a low-level reservoir and a first water turbine; the first water turbine is arranged between the high-level reservoir and the low-level reservoir; the second turbine drives the water storage pump to pump water to the high-level reservoir. According to the peak regulation coupling energy storage coal-fired unit, the energy storage system is combined into the steam pipeline of the coal-fired unit, the energy storage system can be used for assisting in utilizing generated steam when the boiler is in low load, and therefore energy storage is achieved, and boiler combustion is stabilized; and in the peak load period of the power grid, the electric power is generated by releasing the stored water.

Description

Technical Field

[0001] The utility model belongs to the technical field of power generation and energy storage, and particularly relates to a peak-shaving coupled energy storage coal-fired unit. Background Art

[0002] Peak shaving refers to the process of systematically adjusting generator output within a specified output adjustment range to track peak and valley variations in power load, based on grid demand. This process requires generators to respond to load changes at a specific adjustment rate to provide appropriate power services.

[0003] In recent years, with the large-scale integration of renewable energy sources (such as wind power and photovoltaics), grid load volatility has increased significantly, placing higher demands on the peak-shaving capabilities of traditional coal-fired power plants. In addition to basic peak-shaving, many coal-fired power plants also require deep peak-shaving, sometimes even requiring output reductions to below 30% of the unit's rated capacity. However, the peak-shaving capabilities of coal-fired power plants are limited by the operating characteristics of their boilers, particularly the boiler's ability to maintain stable combustion under low-load conditions—known as minimum stable combustion capability—which is a key factor in determining the minimum load level of coal-fired power plants.

[0004] In actual operation, deep peak load regulation can make it difficult for boilers to maintain stable combustion at low loads, or even cause flameout. This not only limits the peak load regulation capabilities of the units but can also adversely affect the stable operation of the power grid. Therefore, improving the peak load regulation capabilities of coal-fired power units, particularly ensuring stable boiler operation under deep peak load regulation conditions, has become a pressing issue.

[0005] Therefore, a solution is needed that can combine energy storage technology with coal-fired power units. When the boiler is under low load, energy storage equipment can be used to help absorb excess electricity and stabilize boiler combustion. During peak load periods, the stored electricity can be released to increase power generation output, thereby optimizing energy utilization efficiency and better meeting the grid's needs for flexibility and stability. Utility Model Content

[0006] One of the purposes of the present invention is to solve at least one or more of the above-mentioned problems existing in the prior art. In other words, one of the purposes of the present invention is to provide a peak-shaving coupled energy storage coal-fired unit that meets one or more of the above-mentioned needs.

[0007] In order to achieve the above-mentioned purpose of the utility model, the utility model adopts the following technical solutions:

[0008] In the first aspect, the utility model provides a peak-shaving coupled energy storage coal-fired unit, comprising a main steam system, a first steam turbine, a second steam turbine and a water storage energy storage system, wherein the outlet of the main steam system is connected to the high-pressure cylinder of the first steam turbine, the high-pressure cylinder of the first steam turbine is provided with an energy storage branch, the energy storage branch is connected to the second steam turbine, and a switch valve is provided on the energy storage branch; the water storage energy storage system comprises a water storage pump, a high-level water reservoir, a low-level water reservoir and a first water turbine; the first water turbine is arranged between the high-level water reservoir and the low-level water reservoir; the second steam turbine drives the water storage pump to pump water to the high-level water reservoir, and when the high-level water reservoir discharges water into the low-level water reservoir, it drives the first water turbine to generate electricity.

[0009] As a preferred embodiment, the peak-shaving coupled energy storage coal-fired unit also includes a reheat system, the reheat system includes a reheater and a first reheat pipe, the high-pressure cylinder of the first steam turbine is connected to the inlet of the reheater through the exhaust pipe, and the first outlet of the reheater is connected to the medium and low-pressure cylinders of the first steam turbine through the first reheat pipe.

[0010] As a further preferred embodiment, the reheater further has a second outlet, which is integrated into the energy storage branch.

[0011] As a preferred embodiment, the second outlet is provided with a throttle valve

[0012] As a preferred embodiment, the water storage and energy storage module further includes a water pool, a second turbine is provided between the water pool and the low-level water reservoir, and the water pool is connected to a water storage pump.

[0013] As a further preferred embodiment, a pre-pump is provided before the water storage pump, the water tank is connected to the pre-pump, and the pre-pump discharges the air in the water and then delivers water to the water storage pump.

[0014] As a further preferred embodiment, the pre-pump and the second steam turbine are coaxial.

[0015] As a preferred embodiment, a gear box is provided between the second steam turbine and the water storage pump, and the second steam turbine and the water storage pump are driven by the gear box.

[0016] As a preferred embodiment, the gear box increases the speed of the water storage pump.

[0017] As a preferred embodiment, the peak-shaving coupled energy storage coal-fired unit further includes a water tank and a water tank pump. The water tank is connected to the water pool through the water tank pump, and the water tank pump is used to inject water into the water pool.

[0018] As a preferred embodiment, the switching size of the switching valve is adjustable.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This new peak-shaving, energy-storage-coupled coal-fired unit combines energy storage technology with coal-fired power plants. During periods of low boiler load, the energy storage device helps absorb excess power, stabilizing boiler combustion. During peak grid load periods, the stored power is released to increase power generation output. This system not only enhances the peak-shaving capabilities of coal-fired power plants but also optimizes energy efficiency, better meeting the grid's needs for flexibility and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Shown is a structural schematic diagram of a peak-shaving coupled energy storage coal-fired power generation unit according to an embodiment of the present application.

[0022] Figure numbers: 1-main steam system, 2-first steam turbine, 201-high-pressure cylinder, 202-medium and low-pressure cylinders, 3-second steam turbine, 301-energy storage branch, 4-reheater, 401-first reheat pipe, 402-first outlet, 403-second outlet, 5-high-level water reservoir, 501-water storage pump, 502-first turbine, 503-gear box, 6-low-level water reservoir, 601-second turbine, 7-water reservoir, 701-front pump, 8-water tank, 801-water tank pump. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0024] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements described without departing from the scope of the present application. Various examples may appropriately omit, replace, or add various processes or components. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted, or combined. In addition, features described in some examples may be combined in other examples.

[0025] The structure diagram of the peak-shaving coupled energy storage coal-fired unit in this embodiment is as follows: Figure 1 shown.

[0026] The coal-fired unit includes a main steam system 1 for generating superheated steam, a first steam turbine 2 and a second steam turbine 3 for converting energy using the superheated steam, and an energy storage system for storing excess output.

[0027] The superheated steam outlet of the main steam system 1 is connected to the high-pressure cylinder 201 of the first steam turbine 2, feeding the superheated steam into this cylinder. The high-pressure cylinder 201 is connected to the intermediate- and low-pressure cylinders 202, and its outlet is split into two paths, connecting to the first reheat pipe 401 and the energy storage branch 301, respectively. The other end of the first reheat pipe 401 is connected to the reheater 4, while the other end of the energy storage branch 301 is connected to the second steam turbine 3. An on-off valve is installed on this energy storage branch 301.

[0028] After performing work in the high-pressure cylinder 201, the superheated steam enters the intermediate- and low-pressure cylinders 202 to continue performing work. Simultaneously, it bypasses the first reheat pipe 401 and the energy storage branch 301. The steam passing through the first reheat pipe 401 enters the reheater 4 for reheating. The steam passing through the energy storage branch 301 enters the second steam turbine 3 to drive its operation.

[0029] The rotating shaft of the second steam turbine 3 is connected to the pre-pump 701 via a coupling. The rotating shaft of the second steam turbine 3 is also connected to the rotating shaft of the water storage pump 501 via a gearbox 503. Rotation of the second steam turbine 3 drives the pre-pump 701 and the water storage pump 501. The gearbox 503 is configured to increase the rotating shaft speed of the water storage pump 501 during transmission, thereby increasing the water supply rate of the water storage pump 501.

[0030] The inlet of the pre-pump 701 is connected to the water tank 7, and the outlet is connected to the inlet of the water storage pump 501. When the pre-pump 701 is running, it draws water from the water tank 7, increases the water supply pressure, removes air from the water, and then sends the water to the water storage pump 501. The water drawn in by the pre-pump 701 and supplied to the water storage pump 501 eliminates air from the water, thus avoiding the risk of water erosion in the water storage pump.

[0031] The outlet of the water storage pump 501 is connected to the high-level water storage tank 5. When the water storage pump 501 is running, the water level is raised, so that the kinetic energy of the water storage pump 501 is stored as the gravitational potential energy of the water in the high-level water storage tank 5.

[0032] The outlet of the high-level water reservoir 5 is connected to the inlet of the low-level water reservoir 6 through the first turbine 502. When the high-level water reservoir 5 is opened, the stored water converts the gravitational potential energy into electrical energy through the first turbine 502 in the process of flowing to the low-level water reservoir 6, thereby releasing the stored energy.

[0033] The outlet of the low-level water reservoir 6 is connected to the water tank 7 through the second turbine 601. When the water storage capacity of the low-level water reservoir 6 is sufficient and the low-level water reservoir 6 is opened, the stored water converts the gravitational potential energy into electrical energy through the second turbine 601 in the process of flowing to the water tank 7, thereby releasing the stored energy.

[0034] The coal-fired unit of this embodiment is further provided with a water tank 8 for replenishing water. The water tank 8 is connected to the water pool 7 via a water tank pump 801 . When the water tank pump 801 is in operation, water is replenished into the water pool 7 .

[0035] The above-mentioned peak-shaving coupled energy storage coal-fired units integrate the energy storage system into the steam pipeline of the coal-fired power unit. When the boiler is under low load, the energy storage system can be used to assist in utilizing the generated steam, thereby realizing the storage of production capacity and stabilizing boiler combustion; and during peak load periods of the power grid, electricity is generated by releasing stored water to increase power generation output.

[0036] In order to improve the utilization efficiency of heat energy and steam, the reheater 4 of this embodiment is also provided with a branch line directly leading to the second steam turbine 3. Figure 1 : The reheater 4 has two outlets, the first outlet 402 is connected to the inlet of the intermediate and low pressure cylinder 202, and the second outlet 403 is connected to the inlet of the second steam turbine 3. The steam enters the reheater 4 through the first reheat pipe 401 for reheating, and is then transported to the intermediate and low pressure cylinder 202 and the second steam turbine 3 respectively. The reheated steam transported to the intermediate and low pressure cylinder 202 is used for direct power generation, and the reheated steam input to the second steam turbine 3 is used for energy storage.

[0037] In order to facilitate the coal-fired power unit to control the proportion of power generation and energy storage according to the current electricity consumption, this embodiment also sets the switch valve on the energy storage branch 301 as a switch valve with adjustable flow rate. When the flow rate of the switch valve is increased, more steam flows from the high-pressure cylinder 201 to the second steam turbine 3, and less steam flows to the medium and low-pressure cylinders 202, thereby reducing the electricity generated by the medium and low-pressure cylinders and increasing the water stored by the water storage pump 501.

[0038] Because the load on the first steam turbine 2 decreases when the grid load is low, the operating parameters and exhaust temperature of the first steam turbine 2 are also low when the load is low. At this time, the steam input to the second steam turbine 3 through the energy storage branch 301 is difficult to drive the second steam turbine 3. Therefore, the coal-fired power unit of this embodiment is also provided with a throttle valve at the second outlet 403. When the grid load is low, the on-off valve on the energy storage branch 301 is adjusted to reduce or close the steam supplied to the second steam turbine 3 through the energy storage branch 301. At the same time, the throttle valve on the second outlet 403 is adjusted to increase the reheated steam supplied to the second steam turbine 3 through the reheater 4, thereby improving the energy storage efficiency of the coal-fired power unit of this embodiment under low grid load and low turbine operating conditions.

[0039] The coal-fired power unit of the above embodiment is used as follows:

[0040] When the grid load is high, the coal-fired power unit operates at full load, the switch valve on the energy storage branch 301 is closed, and the throttle valve on the second outlet 403 is also closed, so that all the reheated steam and the steam output from the high-pressure cylinder 201 enter the medium and low-pressure cylinders 202 to generate electricity.

[0041] When the grid load is low, the switch valve on the energy storage branch 301 is opened, and the steam drives the second steam turbine 3 to operate, thereby driving the water storage pump 501 to store water in the high-level water reservoir 5 to achieve energy storage.

[0042] When the grid load further decreases, the switch valve on the energy storage branch 301 is gradually reduced to closed, and the throttle valve on the second outlet 403 is gradually opened, and the reheated steam is gradually used to drive the second steam turbine 3, thereby realizing the steam source replacement of the second steam turbine 3. The second steam turbine 3 drives the water storage pump 501 to store water in the high-level water tank 5 to realize energy storage.

[0043] When the load on the power grid increases and exceeds the power supply of the coal-fired power unit, resulting in a power shortage, the valve of the high-level water reservoir 5 is opened to allow the stored water to enter the first turbine 502 to drive the turbine to generate electricity, thereby making up for the power shortage.

[0044] When the water stored in the low-level water reservoir 6 meets the specified water volume and can be used for power generation, the valve of the low-level water reservoir 6 is opened to allow the stored water to enter the second turbine 601 to drive the turbine to continue generating electricity.

[0045] The above-mentioned peak-shaving coupled energy storage coal-fired unit in this embodiment integrates the energy storage system into the steam pipeline of the coal-fired power unit. When the boiler is under low load, the energy storage system can be used to assist in utilizing the generated steam, thereby achieving production capacity storage and stabilizing boiler combustion; and during peak load periods of the power grid, electricity is generated by releasing stored water to increase power generation output.

[0046] The above description is merely an exemplary embodiment of the present disclosure and is not intended to limit the scope of the present disclosure. That is, any equivalent changes and modifications made in accordance with the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure herein, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not recorded in the present disclosure. The description and examples are to be regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A coal-fired unit with peak load regulation and energy storage, comprising a main steam system and a first steam turbine, characterized in that: It also includes a second steam turbine and a water storage and energy storage system. The outlet of the main steam system is connected to the high-pressure cylinder of the first steam turbine. The high-pressure cylinder of the first steam turbine is provided with an energy storage branch. The energy storage branch is connected to the second steam turbine, and a switch valve is provided on the energy storage branch. The water storage and energy storage system includes a water storage pump, a high-level water reservoir, a low-level water reservoir and a first water turbine. The first water turbine is arranged between the high-level water reservoir and the low-level water reservoir. The second steam turbine drives the water storage pump to pump water to the high-level water reservoir, and when the high-level water reservoir releases water to the low-level water reservoir, it drives the first water turbine to generate electricity.

2. A peak-shaving coupled energy storage coal-fired unit according to claim 1, characterized in that: The peak-shaving coupled energy storage coal-fired unit also includes a reheat system, which includes a reheater and a first reheat pipe. The high-pressure cylinder of the first steam turbine is connected to the inlet of the reheater through an exhaust pipe, and the first outlet of the reheater is connected to the medium and low-pressure cylinders of the first steam turbine through the first reheat pipe.

3. A peak-shaving coupled energy storage coal-fired unit according to claim 2, characterized in that: The reheater further has a second outlet, which is connected to the energy storage branch.

4. A peak-shaving coupled energy storage coal-fired unit according to claim 3, characterized in that: The second outlet is provided with a throttle valve.

5. The peak-shaving coupled energy storage coal-fired unit according to claim 1, characterized in that: The water storage and energy storage module further includes a water pool, a second turbine is provided between the water pool and the low-level water reservoir, and the water pool is connected to the water storage pump.

6. A peak-shaving coupled energy storage coal-fired unit according to claim 5, characterized in that: A pre-pump is provided before the water storage pump, the water pool is communicated with the pre-pump, and the pre-pump discharges air in the water and then delivers water to the water storage pump.

7. A peak-shaving coupled energy storage coal-fired unit according to claim 6, characterized in that: The pre-pump and the second steam turbine are coaxial.

8. The peak-shaving coupled energy storage coal-fired unit according to claim 1, characterized in that: A gear box is provided between the second steam turbine and the water storage pump, and the second steam turbine and the water storage pump are driven by the gear box.

9. The peak-shaving coupled energy storage coal-fired unit according to claim 1, characterized in that: The peak-shaving coupled energy storage coal-fired unit further includes a water tank and a water tank pump. The water tank is connected to the water pool through the water tank pump, and the water tank pump is used to inject water into the water pool.

10. The peak-shaving coupled energy storage coal-fired unit according to claim 1, characterized in that: The size of the switch valve is adjustable.

Images