Salt-water double-medium low-cost heat storage system coupled with coal gas recovery

Abstract

The utility model relates to a salt-water double-medium low-cost heat storage system coupled with coal gas recovery, which comprises a coal gas cabinet, a gas-fired boiler, a steam turbine, a generator, a peak regulation gas-fired boiler and a heat storage tank, on one hand, the coal gas cabinet is connected with the gas-fired boiler through a coal gas power generation coal gas regulating valve group, and on the other hand, the coal gas power generation coal gas regulating valve group is connected with the steam turbine; on the other hand, the system is connected with the peak-shaving gas-fired boiler through an energy storage peak-shaving gas regulating valve group; a feed water inlet of the gas-fired boiler is connected with an outlet of the steam turbine; the steam turbine is electrically connected with the power generator at the same time. A steam outlet of the peak-shaving gas-fired boiler is connected with a steam inlet of the heat storage tank, and a water supply inlet of the peak-shaving gas-fired boiler is connected to a pipeline through which the gas-fired boiler water supply valve group is connected with the boiler water supply pump. The double-medium heat storage tank with the fused salt heat exchange pipe arranged in the tank is used for heat storage, meanwhile, the gas boiler and the peak regulation gas boiler are coupled together to share the generator, the equipment investment cost and the occupied space are remarkably reduced, and meanwhile the good heat storage effect is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal gas flexible peak regulation, and in particular relates to a low-cost heat storage system of salt water dual medium coupled with coal gas recovery. Background Art

[0002] According to incomplete statistics, the installed capacity of waste heat and waste energy power generation in the steel industry in 2020 was 45.312 million kilowatts, with an average self-generation rate of 53%. The main installed forms are gas power generation, CCPP, waste heat power generation and steam power generation, of which gas power generation accounts for 76% of the self-generation installed capacity. Based on this data, the peak-shaving potential is relatively large, estimated to reach 3GW, and the peak-shaving time is considered to be 6 hours, and the daily peak-shaving capacity reaches 18GWh.

[0003] In addition, gas-fired power generation and heat storage peak regulation can be used as an important peak regulation resource on the user side. The electricity load in each link of the production process of steel enterprises has no large-scale regulation capability, and there are few flexible loads. The production load can be adjusted through flexible load regulation to avoid peak electricity consumption with a small adjustable margin. Steel enterprises have abundant waste heat resources, and the peak regulation potential is still large. During the maintenance of gas turbines, gas is usually treated by ignition and dispersion, resulting in a large amount of energy waste. According to statistics, taking a steel enterprise in Inner Mongolia as an example, the gas turbine is overhauled for 120 days throughout the year. During this period, the blast furnace, coke oven, and converter gas emissions were about 38,000 cubic meters / h, and the average calorific value was 3400kj / m3, which is equivalent to an hourly energy loss of about 35,000 kWh. The existing gas peak regulation energy storage and heat storage equipment is relatively complex and has a high investment cost, which is not conducive to promotion and use. Utility Model Content

[0004] In view of the deficiencies in the prior art, the technical problem that the utility model intends to solve is to provide a low-cost dual-medium heat storage system of brine coupled with gas recovery.

[0005] The technical solution adopted by the utility model to solve the technical problem is as follows:

[0006] A low-cost heat storage system of salt water dual medium coupled with coal gas recovery, comprising a gas holder, a gas boiler, a steam turbine, a generator, a peaking gas boiler and a heat storage tank, wherein the gas holder comprises at least one;

[0007] The gas cabinet is connected to the gas boiler through a gas power generation gas regulating valve group on the one hand, and is connected to the peak-shaving gas boiler through an energy storage peak-shaving gas regulating valve group on the other hand;

[0008] The feedwater inlet of the gas boiler is connected to the gas boiler feedwater valve group, boiler feedwater pump, deaerator, shaft seal heater, condensate pump, condenser, and steam turbine outlet in sequence; the steam turbine is also electrically connected to the generator;

[0009] The steam outlet of the gas boiler is connected to the steam inlet of the steam turbine through the main steam regulating valve, and the heat storage tank is connected to the steam inlet of the steam turbine through the energy storage peak-shaving steam regulating valve and the main steam regulating valve;

[0010] The steam outlet of the peak-shaving gas boiler is connected to the steam inlet of the heat storage tank, and the feed water inlet of the peak-shaving gas boiler is connected to the pipeline connecting the gas boiler feed water valve group and the boiler feed water pump;

[0011] The inner cavity of the heat storage tank is filled with water medium, a steam collecting pipe for steam to pass through is arranged in the heat storage tank, the steam sprayed from the spray holes of the collecting pipe is mixed with the water medium, and a heat exchange tube for molten salt storage is wound on the collecting pipe.

[0012] A heat storage tank steam inlet valve group is arranged on the pipeline connected to the steam inlet of the heat storage tank, and a heat storage tank steam outlet valve group is arranged on the pipeline near the steam outlet of the heat storage tank.

[0013] There are three kinds of pipes inside the heat storage tank, namely, a steam collecting pipe, an annular pipe and a serpentine pipe. The steam collecting pipe is formed by spirally wound pipes arranged in three layers, namely, upper, middle and lower layers and connected in sequence, and spray holes are arranged on the pipe wall of the steam collecting pipe. The annular pipe is evenly surrounded on the three-layer steam collecting pipe, and the nozzles on the annular pipe and the pipe wall of the steam collecting pipe do not interfere with each other. The serpentine pipe is arranged on the plane of the central axis of the inner cavity of the heat storage tank, and the steam collecting pipe, the annular pipe and the serpentine pipe are independent of each other and do not interfere with each other. Steam is introduced into the steam collecting pipe, the inner cavities of the annular pipe and the serpentine pipe are filled with phase change salt, and the inner cavity of the heat storage tank is filled with water medium.

[0014] A steam-water separator is arranged in the heat storage tank, and the steam outlet of the steam-water separator is connected to the steam outlet of the heat storage tank; the steam-water separator is located on the upper part of the water medium of the heat storage tank.

[0015] In the utility model, different types of phase change salts can be filled in the annular tube and the serpentine tube according to actual working conditions.

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] The utility model uses a dual-medium heat storage tank with a molten salt heat exchange tube arranged in the tank for heat storage, and at the same time couples the gas boiler and the peak-shaving gas boiler together to share a generator. Through the loop setting, the equipment investment cost and the floor space occupied can be significantly reduced, while ensuring a better heat storage effect, making the heat storage system more concise and conducive to popularization and use.

[0018] The utility model combines gas power generation and energy storage in the same heat storage tank, which minimizes the impact on the energy consumption, efficiency and life cycle of the unit, improves the peak-shaving capability, increases the peak-shaving capacity, solves the difficulty of peak-shaving of the power grid, and can reasonably allocate power resources to ensure that the power supply can meet the peak demand while avoiding waste of resources. For example, during peak production periods, power peak-shaving can meet demand by releasing the steam heat energy of the heat storage tank, while during low periods, the heat storage tank can be used to store heat to ensure stable operating loads. It has the characteristics of high energy storage efficiency, flexibility and fast response speed, has a larger storage capacity and rapid regulation capability, and ensures the operating energy efficiency and operating safety of the generator set.

[0019] In the utility model, only one heat storage tank is provided, and the molten salt and water are both located inside the heat storage tank, thereby ensuring a better heat exchange and heat storage effect while minimizing the equipment investment.

[0020] The utility model configures energy storage to fully recycle and utilize the coal gas released during the maintenance of the gas turbine. After the coal gas is burned, it is stored as high-grade energy in the brine dual medium in the same heat storage tank, fully releasing the peak-shaving capacity of the steel enterprise in the recycling of waste heat and waste energy, forming an important peak-shaving resource on the user side, thereby greatly reducing the enterprise's energy consumption per ton of steel production, which is of great significance for promoting the high-quality development of the steel industry and forming new quality productivity.

[0021] The utility model integrates gas recovery, peak regulation, energy storage, low cost and high efficiency, and solves the problem of energy loss caused by gas release during gas turbine maintenance, as well as the problems of large space occupation and high investment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be described in detail below in conjunction with the accompanying drawings, in which:

[0023] Figure 1 It is a schematic diagram of the connection structure of the utility model's low-cost heat storage system of salt water dual medium coupled with gas recovery.

[0024] Among them: gas tank group 1, fan 2, gas power generation gas regulating valve group 3, gas boiler 4, steam turbine 5, generator 6, condenser 7, condensate pump 8, shaft seal heater 9, deaerator 10, boiler feed water pump 11, gas boiler feed water valve group 12, energy storage peak-shaving gas regulating valve group 13, peak-shaving gas boiler 14, peak-shaving gas boiler feed water valve group 15, heat storage tank steam inlet valve group 16, heat storage tank steam outlet valve group 17, heat storage tank 18, energy storage peak-shaving steam regulating valve 19, main steam regulating valve 20. DETAILED DESCRIPTION

[0025] The following describes the implementation of the present invention through specific examples.

[0026] Reference Figure 1 The utility model provides a low-cost heat storage system of salt water dual medium coupled with coal gas recovery, including a gas cabinet 1, a fan 2, a coal gas power generation gas regulating valve group 3, a gas boiler 4, a steam turbine 5, a generator 6, a condenser 7, a condensate pump 8, a shaft seal heater 9, a deaerator 10, a boiler feed water pump 11, a gas boiler feed water valve group 12, an energy storage peak-shaving gas regulating valve group 13, a peak-shaving gas boiler 14, a peak-shaving gas boiler feed water valve group 15, a heat storage tank steam inlet valve group 16, a heat storage tank steam outlet valve group 17, a heat storage tank 18, an energy storage peak-shaving steam regulating valve 19, and a main steam regulating valve 20.

[0027] The gas tank 1 is connected to the gas boiler 4 through the fan 2, and the connecting pipeline is provided with a gas power generation gas regulating valve group 3 that can adjust the gas volume. The gas boiler 4 is connected to the steam turbine 5, and the connecting pipeline is provided with a main steam regulating valve 20 to adjust the steam volume. The steam turbine 5 is connected to the generator 6 through a pipeline to supply steam for power generation. After the steam turbine 5 works, the steam is sent to the condenser 7 through the pipeline for cooling and condensation. The condenser 7 is connected to the condensate pump 8, the shaft seal heater 9, the deaerator 10, and the boiler feed water pump 11 through pipelines in sequence. The boiler feed water pump 11 is connected to the water inlet of the gas boiler 4 through a pipeline, and a gas boiler feed water valve group 12 is provided on the connecting pipeline to adjust the water supply volume.

[0028] The gas cabinet 1 is connected to the peak-shaving gas boiler 14 through the fan 2, and the connecting pipeline is provided with an energy storage peak-shaving gas regulating valve group 13 that can adjust the gas volume. The peak-shaving gas boiler 14 is connected to the heat storage tank 18, and a heat storage tank steam inlet valve group is provided on the connecting pipeline to adjust the steam inlet volume. The heat storage tank 18 is connected to the outlet pipeline of the gas boiler 4, and the pipeline connection point is provided before the main steam regulating valve 20. The heat storage tank steam outlet valve group 17 and the energy storage peak-shaving steam regulating valve 19 are provided on the connecting pipeline. The boiler feed water pump 11 is connected to the water inlet of the peak-shaving gas boiler 14, and a peak-shaving gas boiler feed water valve group 15 is provided on the connecting pipeline.

[0029] The heat storage tank 18 uses phase change salt and water as heat storage media. The interior of the heat storage tank 18 is provided with three kinds of pipes, namely, a steam collecting pipe 1801, an annular pipe 1802 and a serpentine pipe 1803. The steam collecting pipe 1801 is formed by a spirally wound pipe which is arranged in three layers, namely, upper, middle and lower layers and connected in sequence. A spray hole is arranged on the pipe wall of the steam collecting pipe 1801. The annular pipe 1802 is evenly surrounded on the three-layer steam collecting pipe 1801, and the nozzles on the annular pipe 1802 and the pipe wall of the steam collecting pipe 1801 do not interfere with each other. The serpentine pipe 1803 is arranged on the plane of the central axis of the inner cavity of the heat storage tank 18. The steam collecting pipe 1801, the annular pipe 1802 and the serpentine pipe 1803 are independent of each other and do not interfere with each other.

[0030] Furthermore, steam is introduced into the steam collecting pipe 1801, the inner cavities of the annular pipe 1802 and the serpentine pipe 1803 are filled with phase change salt, the inner cavity of the heat storage tank 18 is filled with water medium, and a certain space is reserved at the top to place a steam-water separator, and at least 2m of space is reserved. The steam-water separator can be Inco CF41-16C, and the steam-water separator is connected to the steam outlet of the heat storage tank 18. The steam collecting pipe 1801 is connected to the steam inlet of the heat storage tank 18.

[0031] The utility model includes at least one gas tank, which supplies gas to the gas boiler, and the steam generated by the gas boiler drives the steam turbine and the generator to generate electricity. There is only one heat storage tank (water medium is filled in the heat storage tank, heat exchange pipes and heat exchange tubes are arranged in the heat storage tank, and molten salt is filled in the heat exchange tube) to store energy and release energy to meet the needs of working conditions. The complexity of the process and flow caused by the use of multiple heat storage tanks (such as high-temperature molten salt storage tanks, low-temperature molten salt storage tanks, etc.) in the prior art is avoided.

[0032] Furthermore, the gas holder is connected to the gas boiler via a gas power generation gas regulating valve group; the gas holder is connected to the peak-shaving gas boiler via an energy storage peak-shaving gas regulating valve group. The gas holder, gas boiler, steam turbine, generator, condenser, condensate pump, shaft seal heater, deaerator, boiler feed pump are connected in sequence to form a loop.

[0033] Furthermore, the boiler feed water pump is connected to the feed water inlet of the gas boiler via the gas boiler feed water valve group; the boiler feed water pump is connected to the feed water inlet of the peak-shaving gas boiler via the peak-shaving gas boiler feed water valve group. The peak-shaving gas boiler is connected to the steam inlet of the heat storage tank via the heat storage tank steam inlet valve group; the heat storage tank is connected to the gas boiler outlet via the heat storage tank steam outlet valve group and the energy storage peak-shaving steam regulating valve. The gas boiler is connected to the steam turbine via the main steam regulating valve. This allows the peak-shaving gas boiler to achieve effective power generation with only one set of generators.

[0034] Furthermore, there are three types of pipes inside the heat storage tank, namely, a steam collecting pipe, an annular pipe and a serpentine pipe. The steam collecting pipe is formed by a spirally wound pipe arranged in three layers, namely, upper, middle and lower layers, and connected in sequence. A spray hole is arranged on the pipe wall of the steam collecting pipe. The annular pipe is evenly surrounded on the three layers of the steam collecting pipe, and the nozzles on the annular pipe and the pipe wall of the steam collecting pipe do not interfere with each other. The serpentine pipe is arranged on the plane of the central axis of the inner cavity of the heat storage tank. The three pipes, namely, the steam collecting pipe, the annular pipe and the serpentine pipe, are independent of each other and do not interfere with each other. Steam is introduced into the steam collecting pipe, the inner cavities of the annular pipe and the serpentine pipe are filled with phase change salt, and the inner cavity of the heat storage tank is filled with water medium.

[0035] The specific working process of the utility model's low-cost heat storage system with salt water and dual medium coupled with gas recovery is as follows:

[0036] (1) Energy storage operation mode

[0037] During the period of low electricity consumption, the system will start the main steam regulating valve 20, which will be adjusted to the minimum position to reduce the load of the turbine 5, and maximize heat and energy storage by adjusting the gas power generation gas regulating valve group 3, the energy storage peak-shaving gas regulating valve group 13, and the heat storage tank steam inlet valve group 16.

[0038] Specifically, due to the decrease in power demand, the load of the steam turbine 5 is significantly reduced. In this way, a surplus amount of gas is generated, which is then transferred to the gas tank 1 for storage.

[0039] Under the energy storage condition, the system adjusts the opening of the energy storage peak-shaving gas regulating valve group 13 and the heat storage tank steam inlet valve group 16, so that the steam generated by the peak-shaving gas boiler 14 enters the heat storage tank 18 for heat storage and energy storage. The steam enters the steam collecting pipe 1801 through the steam inlet of the heat storage tank 18, and is released through the nozzle of the steam collecting pipe 1801 to heat and raise the temperature of the water medium in the inner cavity of the heat storage tank 18. At the same time, the steam heat in the steam collecting pipe 1801 is transferred to the phase change salt in the annular pipe 1802 through the pipe wall in the form of convection heat transfer and heat conduction, so that the phase change salt in the annular pipe 1802 starts to store heat. After the water medium in the inner cavity of the heat storage tank 18 is heated, the heat of the water medium is transferred to the phase change salt in the serpentine pipe 1803 through the pipe wall in the form of convection heat transfer, so that it can store heat. When the temperature of the heat storage tank 18 reaches the set temperature, the energy storage peak-shaving unit gas regulating valve group 13 and the heat storage tank steam inlet valve group 16 are closed, and the heat storage and energy storage is completed.

[0040] (2) Energy release operation mode

[0041] During the peak power consumption period, the main steam regulating valve 20 is adjusted to make the load of the turbine 5 reach the maximum value, and the gas power generation gas regulating valve group 3, the heat storage tank steam outlet valve group 17, and the energy storage peak-shaving steam regulating valve 19 are adjusted to achieve the maximum energy release peak regulation.

[0042] Specifically, in the energy release condition, the system adjusts the opening sizes of the gas power generation gas regulating valve group 3, the heat storage tank steam outlet valve group 17, the energy storage peak-shaving steam regulating valve 19, and the main steam regulating valve 20. The water medium inside the heat storage tank 18 flashes to generate steam. At the same time, the heat of the phase change salt in the annular tube 1802 and the serpentine tube 1803 in the heat storage tank 18 is transferred to the water medium in the inner cavity, which alleviates the cooling rate of the water medium and provides more heat energy release, thereby driving the steam turbine 5 to work and the generator 6 to generate electricity. After the steam turbine 5 works, the steam is sent to the condenser 7 for condensation, and is sent to the shaft seal heater 9 and the deaerator 10 for heating and deoxygenation through the condensate pump 8, and finally is sent to the boiler through the boiler feed water pump 11 to generate steam.

[0043] By coupling the energy storage and release of the heat storage tank with the power generation system, the heat storage tank can be operated to store or release energy according to the actual power generation needs. The energy storage peak-shaving gas regulating valve group 13, the heat storage tank steam inlet valve group 16 or the heat storage tank steam outlet valve group 17, and the energy storage peak-shaving steam regulating valve 19 can be opened and closed to maintain the load balance of the power grid.

[0044] Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

[0045] Anything not described in the present invention is applicable to the prior art.

Claims

1. A low-cost dual-medium heat storage system of brine coupled with gas recovery, comprising a gas holder, a gas boiler, a steam turbine, a generator, a peak-shaving gas boiler and a heat storage tank, wherein the gas holder comprises at least one, characterized in that: The gas cabinet is connected to the gas boiler through a gas power generation gas regulating valve group on the one hand, and is connected to the peak-shaving gas boiler through an energy storage peak-shaving gas regulating valve group on the other hand; The feedwater inlet of the gas boiler is connected to the gas boiler feedwater valve group, boiler feedwater pump, deaerator, shaft seal heater, condensate pump, condenser, and steam turbine outlet in sequence; the steam turbine is also electrically connected to the generator; The steam outlet of the gas boiler is connected to the steam inlet of the steam turbine through the main steam regulating valve, and the heat storage tank is connected to the steam inlet of the steam turbine through the energy storage peak-shaving steam regulating valve and the main steam regulating valve; The steam outlet of the peak-shaving gas boiler is connected to the steam inlet of the heat storage tank, and the feed water inlet of the peak-shaving gas boiler is connected to the pipeline connecting the gas boiler feed water valve group and the boiler feed water pump; The inner cavity of the heat storage tank is filled with water medium, a steam collecting pipe for steam to pass through is arranged in the heat storage tank, the steam is sprayed out from the spray holes of the collecting pipe and mixed with the water medium, and a heat exchange tube for molten salt storage is wound on the collecting pipe.

2. The thermal storage system according to claim 1, characterized in that: A heat storage tank steam inlet valve group is arranged on the pipeline connected to the steam inlet of the heat storage tank, and a heat storage tank steam outlet valve group is arranged on the pipeline near the steam outlet of the heat storage tank.

3. The thermal storage system according to claim 1, characterized in that: There are three kinds of pipes inside the heat storage tank, namely, a steam collecting pipe, an annular pipe and a serpentine pipe. The steam collecting pipe is formed by spirally wound pipes arranged in three layers, namely, upper, middle and lower layers and connected in sequence, and spray holes are arranged on the pipe wall of the steam collecting pipe. The annular pipe is evenly surrounded on the three-layer steam collecting pipe, and the nozzles on the annular pipe and the pipe wall of the steam collecting pipe do not interfere with each other. The serpentine pipe is arranged on the plane of the central axis of the inner cavity of the heat storage tank, and the steam collecting pipe, the annular pipe and the serpentine pipe are independent of each other and do not interfere with each other. Steam is introduced into the steam collecting pipe, the inner cavities of the annular pipe and the serpentine pipe are filled with phase change salt, and the inner cavity of the heat storage tank is filled with water medium.

4. The thermal storage system according to claim 1, characterized in that: A steam-water separator is arranged in the heat storage tank, and the steam outlet of the steam-water separator is connected to the steam outlet of the heat storage tank; the steam-water separator is located on the upper part of the water medium of the heat storage tank.

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