Solid heat storage electric boiler system coupled with subcritical water heat storage

Abstract

The utility model relates to a solid heat storage electric boiler system coupled with subcritical water heat storage, which comprises a solid heat storage electric boiler, a subcritical water heat storage tank, a steam generator and a superheater, a superheating cavity is arranged in the superheater, and a superheated steam pipeline is arranged in the superheating cavity; a first electric heating device and a magnesium oxide brick are arranged in a heat storage cavity of the solid heat storage electric boiler, the high-temperature magnesium oxide brick exchanges heat with air, a circulating fan provides power to form hot air, and the hot air sequentially passes through an overheating cavity of the superheater and a heating cavity of the steam generator, enters an air flue of the electric boiler and then circularly runs; the hot air heats subcritical water in the saturated steam pipeline to be saturated and forms saturated steam, and the saturated steam enters the superheated steam pipeline and is heated into superheated steam by the hot air in the superheated steam pipeline in the superheater. Compared with a single solid heat storage electric boiler, the system has the advantages that the heat efficiency is higher, the manufacturing cost is low, and the system operation is more stable.

Description

Technical Field

[0001] This utility model relates to the field of energy storage and comprehensive energy utilization technology, specifically to a solid thermal energy storage electric boiler system coupled with subcritical water thermal storage. Background Technology

[0002] Currently, large-scale, high-proportion renewable energy power generation still faces certain technical bottlenecks in grid connection, affecting its absorption rate. Furthermore, due to susceptibility to natural conditions, renewable energy output generally exhibits randomness and volatility, which can impact the maintenance of power balance in the grid. Simultaneously, the immaturity of renewable energy power market trading mechanisms also contributes to this problem. Therefore, improving the power system's capacity to absorb renewable energy has become an urgent priority in my country's energy structure transformation process.

[0003] In response to the above situation, energy storage technology has emerged. Energy storage is an important way of energy consumption, and the main energy storage methods at present include electrochemical energy storage, gravity energy storage, compressed air energy storage, molten salt energy storage, flywheel energy storage, supercapacitor energy storage, and solid-state energy storage.

[0004] Among various energy storage methods, solid-state energy storage is a clean energy storage method. Compared with other heat sources, solid-state thermal storage electric boilers have advantages such as high heat storage density, no pollution, economic efficiency, and ease of installation. They can also provide heating by absorbing off-peak electricity and wind and solar power curtailment, achieving energy conservation, emission reduction, peak shaving, and valley filling. They can be applied on a large scale in centralized applications such as the utilization of waste electricity from new energy sources and grid peak shaving, or distributed applications such as smart energy, centralized heating of clean energy, and combined heat and power (CHP) of clean energy.

[0005] However, current solid thermal storage devices are all single-form thermal storage and cannot form composite energy storage, resulting in insufficient energy utilization. Utility Model Content

[0006] This invention addresses the shortcomings of existing technologies by providing a solid thermal energy storage electric boiler system coupled with subcritical water thermal energy storage. By coupling solid thermal energy storage and subcritical water thermal energy storage, a composite energy storage application system is constructed, which enriches the application scenarios of energy storage, improves the comprehensive utilization rate of energy, and reduces the unit energy storage cost.

[0007] This utility model is achieved through the following technical solution: a solid thermal storage electric boiler system coupled with subcritical water thermal storage is provided, including a solid thermal storage electric boiler with a thermal storage chamber and a steam generator with a heating chamber. A superheater is provided between the air outlet of the thermal storage chamber and the air inlet of the heating chamber. The superheater contains a superheated chamber and a superheated steam pipe. A first electric heating device and magnesia bricks are provided in the thermal storage chamber, and a saturated steam pipe is provided in the heating chamber. The air outlet of the thermal storage chamber is connected to the air inlet of the superheated chamber, the air outlet of the superheated chamber is connected to the air inlet of the heating chamber, and the air outlet of the heating chamber is connected to the air inlet of the thermal storage chamber. A circulating fan is provided on the circulation channel formed by the thermal storage chamber, the superheated chamber, and the heating chamber.

[0008] The inlet of the saturated steam pipeline is connected to the subcritical water storage tank via a water inlet pipe. The subcritical water storage tank contains subcritical water, and a water pump is installed on the water inlet pipe. The outlet of the saturated steam pipeline is connected to the inlet of the hot steam pipeline, and the outlet of the superheated steam pipeline is connected to the steam supply pipeline.

[0009] The electric boiler system of this scheme is designed so that during off-peak electricity prices, the first electric heating device is activated to heat the magnesium oxide bricks to the target temperature and store heat. During peak electricity prices, the energy release process is initiated, and the high-temperature magnesium oxide bricks in the heat storage chamber of the solid thermal storage electric boiler exchange heat with the air. Powered by a circulating fan, hot air is generated and flows through the superheating chamber of the superheater, the heating chamber of the steam generator, and then circulates in the boiler's air duct. The hot air heats the subcritical water in the saturated steam pipe to saturation, forming saturated steam. The saturated steam enters the superheated steam pipe and is further heated by the hot air in the superheated steam pipe within the superheater, becoming superheated steam, which is then supplied through the steam supply pipe.

[0010] As an optimization, the circulating fan is located between the steam generator and the air inlet of the heat storage chamber. The air inlet of the circulating fan is connected to the air outlet of the heating chamber, and the air outlet of the circulating fan is connected to the air inlet of the heat storage chamber. In this application, the circulating fan is placed after the air outlet of the heating chamber, where the temperature of the hot air is lowest in the entire circulating air duct, thereby reducing the damage of high temperature to the circulating fan.

[0011] As an optimization, a second electric heating device is installed inside the subcritical water thermal storage tank. This optimized solution, by incorporating the second electric heating device, allows the water in the subcritical water thermal storage tank to be heated to subcritical water during off-peak electricity prices, further reducing energy costs and improving the utilization rate of the thermal energy from the hot air in the storage chamber.

[0012] As an optimization, the inlet of the subcritical water thermal storage tank is connected to a water source via a water supply pipe, which is equipped with a water supply pump. This optimized design facilitates the replenishment of water into the subcritical water thermal storage tank.

[0013] As an optimization, a water softener is also installed on the water supply pipe, located upstream of the water supply pump. This optimized solution softens the tap water by installing the water softener to meet water quality requirements.

[0014] The beneficial effects of this invention are as follows: by combining subcritical water heat storage and magnesia brick heat storage, the overall thermal efficiency is greatly improved. Moreover, compared with a single solid heat storage system, the steam produced is more stable, and the industrial application is safer, more stable and more effective. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the process structure of this utility model;

[0016] As shown in the figure:

[0017] 1. Solid thermal storage electric boiler; 2. Subcritical water thermal storage tank; 3. Superheater; 4. Steam generator; 5. Circulating fan; 6. Electrical cabinet; 7. Feed water pump; 8. Make-up water pump; 9. Softened water processor; 10. Second electric heating device. Detailed Implementation

[0018] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0019] like Figure 1 The system shown is a solid thermal energy storage electric boiler system coupled with subcritical water thermal energy storage, including a solid thermal energy storage electric boiler 1 with a thermal energy storage chamber and a steam generator 4 with a heating chamber. A superheater 3 is provided between the air outlet of the thermal energy storage chamber and the air inlet of the heating chamber. The superheater has a superheated chamber and a superheated steam pipe. The thermal energy storage chamber is provided with a first electric heating device and magnesia bricks. The heating chamber has a saturated steam pipe.

[0020] The air outlet of the heat storage chamber is connected to the air inlet of the superheated chamber via an air outlet pipe. The air outlet of the superheated chamber is connected to the air inlet of the heating chamber via a pipe. The air outlet of the heating chamber is connected to the air inlet of the heat storage chamber via an air inlet pipe. A circulating fan 5 is installed on the circulation channel formed by the heat storage chamber, superheated chamber, and heating chamber. The circulating fan is a high-temperature resistant, high-flow-rate blower that provides power for the circulation of heat exchange air, allowing the hot air in the heat storage chamber to pass through the heat exchanger and steam generator in sequence before re-entering the heat storage chamber. In this embodiment, to reduce the damage of high temperature to the circulating fan, the circulating fan 5 is located between the steam generator and the air inlet of the heat storage chamber. The air inlet of the circulating fan is connected to the air outlet of the heating chamber, and the air outlet of the circulating fan is connected to the air inlet of the heat storage chamber.

[0021] The inlet of the saturated steam pipeline is connected to the subcritical water storage tank 2 via the water inlet pipe, the outlet of the saturated steam pipeline is connected to the inlet of the hot steam pipeline, and the outlet of the superheated steam pipeline is connected to the steam supply pipeline.

[0022] The superheater uses the hot air exchanged from the magnesium oxide bricks to heat the saturated steam generated by the steam generator to a maximum of 250°C, thus turning it into superheated steam.

[0023] The steam generator uses hot air exchanged from magnesium oxide bricks to heat the feedwater and evaporate it into saturated steam.

[0024] Subcritical water storage tank 2 contains subcritical water, and a second electric heating device 10 is installed inside the subcritical water storage tank to heat the water to 150~185℃. In this embodiment, both the first and second electric heating devices can be based on existing technology; the second electric heating device is an electric heating rod. The subcritical water storage tank uses subcritical water for heat storage, with an operating pressure of 0.5~1.25MPa and an operating temperature of 150~185℃. A feed water pump 7 is installed on the inlet pipe, which pressurizes the subcritical water and sends it to the steam generator, allowing the hot water in the subcritical water storage tank to enter the saturated steam pipe of the steam generator after being pressurized by the feed water pump.

[0025] The inlet of the subcritical water storage tank is connected to a water source via a water supply pipe. A water supply pump 8 is installed on the water supply pipe to replenish the subcritical water storage tank. In this example, the water source is a tap water pipe. To treat the tap water, a water softener 9 is also installed on the water supply pipe upstream of the water supply pump 8 to soften the tap water and meet water quality requirements. The water softener uses existing technology and can be purchased externally.

[0026] This embodiment also includes an electrical cabinet 6 for controlling the power supply of the electric boiler system. The electrical cabinet is determined according to the voltage level connected. If it is connected to 380V, it is a low-voltage switch cabinet; if it is connected to 10KV or 35KV high voltage, it is a high-voltage starter cabinet.

[0027] The solid thermal storage electric boiler system coupled with subcritical water thermal storage in this embodiment includes solid magnesia brick thermal storage and subcritical water thermal storage. The magnesia thermal storage temperature can reach up to 750~800℃, and the subcritical water thermal storage temperature can reach up to 185℃.

[0028] When the electricity price is low, the first and second electric heating devices are activated to heat the magnesium oxide bricks and subcritical water to the target temperature and store the heat.

[0029] During peak electricity prices, the energy release process is activated. The high-temperature magnesia bricks in the solid thermal storage boiler exchange heat with the air, and the circulating fan provides power to generate hot air, which can reach a maximum temperature of 400°C. This hot air passes through the superheater, steam generator, and circulating fan in sequence, and then enters the boiler's air duct for circulation. The hot air heats the subcritical feedwater to saturation and forms saturated steam, which is then heated into superheated steam in the superheater.

[0030] The solid-state thermal storage electric boiler system coupled with subcritical water thermal storage, through the above-mentioned setup, can fully utilize the price advantage of off-peak electricity for energy storage and thermal storage, reducing energy costs, improving energy utilization efficiency, and ensuring safety and effectiveness. In this embodiment, the coupled subcritical water thermal storage and solid-state thermal storage electric boiler produce superheated steam. The subcritical thermal storage system preheats the feedwater for the solid-state thermal storage steam production system, resulting in high thermal efficiency. The overall thermal efficiency of this system reaches 95%, higher than that of single solid-state thermal storage. Moreover, it has lower costs; the cost of water thermal storage materials is low in the low-temperature range, while the solid-state thermal storage system uses magnesia bricks with high thermal density and low cost in high-temperature thermal storage. The coupling of the two fully utilizes the advantages of off-peak electricity, resulting in an overall lower cost compared to single solid-state or water thermal storage. Operation is safe and stable; the solid-state thermal storage electric boiler system coupled with subcritical water thermal storage produces more stable steam than a single solid-state thermal storage system, making it safer, more stable, and more effective in industrial applications.

[0031] Of course, the above description is not limited to the examples above. Technical features of this utility model not described can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solution of this utility model and are not intended to limit this utility model. This utility model has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this utility model do not depart from the spirit of this utility model and should also fall within the protection scope of the claims of this utility model.

Claims

1. A solid thermal storage electric boiler system coupled with subcritical water thermal storage, comprising a solid thermal storage electric boiler (1) with a thermal storage chamber and a steam generator (4) with a heating chamber, characterized in that: A superheater (3) is provided between the air outlet of the heat storage chamber and the air inlet of the heating chamber. The superheater is provided with a superheated chamber and a superheated steam pipe. The heat storage chamber is provided with a first electric heating device and magnesium oxide bricks. The heating chamber is provided with a saturated steam pipe. The air outlet of the heat storage chamber is connected to the air inlet of the superheated chamber, the air outlet of the superheated chamber is connected to the air inlet of the heating chamber, the air outlet of the heating chamber is connected to the air inlet of the heat storage chamber, and a circulating fan (5) is provided on the circulation channel formed by the heat storage chamber, the superheated chamber and the heating chamber. The inlet of the saturated steam pipeline is connected to the subcritical water storage tank (2) through the water inlet pipe. The subcritical water storage tank (2) contains subcritical water, and a water pump (7) is installed on the water inlet pipe. The outlet of the saturated steam pipeline is connected to the inlet of the hot steam pipeline, and the outlet of the superheated steam pipeline is connected to the steam supply pipeline.

2. The solid thermal storage electric boiler system coupled with subcritical water thermal storage according to claim 1, characterized in that: The circulating fan (5) is located between the steam generator and the air inlet of the heat storage chamber. The air inlet of the circulating fan is connected to the air outlet of the heating chamber, and the air outlet of the circulating fan is connected to the air inlet of the heat storage chamber.

3. The solid thermal storage electric boiler system coupled with subcritical water thermal storage according to claim 1, characterized in that: The subcritical water thermal storage tank is equipped with a second electric heating device (10).

4. A solid thermal storage electric boiler system coupled with subcritical water thermal storage according to claim 1, characterized in that: The inlet of the subcritical water storage tank is connected to the water source through a water supply pipe, and a water supply pump (8) is installed on the water supply pipe.

5. A solid thermal storage electric boiler system coupled with subcritical water thermal storage according to claim 4, characterized in that: The water supply pipe is also equipped with a water softener (9) located upstream of the water supply pump (8).

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