Electric steam boiler system based on multi-stage heat storage

Abstract

The electric steam boiler system is characterized in that a water supplementing pipeline is connected with an electrode boiler through a fourth valve, the output of the electrode boiler is connected with a spherical tank through a pipeline and a first valve, and saturated steam directly discharged from the spherical tank is connected with a user side through a pipeline and a tenth valve; and the output of the spherical tank passes through the solid energy storage superheater before being connected with the user side through a pipeline and a third valve. The system is high in energy storage efficiency, long in service life and high in safety, the solid energy storage superheater directly heats saturated steam stored in the spherical tank, simultaneous charging and discharging can be achieved, the electric steam boiler system can rapidly adapt to changes of different heat using scenes and requirements, and the electric steam boiler system can produce both saturated steam and superheated steam.

Description

Technical Field

[0001] The present invention relates to the technical field of boilers, and in particular to an electric steam boiler system based on multi-stage heat storage. Background Art

[0002] The development of electrode boilers is driven by energy conservation and environmental protection considerations. With the rapid growth of installed power capacity and power generation, the peak-to-valley difference in the power grid is also widening, directly impacting the safe and economical operation of the grid. Solid energy storage superheaters, as devices that store thermal energy during off-peak periods and release it during peak periods, help increase off-peak power consumption and balance the grid load, thereby improving the operating efficiency of generator sets and reducing energy waste.

[0003] However, a single electrode boiler can only be used to produce saturated steam. On the other hand, even if it is equipped with steam superheating equipment, it is impossible to fully utilize off-peak electricity when generating superheated steam. This is mainly because general electrode boilers do not have large-scale storage functions, resulting in the inability to operate continuously and stably during off-peak periods to fully utilize off-peak electricity. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects existing in the prior art, and to provide an electric steam boiler system based on multi-stage heat storage by utilizing electrode boiler coupled spherical tank heat storage technology and solid energy storage superheater technology. The system can produce both saturated steam and superheated steam, thus solving the problem that the superheated steam generated by the electrode boiler equipped with a traditional electric superheater cannot fully utilize valley electricity.

[0005] To achieve the above objectives, the present invention designs an electric steam boiler system based on multi-stage heat storage. The boiler system includes at least a solid energy storage superheater, an electrode boiler, and a spherical tank. The water supply pipe is connected to the electrode boiler via a fourth valve, and the output of the electrode boiler is connected to the spherical tank via a pipe via a first valve. The output of the spherical tank is connected to the user end via a saturated steam pipe to output saturated steam. Another output of the spherical tank is connected to the superheating section of the solid energy storage superheater via a pipe and a third valve to ensure that superheated steam can be output to the user end. The solid energy storage superheater also includes at least a heat storage body and an electric heating component. The internal circulation hot air pipeline (i.e., the air duct of the solid energy storage superheater) passes through the heat storage body. A fan is provided on one side of the heat storage body, and the other side is the superheating section of the hot air pipeline.

[0006] Furthermore, the heat storage body is placed on refractory bricks.

[0007] Furthermore, the water supply pipe is directly connected to the superheating section of the solid energy storage superheater through the 7th valve; the water supply pipe is connected to the water purification equipment and then to the electrode boiler to ensure that the water enters the boiler after desalination and other treatments to ensure water quality.

[0008] Furthermore, the water supply pipeline is connected to the spherical tank via the second valve, the second valve and the fourth valve are interconnected via the water supply pipeline, and at least one main valve is provided at the common water supply inlet.

[0009] Furthermore, a saturated steam regulating valve is provided in the middle of the saturated steam pipeline between the spherical tank and the user end to regulate the saturated steam output to the user.

[0010] Furthermore, a superheated steam regulating valve is provided in the middle of the superheated steam pipeline between the superheating section and the user end to regulate the superheated steam output to the user.

[0011] Furthermore, a movable air duct connected by a hinge is provided between the heat storage body and the fan in the hot air duct, on the side close to the fan, and the air outlet end of the movable air duct is supported by a telescopic rod, and the telescopic rod adjusts the air outlet end of the movable air duct to stop at any height position by changing the height.

[0012] Furthermore, the system stable heating control method includes a fitting relationship method, where the heat supply per unit time is Q, the measured temperature of the heat storage body is T, the fan frequency is F, and the height of the air outlet is H; different F and H sampling curves are established under different combination values ​​of Q and T through experiments, and different fitting relationships between the above parameters are established according to the curve combination.

[0013] Furthermore, the fitting relationship includes a fitting relationship between T and H under a specific Q value and a fixed frequency F, or a fitting relationship between T and F under a specific Q value and a fixed distance H; the system stable heating control method includes prioritizing fixing F or prioritizing fixing H, or prioritizing determining a fixed adjustment target of any one of the physical quantities F and H, and automatically adjusting the other physical quantity according to the corresponding fitting relationship.

[0014] The advantages and beneficial effects of the present invention are that: with the gradual formation of a power system with a high proportion of new energy and the adjustment of a new round of peak-valley time-of-use electricity price mechanism, the fluctuation ratio of peak electricity price and valley electricity price is higher, which means that the difference between peak and valley electricity prices is further widened. The new energy storage technology can utilize the peak-valley time-of-use electricity price mechanism to store heat and energy when electricity prices are low and provide heat during peak electricity consumption, which not only reduces electricity costs but also makes more full and effective use of valley electricity.

[0015] The present invention provides an electric steam boiler system based on multi-stage heat storage, which adopts electrode boiler coupled spherical tank heat storage technology and solid energy storage superheater technology. The electrode boiler has high heating power and fast response. The spherical tank heat storage technology is adopted. Compared with cylindrical containers of the same capacity, the spherical container has the smallest surface area and the smallest heat dissipation loss, which has the advantages of steam heat storage technology. The solid energy storage superheater can make full use of the peak-valley electricity difference and is applied to large-scale energy storage scenarios. It has the characteristics of high energy storage efficiency, long life and high safety. The solid energy storage superheater directly heats the saturated steam stored in the spherical tank, which can quickly adapt to changes in different heat usage scenarios and demands, and solves the problem that the superheated steam generated by the electrode boiler supporting the superheater cannot make full use of valley electricity. The electric steam boiler system based on multi-stage heat storage can produce both saturated steam and superheated steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a connection principle diagram of the electric steam boiler system based on multi-stage heat storage of the present invention.

[0017] Markings in the figure: 1. Water purification equipment; 2. Electrode boiler; 3. Electrode rod; 4. Spherical tank; 5. Superheating section; 6. Refractory bricks; 7. Fan; 8. Thermal storage element; 9. Electric heating component; 10. Hinge; 11. Movable air duct; 12. Telescopic rod; 13. Saturated steam pipe; 14. Superheated steam pipe F1~F8 are the 1st to 8th valves of electrode boiler respectively; F9 is superheated steam regulating valve; F10 is saturated steam regulating valve. DETAILED DESCRIPTION

[0018] The following embodiments are further described in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0019] Example 1: An electric steam boiler system based on multi-stage heat storage, such as Figure 1 As shown, the boiler system at least includes a solid energy storage superheater, an electrode boiler 2, and a spherical tank 4. The water supply pipe is connected to the electrode boiler 2 via the fourth valve F4, and the output of the electrode boiler is connected to the spherical tank 4 via a pipe via the first valve F1. The output of the spherical tank 4 is connected to the user end via the saturated steam pipe 13 and the saturated steam regulating valve F10 to adjust and control the output of saturated steam at the user end. Another output of the spherical tank 4 is connected to the superheating section 5 of the solid energy storage superheater via a pipe and the third valve F3. The saturated steam is mainly superheated by the hot air after passing through the heat storage body 8 of the solid energy storage superheater, thereby generating superheated steam. The output of the superheated steam at the user end is controlled via the hot steam pipe 14 and the superheated steam regulating valve F9. The solid energy storage superheater includes at least a thermal storage body 8 and an electric heating element 9, such as an electric heating wire. When the thermal storage body temperature falls below a threshold or during off-peak periods, the electric heating wire is energized, heating the thermal storage body and storing energy. An internally circulating hot air duct (i.e., the solid energy storage superheater's air duct) passes through the thermal storage body 8. A fan 7 is located on one side of the thermal storage body, and the other side forms the superheating section 5 of the hot air duct. The fan is located within the air duct. The air blown out, heated by the thermal storage body, forms hot air that flows toward the superheating section. This hot air heats the objects in the superheating section. This present invention utilizes saturated steam superheating. After heating, the hot air cools down and returns to the inlet of the fan 7 through the hot air duct, achieving cyclic heating and energy conservation and environmental protection.

[0020] The present invention adopts spherical tank heat storage technology. Compared with cylindrical containers of the same capacity, the surface area of ​​the spherical container is the smallest and the heat dissipation loss is the smallest. The solid energy storage superheater can make full use of the peak-valley electricity difference and store valley electricity energy. It can be applied to large-scale energy storage scenarios and has the characteristics of high energy storage efficiency, long life and high safety. The solid energy storage superheater is used to directly heat the saturated steam stored in the spherical tank, which solves the problem that the superheated steam generated by the electrode boiler cannot make full use of valley electricity. The system as a whole adopts the electrode boiler coupled spherical tank heat storage technology and the solid energy storage superheater technology, making full use of the characteristics of the electrode boiler such as high heating power, large saturated steam production and fast response, as well as the characteristics of the solid energy storage superheater such as high efficiency, long life and high safety. Preferably, the heat storage body 8 is placed on the refractory bricks 6.

[0021] Preferably, the water supply pipe is connected to the water purification equipment 1 and then to the electrode boiler 2 to ensure that the supply water enters the boiler after desalination and other treatments to ensure water quality; the water supply pipe is directly connected to the water inlet pipe of the superheating section 5 of the solid energy storage superheater through the 7th valve F7.

[0022] Preferably, the water supply pipeline is connected to the spherical tank 4 via the second valve F2, the second valve F2 and the fourth valve F4 are interconnected via the water supply pipeline, and at least one main valve is provided at the common water supply inlet. In this embodiment, two valves are provided, namely the fifth valve F5 and the sixth valve F6, to ensure controllability and reliability; this design can realize water supply for the spherical tank and the electrode boiler separately or simultaneously, and is conducive to the segmented maintenance of equipment and pipelines; at the same time, the water supply can directly enter the superheating section of the solid energy storage superheater, and fully utilize off-peak electricity to produce saturated steam or superheated steam, which can reduce the cost consumption of the steam supply enterprise.

[0023] Preferably, the power configuration ratio of the electrode boiler to the solid energy storage superheater is substantially 3:1. For example, if a 3MW electrode boiler outputs saturated steam and needs to be superheated to 350°C, only a 1MW solid energy storage superheater is required.

[0024] Preferably, a movable air duct 11 connected by a hinge 10 is provided between the heat storage body 8 and the fan 7 in the hot air duct, on the side close to the fan, and the air outlet end of the movable air duct is supported by a telescopic rod 12. The telescopic rod adjusts the air outlet end of the movable air duct to stop at any height position by changing the height. Combined with the adjustable speed (frequency) of the fan, the position, direction and flow rate of the air flow at the air outlet end through the heat storage body are controlled, thereby controlling and adjusting the hot air flow (or flow rate, the same below) and temperature, that is, controlling the heating effect of the overheating section.

[0025] Working principle of the system: After the make-up water is purified by desalination and other means in the water purification equipment 1, it can be used to make up water for the electrode boiler 2 or the spherical tank 4 respectively through valve control. The make-up water entering the electrode boiler is heated by the electrode rod 3 to generate saturated steam and enter the spherical tank 4; the saturated steam in the spherical tank 4 passes through the third valve in the overheating section 5, is superheated by the hot air in the solid energy storage superheater, and generates superheated steam, which is output to the user end through the superheated steam pipe 14 and the superheated steam regulating valve F9.

[0026] When the thermal storage body has sufficient energy or the user's steam demand is not large, F2, F3, and F4 are closed, and the water supply pipeline directly supplies water to the superheating section through the 7th valve. The superheating section directly heats the supply water into superheated steam, and can directly use off-peak electricity to produce superheated steam. Therefore, this system is very flexible and adaptable.

[0027] When the solid energy storage superheater (superheating section) is not working, the spherical tank can directly output saturated steam to the user end through the saturated steam pipe and saturated steam valve.

[0028] Figure 1 The right side is the solid energy storage superheater part. During the off-peak period, the electric heating wire is energized, and the electrical energy is converted into heat and stored in the heat storage body 8. When the user needs superheated steam, the fan 7 starts to blow out the heat stored in the heat storage body, completing the circulation around the solid energy storage superheater air duct.

[0029] Preferably, a method for controlling stable system heating, taking the more complex superheated steam supply as an example, includes a fitting relationship method. Based on the user's heating (superheated steam) demand, as well as the saturated steam flow rate, pressure, and temperature, the heat supply per unit time is denoted as Q (in this embodiment, kW), the measured temperature of the thermal storage body is T, the fan frequency is F, and the air outlet height is H. Under specific combinations of Q and T, different F and H curves (curves composed of sampling points) containing boundary information can be established through experiments. Through curve fitting, different fitting relationships between the above parameters can be established.

[0030] Preferably, typical fitting relationships include a fitting relationship between T and H at a specific Q value (generally for commonly used heating amounts) and a fixed frequency F, or a fitting relationship between T and F at a specific Q value and a fixed H; the system stable heating control method includes, based on the fitting relationship and the system control strategy, giving priority to fixing F or giving priority to fixing H, or giving priority to determining a fixed adjustment target for any one of the physical quantities F and H, and automatically adjusting the other physical quantity according to the corresponding fitting relationship.

[0031] Example 2: The difference from Example 1 is that in this embodiment, only one valve, namely the fifth valve F5, is provided at the water replenishment inlet.

[0032] Example 3: The difference from Example 1 is that this embodiment abandons the movable air duct and hinge connection, and instead uses a fixed direction and position for air discharge, and mainly relies on the fan speed to adjust the hot air in the air duct.

[0033] The basic principles and advantages of the present invention include: 1. The combination of electrode boiler, spherical tank and solid heat storage can give full play to the advantages of electrode boiler in producing large amount of saturated steam quickly; the solid energy storage superheater acts as the superheating section to superheat the saturated steam, and solves the disadvantage that the superheater supporting the electrode boiler cannot use valley electricity to produce superheated steam, which can reduce costs.

[0034] 2. The spherical tank is both a direct supply spherical tank and a storage spherical tank. Only one electrode boiler is needed to supply saturated steam and superheated steam at the same time and realize real-time switching, which further meets customer needs; 3. The solid energy storage superheater can use valley electricity to generate hot air, which can be used to superheat saturated steam, thus saving energy and protecting the environment. 4. By adjusting the hot air temperature and flow, the purpose of accurately adjusting the output steam can be achieved.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An electric steam boiler system based on multi-stage heat storage, characterized in that: The boiler system at least comprises a solid energy storage superheater, an electrode boiler (2), and a spherical tank (4); a water supply pipe is connected to the electrode boiler (2) via a fourth valve (F4); and the output of the electrode boiler is connected to the spherical tank (4) via a pipe via a first valve (F1); the saturated steam output of the spherical tank (4) is connected to a user end via a saturated steam pipe (13); and another output of the spherical tank (4) is connected to the superheating section (5) of the solid energy storage superheater via a pipe and a third valve (F3); The solid energy storage superheater at least includes a heat storage body (8) and an electric heating component (9). The internal circulation hot air pipeline passes through the heat storage body (8). A fan (7) is provided on one side of the heat storage body, and the other side is a superheating section (5) of the hot air pipeline.

2. The electric steam boiler system based on multi-stage heat storage according to claim 1, characterized in that: The heat storage body (8) is placed on the refractory bricks (6).

3. The electric steam boiler system based on multi-stage heat storage according to claim 1, characterized in that: The water supply pipe is directly connected to the superheating section (5) of the solid energy storage superheater via the seventh valve (F7).

4. The electric steam boiler system based on multi-stage heat storage according to claim 1, characterized in that: The water supply pipeline is connected to the spherical tank (4) via the second valve (F2), the second valve (F2) and the fourth valve (F4) are interconnected via the water supply pipeline, and at least one main valve is provided at the common water supply inlet.

5. The electric steam boiler system based on multi-stage heat storage according to claim 1, characterized in that: A saturated steam regulating valve (F10) is provided in the middle of the saturated steam pipe (13) between the spherical tank (4) and the user end.

6. The electric steam boiler system based on multi-stage heat storage according to claim 1, characterized in that: A superheated steam regulating valve (F9) is provided in the middle of the superheated steam pipe (14) between the superheated section (5) and the user end.

7. The electric steam boiler system based on multi-stage heat storage according to claim 1, characterized in that: A movable air duct (11) connected via a hinge (10) is provided between the heat storage body (8) and the fan (7) in the hot air duct, on a side close to the fan. The air outlet end of the movable air duct is supported by a telescopic rod (12). The telescopic rod adjusts the air outlet end of the movable air duct to stop at any height position by changing its height.

8. The electric steam boiler system based on multi-stage heat storage according to claim 1, characterized in that: The method for controlling the stable heat supply of the system includes a fitting relationship method, where the heat supply per unit time is Q, the measured temperature of the heat storage body is T, the fan frequency is F, and the air outlet height is H; different F and H sampling curves are established under different combination values ​​of Q and T through experiments, and different fitting relationships between the above parameters are established according to the curve combination.

9. The electric steam boiler system based on multi-stage heat storage according to claim 8, characterized in that: The fitting relationship includes a fitting relationship between a specific heat value Q, temperature T at a fixed frequency F, and height H, or a fitting relationship between a specific heat value Q, temperature T at a fixed height H, and frequency F; the system stable heating control method includes prioritizing fixing F or prioritizing fixing H, or prioritizing determining a fixed adjustment target of any one of the physical quantities F and H, and automatically adjusting the other physical quantity according to the corresponding fitting relationship.

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