Phase change heat storage medium melting device and melting system

Abstract

The present invention relates to a phase-change heat storage medium melting device and a melting system, wherein the phase-change heat storage medium melting device comprises a heat-insulating container; the heat-insulating container is provided with at least one inlet for solid phase-change heat storage medium to enter, and at least one outlet for liquid phase-change heat storage medium to flow out; the heat-insulating container is provided with at least one group of heating tubes for circulating combustion gas; the exhaust port of the heating tube group extends out of the heat-insulating container; the heat-insulating container is provided with a stirrer; the driving device of the stirrer is fixedly arranged on the top of the heat-insulating container, and the stirring shaft of the stirrer extends into the heat-insulating container; the heating tube group is arranged between the middle and the bottom of the heat-insulating container; the heat-insulating container is provided with at least one inlet for liquid phase-change heat storage medium to flow in. The melting system mainly utilizes a heat exchanger and a liquid phase-change heat storage medium to melt the solid phase-change heat storage medium, which greatly reduces the production cost.

Description

Technical Field

[0001] The invention relates to phase change heat storage equipment, and in particular to a phase change heat storage medium melting device and a melting system. Background Art

[0002] Energy storage is a key and essential part of solar thermal power generation system. The energy storage medium is mostly phase-change heat storage medium, such as molten salt. The energy storage function is achieved by heating the heat storage medium.

[0003] In the solar thermal power generation system, the phase change heat storage medium melting furnace is the most common heat storage device, and the phase change medium usually used is molten salt. The phase change medium melting furnace usually uses the combustion gas flowing in the heating tube to heat the phase change medium. In order to ensure the salting effect, it is often necessary to arrange a large number of heating tubes in the furnace body, and each heating tube is equipped with a heating nozzle. Therefore, the entire salting process requires a large amount of gas, high energy consumption, and high production costs. In addition, the emission of gas also has certain environmental problems. Summary of the invention

[0004] The first object of the present invention is to provide a phase-change heat storage medium melting device with low energy consumption.

[0005] The technical solution for achieving the first object of the present invention is as follows: the phase change heat storage medium melting device of the present invention comprises a heat-insulating container; the heat-insulating container is provided with at least one inlet for solid phase change heat storage medium to enter, and at least one outlet for liquid phase change heat storage medium to flow out; at least one group of heating tube groups for circulating combustion gas is provided in the heat-insulating container; the exhaust port of the heating tube group extends out of the heat-insulating container; an agitator is provided on the heat-insulating container; the driving device of the agitator is fixedly arranged on the top of the heat-insulating container, and the agitator shaft of the agitator extends into the heat-insulating container; the heating tube group is arranged between the middle and the bottom of the heat-insulating container; the heat-insulating container is provided with at least one inlet for liquid phase change heat storage medium to flow in.

[0006] A jet tube for spraying liquid phase-change heat storage medium is arranged on the top of the heat preservation container; the liquid inlet of the jet tube is connected to the inlet; and a jet port is arranged on the jet tube.

[0007] The jet pipes are distributed along the inner wall of the heat-insulating container and are in a ring shape.

[0008] The bottom of the heat preservation container is also provided with an electric heating device for heating the phase change heat storage medium. The electric heating device is a common component in the phase change heat storage medium melting equipment and will not be described in detail here.

[0009] The above-mentioned heating tube group includes a heating chamber, a heating tube and a smoke exhaust pipe connected together in sequence along the flow direction of the combustion gas; the heating chamber passes through the insulation container, and the smoke exhaust pipe passes through the insulation container; a heating nozzle is fixed on the insulation container, and the heating nozzle faces the heating chamber.

[0010] The phase change heat storage medium is mainly inorganic salts, such as NaNO3, KNO3 and their mixtures.

[0011] The bottom of the heat preservation container is a sedimentation area, and the heat preservation container is also provided with a sewage outlet for discharging the sediment in the sedimentation area. The sewage outlet can effectively ensure the cleanliness of the heat preservation container.

[0012] As an optimized design, the sewage outlet is arranged on the side wall of the heat-insulating container; the sewage outlet is connected to one end of a sewage siphon pipe, and the other end of the sewage siphon pipe is placed in the sedimentation area.

[0013] The second object of the present invention is to provide a phase change heat storage medium melting system, which utilizes solar energy and liquid phase change heat storage medium to melt solid phase change heat storage medium with low energy consumption.

[0014] The technical solution for achieving the second object of the present invention is: the phase change heat storage medium melting system of the present invention comprises the above-mentioned phase change heat storage medium melting device, a heat exchange device for heating the liquid phase change heat storage medium, a low-temperature molten salt tank and a buffer tank; the heat preservation container of the phase change heat storage medium melting device is provided with two inlets for the liquid phase change heat storage medium to flow in, namely a first inlet and a second inlet, and an overflow port for the liquid phase change heat storage medium to flow out;

[0015] The overflow port is connected to the inlet of the buffer tank, and the outlet of the buffer tank is connected to the liquid inlet of the heat exchange device; the liquid outlet of the heat exchange device is connected to the inlet and the first inlet of the low-temperature molten salt tank through pipelines, and a valve is provided on the pipeline; the outlet of the low-temperature molten salt tank is connected to the second inlet through a pipeline, and a high-pressure pump is provided on the pipeline. The liquid phase-change heat storage medium in the buffer tank is discharged from the outlet of the buffer tank under the action of the pump provided by the buffer tank.

[0016] The invention also includes a conveyor belt for conveying the solid phase-change heat storage medium to the inlet of the heat preservation container.

[0017] The above heat exchange device is a solar oil-smoke heat exchanger. Since the solar oil-smoke heat exchanger is a prior art, it will not be described in detail here.

[0018] The present invention has positive effects: (1) The phase change heat storage medium melting device of the present invention melts the solid phase change heat storage medium by introducing liquid phase change heat storage medium, a stirrer and a heating tube group located at the bottom of the heat preservation container. The solid phase change heat storage medium can be melted by only one or a few heating tube groups, which greatly saves production costs.

[0019] (2) Since the solid phase-change heat storage medium will float on the surface of the liquid phase-change heat storage medium after being added to the heat preservation container, the present invention can use the jet tube to allow the liquid phase-change heat storage medium to fully contact and mix with the solid phase-change heat storage medium on the surface, thereby improving the melting efficiency and melting effect.

[0020] (3) The jet tube of the present invention adopts an annular design, which further increases the spray range and thus improves the mixing effect.

[0021] (4) The present invention can further improve the melting efficiency and melting effect through the electric heating device, thereby playing an auxiliary melting role.

[0022] (6) In the phase change heat storage medium melting system of the present invention, liquid phase change heat storage medium is first pre-stored in a low-temperature molten salt tank, and the entire system can be operated after reaching a certain amount.

[0023] (7) The phase change heat storage medium melting system of the present invention heats up the liquid phase change heat storage medium involved in the melting through a heat exchanger (especially a solar oil-smoke heat exchanger), so that the liquid phase change heat storage medium is recycled to meet the melting requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments and in conjunction with the accompanying drawings, wherein

[0025] Figure 1 It is a structural schematic diagram of the molten salt salting device in the present invention;

[0026] Figure 2 It is a structural schematic diagram of the salt system in the present invention;

[0027] Figure 3 It is a schematic diagram of the structure of the jet tube in the present invention;

[0028] Figure 4 It is a structural schematic diagram of the heating tube assembly in the present invention;

[0029] Figure 5 FIG. 2 is another structural schematic diagram of the heating tube assembly in the present invention. DETAILED DESCRIPTION

[0030] See Figure 1The phase-change heat storage medium melting device of the present invention comprises a heat-insulating container 1; the heat-insulating container 1 is provided with an inlet 11 for solid phase-change heat storage medium to enter, and an overflow port 14 for liquid phase-change heat storage medium to flow out; a group of heating tube groups 2 for circulating combustion gas are arranged in the heat-insulating container 1; the exhaust port of the heating tube group 2 extends out of the heat-insulating container 1; a stirrer 3 is arranged on the heat-insulating container 1; a driving device 31 of the stirrer 3 is fixedly arranged on the top of the heat-insulating container 1, and a stirring shaft 32 of the stirrer 3 extends into the heat-insulating container 1; the heating tube group 2 is arranged at the bottom of the heat-insulating container 1; the heat-insulating container 1 is provided with two inlets for liquid phase-change heat storage medium to flow in, which are a first inlet 12 and a second inlet 13.

[0031] See Figure 1 and Figure 3 A jet tube 4 for spraying liquid phase-change heat storage medium is arranged at the top of the heat preservation container 1 ; the liquid inlet of the jet tube 4 is connected to the inlet 13 ; and a jet port 41 is arranged on the jet tube 4 .

[0032] The jet pipe 4 is distributed along the inner wall of the heat-insulating container 1 and is annular.

[0033] The bottom of the heat-insulating container 1 is also provided with an electric heating device 5 for heating the phase-change heat storage medium.

[0034] See Figure 1 The bottom of the heat preservation container 1 is a sedimentation area, and a sewage outlet 15 for discharging the sediment in the sedimentation area is also provided on the side wall of the heat preservation container 1; the sewage outlet 15 is connected to one end of a sewage siphon 16, and the other end of the sewage siphon 16 is placed in the sedimentation area.

[0035] See Figure 4 The heating tube group 2 includes a heating chamber 21, a heating tube 22 and a smoke exhaust pipe 23 connected in sequence along the flow direction of the combustion gas; the heating chamber 21 passes through the heat preservation container 1, and the smoke exhaust pipe 23 passes through the heat preservation container 1; a heating nozzle is fixed on the heat preservation container 1, and the heating nozzle faces the heating chamber 21. Of course, the heating tube 22 can be composed of multiple tubes, see Figure 5 .

[0036] See Figure 2 The phase change heat storage medium melting system of the present invention comprises the above-mentioned phase change heat storage medium melting device, a heat exchange device 6 for heating the liquid phase change heat storage medium, a low-temperature molten salt tank 7 and a buffer tank 8; the buffer tank 8 is equipped with a pump for pumping the liquid phase change heat storage medium in the buffer tank 8.

[0037] The overflow port 14 is connected to the inlet of the buffer tank 8; the outlet of the buffer tank 8 is connected to the liquid inlet of the heat exchange device 6; the liquid outlet of the heat exchange device 6 is connected to the inlet of the low-temperature molten salt tank 7 and the first inlet 12 through pipelines, and a valve is provided on the pipeline; the outlet of the low-temperature molten salt tank 7 is connected to the second inlet 13 through a pipeline, and a high-pressure pump is provided on the pipeline.

[0038] It also includes a conveyor belt 9 for conveying the solid phase-change heat storage medium to the inlet 11 of the heat preservation container 1 .

[0039] The heat exchange device 6 is a solar oil-fume heat exchanger.

[0040] The melting process of the phase change heat storage medium melting system of the present invention is as follows:

[0041] First, the solid phase change heat storage medium is put into the insulation container 1 from the inlet 11 through the conveyor belt 9; then the solid phase change heat storage medium is heated and melted by the heating nozzle and the heating tube group 2, and the electric heating device 5 can be used if necessary; then the molten liquid phase change heat storage medium is extracted through the buffer tank 8 and injected into the solar oil-smoke heat exchanger, and the liquid phase change heat storage medium is heated by the solar mirror field, and then the heated liquid phase change heat storage medium is passed into the low-temperature molten salt tank 7 for storage. At the same time, the low-temperature molten salt tank 7 uses a high-pressure pump to inject the liquid phase change heat storage medium into the jet tube 4, and the jet tube 4 sprays to effectively mix the solid phase change heat storage medium in the insulation container 1.

[0042] When the temperature and liquid phase-change heat storage medium in the heat-insulating container 1 reach a certain amount, the valve between the heat exchange device 6 and the inlet of the low-temperature molten salt tank 7 is closed, and the valve between the heat exchange device 6 and the first inlet 12 is opened; at this time, the liquid phase-change heat storage medium coming out of the heat exchange 6 is directly passed into the jet tube 4 to form a circulation.

[0043] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A phase-change heat storage medium melting device, comprising a heat-insulating container (1); the heat-insulating container (1) is provided with at least one inlet (11) for solid phase-change heat storage medium to enter, and at least one outlet for liquid phase-change heat storage medium to flow out; the heat-insulating container (1) is provided with at least one group of heating tubes (2) for circulating combustion gas; the exhaust port of the heating tubes (2) protrudes out of the heat-insulating container (1); the characteristics are: The heat-insulating container (1) is provided with a stirrer (3); a driving device (31) of the stirrer (3) is fixedly arranged on the top of the heat-insulating container (1), and a stirring shaft (32) of the stirrer (3) extends into the heat-insulating container (1); the heating tube group (2) is arranged between the middle and the bottom of the heat-insulating container (1); the heat-insulating container (1) is provided with at least one inlet for the inflow of a liquid phase-change heat storage medium; A jet tube (4) for spraying liquid phase-change heat storage medium is arranged at the top of the heat-insulating container (1); a liquid inlet of the jet tube (4) is connected to the inlet (13); and a jet port (41) is arranged on the jet tube (4); The jet pipe (4) is distributed along the inner wall of the heat-insulating container (1) and is in a ring shape; The bottom of the heat-insulating container (1) is also provided with an electric heating device (5) for heating the phase-change heat storage medium; The bottom of the heat-insulating container (1) is a sedimentation zone, and the heat-insulating container (1) is also provided with a sewage outlet (15) for discharging sediment from the sedimentation zone.

2. The phase change heat storage medium melting device according to claim 1, characterized in that: The sewage outlet (15) is arranged on the side wall of the heat-insulating container (1); the sewage outlet (15) is connected to one end of a sewage siphon (16), and the other end of the sewage siphon (16) is placed in a sedimentation area.

3. Phase change heat storage medium melting system, characterized by: A phase-change heat storage medium melting device according to claim 1 or 2, a heat exchange device (6) for heating a liquid phase-change heat storage medium, a low-temperature molten salt tank (7) and a buffer tank (8); the heat preservation container (1) of the phase-change heat storage medium melting device is provided with two inlets for the liquid phase-change heat storage medium to flow in, namely a first inlet (12) and a second inlet (13), and an overflow port (14) for the liquid phase-change heat storage medium to flow out; The overflow port (14) is connected to the inlet of the buffer tank (8), and the outlet of the buffer tank (8) is connected to the liquid inlet of the heat exchange device (6); the liquid outlet of the heat exchange device (6) is connected to the inlet of the low-temperature molten salt tank (7) and the first inlet (12) through pipelines, and valves are provided on the pipelines; the outlet of the low-temperature molten salt tank (7) is connected to the second inlet (13) through pipelines, and a high-pressure pump is provided on the pipeline.

4. The phase change heat storage medium melting system according to claim 3, characterized in that: The bottom of the heat-insulating container (1) is also provided with an electric heating device (5) for heating the phase-change heat storage medium.

5. The phase change heat storage medium melting system according to claim 3, characterized in that: It also includes a conveyor belt (9) for conveying the solid phase-change heat storage medium to the inlet (11) of the heat-insulating container (1).

6. The phase change heat storage medium melting system according to claim 3, characterized in that: The heat exchange device (6) is a solar oil-fume heat exchanger.

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