A slag well molten salt waste heat recovery system and method

Abstract

The present invention discloses a slag well molten salt waste heat recovery system and method. A heat absorption pipe row is provided on the inner side of the slag well. The molten salt outlet at the bottom of the molten salt tank is divided into three routes, wherein one route is connected with the inlet of the molten salt tank, and the other route is connected with the molten salt side inlet of the molten salt heat exchanger and the inlet of the heat absorption pipe row after passing through the molten salt delivery pipeline. The molten salt side outlet of the molten salt heat exchanger is connected with the inlet of the heat absorption pipe row, and the outlet of the heat absorption pipe row is connected with the inlet of the molten salt tank; the outlet of the deaerator water supply pipe is connected with the inlet of the hot water tank and the water side inlet of the molten salt heat exchanger, the water side of the molten salt heat exchanger is connected with the inlet of the heat exchange pipe in the molten salt tank and the inlet of the hot water tank, and the outlet of the hot water tank is connected with the inlet of the water supply pump. The system and method can realize the recovery of slag heat.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy conservation and relates to a slag well molten salt waste heat recovery system and method. Background Art

[0002] The boiler slag falling from the furnace enters the slag pit. Since the heat of the slag cannot be recovered, the existing technology generally uses industrial water to cool the slag, resulting in a waste of industrial water. Preliminary estimates show that a 600,000-kilowatt unit produces an average of nearly 200 tons of 800°C slag per day. This part of the heat is not effectively utilized. How to recover this part of the heat will effectively reduce the waste of industrial water, increase the negative pressure level of the boiler furnace, and reduce the output of the induced draft fan. However, corresponding technical solutions are currently provided. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a slag well molten salt waste heat recovery system and method, which can realize the recovery of slag heat.

[0004] To achieve the above-mentioned purpose, the slag well molten salt waste heat recovery system of the present invention comprises a slag well, a molten salt tank, a molten salt delivery pipeline, a molten salt electric heater, a molten salt heat exchanger, a deaerator water supply pipeline, a water supply pump and a hot water tank;

[0005] A heat absorption pipe row is provided inside the slag pit, and the molten salt outlet at the bottom of the molten salt tank is divided into three routes, wherein the first route is connected to the inlet of the molten salt tank, the second route is connected to the molten salt side inlet of the molten salt heat exchanger after passing through the molten salt delivery pipeline, and the third route is connected to the inlet of the heat absorption pipe row, the molten salt side outlet of the molten salt heat exchanger is connected to the inlet of the heat absorption pipe row, and the outlet of the heat absorption pipe row is connected to the inlet of the molten salt tank;

[0006] The deaerator feed water goes directly into the hot water tank.

[0007] The further improvement of the slag well molten salt waste heat recovery system of the present invention is:

[0008] Furthermore, the molten salt outlet at the bottom of the molten salt tank is divided into two paths after passing through the molten salt pump and the molten salt electric heater.

[0009] Furthermore, a safety valve is provided on the top of the hot water tank.

[0010] Furthermore, a breathing valve is provided on the top of the molten salt tank.

[0011] Furthermore, a breathing valve is provided on the water side of the molten salt heat exchanger.

[0012] The slag well molten salt waste heat recovery method of the present invention is based on a slag well molten salt waste heat recovery system, comprising the following steps:

[0013] The molten salt output from the molten salt tank enters the molten salt side of the molten salt heat exchanger to release heat, then enters the heat absorbing pipe row, absorbs the heat of the ash in the slag pit, and then enters the molten salt tank.

[0014] The further improvement of the slag well molten salt waste heat recovery method of the present invention is:

[0015] Furthermore, it also includes:

[0016] The hot water output from the hot water tank enters the molten salt of the molten salt heat exchanger through the water feed pump to absorb heat. The auxiliary steam generated is supplied to the heat user. In the case of reverse steam supply, the steam is used to heat the molten salt to liquefy the molten salt. The high-temperature condensed water generated is divided into two paths, one of which enters the hot water tank, and the other enters the molten salt tank pipe to complete the heat transfer and then enter the drain hole container.

[0017] Furthermore, the molten salt outlet at the bottom of the molten salt tank is divided into three paths after passing through the molten salt pump and the molten salt electric heater.

[0018] Furthermore, a safety valve is provided on the top of the hot water tank.

[0019] Furthermore, breathing valves are provided on the top of the molten salt tank and the water side of the molten salt heat exchanger.

[0020] The present invention has the following beneficial effects:

[0021] During the specific operation of the slag well molten salt waste heat recovery system and method described in the present invention, the molten salt output from the molten salt box enters the molten salt side of the molten salt heat exchanger to release heat, then enters the heat absorption pipe row, absorbs the heat of the ash in the slag well in the heat absorption pipe row, and then enters the molten salt box, so that the heat of the ash is recovered through the molten salt heat exchanger in a heat exchange manner to realize the recovery of the slag heat. The operation is simple, convenient and practical. The molten salt electric heater also has the function of converting electrical energy into thermal energy, which meets the unit's demand for steam and has high flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 It is a structural diagram of the present invention.

[0024] Among them, 1 is a hot water tank, 2 is a molten salt slag well, 3 is a salt dissolving box, 4 is a molten salt electric heater, and 5 is a molten salt heat exchanger. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] In the description of the present invention, it is to be understood that the terms “include” and “comprise” indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0027] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] It should be further understood that the term "and / or" as used in the present specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0029] It should be understood that although the terms "first," "second," and "third" may be used to describe preset ranges in embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are merely used to distinguish one preset range from another. For example, without departing from the scope of embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0030] The word "if," as used herein, may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments disclosed herein. These figures are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0033] Example 1

[0034] refer to Figure 1 The slag well molten salt waste heat recovery system of the present invention includes a slag well, a molten salt tank 3, a molten salt delivery pipeline, a molten salt electric heater 4, a molten salt heat exchanger 5, a deaerator water supply pipeline, a water supply pump and a hot water tank 1;

[0035] The molten salt outlet at the bottom of the molten salt tank 3 is divided into two paths after passing through the molten salt pump and the molten salt electric heater 4. One path is connected to the inlet of the molten salt tank 3, and the other path is connected to the molten salt inlet of the molten salt heat exchanger 5 and the inlet of the molten salt slag well 2 after passing through the molten salt delivery pipeline. The molten salt outlet of the molten salt heat exchanger 5 is connected to the inlet of the molten salt slag well 2, and the outlet of the molten salt slag well 2 is connected to the inlet of the molten salt tank 3.

[0036] The deaerator water supply pipe is connected to the inlet of the water supply pump through the hot water tank 1, the outlet of the water supply pump is connected to the inlet of the hot water tank 1, the water side inlet of the molten salt heat exchanger 5 and the heating exhaust pipe inside the molten salt tank 3, the water side of the molten salt heat exchanger 5 is connected to the inlet of the heating exhaust pipe in the molten salt tank 3 and the inlet of the hot water tank 1, and the outlet of the hot water tank 1 is connected to the inlet of the water supply pump.

[0037] When the present invention is working, the molten salt absorbs the heat of the hot slag to form high-temperature molten salt, which then enters the molten salt tank 3. The high-temperature molten salt output by the molten salt tank 3 enters the molten salt heat exchanger 5 through the molten salt pump and the molten salt electric heater 4 to release heat, so as to heat the high-temperature condensed water in the water side of the molten salt heat exchanger 5 to form auxiliary steam. The auxiliary steam is used as an industrial steam and heating user. The greater the slag discharge volume, the more obvious the use effect, which meets the power generation capacity of the unit under high load.

[0038] Example 2

[0039] refer to Figure 1 The slag well molten salt waste heat recovery method of the present invention is based on a slag well molten salt waste heat recovery system. The slag well molten salt waste heat recovery system includes a slag well, a molten salt tank 3, a molten salt delivery pipeline, a molten salt electric heater 4, a molten salt heat exchanger 5, a deaerator water supply pipeline, a water supply pump and a hot water tank 1. Specifically, the slag well molten salt waste heat recovery method includes the following steps:

[0040] The molten salt output from the molten salt tank 3 enters the molten salt side of the molten salt heat exchanger 5 to release heat, then enters the heat absorbing pipe row, absorbs the heat of the ash in the slag pit, and then enters the molten salt tank 3.

[0041] As an embodiment of the present invention, it also includes:

[0042] The hot water output from the hot water tank 1 enters the molten salt of the molten salt heat exchanger 5 through the water feed pump to absorb heat, wherein the auxiliary steam generated is supplied to the heat user to realize steam supply.

[0043] As an embodiment of the present invention, the molten salt outlet at the bottom of the molten salt tank 3 is divided into three paths after passing through the molten salt pump and the molten salt electric heater 4.

[0044] As an embodiment of the present invention, a safety valve is provided on the top of the hot water tank 1 to prevent the gas pressure in the hot water tank 1 from being too high, thereby improving the safety of the hot water tank 1 .

[0045] As an embodiment of the present invention, breathing valves are provided on the top of the molten salt tank 3 and the water side of the molten salt heat exchanger 5 .

[0046] Example 3

[0047] refer to Figure 1 The slag well molten salt waste heat recovery method of the present invention comprises the following steps:

[0048] 1) Design the thermal power generator slag hopper with horizontal serpentine and spiral heat absorption pipe rows. These pipes are enclosed in the slag well near the ash side and within the castable material. This allows the slag wells of two units to be paralleled, improving the efficiency and reliability of the molten salt waste heat utilization system. Based on the slag well of a 350MW boiler, under BMCR operating conditions, the designed coal slag discharge volume is 3.83 tons, and under sootblowing conditions, the designed coal slag discharge volume is 8 tons (assuming a 3-hour operation per day), with a slag discharge temperature of approximately 800°C. The heat release formula is: Q release = cm(t0-t) = 0.963 kJ / kg.°C × 3.83 t × 450°C = 1.66 GJ, where c represents the specific heat capacity (0.963 kJ / kg.°C), m represents the mass of the material, C represents the specific heat capacity (0.963 kJ / kg.°C) of the slag, t0 = 800°C represents the initial temperature, and t = 350°C represents the final temperature. Slag pit slag can release at least 39.8GJ of heat every day.

[0049] 2) Design a molten salt tank 3 to allow the ternary molten salt to flow through the slag well. The molten salt absorbs the heat of the slag, forming a 400°C liquid molten salt that flows by gravity into the molten salt tank 3, storing heat. How much weight of the ternary molten salt (53% potassium nitrate, 40% sodium nitrite, 7% sodium nitrate) is needed to absorb the heat released by the slag daily? m = Qabs / [c * (t0 - t)] = cm (t0 - t) = 39.8 GJ / (1.34 kJ / kg.°C × 250°C) = 118.8 t, where c represents the specific heat capacity (1.34 kJ / kg.°C), m represents the mass of the substance, t0 = 400°C represents the final temperature, and t represents the initial temperature (t0 = 150°C). The slag can heat 118.8 tons of molten salt from 150°C to 400°C daily.

[0050] 3) The molten salt pump delivers the molten salt in the molten salt tank 3 to the molten salt heat exchanger 5, which heats the high-temperature feed water to produce industrial steam. The mass of water is converted into high-pressure steam through the molten salt heat exchanger 5, m=Qabsorption / [c*(t0-t)]=cm(t0-t)=39.8GJ / (4.2kJ / kg.℃×240℃)=39t, c represents the specific heat capacity of 4.2kJ / kg.℃, m represents the mass of the substance, t0=400℃ represents the final temperature, t represents the initial temperature t0=160℃, and the molten salt can heat 39t of feed water from 160℃ to 400℃ every day.

[0051] 4) The molten salt pump transports the molten salt in the molten salt tank 3 to the heat absorbing pipe bank for circulation heating to the required temperature. At the same time, the molten salt (temperature is about 180°C) passing through the molten salt heat exchanger flows into the heat absorbing pipe bank under the action of gravity for molten salt heating.

[0052] 5) A molten salt electric heater 4 is provided to adjust the molten salt temperature to ensure the stability of the auxiliary steam supply. During the startup of the unit, the auxiliary steam required for boiler startup is supplied through the molten salt tank 3 and the molten salt heat exchanger.

[0053] 6) The deaerator water supply is divided into two routes, one of which is sent to the molten salt heat exchanger for heating through the water supply pump, and the other enters the hot water tank 1 and then enters the molten salt heat exchanger through the water supply pump.

[0054] 7) The heat exchange tubes in the molten salt tank 3 are steam coils, which can heat the low-temperature molten salt through high-temperature hydrophobicity and steam. When the molten salt waste heat utilization device is shut down for a long time, the auxiliary steam of the adjacent unit can also be used to liquefy the molten salt. When both units are shut down for a short period of time, the molten salt electric heater 4 can be used to heat the molten salt to meet the normal startup of the unit and ensure that the molten salt temperature is stable at around 400°C.

[0055] Example 4

[0056] A computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the slag well molten salt waste heat recovery method are implemented, including: the molten salt output from the molten salt tank 3 enters the molten salt side of the molten salt heat exchanger 5 to release heat, then enters the heat absorption pipe row, absorbs the heat of the ash in the slag well in the heat absorption pipe row, and then enters the molten salt tank 3; the hot water output from the hot water tank 1 enters the molten salt of the molten salt heat exchanger 5 through a water supply pump to absorb heat, wherein the auxiliary steam generated is supplied to heat users; the molten salt outlet at the bottom of the molten salt tank 3 is divided into three paths after passing through the molten salt pump and the molten salt electric heater 4; a safety valve is provided on the top of the hot water tank 1; a breathing valve is provided on the top of the molten salt tank 3 and on the water side of the molten salt heat exchanger 5. The memory may include internal memory, such as high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus. This internal bus may be an Industry Standard Architecture bus, a Peripheral Component Interconnect Standard bus, an Extended Industry Standard Architecture bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory is used to store programs. Specifically, the program may include program code, and the program code includes computer operating instructions. The memory may include internal memory and non-volatile memory, and provides instructions and data to the processor.

[0057] Example 5

[0058] A computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a slag pit molten salt waste heat recovery method, including: molten salt output from the molten salt tank 3 enters the molten salt side of the molten salt heat exchanger 5 to release heat, then enters the heat absorption pipe bank to absorb heat from the ash in the slag pit, and then enters the molten salt tank 3; hot water output from the hot water tank 1 enters the molten salt in the molten salt heat exchanger 5 via a feed water pump to absorb heat, wherein the generated auxiliary steam is supplied to heat users; the molten salt outlet at the bottom of the molten salt tank 3 is divided into three paths after passing through the molten salt pump and the molten salt electric heater 4; a safety valve is provided at the top of the hot water tank 1; and a breathing valve is provided at the top of the molten salt tank 3 and on the water side of the molten salt heat exchanger 5. Specifically, for example, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include a read-only memory (ROM), a hard disk, a flash memory, an optical disk, a magnetic disk, and the like.

[0059] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0060] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0061] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1The function specified in one or more boxes.

[0062] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0063] Those skilled in the art will readily identify other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0064] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0065] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A slag well molten salt waste heat recovery system, characterized in that: It includes a slag pit, a molten salt tank (3), a molten salt delivery pipeline, a molten salt electric heater (4), a molten salt heat exchanger (5), a deaerator water supply pipeline, a water supply pump and a hot water tank (1); A heat absorbing pipe row is provided on the inner side of the slag pit, and the molten salt outlet at the bottom of the molten salt tank (3) is divided into three routes, wherein the first route is connected to the inlet of the molten salt tank (3), the second route is connected to the molten salt side inlet of the molten salt heat exchanger (5) after passing through the molten salt delivery pipeline, and the third route is connected to the inlet of the heat absorbing pipe row, the molten salt side outlet of the molten salt heat exchanger (5) is connected to the inlet of the heat absorbing pipe row, and the outlet of the heat absorbing pipe row is connected to the inlet of the molten salt tank (3); The outlet of the deaerator water supply pipe is divided into two paths, one of which is connected to the inlet of the water supply pump, the outlet of the water supply pump is connected to the inlet of the hot water tank (1) and the water side inlet of the molten salt heat exchanger (5), the water side outlet of the molten salt heat exchanger (5) is connected to the inlet of the heat exchange pipe in the molten salt tank (3) and the inlet of the hot water tank (1), and the outlet of the hot water tank (1) is connected to the inlet of the water supply pump.

2. The slag well molten salt waste heat recovery system according to claim 1 is characterized in that: The molten salt outlet at the bottom of the molten salt tank (3) is divided into three paths after passing through a molten salt pump and a molten salt electric heater (4).

3. The slag well molten salt waste heat recovery system according to claim 1, characterized in that: A safety valve is provided on the top of the hot water tank (1).

4. The slag well molten salt waste heat recovery system according to claim 1, characterized in that: A breathing valve is provided on the top of the molten salt box (3).

5. The slag well molten salt waste heat recovery system according to claim 1, characterized in that: A breathing valve is provided on the water side of the molten salt heat exchanger (5).

6. A method for recovering waste heat from molten salt in a slag well, characterized in that: The slag well molten salt waste heat recovery system according to claim 1 comprises the following steps: The molten salt output from the molten salt tank (3) enters the molten salt side of the molten salt heat exchanger (5) to release heat, then enters the heat absorbing pipe row, absorbs the heat of the ash in the slag pit in the heat absorbing pipe row, and then enters the molten salt tank (3).

7. The slag well molten salt waste heat recovery method according to claim 6, characterized in that: Also includes: The hot water output from the hot water tank (1) enters the molten salt of the molten salt heat exchanger (5) through the water feed pump to absorb heat, wherein the auxiliary steam generated is supplied to the heat user.

8. The slag well molten salt waste heat recovery method according to claim 6, characterized in that: The molten salt outlet at the bottom of the molten salt tank (3) is divided into three paths after passing through a molten salt pump and a molten salt electric heater (4).

9. The slag well molten salt waste heat recovery method according to claim 6, characterized in that: A safety valve is provided on the top of the hot water tank (1).

10. The slag well molten salt waste heat recovery method according to claim 6, characterized in that: Breathing valves are provided on the top of the molten salt tank (3) and the water side of the molten salt heat exchanger (5).

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