Slag well molten salt waste heat recovery system and method

Abstract

The slag well molten salt waste heat recovery system is characterized in that a heat absorption pipe row is arranged on the inner side of a slag well, a molten salt outlet in the bottom of a molten salt box is divided into three paths, one path is communicated with an inlet of the molten salt box, and the other path is communicated with a molten salt side inlet of a molten salt heat exchanger and an inlet of the heat absorption pipe row after passing through a molten salt conveying pipeline; a fused salt side outlet of the fused salt heat exchanger is communicated with an inlet of the heat absorption pipe row, and an outlet of the heat absorption pipe row is communicated with an inlet of the fused salt box; an outlet of the deaerator water supply pipeline communicates with an inlet of the hot water tank and a water side inlet of the fused salt heat exchanger, the water side of the fused salt heat exchanger communicates with an inlet of the heat exchange pipe in the fused salt box and an inlet of the hot water tank, an outlet of the hot water tank communicates with an inlet of the water supply pump, and the system and the method can achieve recovery of slag heat.

Description

Technical Field

[0001] The 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, in the existing technology, the slag is generally cooled by industrial water, resulting in a waste of industrial water. According to preliminary estimates, a 600,000-kilowatt unit produces nearly 200 tons of 800°C slag per day on average. 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, the corresponding technical solutions are currently given. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings of the 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 absorbing pipe row is arranged inside the slag pit, and the molten salt outlet at the bottom of the molten salt box is divided into three routes, wherein the first route is connected to the inlet of the molten salt box, 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 absorbing pipe row, the molten salt side outlet of the molten salt heat exchanger 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 box;

[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 box.

[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, and comprises the following steps:

[0013] 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 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 box.

[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, among which the auxiliary steam formed 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 formed 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 box 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 on the water side of the molten salt heat exchanger.

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

[0021] During 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, and then enters the heat absorbing pipe row to absorb the heat of the ash in the slag well, 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 and convenient, and the practicability is strong. The molten salt electric heater also has the function of converting electrical energy into thermal energy, thereby meeting the unit's demand for steam and having high flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper 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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of 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 specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0028] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, 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, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the 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 determining" 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, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually 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 in 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] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0033] Embodiment 1

[0034] refer to Figure 1 The slag well molten salt waste heat recovery system of the present invention comprises 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 box 3 is divided into two paths after passing through the molten salt pump and the molten salt electric heater 4, one of which is connected to the inlet of the molten salt box 3, and the other 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 box 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 box 3. The high-temperature molten salt output by the molten salt box 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 larger the slag discharge amount, the more obvious the use effect is, which can meet the power generation capacity of the unit at high load.

[0038] Embodiment 2

[0039] refer to Figure 1 The slag well molten salt waste heat recovery method of the present invention is based on the slag well molten salt waste heat recovery system, which includes a slag well, a molten salt box 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 in the heat absorbing pipe row, and then enters the molten salt tank 3.

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

[0042] The hot water outputted 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 formed is supplied to the heat user to realize steam supply.

[0043] As an implementation mode of the present invention, the molten salt outlet at the bottom of the molten salt tank 3 is divided into three routes 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 in use.

[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] Embodiment 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) The slag bucket of the thermal power generator set is designed to be a horizontal serpentine and spiral heat absorption pipe row, and the heat absorption pipe row is enclosed in the slag well near the ash side, and the heat absorption pipe row is enclosed in the casting material. The slag wells of two units can be paralleled to improve the efficiency and reliability of the molten salt waste heat utilization system. According to the slag well of a 350MW boiler, under the BMCR working condition, the designed coal slag discharge volume is 3.83t, and the designed coal slag discharge volume under the soot blowing state is 8t (considered as 3h per day), and the slag discharge temperature is about 800℃. The heat release formula is: Q release = cm (t0-t) = 0.963kJ / kg.℃ × 3.83t × 450℃ = 1.66GJ, where c represents the specific heat capacity of 0.963kJ / kg.℃, m represents the mass of the substance, C is the specific heat capacity of the slag of 0.963kJ / kg.℃, t0 = 800℃ represents the initial temperature, and t represents the final temperature t = 350℃. Slag pit slag can release at least 39.8GJ of heat every day.

[0049] 2) Design the molten salt box 3, and let the ternary molten salt flow through the slag well by itself, so that the molten salt absorbs the heat of the slag, forming a 400℃ liquid molten salt that flows into the molten salt box 3 by its own gravity, and stores heat through the molten salt. How much weight of the ternary molten salt (53% potassium nitrate, 40% sodium nitrite, 7% sodium nitrate) can absorb the heat released by the slag every day. m=Qabsorption / [c*(t0-t)]=cm(t0-t)=39.8GJ / (1.34kJ / kg.℃×250℃)=118.8t, c represents the specific heat capacity of 1.34kJ / kg.℃, m represents the mass of the substance, t0=400℃ represents the final temperature, and t represents the initial temperature t0=150℃. The slag can heat 118.8t of molten salt from 150℃ to 400℃ every day.

[0050] 3) The molten salt pump delivers the molten salt in the molten salt tank 3 to the molten salt heat exchanger 5, heats the high-temperature feed water to produce industrial steam, and 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 row 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 row 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 start-up of the unit, the auxiliary steam required for the boiler start-up is supplied through the molten salt tank 3 and the molten salt heat exchanger.

[0053] 6) The water supply to the deaerator 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 box 3 are steam coils, which can heat the low-temperature molten salt through high-temperature drain 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 about 400°C.

[0055] Embodiment 4

[0056] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the slag well molten salt waste heat recovery method when executing the computer program, comprising: the molten salt outputted 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 well in the heat absorbing pipe row, and then enters the molten salt tank 3; the hot water outputted 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 formed 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 a molten salt pump and a molten salt electric heater 4; a safety valve is arranged on the top of the hot water tank 1; a breathing valve is arranged 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 a memory, such as a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk memory, etc. The processor, network interface, and memory are interconnected through an internal bus, and the internal bus may be an industrial standard architecture bus, a peripheral component interconnection standard bus, an extended industrial standard architecture bus, etc. The bus may 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 a program code, and the program code includes computer operation instructions. The memory may include a memory and a non-volatile memory, and provide instructions and data to the processor.

[0057] Embodiment 5

[0058] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the slag well molten salt waste heat recovery method are implemented, including: the molten salt output by the molten salt tank 3 enters the molten salt side of the molten salt heat exchanger 5 to release heat, and 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 by the hot water tank 1 enters the molten salt of the molten salt heat exchanger 5 through the water supply pump to absorb heat, wherein the auxiliary steam formed is supplied to the heat user, and the molten salt outlet at the bottom of the molten salt tank 3 is divided into three paths after the molten salt pump and the molten salt electric heater 4; the top of the hot water tank 1 is provided with a safety valve; the top of the molten salt tank 3 and the water side of the molten salt heat exchanger 5 are provided with a breathing valve. For example, specifically, the computer-readable storage medium includes but is not limited to, for example, volatile memory and / or non-volatile memory. The volatile memory may include a random access memory (RAM) and / or a cache memory (cache), etc. 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 may be provided as methods, systems, or computer program products. Therefore, the present application may 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 may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include 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 generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. 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 capable of directing a computer or other programmable data processing device to operate 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 1A 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 operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0063] Those skilled in the art will readily appreciate 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 present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0064] It should be understood that the present invention is not limited to the exact construction that has been 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 still falls within the protection scope 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 box (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 arranged inside the slag pit, and the molten salt outlet at the bottom of the molten salt box (3) is divided into three routes, wherein the first route is connected to the inlet of the molten salt box (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 box (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 tube 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 box (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 is 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 is 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 is 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 method for recovering waste heat from molten salt in a slag well 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 a water supply pump to absorb heat, wherein the auxiliary steam generated is supplied to the heat user.

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

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

10. The method for recovering waste heat from molten salt in a slag well according to claim 6, characterized in that: The top of the molten salt tank (3) and the water side of the molten salt heat exchanger (5) are both provided with breathing valves.

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