Feed water preheating device of full-dry-method waste heat recovery system

Abstract

The utility model discloses a feed water preheating device of a full dry method waste heat recovery system, and belongs to the technical field of converter steelmaking energy conservation and emission reduction. The device comprises a water feeding pump, a water inlet container, a heat exchanger, a water outlet container, a stop valve and a deaerator which are sequentially connected through a pipeline, a fourth thermometer is arranged on a connecting pipeline between the water feeding pump and the water inlet container; a second thermometer is arranged on a connecting pipeline between the water outlet container and the stop valve; one end of the heat exchanger is provided with a flue gas inlet, and the other end of the heat exchanger is provided with a flue gas outlet; one side, close to the flue gas outlet, of the heat exchanger is provided with a water inlet connected with a water inlet container, and one side, close to the flue gas inlet, of the heat exchanger is provided with a water outlet connected with a water outlet container. According to the utility model, cold water is preheated by waste heat in flue gas, the cold water is heated to 80 DEG C from the original 20 DEG C, and the flue gas is cooled to 70 DEG C from the original 200 DEG C; and heat energy which is possibly wasted originally is effectively recycled.

Description

Technical Field

[0001] The utility model belongs to the technical field of energy conservation and emission reduction in converter steelmaking, and relates to a feed water preheating device of a full dry waste heat recovery system. Background Art

[0002] As an energy and resource intensive industry, the steel industry consumes huge amounts of energy. In the context of global energy conservation and emission reduction, it is of great significance to vigorously develop new technologies to promote low-energy steel production. During the converter steelmaking process, the carbon-oxygen reaction produces a large amount of high-temperature flue gas (1550-1700℃). The high-temperature flue gas enters the vaporization cooling flue for cooling. The flue gas temperature at the cooling flue outlet is 800-850℃. The rapid cooling heat exchanger reduces the flue gas temperature from 800~1000℃ to about 200℃. The flue gas is removed by bag dust collector to meet the standard and reduce the dust content of the flue gas to 10mg / m 3 Below, the fine dust removal is completed. The outlet flue gas temperature is about 200℃ with high sensible heat.

[0003] During converter steelmaking, the high-temperature reactions within the furnace generate large quantities of hot flue gas exceeding 1400°C. This flue gas contains enormous amounts of thermal energy, accounting for approximately 20% of the total energy input to the electric furnace. This considerable thermal energy content makes it a crucial secondary energy source in the steelmaking process, with high recycling value. Despite this enormous potential for waste heat from high-temperature flue gas, most steel companies currently use more traditional methods to treat this flue gas. While these methods can reduce the flue gas temperature to a certain extent, the waste heat recovery efficiency is generally low, resulting in significant waste of heat energy.

[0004] In summary, it is urgent to develop a device for recovering and utilizing the high-temperature flue gas waste heat generated by converter steelmaking to reuse the high-temperature waste heat for a secondary purpose and reduce the environmental burden. Utility Model Content

[0005] The purpose of the utility model is to provide a water preheating device for a full dry waste heat recovery system to solve the technical problem that the high-temperature flue gas waste heat generated by converter steelmaking in the prior art is difficult to utilize and is directly discharged to pollute the atmosphere.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The utility model provides a water preheating device for a fully dry waste heat recovery system, comprising a water feed pump, a water inlet container, a heat exchanger, a water outlet container, a stop valve and a deaerator which are connected in sequence through pipelines; a fourth thermometer is provided on the connecting pipeline between the water feed pump and the water inlet container; a second thermometer is provided on the connecting pipeline between the water outlet container and the stop valve; a flue gas inlet is provided at one end of the heat exchanger, and a flue gas outlet is provided at the other end of the heat exchanger; a water inlet is provided on a side of the heat exchanger close to the flue gas outlet and connected to the water inlet container, and a water outlet is provided on a side of the heat exchanger close to the flue gas inlet and connected to the water outlet container.

[0008] Furthermore, a first pressure gauge and a relief valve are provided on the connecting pipeline between the water outlet container and the stop valve; the relief valve is provided close to the stop valve.

[0009] Furthermore, a check valve is provided on the connecting pipeline between the relief valve and the stop valve.

[0010] Furthermore, a second safety valve is provided on the connecting pipeline between the relief valve and the check valve.

[0011] Furthermore, a first thermometer and a third thermometer are installed on the heat exchanger; the first thermometer is arranged close to the flue gas inlet of the heat exchanger, and the third thermometer is arranged close to the flue gas outlet of the heat exchanger.

[0012] Furthermore, a first safety valve is provided on the heat exchanger near the flue gas inlet.

[0013] Furthermore, the heat exchanger includes a heat exchanger shell; radial heat exchange tubes are arranged in the heat exchanger shell; and the radial heat exchange tubes are respectively connected to the water inlet and the water outlet of the heat exchanger.

[0014] Furthermore, the outer wall of the heat exchanger shell is provided with a plurality of fins, and the fins close to the smoke inlet of the heat exchanger are made of stainless steel.

[0015] Furthermore, the water provided by the water supply pump is desalted water.

[0016] Furthermore, the heat exchanger shell is made of aluminum alloy material.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention discloses a feedwater preheating device for a fully dry waste heat recovery system. The device, which uses a feedwater pump and a water inlet container to enter a heat exchanger, exchanges heat with high-temperature flue gas in the heat exchanger, and then passes the heated cold water into a deaerator for utilization. The present invention utilizes the waste heat in the flue gas to preheat the cold water, heating the cold water from 20°C to 80°C and cooling the flue gas from 200°C to 70°C, effectively recovering heat energy that would otherwise be wasted. This preheating process also reduces the energy required for subsequent feedwater heating, thereby improving the energy efficiency of the entire thermal system and reducing energy consumption and operating costs. Furthermore, during the feedwater preheating process, the present invention uses a fourth thermometer to monitor the water temperature between the feedwater pump and the water inlet container, and a second thermometer to monitor the water temperature between the outlet container and the shut-off valve. This allows for real-time monitoring of temperature changes during the feedwater preheating process, helping to promptly detect and address possible temperature anomalies and enhancing the safety and stability of the system.

[0019] Furthermore, the outer wall of the heat exchanger housing of the present invention is provided with a plurality of fins, which significantly increase the effective heat transfer area of the heat pipe. Since fins generally have a large surface area, they can provide more heat exchange interfaces, allowing heat to be transferred more efficiently within the same volume of space.

[0020] Furthermore, the utility model also provides a relief valve and a safety valve on the pipeline, which can be adjusted in time when the equipment pressure is too high to ensure the normal and safe operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 It is a structural diagram of the device of the utility model;

[0023] Figure 2 It is a partial schematic diagram of the radial heat exchange tube of the utility model.

[0024] Among them: 1-first thermometer; 2-first safety valve; 3-water outlet container; 4-first pressure gauge; 5-second thermometer; 6-release valve; 7-second safety valve; 8-check valve; 9-stop valve; 10-heat exchanger shell; 11-radial heat exchange tube; 12-third thermometer; 13-water inlet container; 14-fourth thermometer; 15-water feed pump; 16-deaerator. DETAILED DESCRIPTION

[0025] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all 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.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0028] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear to indicate an orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings, or are the orientation or positional relationship in which the product of the present invention is typically placed when in use. These terms are used solely to facilitate the description of the present invention and to simplify the description. They do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0031] The present invention is described in further detail below with reference to the accompanying drawings:

[0032] See also Figure 1 The present invention discloses a feedwater preheating device for a fully dry waste heat recovery system, characterized by comprising a feedwater pump 15, a water inlet container 13, a heat exchanger, a water outlet container 3, a shutoff valve 9, and a deaerator 16, connected sequentially via pipelines. A fourth thermometer 14 is provided on the connecting pipeline between the feedwater pump 15 and the water inlet container 13; a second thermometer 5 is provided on the connecting pipeline between the water outlet container 3 and the shutoff valve 9. A flue gas inlet is provided at one end of the heat exchanger, and a flue gas outlet is provided at the other end. A water inlet is provided on the side of the heat exchanger near the flue gas outlet, connected to the water inlet container 13; and a water outlet is provided on the side of the heat exchanger near the flue gas inlet, connected to the water outlet container 3. The inlet water of this device is heated from 20°C to 80°C before entering the deaerator 16, fully utilizing the low-temperature waste heat. The waste gas is cooled to 70°C through heat exchange, and the converter gas is pressurized by a fan and then recycled into a gas tank.

[0033] In one feasible embodiment of the present invention, the connecting pipeline between the water outlet container 3 and the shut-off valve 9 is sequentially provided with a first pressure gauge 4, a second thermometer 5, a relief valve 6, a second safety valve 7, and a check valve 8; the check valve 8 is located near the shut-off valve 9. The relief valve 6 and the second safety valve 7 automatically discharge a certain amount of gas when the internal pressure of the pipeline system exceeds a set value, ensuring safe and stable operation of the system. The check valve 8, also known as a reverse flow valve, non-return valve, back pressure valve, or one-way valve, is a valve that automatically opens and closes based on the force generated by the flow of the medium in the pipeline. Its primary function is to prevent backflow of the medium and to allow the release of the container's medium.

[0034] In one feasible embodiment of the present invention, the heat exchanger is equipped with a first thermometer 1 and a third thermometer 12. The first thermometer 1 is located near the heat exchanger's flue gas inlet, and the third thermometer 12 is located near the heat exchanger's flue gas outlet. A first safety valve 2 is also installed near the flue gas inlet. This valve can be adjusted to prevent explosion if the heat exchanger's pressure is too high.

[0035] In a feasible embodiment of the present invention, see Figure 2 The heat exchanger includes a heat exchanger shell 10; a radial heat exchange tube 11 is provided in the heat exchanger shell 10; the radial heat exchange tube 11 is connected to the water inlet and the water outlet of the heat exchanger respectively. The manufacturing process of the radial heat pipe is usually to draw the cavity into 1.3×(10 -1 ~10 -4)Pa of negative pressure, an appropriate amount of working fluid is filled in, and then the outer tube, inner tube and end cover are welded into a closed cavity. When the hot flue gas passes through the outer tube, the liquid working fluid in the liquid absorption core is heated and vaporized, and flows to the inner tube under the action of the pressure difference. The gaseous working fluid releases heat after encountering the cold fluid, and then condenses into liquid on the outer wall of the inner tube, and the cold fluid in the inner tube is heated. The condensed liquid working fluid flows back to the evaporation section under the action of gravity and capillary action, and the cycle continues. The heat pipe realizes the transfer and transfer of heat in this process.

[0036] The water provided by the water supply pump 15 is demineralized water, ensuring that the water quality is qualified and the heat exchange tubes are corrosion-free; the heat exchanger shell 10 is made of aluminum alloy material, which has the advantages of light weight, high strength, high heat transfer coefficient, and high thermal efficiency. The outer wall of the heat exchanger shell 10 is provided with a number of fins, and the presence of the fins significantly increases the effective heat transfer area of the heat pipe. Since fins usually have a large surface area, they can provide more heat exchange interfaces, so that heat can be transferred more efficiently in the same volume of space. The fins near the flue gas inlet of the heat exchanger are made of 304 stainless steel to prevent impurities from causing impact wear on the heat exchange tubes, improve the wear resistance of the material, and ensure the long life of the heat exchanger. The heat exchanger shell 10 is designed and manufactured in accordance with NB / T47003.1-2009 steel welded atmospheric pressure vessels; the radial heat exchange tubes 11, water inlet container 13, and water outlet container 3 constitute the fluid conveying and heat exchange components, and the manufacturing acceptance inspection is carried out in accordance with GB150-2011 pressure vessel and GB151-2014 heat exchanger standards; the first thermometer 1, first pressure gauge 4, second thermometer 5, third thermometer 12, and fourth thermometer 14 comply with national standards.

[0037] The working process of this utility model is as follows:

[0038] Cold water enters the water inlet container 13 through the water feed pump 15, and then enters the radial heat exchange tube 11 through the water inlet of the heat exchanger; the high-temperature flue gas generated by converter steelmaking enters the heat exchanger through the flue gas inlet of the heat exchanger, exchanges heat with the cold water in the radial heat exchange tube 11 and cools down, and the cooled flue gas is discharged from the flue gas outlet; the cold water is heated after passing through the radial heat exchange tube 11 and enters the water outlet container 3, and then flows into the deaerator 16 through the pipeline, sending the sensible heat in the flue gas to the deaerator 16 for utilization.

[0039] Before entering the deaerator 16, the preheated feed water of the present invention undergoes heat exchange with the high-temperature flue gas through a heat exchanger. This helps reduce dissolved oxygen and other non-condensable gases in the feed water, thereby improving the quality of the feed water. By recovering waste heat from the flue gas, it reduces thermal pollution caused by the discharge of high-temperature flue gas, which helps reduce carbon emissions and environmental pollution. Furthermore, the modular design includes components such as the feed water pump 15, the water inlet container 13, the heat exchanger, the water outlet container 3, and the shut-off valve 9, which are connected in sequence via piping, resulting in a compact structure and a rational layout. This design facilitates installation, maintenance, and overhaul, while also improving the overall performance and reliability of the system.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A water preheating device for a fully dry waste heat recovery system, characterized in that: The invention comprises a water supply pump (15), a water inlet container (13), a heat exchanger, a water outlet container (3), a stop valve (9) and a deaerator (16) connected in sequence through pipelines; a fourth thermometer (14) is provided on the connecting pipeline between the water supply pump (15) and the water inlet container (13); a second thermometer (5) is provided on the connecting pipeline between the water outlet container (3) and the stop valve (9); a flue gas inlet is provided at one end of the heat exchanger, and a flue gas outlet is provided at the other end of the heat exchanger; a water inlet is provided on a side of the heat exchanger close to the flue gas outlet and connected to the water inlet container (13); a water outlet is provided on a side of the heat exchanger close to the flue gas inlet and connected to the water outlet container (3).

2. The water preheating device of the full dry waste heat recovery system according to claim 1 is characterized in that: A first pressure gauge (4) and a relief valve (6) are also provided on the connecting pipeline between the water outlet container (3) and the stop valve (9); the relief valve (6) is provided close to the stop valve (9).

3. The water preheating device of the full dry waste heat recovery system according to claim 2 is characterized in that: A check valve (8) is also provided on the connecting pipeline between the relief valve (6) and the stop valve (9).

4. The water preheating device of the full dry waste heat recovery system according to claim 3 is characterized in that: A second safety valve (7) is also provided on the connecting pipeline between the relief valve (6) and the check valve (8).

5. The water preheating device of the full dry waste heat recovery system according to claim 1 is characterized in that: A first thermometer (1) and a third thermometer (12) are installed on the heat exchanger; the first thermometer (1) is arranged close to the flue gas inlet of the heat exchanger, and the third thermometer (12) is arranged close to the flue gas outlet of the heat exchanger.

6. The water preheating device of the full dry waste heat recovery system according to claim 2, characterized in that: A first safety valve (2) is also provided on the heat exchanger near the flue gas inlet.

7. The water preheating device of the full dry waste heat recovery system according to claim 1 is characterized in that: The heat exchanger comprises a heat exchanger shell (10); radial heat exchange tubes (11) are arranged in the heat exchanger shell (10); and the radial heat exchange tubes (11) are respectively connected to a water inlet and a water outlet of the heat exchanger.

8. The water preheating device of the full dry waste heat recovery system according to claim 7, characterized in that: The outer wall of the heat exchanger shell (10) is provided with a plurality of fins, and the fins close to the heat exchanger flue gas inlet are made of stainless steel.

9. The water preheating device of the full dry waste heat recovery system according to claim 7, characterized in that: The water provided by the water supply pump (15) is desalted water.

10. The water preheating device of the full dry waste heat recovery system according to claim 7, characterized in that: The heat exchanger shell (10) is made of aluminum alloy material.

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