Heat recovery process

Abstract

The invention provides a heat recovery process which comprises the following steps: stirring a material and a pressure closed container, and transferring the heat of the material to the pressure closed container; screening the materials subjected to heat transfer and the pressure closed container; performing heat recovery on the pressure closed container with heat; according to the invention, heat can be effectively recovered, for example, the heat can be prevented from being taken away and lost into the atmosphere by steam generated in a water gasification process in a wet quenching and other solid material cooling process, the process investment can be reduced, and the operating cost is reduced, so that the industrial popularization and application of the device are expanded, the industrial application occasions are more, and the economic benefit is high. According to the invention, the consumption in the production process can be reduced, the environmental pollution is reduced, and the effective utilization of resources and energy is realized.

Description

[0001] This application is a divisional application of application number 2022100815276, which describes a heat recovery process and device. The original application was filed on January 24, 2022. Technical Field

[0002] This application relates to the field of chemical equipment technology, specifically to a heat recovery process. Background Technology

[0003] Under the national development strategy of carbon reduction and carbon peaking, enterprises must carry out energy-saving technological transformation to reduce their carbon footprint and carbon dioxide emissions. However, existing technologies in many fields still face the problem of difficulty in recovering heat. In the coke production industry, the temperature of coke exiting the coke oven is relatively high, ranging from 800-1000℃, containing enormous energy. Coke is an important raw material for steelmaking. It is produced by removing the volatile components of coal (which typically account for about 25% of the coal's mass). Ideally, the hot waste gases generated during coke production should be captured and utilized again. Current coke processing technologies mainly include wet quenching and dry quenching. Wet quenching is the oldest quenching method used in the steel industry. Its principle is simple: a large amount of water is sprayed onto the freshly produced red-hot coke to quench it. However, the old-fashioned wet quenching method uses an outdated process of spraying water through pipes with openings. This process is prone to clogging, and prolonged quenching results in high moisture content, while shorter quenching times lead to red-hot coke. After quenching, the coke's strength and moisture content are not stable enough. Furthermore, during the wet quenching process, the gasification of water produces... The steam generated is carried away and lost into the atmosphere. Dry quenching is a major energy-saving and environmentally friendly technology in the steel industry, and it is a quenching technology that replaces wet quenching. Its basic principle is to use inert gas (or waste gas) as circulating gas to exchange heat with hot coke in the dry quenching furnace, cooling the temperature of the coke from 1000℃ to below 250℃, thus achieving the purpose of quenching. The circulating gas that has absorbed the heat of the coke transfers the heat to the waste heat boiler to generate medium-pressure (or high-pressure) steam. The cooled inert gas is then blown into the dry quenching furnace by a circulating fan. Dry quenching technology can improve the quality of coke, avoid the environmental pollution caused by wet quenching, and recover the sensible heat of red coke, thus playing a dual role in energy saving and environmental protection. Dry quenching has many advantages, but the construction cost of dry quenching towers is high, the operating cost is high, and the technology is difficult to obtain. Traditional coking enterprises have large investment amounts for technological transformation, which limits its industrial promotion and application.

[0004] In the field of semi-coke, the main process of turning coal into semi-coke is dry distillation (pyrolysis). After pyrolysis, part of it becomes flue gas, and the rest is further heated and carbonized into semi-coke at a high temperature of 500 to 600 degrees Celsius. Tar and coal gas both come from the volatilized flue gas. The flue gas needs to be washed and cooled with water to remove impurities and recover coal tar. This process generates a large amount of wastewater. After the semi-coke is carbonized, it needs to be cooled down as soon as possible to avoid further combustion. However, the semi-coke quenching process generally adopts a wet method, which not only generates a large amount of phenol-containing wastewater but also wastes heat and increases water consumption significantly. Some processes directly soak the semi-coke in wastewater to cool it down at a temperature of 500-600 degrees Celsius. After the semi-coke absorbs most of the wastewater and vaporizes some of it, there is very little wastewater left, and the temperature of the semi-coke has dropped. This process is called "water quenching" or "water quenching." This extensive process achieves "zero discharge" of wastewater. However, the semi-coke adsorbs pollutants from the wastewater, which is called "pollution transfer." Under the dual-carbon background, reducing consumption in the production process and achieving effective utilization of resources and energy has become the mainstream technological development trend. Therefore, it is necessary to improve the above-mentioned technical solutions so that they do not cause pollution and can effectively recover heat.

[0005] In the steel and cement industries, the challenge of heat recovery from high-temperature solids also exists. For example, patent CN210636002 U proposes a heat recovery device using a kettle-type air heat carrier method, which recovers heat from steel slag through hot air. However, this method suffers from the potential economic problems of low gas heat capacity and high investment and operating costs due to the large circulating air volume. Chinese patent 201310566022.X discloses a method for recovering waste heat from cement clinker by wrapping a circulating water bag around the low-temperature surface of a grate cooler. Chinese patents 201510618017.8, 201510618031.8, 201510617368.7, and 201510618002.1 disclose a waste heat recovery method by arranging heat exchange tubes between the bottom shell of a water cooler and the clinker channel. The main shortcoming of the above patents is that the heat transfer efficiency of the clinker is low during the heat recovery process, and the heat recovery rate and efficiency need to be improved.

[0006] Therefore, a new technical solution is needed to address the above-mentioned technical problems, which can effectively recover heat, reduce pollution, and ensure low cost. Summary of the Invention

[0007] A heat recovery process, characterized by comprising the following steps: The material is brought into contact with and stirred in a pressure-sealed container, transferring the heat of the material to the pressure-sealed container. Screening is performed on materials after heat transfer and on pressurized sealed containers. Heat recovery is performed on a pressure-sealed container that contains heat.

[0008] As a preferred embodiment, a heat recovery process further includes the following steps: the pressure-sealed container after heat recovery is returned to a sealed container storage section.

[0009] As a preferred option, heat recovery can be achieved for pressure-sealed containers containing heat using at least one of the following methods: steam generator, heat carrier furnace, or thermal oil furnace.

[0010] As a preferred embodiment, the pressure-sealed container contains a heat carrier with high heat capacity.

[0011] As a preferred embodiment, the heat transfer medium is one of water, heat transfer oil, or molten salt.

[0012] As a preferred embodiment, the recovered heat ranges from 200 to 1300°C.

[0013] As a preferred embodiment, the contact and stirring method between the material and the pressure-sealed container is either a rotary drum type or a closed-space vibration contact type.

[0014] As a preferred option, the pressure-sealed container is made of one of the following materials: carbon steel, alloy steel, or silicon carbide.

[0015] This invention provides a heat recovery device, comprising: Material conveying device: used for conveying materials; Pressure vessel conveying device: used for conveying pressurized, sealed containers; Mixing device: used to stir materials and pressurized sealed containers, transferring the heat of the materials to the sealed containers; Screening device: used for screening materials after heat transfer and pressurized closed containers; Heat recovery equipment: recovers heat from a pressurized, sealed container.

[0016] As a preferred embodiment, the heat recovery equipment is provided with a transmission device at its outlet, and the transmission device is connected to the sealed container storage section.

[0017] As a preferred embodiment, the sealed container is made of one of the following materials: carbon steel, alloy steel, or silicon carbide.

[0018] As a preferred option, the sealed container is one of the following shapes: spherical, elongated cylindrical, or elliptical; spherical, elongated cylindrical, and elliptical shapes have good pressure resistance and large contact and heat transfer areas.

[0019] As a preferred embodiment, the sealed container includes a cylindrical body with sealed elliptical end caps at both ends.

[0020] As a preferred embodiment, a heat carrier is placed inside the sealed container.

[0021] As a preferred embodiment, the heat transfer medium is one of water, heat transfer oil, or molten salt.

[0022] As a preferred embodiment, the heat recovery equipment employs at least one of a steam generator, a heat carrier furnace, and a thermal oil furnace.

[0023] The heat recovery process of this invention utilizes a dispersed pressure-sealed container to directly stir and mix high-temperature materials, transferring the heat of the materials to the pressure-sealed container. A certain contact time is set according to the temperature difference and heat transfer efficiency of heat recovery. As the temperature rises, the pressure inside the container will rise, but it will not exceed its designed maximum pressure. After the heat is transferred to the sealed container, it is separated from the materials. The separated pressure-sealed container enters a steam generator for heat recovery and utilization.

[0024] This invention can effectively recover heat, such as preventing it from being carried away by steam generated during water vaporization in the wet quenching process and lost into the atmosphere. This invention can also reduce process investment and operating costs, thereby expanding its industrial application and making it applicable to more industrial scenarios. It can reduce consumption in the production process, reduce environmental pollution, and achieve the effective utilization of resources and energy. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the heat recovery device; Figure 2 This is a schematic diagram of one type of sealed container structure; Figure 3 This is a structural diagram of a specific structure of a heat recovery device from one angle. Figure 4 This is a structural diagram of a specific structure of a heat recovery device from another angle. 1. Material conveying device 2. Pressure vessel conveying device 3. Sealed container 4. Mixing device 5. Screening device 6. Material storage device 7. Heat recovery equipment 8. Steam 9. Transmission device 10. Sealed container storage section 11. Cylindrical body 12. Elliptical head 13. Material conveyor belt 14. Pressure vessel conveyor belt 15. Conveyor belt support 16. Support leg 17. Mixer 18. Inlet 19. Outlet 20. Vibrating screen 21. Sealed container outlet 22. Material outlet. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention. Example 1

[0027] This embodiment provides a heat recovery process, including the following steps: The contact time between the material and the pressure-sealed container is set based on the temperature difference and heat transfer efficiency of heat recovery. Set the maximum pressure of the pressure-sealed container; the pressure-sealed container contains a heat carrier with high heat capacity, such as water, heat transfer oil, or molten salt.

[0028] High-temperature materials are stirred in a pressure-sealed container, transferring the heat of the materials to the pressure-sealed container. As the temperature rises, the pressure inside the pressure-sealed container will increase, but will not exceed the maximum pressure of the pressure-sealed container. The materials are granular solids, such as coke, semi-coke, ash, steel slag, cement, etc. The contact stirring method between the high-temperature materials and the pressure-sealed container is one of rotary drum type or closed space vibration contact type.

[0029] Screening is performed on materials after heat transfer and on pressurized sealed containers. Heat recovery is performed on a pressure-sealed container containing heat; preferably, the recovered heat range is 200-1300℃; preferably, heat recovery can be performed on the pressure-sealed container containing heat using at least one of a steam generator, a heat carrier furnace, or a thermal oil furnace, and materials such as coke, semi-coke, ash, steel slag, and cement can be processed accordingly, such as for storage and transportation.

[0030] This embodiment can effectively recover heat, reduce process investment, lower operating costs, and thus expand its industrial application, making it applicable to a wider range of industrial scenarios. It can reduce consumption in the production process, reduce environmental pollution, and achieve efficient use of resources and energy. For example, it can prevent the steam generated during the water vaporization process from being carried away and lost into the atmosphere in the wet quenching process. Example 2

[0031] This implementation allows for the recovery of the pressure-sealed container after heat recovery, facilitating its reuse and improving the equipment's versatility and practicality. Specifically: A heat recovery process further includes the following steps: the pressure-sealed container after heat recovery is returned to a sealed container storage section; it can be transferred by a transmission device or the like, and the pressure-sealed container after heat recovery is returned to the sealed container storage section by the transmission device; the sealed container storage section can adopt an open structure to facilitate heat dissipation. Example 3

[0032] This embodiment provides a heat recovery device, including: Material conveying device 1: used for conveying materials. Material conveying device 1 can adopt existing technologies such as belt conveyor and bucket elevator. This invention does not make specific limitations on it, as long as it can realize the conveying of materials. The conveyed materials are high-temperature materials, used for heat recovery. The materials are granular solids, such as coke, semi-coke, ash, steel slag, cement, etc.

[0033] Pressure vessel conveying device 2: used to convey a pressurized sealed container 3; similarly, the pressure vessel conveying device 2 can be any existing belt conveyor, etc., and the present invention does not make specific limitations on it, as long as it can realize the conveying of the pressure vessel 3.

[0034] Mixing device 4: Used to stir the material and the pressurized sealed container 3, transferring the heat of the material to the sealed container 3; the material conveying device 1 and the pressure vessel conveying device 2 convey the material and the pressure vessel 3 into the mixing device 4. The mixing device 4 can be a mixing machine in the prior art. This invention does not make any improvements to it, and will not be described in detail here. It is sufficient to realize the stirring of the material and the sealed container 4 and realize the heat transfer. Horizontal or vertical mixing devices can be selected by technicians according to specific circumstances. This invention does not make specific limitations; multiple sealed containers 3 are used when mixing.

[0035] Screening device 5: The screening device 5 is located at the outlet of the mixing device 4. The mixed material and the sealed container 3 in the mixing device 4 enter the screening device 5 through the discharge port for screening. It is used to screen the material after heat transfer and the pressurized sealed container 3. The screening device 5 can be a screening device in the prior art. The technician can select an appropriate size screen according to the size of the material and the sealed container 3. The screened sealed container 3 enters the next process for heat recovery, and the screened material enters the material storage device 6 for storage or further utilization.

[0036] Heat recovery device 7: recovers heat from the pressurized sealed container 3. After being screened by the screening device 5, the pressurized sealed container is transported to the heat recovery device 7 via a transmission device or manually, as described in the prior art, for heat recovery. In this embodiment, the heat recovery device can be a steam generator, using the sealed container that has absorbed heat to provide heat energy to the steam generator, heating water into hot water or steam for use. Alternatively, the heat recovery device can be a heat carrier furnace, using the sealed container that has absorbed heat to provide heat energy to the heat carrier furnace, heating powdered molten salt to a melting point above 142°C, allowing it to circulate in a molten flow state. Another option is a thermal oil furnace, using the sealed container that has absorbed heat to provide heat energy to the thermal oil furnace, with thermal oil as the circulating medium for heating. Other equipment in the prior art can also be used in the heat recovery device 7; these will not be specifically described here, and those skilled in the art can make the appropriate selection based on specific circumstances.

[0037] Preferably, the outer side of the sealed container 3 is provided with a heat-absorbing layer. Specifically, the outer surface of the sealed container 3 is treated to enhance radiative heat absorption. The treatment method is to apply a black coating or boil it black.

[0038] In this embodiment, the material and the pressurized sealed container 3 are transported to the mixing device 4 through the material conveying device 1 and the pressure vessel conveying device 2, so that the dispersed pressurized sealed container 3 is directly stirred and mixed with the high-temperature material. A certain contact time is set according to the temperature difference and heat transfer efficiency of heat recovery. As the temperature rises, the pressure inside the sealed container 3 will rise, but it will not exceed its maximum design pressure. After the heat is transferred to the sealed container 3, it is separated from the material. The separated pressurized sealed container 3 enters the heat recovery equipment for heat recovery. Example 4

[0039] In this embodiment, it is convenient to recycle the sealed container after heat recovery, specifically: The heat recovery device 7 is equipped with a transmission device 9 at its outlet. The transmission device 9 adopts a belt drive device or the like in the prior art. The transmission device 9 is connected to the sealed container storage section 10. After heat recovery, the sealed container 3 is returned to the sealed container storage section 10 through the transmission device 9. The sealed container storage section 10 can adopt an open structure to facilitate heat dissipation. Example 5

[0040] This embodiment describes the sealed container 3, specifically: The sealed container 3 is a small-volume container, which facilitates mixing and turning, thereby better absorbing and recovering heat. Preferably, the sealed container 3 includes a cylindrical body 11, and the two ends of the cylindrical body 11 are provided with sealed elliptical end caps 12. The sealed container 3 can also be a spherical or other pressure-resistant shape.

[0041] The sealed container 3 is in a vacuum or semi-vacuum state. The sealed container 3 contains a liquid or solid with high heat capacity, such as water, ammonia, molten salt, heat transfer oil and other heat carriers. The heat recovery device 7 uses a steam generator to convert the heat into steam for recovery.

[0042] The sealed container 3 is made of one of the following materials: carbon steel, alloy steel, or silicon carbide. Example 6

[0043] This embodiment provides a specific implementation method, which is as follows: A heat recovery device is mainly used for recovering semi-coke. The semi-coke particles exiting the pyrolysis furnace have a diameter of 30-50 mm and a temperature of 630℃. The pressure vessel has an outer diameter of 80 mm and a length of 240 mm. After being evacuated, some water is drawn in, occupying 90% of the total volume. The material is SS304 stainless steel with a wall thickness of 5 mm. The heat recovery device includes a material conveyor belt 13 for transporting the semi-coke particles. A pressure vessel conveyor belt 14 is provided on one side of the material conveyor belt 13. The material conveyor belt 13 and the pressure vessel conveyor belt 14 adopt the existing technology of conveyor belts. The conveyor belt 13 and the pressure vessel conveyor belt 14 are equipped with a conveyor belt support 15 on their outer sides, and the bottom of the conveyor belt support 15 is in contact with the ground through support legs 16. A mixer 17 is provided on one side of the material conveyor belt 13 and the pressure vessel conveyor belt 14. The mixer 17 is located at the lower part of the material conveyor belt 13 and the pressure vessel conveyor belt 14. The semi-coke granules and the sealed container 3 directly enter the mixer 17 through the feed inlet 18. The mixer 17 can be any existing mixer. The mixer 17 is used to stir the semi-coke granules and the pressurized sealed container 3. The heat of the semi-coke particles is transferred to the sealed container 3. A vibrating screen 20 is installed below the outlet 19 of the mixer 17. Any existing vibrating screen can be used; the specific model is not limited. Engineers can select an appropriate screen size based on the size of the semi-coke particles and the sealed container 3. The screened material in the sealed container 3 enters the next process for heat recovery, while the screened semi-coke particles are stored in a semi-coke particle storage device or used in a further step. The sealed container outlet 21 of the vibrating screen 20 can be connected to a conveying device, which is connected to a steam generator. After passing through the vibrating screen... The sealed container 3, screened by the moving screen, exits through the sealed container outlet 21 and is conveyed to the steam generator via a conveying device. The sealed container 3 absorbs heat and recovers the heat in the form of steam 8, reducing the temperature of the semi-coke particles to about 220 degrees Celsius. Alternatively, the conveying device can be disconnected, and a storage device can be connected, allowing manual transport to the steam generator for recovery. The semi-coke particles screened through the material outlet 22 enter the semi-coke particle storage device for storage or further utilization. This invention is not specifically limited; those skilled in the art can make appropriate choices based on specific circumstances. This invention will not be described in detail here.

[0044] In this embodiment, the semi-coke particles and the pressurized sealed container 3 are transported to the mixer 17 via the semi-coke particle conveyor belt 13 and the pressure vessel conveyor belt 14. This allows the dispersed pressurized sealed container 3 to be directly stirred and mixed with the high-temperature semi-coke particles. A certain contact time is set according to the temperature difference and heat transfer efficiency of heat recovery. As the temperature rises, the pressure inside the sealed container 3 will rise, but it will not exceed its maximum design pressure. After the heat is transferred to the sealed container 3, it is separated from the semi-coke particles. The separated pressurized sealed container 3 enters the steam generator for heat recovery.

[0045] This embodiment can effectively recover heat, generally within the range of 300-700℃. This embodiment is simple to operate and has strong safety and reliability.

[0046] This invention features a simple process, a simple structure, and convenient use. It utilizes a dispersed, pressurized, sealed container 3 to directly mix with high-temperature semi-coke particles. A certain contact time is set based on the temperature difference and heat transfer efficiency for heat recovery. As the temperature rises, the pressure inside the sealed container 3 will increase, but it will not exceed its designed maximum pressure. After the heat is transferred to the sealed container 3, it is separated from the semi-coke particles. The separated pressurized sealed container 3 then enters the heat recovery device 7 for heat recovery.

[0047] In summary, by adopting the above-mentioned technical solutions, this invention can effectively recover heat. For example, when quenching semi-coke, it can prevent the heat from being carried away by the steam generated during the water gasification process and lost into the atmosphere. It can also reduce process investment and lower operating costs, thereby expanding its industrial application and making it applicable to more industrial scenarios. It can reduce consumption in the production process, reduce environmental pollution, and achieve the effective utilization of resources and energy.

[0048] The devices and connections not specifically described above are all existing technologies, and will not be elaborated upon here. They are all conventional technical means, and those skilled in the art can choose according to the specific circumstances.

[0049] The preferred embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0050] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the various possible combinations in this application will not be described separately.

[0051] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, and such combinations should also be regarded as the content disclosed in this application.

Claims

1. A heat recovery process, characterized in that, Includes the following steps: The material is brought into contact with and stirred in a pressure-sealed container, transferring the heat of the material to the pressure-sealed container. Screening is performed on materials after heat transfer and on pressurized sealed containers. Heat recovery is performed on a pressure-sealed container that contains heat.

2. The heat recovery process according to claim 1, characterized in that, It also includes the following steps: After heat recovery, the pressurized sealed container is returned to the sealed container storage section.

3. The heat recovery process according to claim 1, characterized in that, Heat recovery is achieved for pressure-sealed containers containing heat using at least one of the following methods: steam generator, heat carrier furnace, or thermal oil furnace.

4. The heat recovery process according to claim 1, characterized in that, The pressure-sealed container contains a heat carrier with high heat capacity.

5. The heat recovery process according to claim 4, characterized in that, The heat transfer medium is one of water, heat transfer oil or molten salt.

6. The heat recovery process according to claim 1, characterized in that, The material is stirred in contact with the pressure-sealed container using either a rotary drum type or a closed-space vibration contact type.

7. The heat recovery process according to claim 1, characterized in that, The range of recovered heat is 200-1300℃.

8. The heat recovery process according to claim 1, characterized in that, The pressure-sealed container is made of one of the following materials: carbon steel, alloy steel, or silicon carbide.

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