Calcination equipment system

Abstract

The invention discloses a calcining equipment system which comprises an external heating rotary kiln, a first rotary drum type heat exchanger, a second rotary drum type heat exchanger and a third rotary drum type heat exchanger, the external heating rotary kiln is used for high-temperature section firing of materials, and the first rotary drum type heat exchanger preheats the materials through high-temperature CO2 gas generated by the external heating rotary kiln; the second rotary drum type heat exchanger heats circulating air by using the fired material of the external heating rotary kiln, and the third rotary drum type heat exchanger preheats the material by using the circulating air. The external heating rotary kiln adopts an indirect external heating mode to carry out high-temperature section firing on materials, the calcined materials cannot be polluted by combustion smoke dust in the calcining process, inferior fuel can be adopted, and the requirement for the fuel quality is lowered; the heating furnace does not rotate along with the first rotating cylinder and can be provided with a heat preservation layer, and the surface heat loss of the external heating rotary kiln is reduced; the rotary drum type heat exchanger is of a dividing wall heat exchange structure, a heat exchange medium is separated from materials, and the requirements for the anti-knock property of the materials and the heat intensity after calcination and decomposition are lowered.

Description

Technical Field

[0001] This application relates to the field of metallurgical technology, and in particular to a calcination equipment system. Background Technology

[0002] A conventional rotary kiln is a rotary calcining kiln widely used in the metallurgical industry, such as for the calcination of dolomite and magnesite in magnesium smelting and iron and steel production. Conventional rotary kilns are lined with refractory materials. During calcination, the material comes into direct contact with the flames burning inside the kiln. The material is calcined as it tumbles and moves forward within the inclined rotary kiln, resulting in uniform calcination quality.

[0003] Ordinary rotary kilns also have many shortcomings: 1) The particle size of the material to be calcined is generally required to be 20mm-40mm. The heat and mass transfer resistance inside the particles is much greater than that of powdered materials. To ensure that the material is thoroughly burned and achieves an industrially significant production speed, the calcination temperature must be much higher than that of powdered materials. However, in order to ensure that the rotary kiln lining has sufficient strength and service life, the kiln lining cannot contain loosely textured insulation materials. This results in a very high surface temperature of the rotary kiln and a huge surface heat loss, which not only increases the fuel consumption of the rotary kiln, but also brings serious thermal pollution to the production area; 2) Pulverized coal fuel is used. At the same time, in order to avoid excessive fly ash contamination of calcined materials and to avoid fly ash fusing onto the kiln lining and causing kiln ring formation failure, strict requirements are placed on the ash content and ash melting point of the coal, and inferior coal fuel cannot be used; 3) In order to ensure that the ore has good air permeability in the vertical preheater and vertical cooler, the ore is required not only to have good anti-explosion properties, but also to have good thermal strength after calcination and decomposition. Otherwise, too much crushed material and powder will hinder the airflow in the vertical preheater and vertical cooler, greatly reducing the equipment capacity, which limits the utilization of ores with poor anti-explosion properties and poor thermal strength.

[0004] Fluidized bed roasting system is a relatively advanced roasting system. In a fluidized bed roasting system, the powdered material is fed into a series of four cyclone heat exchangers that flow in the opposite direction to the flue gas flow, allowing the flue gas to fully exchange heat with the powdered material. Then the powdered material is roasted in a high-temperature roasting zone.

[0005] The disadvantages of fluidized bed roasting systems are: 1) The combustion flue gas is directly mixed with the powdered material, and the dust in the flue gas completely enters the powdered material and cannot be separated. Clean fuel with less dust is required, which increases the fuel cost of fluidized bed roasting; 2) The powdered material relies on the flue gas to carry it, which requires higher flue gas pressure to generate sufficient flow velocity to carry the powdered material. This requires greater power consumption and will also increase the production cost of the fluidized bed roasting system to some extent.

[0006] In summary: conventional rotary kilns process materials with large particle sizes, high calcination temperatures, and high kiln surface temperatures, resulting in high calcination heat consumption and certain requirements on the physical anti-explosion properties and thermal strength of the raw materials; fluidized bed roasting systems consume a lot of power; and in both conventional rotary kilns and fluidized bed roasting systems, the materials are in direct contact with the combustion flue gas during the calcination process, which causes the calcined products to be contaminated to varying degrees.

[0007] Therefore, if a calcination equipment system can be provided that can reduce heat loss on the equipment surface and lower energy consumption, obtain pure calcined products, adapt to ore raw materials with poor anti-explosion properties and low thermal strength, reduce the quality requirements of fuel, and have low power consumption and easy control, it would undoubtedly be a better calcination equipment system. Summary of the Invention

[0008] This application proposes a calcination equipment system that uses indirect external heating to ensure that the calcined material is not contaminated by combustion smoke during the calcination process and to reduce the requirements for fuel quality. It combines three methods to reduce the calcination temperature: calcining the material into powder before calcination; heat preservation of the calcination kiln to reduce heat loss from the kiln; and full recovery of waste heat from the calcination products. This reduces the heat consumption of the material during calcination. Furthermore, calcining the material into powder eliminates the need for conventional rotary kilns to calcine granular materials and thus avoids the requirements for their physical properties such as explosion resistance and thermal strength.

[0009] To achieve the above objectives, this application provides a calcination equipment system, including an externally heated rotary kiln, a first rotary heat exchanger, a second rotary heat exchanger, and a third rotary heat exchanger.

[0010] The externally heated rotary kiln includes a first rotating cylinder and a heating furnace. The first rotating cylinder contains materials and has a drive component for moving the materials in the discharge direction. The heating furnace is sleeved outside the first rotating cylinder and does not rotate with the first rotating cylinder. The heating furnace is used to perform high-temperature firing of the materials in the first rotating cylinder to generate high-temperature CO2 gas and fired materials.

[0011] The first rotary heat exchanger is used to preheat the material using the high-temperature CO2 gas; the second rotary heat exchanger is used to heat the circulating heat exchange medium using the calcined material; and the third rotary heat exchanger is used to preheat the material using the circulating heat exchange medium.

[0012] The first, second, and third rotary heat exchangers all include a second rotating cylinder. The second rotating cylinder has an inner cavity and a heat exchange medium channel located outside the inner cavity. The heat exchange medium in the heat exchange medium channel exchanges heat with the material in the inner cavity. The heat exchange medium in the heat exchange medium channel of the first rotary heat exchanger is high-temperature CO2 gas. The heat exchange medium channel of the second rotary heat exchanger is connected to the heat exchange medium channel of the third rotary heat exchanger.

[0013] Preferably, in the above-mentioned calcination equipment system, the first rotating cylinder includes a metal cylinder, a first feed end cover plate, and a first discharge end sealing cover. The first feed end cover plate is rotatably and sealingly connected to a first end of the metal cylinder in the axial direction. A feed pipe is provided on the first feed end cover plate. The first discharge end sealing cover is rotatably and sealingly connected to a second end of the metal cylinder in the axial direction. A discharge pipe is provided on the first discharge end sealing cover.

[0014] Preferably, in the above-mentioned calcination equipment system, the driving component is a first helical blade, which is fixedly connected to the inner wall of the metal cylinder, and the first helical blade is spirally wound along the axis of the metal cylinder.

[0015] Preferably, in the above-mentioned calcination equipment system, an insulation layer is provided outside the externally heated rotary kiln.

[0016] Preferably, in the above-mentioned calcination equipment system, the second rotating cylinder has an inner cylinder, an outer cylinder sleeved outside the inner cylinder, a second feed end cover, an exhaust gas collection hood, an inlet gas collection hood, and a second discharge end sealing cover.

[0017] The heat exchange medium channel is formed between the outer cylinder and the inner cylinder.

[0018] The first ends of the outer cylinder and the inner cylinder are rotatably and sealed to the outlet gas collecting hood, the second ends of the outer cylinder and the inner cylinder are rotatably and sealed to the inlet gas collecting hood, the two ends of the inner cylinder extend out of the outer cylinder and are rotatably and sealed to the second feed end cover plate and the second discharge end sealing cover, respectively, and a third spiral blade is provided inside the inner cylinder.

[0019] Preferably, in the above-mentioned calcination equipment system, a second spiral blade is provided in the heat exchange medium channel.

[0020] Preferably, in the above-mentioned calcination equipment system, the second feed end cover plate and the gas outlet collecting hood are located on the same side of the inner cylinder, and the second discharge end sealing cover and the gas inlet collecting hood are located on the same side of the inner cylinder.

[0021] Preferably, in the above-mentioned calcination equipment system, the outlet of the heat exchange medium channel of the first rotary heat exchanger is connected to the CO2 recovery system, and the induced draft fan of the CO2 recovery system provides power for the movement of the high-temperature CO2 gas in the heat exchange medium channel of the first rotary heat exchanger.

[0022] A dust collector is installed between the outlet of the heat exchange medium channel of the first rotary heat exchanger and the CO2 recovery system to separate dust from the high-temperature CO2 gas. The outlet of the dust collector is connected to the feed pipe of the externally heated rotary kiln.

[0023] Preferably, in the above-mentioned calcination equipment system, the circulating heat exchange medium is air, and the circulation power of the circulating heat exchange medium comes from a fan installed between the second rotary heat exchanger and the third rotary heat exchanger.

[0024] Preferably, in the above-mentioned calcination equipment system, the heat exchange medium channel of the second rotary heat exchanger has a first medium inlet and a first medium outlet, and the heat exchange medium channel of the third rotary heat exchanger has a second medium inlet and a second medium outlet. The first medium outlet of the heat exchange medium channel of the second rotary heat exchanger is connected to the second medium inlet of the heat exchange medium channel of the third rotary heat exchanger, and the second medium outlet of the heat exchange medium channel of the third rotary heat exchanger is connected to the first medium inlet of the heat exchange medium channel of the second rotary heat exchanger.

[0025] The calcination equipment system provided in this application includes an externally heated rotary kiln, a first rotary heat exchanger, a second rotary heat exchanger, and a third rotary heat exchanger. The externally heated rotary kiln is used to calcine preheated materials in a high-temperature section. The first rotary heat exchanger uses high-temperature CO2 gas generated by the decomposition of materials in the externally heated rotary kiln to preheat the materials. The second rotary heat exchanger uses the calcined materials in the externally heated rotary kiln to heat the circulating air. The third rotary heat exchanger uses the circulating air to preheat the materials. The externally heated rotary kiln uses indirect external heating to calcine materials at high temperatures. During the calcination process, the calcined material does not come into contact with the calcination fumes, preventing contamination of the calcined material by combustion fumes. This allows the use of lower-quality fuels and reduces the requirements for fuel quality. The heating furnace of the externally heated rotary kiln is stationary and can be equipped with an insulation layer to reduce the surface temperature of the kiln, thereby reducing surface heat loss, improving thermal efficiency, reducing fuel consumption, and minimizing thermal pollution in the production area. The first rotary heat exchanger, the second rotary heat exchanger, and the... The use of a three-rotor heat exchanger fully recovers the waste heat of the calcined products and uses the waste heat to preheat the materials, which is also an important means to improve thermal efficiency and reduce fuel consumption. Thanks to the fact that the materials do not come into contact with the large flow of air during the entire calcination process and will not be carried away by the airflow, the materials calcined in this system are pre-prepared powders. Calcining powdered materials not only helps to reduce the calcination temperature and create better conditions for reducing heat consumption, but also eliminates the requirements of ordinary rotary kiln calcination of granular materials on the anti-explosion properties of the ore and the thermal strength of the calcined material. Therefore, this system can be applied to ores with any physical properties. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort, and this application can be applied to other similar scenarios based on the provided drawings. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0027] Figure 1 This is a connection diagram of the calcination equipment system of this application;

[0028] Figure 2 This is a schematic diagram of the externally heated rotary kiln in the calcination equipment system of this application;

[0029] Figure 3 This is an assembly cross-sectional view of the rotary heat exchanger of the calcination equipment system of this application;

[0030] Figure 4This is a disassembled view of the rotary heat exchanger in the calcination equipment system of this application.

[0031] The attached diagram is described below:

[0032] 1-Bin; 2-Recovery system; 3-First rotary heat exchanger; 301-Second rotary cylinder; 3011-Outer cylinder; 3012-Second spiral blade; 3013-Inner cylinder; 3014-Third spiral blade; 3015-Inlet gas collection hood; 3016-Second discharge end sealing hood; 3017-Second feed end cover plate; 3018-Outlet gas collection hood; 302-Heat exchange medium channel; 4-Dust collector; 5-Second rotary heat exchanger; 6-Fan; 7-Externally heated rotary kiln; 701-Heating furnace; 702-First rotary cylinder; 7021-Metal cylinder; 7022-First feed end cover plate; 7023-First discharge end sealing hood; 703-First spiral blade; 8-Firing bin; 9-Third rotary heat exchanger. Detailed Implementation

[0033] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. The described embodiments are only a part of the embodiments of the present application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are within the scope of protection of the present application.

[0034] It should be noted that, for ease of description, only the parts relevant to the application are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined, provided that the combined technical features are not contradictory. All feasible combinations of features are the technical content explicitly described herein. Any one of the multiple sub-features contained in the same statement can be applied independently, without necessarily being applied together with other sub-features.

[0035] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0036] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more.

[0037] Please see Figures 1-4 .

[0038] This application discloses a calcination equipment system, including an externally heated rotary kiln 7, a first rotary heat exchanger 3, a second rotary heat exchanger 5, and a third rotary heat exchanger 9. The externally heated rotary kiln 7 is used for high-temperature calcination of materials, where high-temperature CO2 gas and calcined materials are generated during the high-temperature calcination. The first rotary heat exchanger 3 uses the high-temperature CO2 gas generated by the externally heated rotary kiln 7 to preheat the materials, recover the heat of the high-temperature CO2 gas, and cool the high-temperature CO2 gas. The preheated materials enter the externally heated rotary kiln 7 for high-temperature calcination. The second rotary heat exchanger 5 uses the calcined materials from the externally heated rotary kiln 7 to heat the circulating heat exchange medium, recover the heat of the calcined materials, and cool the calcined materials. The third rotary heat exchanger 9 uses the circulating heat exchange medium to preheat the materials, and the preheated materials enter the externally heated rotary kiln 7 for high-temperature calcination.

[0039] The externally heated rotary kiln 7 includes a first rotating cylinder 702 and a heating furnace 701. The first rotating cylinder 702 is used to hold materials and has a drive component inside for moving the materials in the discharge direction. The first rotating cylinder 702 can rotate about its own center line as an axis. The heating furnace 702 is sleeved outside the first rotating cylinder 702 and is fixed and does not rotate.

[0040] The portion of the first rotating cylinder 702 extending outside the heating furnace 702 is supported by rollers, not shown in the figure. The heating furnace 702 can use any fuel, and the combustion system employs a regenerative waste heat recovery method to recover as much waste heat from the flue gas as possible and improve thermal efficiency.

[0041] The calcination equipment system disclosed in this solution adopts an externally heated rotary kiln 7. The heating furnace 702 of the externally heated rotary kiln 7 does not need to rotate with the first rotating cylinder 702, so that an insulation layer can be set on the heating furnace 702 to reduce the surface heat loss of the externally heated rotary kiln 7, reduce fuel consumption, and reduce thermal pollution in the production area.

[0042] The first rotating cylinder 702 includes a metal cylinder 7021, a first feed end cover 7022, and a first discharge end sealing cover 7023. The first feed end cover 7022 and the first discharge end sealing cover 7023 are located at opposite ends of the axial direction of the metal cylinder 7021. During operation, the first rotating cylinder 702 can rotate around its own center line. The first feed end cover 701 and the first discharge end sealing cover 704 are fixed and rotated and sealed with the first rotating cylinder 702.

[0043] The externally heated rotary kiln 7 uses indirect external heating to calcine the preheated material in a high-temperature section. During the calcination process, the calcined material does not come into contact with combustion smoke and dust, and is not polluted by combustion smoke and dust. This allows the use of inferior fuels and reduces the requirements for fuel quality.

[0044] During operation, the material to be calcined is fed into the first rotating cylinder 702 through the first feed end cover plate 701, and the calcined material is discharged from the first rotating cylinder 702 through the first discharge end closure 704. The first feed end cover plate 701 is integrated with a feeding structure, and the first discharge end closure 704 is integrated with a discharge structure. The feeding structure can be a feed pipe, a feed port, or other feeding structure, and the discharge structure can be a discharge pipe, a discharge port, or other discharge structure.

[0045] The calcination equipment system disclosed in this scheme calcines the material after it has been made into powder. The heat and mass transfer resistance of the material during the calcination process is much lower than that of granular materials. Compared with the traditional rotary kiln which requires a temperature of 1250℃~1350℃ to calcine 20-40mm granular materials, the externally heated rotary kiln 7 can achieve the same firing speed at a firing temperature of ≤1050℃ through reasonable design. The first rotating cylinder 702 can be made of heat-resistant steel metal cylinder, which not only meets the maximum operating temperature limit of the heat-resistant steel metal cylinder of the first rotating cylinder 702 of the externally heated rotary kiln 7, but also helps to reduce the heat consumption of the externally heated rotary kiln 7.

[0046] The calcination equipment system disclosed in this scheme only contains the gas generated by the decomposition of calcined materials in the externally heated rotary kiln 7. The amount of gas generated by decomposition is less than 20% of the total flue gas volume of a traditional rotary kiln. The gas flow rate is small, and the amount of material carried from the externally heated rotary kiln 7 to the first rotary heat exchanger 3 is also greatly reduced, which will not affect the normal operation of the system. At the same time, when calcining dolomite and magnesite carbonate minerals, pure CO2 gas can be recovered, which also reduces the emission of CO2 greenhouse gas.

[0047] The first rotary heat exchanger 3 recovers and utilizes the heat from the high-temperature CO2 gas generated by the externally heated rotary kiln 7 to preheat the material supplied to the externally heated rotary kiln 7. The second rotary heat exchanger 5 and the third rotary heat exchanger 9 work together to recover the waste heat from the calcined material. Preheating the material supplied to the externally heated rotary kiln 7 reduces heat loss and fuel consumption.

[0048] The first rotary heat exchanger 3, the second rotary heat exchanger 5, and the third rotary heat exchanger 9 all include a second rotating cylinder 301. The second rotating cylinder 301 has an inner cavity and a heat exchange medium channel located outside the inner cavity. The material in the inner cavity exchanges heat with the heat exchange medium in the heat exchange medium channel. The heat exchange medium in the heat exchange medium channel of the first rotary heat exchanger 3 is high-temperature CO2 gas generated by calcination in the externally heated rotary kiln 7. The heat exchange medium channel 302 of the second rotary heat exchanger 5 is connected to the heat exchange medium channel 302 of the third rotary heat exchanger 9. After the heat exchange medium in the heat exchange medium channel of the second rotary heat exchanger 5 absorbs the heat from the calcined material generated by calcination in the externally heated rotary kiln 7, the heat exchange medium in the heat exchange medium channel of the second rotary heat exchanger 5 enters the heat exchange medium channel 302 of the third rotary heat exchanger 9 and exchanges heat with the material in the inner cavity of the third rotary heat exchanger 9.

[0049] like Figure 1 As shown, the first rotary heat exchanger 3 and the third rotary heat exchanger 9 are arranged in parallel to preheat the material supplied to the externally heated rotary kiln 7.

[0050] In this design, the first rotary heat exchanger 3, the second rotary heat exchanger 5, and the third rotary heat exchanger 9 have the same structure, such as... Figure 3 and Figure 4 As shown, the first rotary heat exchanger 3, the second rotary heat exchanger 5, and the third rotary heat exchanger 9 all include an inner cylinder 3013, an outer cylinder 3011 sleeved outside the inner cylinder 3013, a second feed end cover plate 3017, an exhaust gas collection hood 3018, an inlet gas collection hood 3015, and a second discharge end sealing cover 3016. The inner cavity of the inner cylinder 3013 contains the material. A heat exchange medium channel 302 is formed between the outer cylinder 3011 and the inner cylinder 3013, and the heat exchange medium is contained in the heat exchange medium channel 302.

[0051] The second rotating cylinder 301 can rotate around its own axis; specifically, the outer cylinder 3011 and the inner cylinder 3013 rotate synchronously. For example... Figure 4 As shown, the first ends of the outer cylinder 3011 and the inner cylinder 3013 are rotatably and sealed to the exhaust gas collection hood 3018, and the second ends of the outer cylinder 3011 and the inner cylinder 3013 are rotatably and sealed to the inlet gas collection hood 3015. The exhaust gas collection hood 3018 and the inlet gas collection hood 3015 are fixed and do not rotate with the second rotating cylinder 301.

[0052] The exhaust gas collection hood 3018 is rotatably and sealed to both the outer cylinder 3011 and the inner cylinder 3013. The heat exchange medium in the heat exchange medium channel 302 is discharged through the exhaust gas collection hood 3018. The inlet gas collection hood 3015 is rotatably and sealed to both the outer cylinder 3011 and the inner cylinder 3013. The heat exchange medium is supplied into the heat exchange medium channel 302 through the inlet gas collection hood 3015.

[0053] The heat exchange medium in the heat exchange medium channel 302 of the first rotary heat exchanger 3 is high-temperature CO2 gas. The medium inlet of the heat exchange medium channel 302 of the first rotary heat exchanger 3 is connected to the gas outlet of the metal cylinder 7021. The medium outlet of the heat exchange medium channel 302 of the first rotary heat exchanger 3 is connected to the CO2 recovery system. The induced draft fan of the CO2 recovery system provides power for the movement of high-temperature CO2 gas in the heat exchange medium channel 302 of the first rotary heat exchanger 3.

[0054] The high-temperature CO2 gas generated by the externally heated rotary kiln 7 enters the heat exchange medium channel 302 of the first rotary heat exchanger 3 through the medium inlet. After exchanging heat with the material in the inner cavity of the first rotary heat exchanger 3, it is discharged into the CO2 recovery system for recovery.

[0055] The heat exchange medium channel 302 of the second rotary heat exchanger 5 and the heat exchange medium channel 302 of the third rotary heat exchanger 9 use the same heat exchange medium. The heat exchange medium in the heat exchange medium channel 302 of the second rotary heat exchanger 5 absorbs the heat of the burning material generated by the externally heated rotary kiln 7. After heat exchange, the heat exchange medium enters the heat exchange medium channel 302 of the third rotary heat exchanger 9 and exchanges heat with the material in the inner cavity of the third rotary heat exchanger 9.

[0056] In some embodiments, the heat exchange medium channel 302 of the second rotary heat exchanger 5 has a first medium inlet and a first medium outlet, and the heat exchange medium channel 302 of the third rotary heat exchanger 9 has a second medium inlet and a second medium outlet. The first medium outlet of the heat exchange medium channel 302 of the second rotary heat exchanger 5 is connected to the second medium inlet of the heat exchange medium channel 302 of the third rotary heat exchanger 9, and the second medium outlet of the heat exchange medium channel 302 of the third rotary heat exchanger 9 is connected to the first medium inlet of the heat exchange medium channel 302 of the second rotary heat exchanger 5.

[0057] The heat exchange medium circulates within the heat exchange medium channel 302 of the second rotary heat exchanger 5 and the heat exchange medium channel 302 of the third rotary heat exchanger 9.

[0058] like Figure 3As shown, the two ends of the inner cylinder 3013 extend out of the ends of the outer cylinder 3011 and are rotatably sealed to the second feed end cover plate 3017 and the second discharge end sealing cover 3016 respectively. The second feed end cover plate 3017 and the second discharge end sealing cover 3016 are fixed and do not rotate with the inner cylinder 3013. The material enters the inner cylinder 3013 through the second feed end cover plate 3017 and is discharged through the second discharge end sealing cover 3016 after heat exchange.

[0059] like Figure 1 As shown, the feed pipe of the first feed end cover plate 701 of the externally heated rotary kiln 7 is connected to the second discharge end sealing cover 3016 of the first rotary heat exchanger 3 and the third rotary heat exchanger 9. The high-temperature CO2 gas emission port of the externally heated rotary kiln 7 is connected to the inlet gas collection cover 3015 of the first rotary heat exchanger 3. The outlet gas collection cover 3018 of the first rotary heat exchanger 3 is connected to the dust collector 4. The dust collector 4 is connected to the CO2 recovery system 2. The dust separated by the dust collector 4 returns to the feed pipe of the first feed end cover plate 701 of the externally heated rotary kiln 7.

[0060] The first discharge end sealing cover 704 of the externally heated rotary kiln 7 is connected to the feed pipe of the second feed end cover plate 3017 of the second rotary heat exchanger 5. The second discharge end sealing cover 3016 of the second rotary heat exchanger 5 is connected to the calcining silo 8. The air inlet collecting cover 3015 of the second rotary heat exchanger 5 is connected to the air outlet collecting cover 3018 of the third rotary heat exchanger 9. The air outlet collecting cover 3018 of the second rotary heat exchanger 5 is connected to the air inlet collecting cover 3015 of the third rotary heat exchanger 9.

[0061] The feed pipes of the second feed end cover plate 3017 of the first rotary heat exchanger 3 and the third rotary heat exchanger 9 are connected to the silo 1.

[0062] In some embodiments, a second spiral blade 3012 is provided inside the heat exchange medium channel 302. The outer periphery of the second spiral blade 3012 is fixedly connected to the inner wall of the outer cylinder 3011 and the outer wall of the inner cylinder 3013. The second spiral blade 3012 cooperates with the heat exchange medium channel 302 to form a spiral channel. The second spiral blade 3012 causes the heat exchange medium passing through the heat exchange medium channel 302 to flow along the spiral channel, thereby increasing the heat exchange area of ​​the heat exchange medium channel 302 and prolonging the flow time of the heat exchange medium in the heat exchange medium channel 302, thus improving the thermal efficiency.

[0063] In the operation of the calcination equipment system disclosed in this scheme, the flow of material in the first rotating cylinder 702 of the externally heated rotary kiln 7 and the second rotating cylinder 301 of the rotary heat exchanger (the first rotary heat exchanger 3, the second rotary heat exchanger 5, and the third rotary heat exchanger 9 are collectively referred to as rotary heat exchangers) is entirely driven by the mechanical movement of the spiral blades. Compared with the fluidized bed calcination system, the power consumption is small. The calcination temperature of the calcination equipment system is controlled by a single combustion temperature, and the calcination time of the material is controlled by a simple rotary speed. Therefore, its control and adjustment are as easy as those of a conventional rotary kiln. Moreover, compared with a conventional rotary kiln, since the combustion air supply does not have the resistance of the calcined material and the flue gas does not have the resistance of the raw material layer, its adjustment is even easier.

[0064] During the heat exchange process, solid materials cannot convect internally. The first rotary heat exchanger 3, the second rotary heat exchanger 5, and the third rotary heat exchanger 9 provided in this solution allow the solid material to move forward and tumble within the cavity, helping the solid powder material to achieve internal heat transfer. Compared with other types of heat exchangers for solid powder and gas media, this solution has significant advantages in terms of heat exchange efficiency, equipment failure rate, and reliability.

[0065] When the externally heated rotary kiln 7 of the calcination equipment system calcines carbonate ore powder, since there is no flue gas polluting the material, the purity of the CO2 gas generated by the decomposition of the material can meet the requirements of food grade. Recycling and selling it not only contributes to reducing costs, but also reduces CO2 greenhouse gas emissions.

[0066] In this design, the second feed end cover 3017 and the exhaust gas collection hood 3018 are located on the same side of the inner cylinder 3013, and the second discharge end sealing cover 3016 and the inlet gas collection hood 3015 are located on the other side of the inner cylinder 3013. The material moves in the opposite direction to the heat exchange medium in the heat exchange medium channel 302, thus achieving countercurrent heat exchange. Compared with cocurrent heat exchange, this can achieve maximum heat exchange.

[0067] like Figure 1 As shown, the high-temperature CO2 gas emission port of the externally heated rotary kiln 7, the inlet gas collection hood 3015 of the first rotary heat exchanger 3, the outlet gas collection hood 3018 of the first rotary heat exchanger 3, and the CO2 recovery system are connected in series. The flow power of the high-temperature CO2 gas in the heat exchange medium channel 302 of the first rotary heat exchanger 3 comes from the suction of the induced draft fan of the CO2 recovery system.

[0068] The heat exchange circulating medium in the second rotary heat exchanger 5 and the third rotary heat exchanger 9 is air, and the circulation power of the circulating heat exchange medium comes from the fan 6 located between the second rotary heat exchanger 5 and the third rotary heat exchanger 9.

[0069] The following explanation uses dolomite powder as an example of calcined material:

[0070] Dolomite powder is calcined and decomposed in the externally heated rotary kiln 7. The CO2 generated by the decomposition exchanges heat with the dolomite powder through the first rotary heat exchanger 3 to preheat the dolomite powder. After heat exchange, the CO2 enters the CO2 recovery system after dust removal, and the dust returns to the externally heated rotary kiln 7. The calcined dolomite is discharged from the first discharge end of the first rotary cylinder 702 through the closed cover 704 and enters the second rotary heat exchanger 5 to exchange heat with the air. After the air absorbs heat and heats up, it enters the third rotary heat exchanger 9 to preheat the dolomite powder. After heat exchange and cooling, the air returns to the second rotary heat exchanger 5 to exchange heat with the calcined dolomite.

[0071] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed, and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. The scope of this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described application concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A calcining equipment system, characterized in that: It comprises an externally heated rotary kiln (7), a first rotary heat exchanger (3), a second rotary heat exchanger (5), and a third rotary heat exchanger (9); The externally heated rotary kiln (7) comprises a first rotating cylinder (702) and a heating furnace (701), wherein the first rotating cylinder (702) contains materials and has a driving member for moving the materials in a discharge direction, and the heating furnace (701) is sleeved outside the first rotating cylinder (702) and does not rotate with the first rotating cylinder (702), and the heating furnace (701) is used to perform high-temperature section calcination on the materials in the first rotating cylinder (702) to generate high-temperature CO2 gas and calcined materials; The first rotary heat exchanger (3) is used to preheat the material using the high-temperature CO2 gas, the second rotary heat exchanger (5) is used to heat the circulating heat exchange medium using the sintered material, and the third rotary heat exchanger (9) is used to preheat the material using the circulating heat exchange medium. The first rotary heat exchanger (3), the second rotary heat exchanger (5) and the third rotary heat exchanger (9) all comprise a second rotating drum (301), the second rotating drum (301) having an inner cavity and a heat exchange medium channel (302) located outside the inner cavity, the heat exchange medium in the heat exchange medium channel (302) performing heat exchange with the material in the inner cavity, the heat exchange medium in the heat exchange medium channel (302) of the first rotary heat exchanger (3) being high-temperature CO2 gas, and the heat exchange medium channel (302) of the second rotary heat exchanger (5) being connected to the heat exchange medium channel (302) of the third rotary heat exchanger (9).

2. The calcining equipment system according to claim 1, characterized in that: The first rotating cylinder (702) comprises a metal cylinder (7021), a first feed end cover plate (7022) and a first discharge end closure cover (7023); the first feed end cover plate (7022) is rotatably sealed to a first end of the metal cylinder (7021) in an axial direction; a feed pipe is arranged on the first feed end cover plate (7022); the first discharge end closure cover (7023) is rotatably sealed to a second end of the metal cylinder (7021) in an axial direction; and a discharge pipe is arranged on the first discharge end closure cover (7023).

3. The calcining equipment system according to claim 2, characterized in that: The driving member is a first spiral blade (703), the first spiral blade (703) is fixedly connected to the inner wall of the metal cylinder (7021), and the first spiral blade (703) is spirally wound along the axis of the metal cylinder (7021).

4. The calcining equipment system according to any one of claims 1 to 3, characterized in that: The externally heated rotary kiln (7) is provided with a heat-insulating layer outside.

5. The calcining equipment system according to claim 1, characterized in that: The second rotating cylinder (301) comprises an inner cylinder (3013), an outer cylinder (3011) sleeved outside the inner cylinder (3013), a second feed end cover plate (3017), an air outlet collecting hood (3018), an air inlet collecting hood (3015) and a second discharge end sealing hood (3016). The inner cavity is formed in the inner cylinder (3013), and the heat exchange medium channel (302) is formed between the outer cylinder (3011) and the inner cylinder (3013). The first ends of the outer cylinder (3011) and the inner cylinder (3013) are rotationally sealed connected to the air outlet collecting hood (3018), and the second ends of the outer cylinder (3011) and the inner cylinder (3013) are rotationally sealed connected to the air inlet collecting hood (3015). Both ends of the inner cylinder (3013) extend out of the outer cylinder (3011) and are rotationally sealed connected to the second feed end cover plate (3017) and the second discharge end closing hood (3016), respectively. A third spiral blade (3014) is arranged in the inner cylinder (3013).

6. The calcining equipment system according to claim 5, characterized in that: A second spiral blade (3012) is provided in the heat exchange medium channel (302).

7. The calcining equipment system according to claim 5, characterized in that: The second feed end cover plate (3017) and the air outlet collecting hood (3018) are located on the same side of the inner cylinder (3013), and the second discharge end closing hood (3016) and the air inlet collecting hood (3015) are located on the same side of the inner cylinder (3013).

8. The calcining equipment system according to claim 1, characterized in that: The outlet of the heat exchange medium channel (302) of the first rotary heat exchanger (3) is in communication with a CO2 recovery system, and the induced draft fan of the CO2 recovery system provides power for the movement of the high-temperature CO2 gas in the heat exchange medium channel (302) of the first rotary heat exchanger (3); A dust collector (4) is provided between the outlet of the heat exchange medium channel (302) of the first rotary heat exchanger (3) and the CO2 recovery system, and is used to separate dust from the high-temperature CO2 gas. The outlet of the dust collector (4) is connected to the feed pipe of the externally heated rotary kiln (7).

9. The calcining equipment system according to claim 1, characterized in that: The circulating heat exchange medium is air, and the circulating power of the circulating heat exchange medium comes from a fan (6) arranged between the second rotary heat exchanger (5) and the third rotary heat exchanger (9).

10. The calcining equipment system according to claim 1, characterized in that: The heat exchange medium channel (302) of the second rotary heat exchanger (5) has a first medium inlet and a first medium outlet, and the heat exchange medium channel (302) of the third rotary heat exchanger (9) has a second medium inlet and a second medium outlet. The first medium outlet of the heat exchange medium channel (302) of the second rotary heat exchanger (5) is connected to the second medium inlet of the heat exchange medium channel (302) of the third rotary heat exchanger (9), and the second medium outlet of the heat exchange medium channel (302) of the third rotary heat exchanger (9) is connected to the first medium inlet of the heat exchange medium channel (302) of the second rotary heat exchanger (5).

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