Vacuum annular structure lime kiln

Abstract

The present application relates to lime kiln technical field, specifically disclose a kind of vacuum annular structure lime kiln, including feed section, still including preheating section, combustion section and cooling section, sequentially sealed and connected in the lower of feed section, the shape of preheating section, combustion section and cooling section are annular and are all arranged with concentric heat transfer wall one and heat transfer wall two inside, and the channel is formed between heat transfer wall one and heat transfer wall two;A kind of vacuum annular structure lime kiln of the present application, through the independent chamber design of annular channel and combustion chamber, flue gas chamber, realize indirect processing between whole process of limestone heating, preheating, cooling, limestone is always with fuel combustion flue gas, combustion air, cooling air and other media physical isolation, only flows in closed channel, avoids mixing dilution from source, without complex separation and purification equipment, can obtain high-purity carbon dioxide, reduce recovery cost while improving resource utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of lime kiln technology, and specifically to a vacuum annular structure lime kiln. Background Technology

[0002] Lime, a key raw material in metallurgy, chemical industry, and building materials, is produced through a core process: the calcination and decomposition reaction of limestone. The lime kiln is the core equipment for realizing this reaction. Currently, the mainstream limestone calcination technology in the industry is direct calcination, including traditional equipment such as vertical kilns, rotary kilns, and sleeve kilns. The basic principle is to directly contact and burn fuel with limestone, transferring heat through flame radiation and flue gas convection to bring the limestone to its decomposition temperature and complete the calcination process.

[0003] In traditional direct calcination, the carbon dioxide produced by limestone decomposition mixes directly with the flue gas from fuel combustion and the combustion air, resulting in a significant dilution of the carbon dioxide and a substantial decrease in its purity. If carbon dioxide is to be recovered subsequently, complex separation and purification equipment is required, which not only increases production costs but also leads to problems such as low recovery efficiency and high energy consumption. Furthermore, traditional direct calcination equipment is mainly designed for large-diameter limestone. For small-diameter limestone, the large specific surface area makes it prone to the problem of "sandwich" where the surface is sintered too quickly and the interior remains undecomposed when in direct contact with a high-temperature flame, resulting in uneven calcination and a high under-calcination rate.

[0004] Therefore, a vacuum annular structure lime kiln is needed to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a vacuum annular structure lime kiln, which aims to solve the technical problems in related technologies, such as the inconvenience of carbon dioxide recovery due to direct calcination and the unsuitability of direct calcination for small-particle-size limestone.

[0006] The present invention provides a vacuum annular structure lime kiln, comprising a feeding section, and further comprising:

[0007] The preheating section, combustion section, and cooling section are sequentially and sealed below the feeding section. The preheating section, combustion section, and cooling section are all annular in shape and each has a concentrically arranged heat transfer wall 1 and heat transfer wall 2 inside. A material channel is formed between heat transfer wall 1 and heat transfer wall 2. The material channels inside the preheating section, combustion section, and cooling section are interconnected. The combustion section includes an outer cylinder, an insulation layer, a refractory layer, a flue gas chamber, a flue gas passage, and an inner cylinder. The insulation layer is connected to the inner wall of the outer cylinder, and the refractory layer is connected to the inner wall of the insulation layer. The heat transfer wall 1 inside the combustion section is located inside the refractory layer. A combustion chamber is formed between the heat transfer wall 1 inside the combustion section and the refractory layer. The flue gas chamber is located inside the heat transfer wall 2 inside the combustion section. There are multiple sets of flue gas passages. The flue gas passages are located between the heat transfer wall 1 and heat transfer wall 2 inside the combustion section. The inner cylinder is located inside the flue gas chamber.

[0008] The discharge section is connected to the bottom of the cooling section. Both the discharge section and the feed section are equipped with vacuum equipment. The vacuum equipment is used to ensure that the material remains in a vacuum state after it enters the preheating section and after it is discharged from the discharge section.

[0009] Preferably, an indirect heat exchange device is installed inside the cooling section. The indirect heat exchange device is connected to the inner cylinder and is connected to an air supply device. The air supply device is used to generate combustion air, and the indirect heat exchange device is used to transport the preheated combustion air inside the cooling section to the inside of the inner cylinder.

[0010] Its effect is that: by using indirect heat exchange equipment, the combustion air and calcium oxide can be indirectly exchanged, and the residual heat can be recovered without contaminating the calcium oxide. The temperature of the combustion air can be raised in advance, which reduces energy consumption and improves subsequent combustion efficiency. At the same time, the indirect heat exchange mode avoids the mixing of impurities caused by direct contact between the combustion air and the material.

[0011] Preferably, the preheating section is equipped with an indirect heat exchange device 2 and a direct heat exchange device. The indirect heat exchange device 2 is connected to the flue gas chamber and is externally connected to a flue gas duct. The flue gas duct is connected to a flue gas purification device. The direct heat exchange device is connected to a carbon dioxide recovery pipe, which is connected to a vacuum pump group. The vacuum pump group is connected to a carbon dioxide recovery device.

[0012] Its effects are as follows: the indirect heat exchanger can recover the waste heat of flue gas to preheat limestone, and the direct heat exchanger can utilize high-temperature carbon dioxide for countercurrent heat exchange, thus improving energy utilization efficiency through dual heat exchange.

[0013] Preferably, at least four sets of burners are evenly arranged on the outer circumferential surface above the combustion section. Each set of burners is equipped with a combustion air inlet. Each combustion air inlet is connected to the inner cylinder through a pipe to deliver combustion air from inside the inner cylinder to the inside of the burner. Each set of burners is connected to a fuel regulation control device, and each fuel regulation control device is connected to a fuel delivery pipe.

[0014] Its effects are as follows: the annularly arranged burner structure can form an annular hot airflow, ensuring a uniform temperature distribution in the combustion chamber; the combustion air interface is connected to the inner cylinder to obtain preheated high-temperature combustion air, improving the combustion effect; and the fuel adjustment and control device can achieve precise control of a single set of burners, adapting to different calcination requirements and ensuring combustion stability and controllability.

[0015] Preferably, the air supply device includes a fan and a combustion air duct. The fan is located on one side of the discharge section, and the combustion air duct is connected to the fan. The combustion air duct is arranged in a ring outside the cooling section, and the ring-shaped part of the combustion air duct is connected to an indirect heat exchange device through a pipe.

[0016] Its effect is that the ring-shaped combustion air duct can evenly distribute the combustion air to the interior of the cooling section, realize all-round indirect heat exchange with the high-temperature calcium oxide in the cooling section, ensure that the cold air in each duct can fully absorb the residual heat of the calcium oxide, greatly improve the heat exchange efficiency between the combustion air and the calcium oxide, and make the combustion air preheat more fully.

[0017] Preferably, both the discharge section and the feed section are vacuum tanks sealed at both ends, and both the discharge section and the feed section are equipped with an upper sealing valve and a lower sealing valve.

[0018] Its effect is that the double-layer sealing valve and the vacuum tank structure form a double sealing guarantee, which can effectively isolate the atmosphere from the inside of the equipment, ensure that the material is in a vacuum environment throughout the calcination process, and prevent impurities such as oxygen and nitrogen from mixing in. This ensures the purity of the lime product and prevents carbon dioxide from being diluted. At the same time, the alternating opening and closing of the sealing valve can realize continuous feeding and discharging without disrupting the internal vacuum state, thus improving the continuity of production.

[0019] Preferably, multiple observation windows are provided between the insulation layer, the fire-resistant layer and the outer cylinder. The number of observation windows corresponds to the number of flue gas passages, the position of the observation windows corresponds to the position of the flue gas passages, and there is a one-to-one correspondence between the observation windows and the flue gas passages.

[0020] Its advantages are: the one-to-one correspondence between the observation window and the flue gas passage allows for direct observation of the combustion and flue gas conditions inside the combustion chamber, facilitating timely detection and adjustment of combustion anomalies, and providing visual monitoring support for stable equipment operation. At the same time, the observation window is located between the insulation layer, the fire-resistant layer, and the outer cylinder, without affecting the insulation and fire-resistant performance of the equipment.

[0021] Preferably, heat transfer wall one and heat transfer wall two are annular structures composed of silicon carbide bricks, silicon carbide plates or heat-resistant steel, the inner cylinder is a silicon carbide pipe or a heat-resistant steel pipe, the insulation layer is an annular structure composed of insulation bricks, and the refractory layer is an annular structure composed of refractory bricks.

[0022] Preferably, a feeding hopper is connected to the feeding section, an automatic feeding device is connected to the feeding port of the feeding hopper, and a storage hopper is set at the bottom of the automatic feeding device.

[0023] The beneficial effects of this invention are:

[0024] 1. Through the independent chamber design of the annular material channel, combustion chamber, and flue gas chamber, the entire process of limestone heating, preheating, and cooling is indirectly processed. The limestone is always physically isolated from fuel combustion flue gas, combustion air, cooling air, and other media. The carbon dioxide produced by decomposition flows only in the closed material channel, avoiding mixing and dilution from the source. High-purity carbon dioxide can be obtained without complex separation and purification equipment, reducing recycling costs while improving resource utilization efficiency.

[0025] 2. The annular structure forms a uniform heat transfer surface, and the double-layer annular heat transfer wall realizes the uniform transfer of heat to the interior of the material. This not only solves the problems of local overheating and incomplete burning in traditional direct calcination, but also reduces the generation of over-burned and under-burned ash, improves lime activity and qualification rate, and can also be adapted to small-diameter limestone with a particle size of <20mm, avoiding the "sandwich" problem of its surface sintering too quickly. It achieves rapid and complete decomposition through efficient and uniform heat transfer, taking into account the processing needs of small-diameter materials and the quality of finished products.

[0026] 3. Construct a multi-stage heat exchange system. The high-temperature carbon dioxide generated by calcination directly exchanges heat with the limestone in the preheating section in a countercurrent flow. The hot flue gas in the combustion chamber preheats the limestone through the second indirect heat exchange device. After the calcium oxide in the cooling section exchanges heat indirectly with the combustion air, the combustion air is heated again through the flue gas chamber. This achieves the cascade recovery and efficient utilization of heat, reducing the overall production energy consumption.

[0027] 4. The feeding and discharging sections are equipped with double-layer sealing valves and vacuum equipment to isolate limestone from the atmosphere throughout the calcination process, preventing impurities such as oxygen and nitrogen from entering, and further ensuring the purity of lime products and the quality of carbon dioxide recovery. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention.

[0029] Figure 2 This is a top view of the combustion section of the present invention.

[0030] Figure 3 This is a schematic diagram of the workflow of the present invention.

[0031] Figure label:

[0032] 10. Feeding section; 11. Feeding hopper; 12. Automatic feeding equipment; 13. Storage hopper; 20. Preheating section; 21. Flue gas duct; 22. Carbon dioxide recovery pipe; 30. Combustion section; 31. Heat transfer wall one; 32. Heat transfer wall two; 33. Material channel; 34. Outer cylinder; 35. Insulation layer; 36. Refractory layer; 37. Combustion chamber; 38. Flue gas chamber; 39. Flue gas passage; 310. Inner cylinder; 311. Burner; 312. Observation window; 40. Cooling section; 50. Discharge section; 51. Fan; 52. Combustion air duct. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] like Figures 1 to 3As shown, a vacuum annular structure lime kiln of the present invention includes a feeding section 10, a preheating section 20, a combustion section 30, a cooling section 40, and a discharging section 50 connected sequentially from top to bottom. The preheating section 20, the combustion section 30, and the cooling section 40 are all annular in shape. Each of the preheating section 20, the combustion section 30, and the cooling section 40 is provided with a heat transfer wall 1 31 and a heat transfer wall 2 32. The heat transfer wall 1 31 and the heat transfer wall 2 32 are arranged concentrically. The inner diameter of the heat transfer wall 1 31 is larger than the outer diameter of the heat transfer wall 2 32. A material channel 33 is formed between the heat transfer wall 1 31 and the heat transfer wall 2 32. The material channels 33 inside the preheating section 20, the combustion section 30, and the cooling section 40 are connected to each other. Vacuum pumping equipment is connected to both the discharging section 50 and the feeding section 10. The vacuum pumping equipment is used to ensure that the whole is still in a vacuum state after the material enters the interior of the preheating section 20 and after the material is discharged from the discharging section 50.

[0035] The combustion section 30 includes an outer cylinder 34, the inner wall of which is connected to an insulation layer 35, and the inner wall of the insulation layer 35 is connected to a refractory layer 36. A heat transfer wall 31 is located inside the refractory layer 36 within the combustion section 30. A combustion chamber 37 is located between the heat transfer wall 31 and the refractory layer 36. The material channel 33 and the combustion chamber 37 are two independent chambers. The heat generated by combustion in the combustion chamber 37 is conducted through the heat transfer wall 31 to the material channel 33, heating and calcining the material inside. A flue gas chamber 38 is located inside a second heat transfer wall 32 within the combustion section 30. Multiple sets of flue gas passages 39 are located between the heat transfer wall 31 and the second heat transfer wall 32 within the combustion section 30, connecting the flue gas chamber 38 and the combustion chamber 37. An inner cylinder 310 is located inside the flue gas chamber 38. The cooling section 40 is equipped with an indirect heat exchange device 1 (not shown in the figure), which is connected to the inner cylinder 310. The indirect heat exchange device 1 is used to transport the preheated combustion air inside the cooling section 40 to the inside of the inner cylinder 310. The preheating section 20 is equipped with an indirect heat exchange device 2 and a direct heat exchange device (not shown in the figure). The indirect heat exchange device 2 is connected to the flue gas chamber 38. The indirect heat exchange device 2 converts the high-temperature exhaust gas into low-temperature exhaust gas. The indirect heat exchange device 2 is externally connected to the flue gas duct 21, which is connected to the flue gas purification device. The low-temperature exhaust gas after heat exchange is purified and discharged through the flue gas duct 21 and the flue gas purification device to meet the emission standards. The direct heat exchange device is connected to a carbon dioxide recovery pipe 22, which is connected to a vacuum pump group, which is connected to the carbon dioxide recovery device.

[0036] During limestone processing, the limestone enters the feed channel 33 inside the preheating section 20 via the feed section 10. After being preheated by the preheating section 20, the limestone in the feed channel 33 inside the preheating section 20 enters the feed channel 33 inside the combustion section 30. At this time, the combustion chamber 37 is heated by the combustion of external fuel, and an annular hot airflow is generated in the combustion chamber. During the combustion process, high-heat flue gas is generated, and the hot flue gas enters the flue gas chamber 38 through the flue gas passage 39. Indirect heat transfer is performed on the limestone inside the material channel 33 through heat transfer wall 31 and heat transfer wall 32, raising the temperature inside the material channel 33 to the decomposition temperature of the limestone. This decomposes the limestone inside the material channel 33 in the combustion section 30 into calcium oxide and carbon dioxide. The carbon dioxide produced by decomposition flows upward through the material channel 33 in the combustion section 30 and enters the material channel 33 in the preheating section 20. The higher-temperature carbon dioxide then flows counter-currently and directly exchanges heat with the limestone inside the material channel 33 in the preheating section 20. The hot flue gas inside flue gas chamber 38 will enter the indirect heat exchanger device 2 inside preheating section 20. Through indirect heat exchanger device 2, the hot flue gas and limestone undergo indirect heat exchange, heating the limestone to 700-800 degrees Celsius inside preheating section 20 before it enters the material channel 33 inside combustion section 30. The calcium oxide produced by decomposition enters the material channel 33 inside cooling section 40 under gravity. The indirect heat exchanger device 1 is externally connected to an air supply device, which generates lower-temperature combustion air. The gas is then fed into the indirect heat exchanger 1, where it exchanges heat with the calcium oxide. During this heat exchange, the temperature of the calcium oxide decreases, while the temperature of the combustion air inside the indirect heat exchanger 1 increases. The heated combustion air then enters the inner cylinder 310. At this time, the temperature inside the flue gas chamber 38 is relatively high. The hot flue gas inside the flue gas chamber 38 indirectly exchanges heat with the combustion air flowing inside the inner cylinder 310, further increasing the temperature of the combustion air and resulting in a better subsequent combustion effect.

[0037] Temperature and humidity detection and vacuum control devices are installed in the feeding section 10. Vacuum gauges, carbon dioxide concentration, temperature, pressure, and dust detection devices are installed in the preheating section 20. Temperature, pressure, air, and fuel metering devices are installed in the combustion section 30. Temperature and pressure detection devices are installed in the cooling section 40. These detection components are electrically connected to the intelligent control device. At the same time, the operation, shutdown, and regulation of each piece of equipment are electrically connected to the intelligent control device to realize sequential control and intelligent regulation. The combustion process, efficiency, limestone feeding, limestone discharge, limestone decomposition rate, and reaction rate in the combustion chamber 37 are regulated and controlled by the concentration, pressure, temperature of carbon dioxide, and the electrical signal of the vacuum gauge in the combustion section. Carbon dioxide is also recovered through the vacuum device.

[0038] The limestone is separated from the external preheating source, heating source, and cooling source by the material channel 33, so that the preheating, heating, and cooling of the limestone are all done indirectly, rather than in direct contact with the limestone. This avoids the mixing of carbon dioxide gas generated during the heating process with fuel combustion flue gas, combustion air, cooling air, and other media. The carbon dioxide only flows within the closed material channel, preventing the dilution of carbon dioxide by other gases from the source. High-purity carbon dioxide can be obtained through the carbon dioxide recovery device, which greatly improves the resource utilization value of carbon dioxide.

[0039] The annular combustion chamber, flue gas chamber, and material channel form a uniform annular heat transfer surface. This indirect heat transfer method ensures that limestone at all locations within the material channel receives stable heat conduction, avoiding problems such as localized overheating and incomplete burning caused by direct combustion. This guarantees the uniformity of limestone calcination and decomposition, reduces the generation of over-burned and under-burned ash, and improves the activity and yield of the finished lime. Furthermore, because the limestone is located inside the material channel 33, heat is uniformly transferred from the channel wall to the internal material through the double-layer annular indirect heat transfer structure formed by heat transfer wall 31 and heat transfer wall 32, achieving efficient heat transfer. The material is heated evenly throughout. Small-diameter limestone (particle size <20mm) is more sensitive to temperature changes. If small-diameter limestone is directly calcined, it is easy to overburn and reduce its activity if the temperature is too high, and incomplete decomposition if the temperature is too low. Small-diameter limestone has a large specific surface area. Under the condition of indirect uniform heat transfer, heat can be transferred to the interior of the material quickly and evenly. The mass and heat transfer efficiency of limestone decomposition reaction is greatly improved. Compared with large-diameter limestone, small-diameter materials can achieve complete decomposition in a shorter calcination time and avoid the problem of overburning of small-diameter materials.

[0040] Both the discharge section 50 and the feed section 10 are vacuum tanks sealed at both ends, and both the discharge section 50 and the feed section 10 are equipped with an upper sealing valve and a lower sealing valve, so that the limestone is isolated from the atmosphere during the process of entering the feed section 10, exiting the feed section 10, entering the discharge section 50, and exiting the discharge section 50, thus ensuring that the limestone does not contain impurities such as oxygen and nitrogen.

[0041] When limestone enters the feeding section 10, the upper sealing valve on the feeding section 10 is opened to allow the limestone to enter the interior of the feeding section 10. Then, the upper sealing valve on the feeding section 10 is closed, the vacuum equipment is started, and the limestone inside the feeding section 10 is placed under vacuum. After that, the vacuum equipment is turned off, and the upper sealing valve on the feeding section 10 is opened to allow the limestone inside the feeding section 10 to enter the material channel 33 inside the preheating section 20. Then, the lower sealing valve on the feeding section 10 is closed, thus completing the feeding operation.

[0042] When calcium oxide enters the discharge section 50 through the material channel 33 inside the cooling section 40, the sealing valve at the top of the discharge section 50 is opened to allow calcium oxide to enter the discharge section 50. The upper valve on the discharge section 50 is then closed. At this time, the discharge section 50 is still in a vacuum state, that is, the preheating section 20, the combustion section 30, and the cooling section 40 are still in a vacuum state. When calcium oxide is discharged, the lower sealing valve on the discharge section 50 is opened. After the calcium oxide is discharged, the lower sealing valve on the discharge section 50 is closed, and the vacuum equipment is started to restore the vacuum state inside the discharge section 50 before the vacuum equipment is turned off.

[0043] A ash discharge machine is installed between the discharge section 50 and the cooling section 40. The outlet of the ash discharge machine is connected to the finished product temporary storage silo. The ash discharge machine can discharge ash continuously or indirectly. The calcium oxide cooled inside the cooling section 40 will be transported to the inside of the finished product temporary storage silo through the ash discharge machine, and then transported to the inside of the discharge section 50 through the finished product temporary storage silo.

[0044] At least four sets of burners 311 are evenly arranged along the circumferential direction on the outer peripheral surface above the combustion section 30. Each set of burners 311 is equipped with a combustion air inlet. Each combustion air inlet is connected to the inner cylinder 310 through a pipe to deliver the combustion air inside the inner cylinder 310 to the inside of the burner 311. Each set of burners 311 is connected to a fuel regulating control device, and each fuel regulating control device is connected to a fuel delivery pipe. The installation angle of each set of burners 311 is 10-20 degrees downward, so that the combustion flame and airflow rotate along the tangent of the combustion chamber 37, extending the flame combustion distance and forming a circulation.

[0045] The air supply device includes a fan 51 installed on one side of the discharge section 50. A combustion air duct 52 is connected to the fan 51. The combustion air duct 52 is arranged in a ring outside the cooling section 40. The ring part of the combustion air duct 52 is connected to an indirect heat exchange device through a pipe. Multiple high-temperature air conditioning and control devices are connected to the ring part of the combustion air duct 52. The high-temperature air conditioning and control devices are connected to the pipes connected to the combustion air port of the burner.

[0046] During the heating of limestone, blower 51 generates low-temperature combustion air, which enters the interior of indirect heat exchanger 1. The indirect heat exchanger 1 initially raises the temperature of the combustion air. The initially raised combustion air then enters the interior of inner cylinder 310. The hot flue gas inside flue gas chamber 38 indirectly exchanges heat with the combustion air flowing inside inner cylinder 310, raising the temperature of the combustion air again. The combustion air, after its second temperature increase, enters the interior of multiple burners 311 through multiple burner combustion air ports, thus providing combustion air to burners 311. At this time, by introducing fuel into burners 311 and igniting it, the combustion air can be ignited. The ignited combustion air then enters the interior of combustion chamber 37, thereby heating combustion chamber 37.

[0047] Burner 311 continuously supplies fuel and combustion air. Based on the set combustion chamber temperature (1000-1300 degrees), the high-temperature air conditioning control device and fuel conditioning control device corresponding to each burner 311 are intelligently adjusted to keep the combustion chamber temperature within ±20 degrees of the set value, thus achieving one-to-one correspondence and intelligent adjustment of fuel and combustion air for burner 311.

[0048] The fuel used in burner 311 can be one of the following: natural gas, hydrogen, various coal gases, pulverized coal, etc., or two of these fuels can be mixed for combustion.

[0049] It should be noted that the number of burners 311 should be selected according to the diameter of the combustion section 30. Usually, the number of burners 311 is 4-12 sets.

[0050] Multiple observation windows 312 are provided between the insulation layer 35, the fire-resistant layer 36 and the outer cylinder 34. The number of observation windows 312 corresponds to the number of flue gas passages 39, the position of observation windows 312 corresponds to the position of flue gas passages 39, and there is a one-to-one correspondence between observation windows 312 and flue gas passages 39. The observation windows 312 are used to observe the combustion situation and flue gas status inside the combustion chamber 37.

[0051] Multiple arc-shaped ash bins (not shown in the figure) are provided at the lower part of both the combustion chamber 37 and the flue gas chamber 38. The number of arc-shaped ash bins corresponds to the number of burners 311, and the positions of the arc-shaped ash bins and burners 311 correspond one-to-one. The arc-shaped ash bins are used to collect dust in the combustion chamber 37 and the flue gas chamber 38.

[0052] Heat transfer wall 1 31 and heat transfer wall 2 32 are annular structures composed of silicon carbide bricks, silicon carbide plates or heat-resistant steel. Inner cylinder 310 is a silicon carbide pipe or a heat-resistant steel pipe. Insulation layer 35 is an annular structure composed of insulation bricks. Refractory layer 36 is an annular structure composed of refractory bricks.

[0053] The heat transfer wall 31, heat transfer wall 32, and inner cylinder 310 are made of high-temperature resistant materials such as silicon carbide and heat-resistant steel. They can adapt to the high-temperature environment of the combustion section, extend the service life of the equipment, and the ring-shaped insulation bricks and refractory bricks can form an all-round insulation and fireproof barrier, reduce heat loss, improve energy utilization, and at the same time ensure the safety of the external temperature of the equipment and reduce heat loss.

[0054] At least four pillars are provided between the preheating section 20 and the combustion section 30, and between the combustion section 30 and the discharge section 50. The pillars support the preheating section 20, the combustion section 30, the cooling section 40 and the discharge section 50. The discharge section 50 can be based on concrete, or multiple pillars can be used to replace concrete to form a frame structure to ensure the stability of the overall lime kiln.

[0055] The feeding section 10 is connected to a feeding bin 11. An automatic feeding device 12 is connected to the feeding port of the feeding bin 11. The automatic feeding device 12 is a bucket elevator, and a storage bin 13 is set at the bottom of the automatic feeding device 12. The discharge port of the storage bin 13 corresponds to the feeding port of the bucket elevator.

[0056] The cooling section 40 includes an upper cooling section and a lower cooling section. The outer shell of the upper cooling section is made of heat-resistant steel or stainless steel, while the material of the lower cooling section is carbon steel. An indirect heat exchange device is installed inside the lower cooling section.

[0057] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A vacuum annular structure lime kiln, comprising a feeding section (10), characterized in that, Also includes: The preheating section (20), combustion section (30), and cooling section (40) are sequentially and sealed below the feeding section (10). The preheating section (20), combustion section (30), and cooling section (40) are all annular in shape and each has a concentrically arranged heat transfer wall 1 (31) and heat transfer wall 2 (32) inside. The inner diameter of heat transfer wall 1 (31) is larger than the outer diameter of heat transfer wall 2 (32). A material channel (33) is formed between heat transfer wall 1 (31) and heat transfer wall 2 (32). The material channels (33) located inside the preheating section (20), combustion section (30), and cooling section (40) are interconnected. The combustion section (30) includes an outer cylinder (34), an insulation layer (35), a refractory layer (36), and a flue gas chamber (38). The combustion section (30) includes a flue gas passage (39) and an inner cylinder (310). The insulation layer (35) is connected to the inner wall of the outer cylinder (34), and the refractory layer (36) is connected to the inner wall of the insulation layer (35). The heat transfer wall 1 (31) inside the combustion section (30) is located inside the refractory layer (36). A combustion chamber (37) is formed between the heat transfer wall 1 (31) inside the combustion section (30) and the refractory layer (36). The flue gas chamber (38) is located inside the heat transfer wall 2 (32) inside the combustion section (30). The flue gas passage (39) is located between the heat transfer wall 1 (31) and the heat transfer wall 2 (32) inside the combustion section (30). The inner cylinder (310) is located inside the flue gas chamber (38). The discharge section (50) is connected to the bottom of the cooling section (40), and both the discharge section (50) and the feeding section (10) are equipped with vacuum equipment.

2. The vacuum annular structure lime kiln according to claim 1, characterized in that, The cooling section (40) is equipped with an indirect heat exchange device, which is connected to the inner cylinder (310). The indirect heat exchange device is connected to an air supply device, which is used to generate combustion air. The indirect heat exchange device is used to transport the preheated combustion air inside the cooling section (40) to the inside of the inner cylinder (310).

3. A vacuum annular structure lime kiln according to claim 1, characterized in that, The preheating section (20) is equipped with an indirect heat exchange device 2 and a direct heat exchange device. The indirect heat exchange device 2 is connected to the flue gas chamber (38) and is externally connected to a flue gas pipe (21). The flue gas pipe (21) is connected to a flue gas purification device. The direct heat exchange device is connected to a carbon dioxide recovery pipe (22). The carbon dioxide recovery pipe (22) is connected to a vacuum pump group. The vacuum pump group is connected to a carbon dioxide recovery device.

4. A vacuum annular structure lime kiln according to claim 1, characterized in that, At least four sets of burners (311) are evenly arranged on the outer circumferential surface above the combustion section (30) along the circumferential direction. Each set of burners (311) is provided with a combustion air interface. Each combustion air interface is connected to the inner cylinder (310) through a pipe to transport the combustion air inside the inner cylinder (310) to the inside of the burner (311). Each set of burners (311) is connected to a fuel regulation control device, and each fuel regulation control device is connected to a fuel delivery pipe.

5. A vacuum annular structure lime kiln according to claim 2, characterized in that, The air supply device includes a fan (51) and a combustion air duct (52). The fan (51) is located on one side of the discharge section (50). The combustion air duct (52) is connected to the fan (51). The combustion air duct (52) is arranged in a ring outside the cooling section (40), and the ring part of the combustion air duct (52) is connected to an indirect heat exchange device through a pipe.

6. A vacuum annular structure lime kiln according to claim 1, characterized in that, Both the discharge section (50) and the feed section (10) are vacuum tanks sealed at both ends, and both the discharge section (50) and the feed section (10) are equipped with an upper sealing valve and a lower sealing valve.

7. A vacuum annular structure lime kiln according to claim 1, characterized in that, Multiple observation windows (312) are provided between the insulation layer (35), the fire-resistant layer (36) and the outer cylinder (34). The number of observation windows (312) corresponds to the number of flue gas passages (39), and the position of the observation windows (312) corresponds to the position of the flue gas passages (39).

8. A vacuum annular structure lime kiln according to claim 1, characterized in that, The heat transfer wall one (31) and heat transfer wall two (32) are annular structures composed of silicon carbide bricks, silicon carbide plates or heat-resistant steel, the inner cylinder (310) is a silicon carbide pipe or a heat-resistant steel pipe, the insulation layer (35) is annular structure composed of insulation bricks, and the refractory layer (36) is annular structure composed of refractory bricks.

9. A vacuum annular structure lime kiln according to claim 1, characterized in that, The feeding section (10) is connected to a feeding bin (11), and an automatic feeding device (12) is connected to the feeding port of the feeding bin (11). A storage bin (13) is provided at the bottom of the automatic feeding device (12).

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