Apparatus for producing carbon dioxide by calcining limestone

Abstract

The utility model provides a device for preparing carbon dioxide by calcining limestone belongs to lime calcining technical field, through the vertical arrangement of calcining pipe in calcining section, the combination of heat accumulating burner surrounded in the circumference of calcining section makes the high temperature flue gas generated by the relatively arranged heat accumulating burner in the calcining pipe heat the limestone raw material in the radiation and convection mode, the limestone raw material is heated evenly in the calcining pipe, and the heating is stable, avoids the "raw overburning" phenomenon, and there is no restriction to the size of limestone raw material, the first material pipe is vertically arranged in the upper end port of carbon dioxide collection section and is connected with the preheating section, the lower end port of first material pipe is butt jointed with the upper end port of calcining pipe, and the outside of first material pipe lower end port is equipped with the inside of calcining pipe upper end port gap, the raw material in the gap forms the first material seal, and the process fan is connected in carbon dioxide collection section, makes the upper part and lower part of carbon dioxide collection section form the material seal, avoids the contact of carbon dioxide and flue gas, and ensures the purity of carbon dioxide.

Description

Technical Field

[0001] This utility model relates to the field of lime calcination technology, and more specifically, to an apparatus for producing carbon dioxide by calcining limestone. Background Technology

[0002] In metallurgy, chemical industry, and many other production fields, the production of calcium oxide from limestone by calcining in lime kilns is a widely adopted process by most manufacturing enterprises. Looking at the currently popular lime kilns, whether it's a sleeve kiln, a Maeltz kiln, a rotary kiln, a double-beam kiln, or a mechanized mixed-firing kiln, regardless of the type of fuel used (liquid, gas, or solid) or the calcination method employed, all involve mixing raw materials and fuel, with the combustion of the fuel providing heat for the decomposition of limestone. However, significant technical bottlenecks exist in terms of heat energy utilization, product application, and resource utilization.

[0003] First, the calcination and decomposition temperature of limestone cannot be kept constant. CaCO3 reaches complete decomposition and its decomposition rate is fastest at 1150°C, and the temperature cannot be stabilized at the critical state, resulting in "under-burning" and "over-burning" of limestone during calcination. Second, the pure carbon dioxide released from the decomposition of calcium carbonate is not well recovered and utilized because it mixes with the exhaust gas produced by fuel combustion. The CO2 from the decomposition of CaCO3 is mixed with the exhaust gas from fuel combustion and combustion air, resulting in a low CO2 concentration of only about 30%, which has low utilization value. If gas separation or recovery were to be carried out, it would require a lot of purification equipment, resulting in huge investment and increased production costs for enterprises. Most enterprises choose to emit it instead of utilizing it. Third, the limitations of different limestone particle sizes in different kilns prevent the full utilization of limestone resources. The limestone particle sizes used in different kilns are mainly concentrated in 30mm-60mm, 40mm-80mm, and 60mm-90mm. Limestone smaller than 30mm is basically unusable in lime kilns, resulting in a large waste of resources.

[0004] In summary, traditional lime kilns can only utilize limestone with a particle size of 30mm-90mm, and cannot utilize smaller particles smaller than 30mm. After the raw materials and fuel are mixed and calcined, the resulting CO2 gas concentration is low, and its utilization value is not high. Furthermore, the temperature of limestone calcination and decomposition cannot be kept constant. CaCO3 reaches complete decomposition and the decomposition rate reaches its fastest at a temperature of 1150°C. Since the temperature cannot be stabilized at the critical state, the limestone will produce the phenomenon of "under-burning and over-burning" during the calcination process. Utility Model Content

[0005] In view of the above problems, the purpose of this utility model is to provide a device for calcining limestone to produce carbon dioxide, so as to solve the problems of traditional lime kiln calcination of limestone to produce carbon dioxide in the prior art, which are basically unable to utilize limestone raw materials with a particle size of less than 30mm, low CO2 gas concentration after calcination of raw materials and fuel, and easy to produce "under-burning and over-burning" due to the inability to keep the temperature of limestone calcination decomposition constant.

[0006] The apparatus for producing carbon dioxide from calcined limestone provided by this utility model includes a furnace body and a combustion mechanism. The furnace body is internally divided into a preheating section, a carbon dioxide collection section, a calcination section, and a cooling section from top to bottom. A calcination tube with an outwardly expanding upper end is vertically arranged in the calcination section. A first material pipe with its upper end connected to the preheating section is vertically arranged in the carbon dioxide collection section. The lower end of the first material pipe is connected to the upper end of the calcination tube, and a gap is provided between the outer wall of the lower end of the first material pipe and the inner wall of the upper end of the calcination tube, forming a first material seal within the gap. A carbon dioxide outlet is provided on the side wall of the furnace body in the carbon dioxide collection section. A process fan is connected to the carbon dioxide outlet via a carbon dioxide conveying pipe. A carbon dioxide recovery process system is connected to the outlet of the process fan. A finished product discharge port is provided at the bottom of the cooling section. A finished product discharge valve is provided at the finished product discharge port. The combustion mechanism includes a combustion chamber surrounding the outer periphery of the outer wall of the furnace body in the calcination section and regenerative burners arranged opposite each other on the outer wall of the combustion chamber.

[0007] Furthermore, a preferred structure is that a second material pipe is vertically arranged between the calcination section and the cooling section, with its upper end connected to the lower end of the calcination tube; the lower end of the second material pipe is connected to the cooling section; and the raw material inside the second material pipe forms a second material seal.

[0008] Furthermore, a preferred structure is that the cooling section is provided with a cooling air inlet and a high-temperature air outlet respectively; a cooling fan is connected to the cooling air inlet; a high-temperature fan is connected to the high-temperature air outlet; and the air outlet of the high-temperature fan is connected to the preheating air inlet of the preheating section.

[0009] Furthermore, a preferred configuration is that the upper end of the first feed tube is shaped like a flared mouth.

[0010] Furthermore, in a preferred configuration, a waste heat recovery device and a dust removal device are sequentially connected between the carbon dioxide outlet and the process fan via the carbon dioxide delivery pipe.

[0011] Furthermore, a preferred structure includes at least two sets of regenerative burners arranged opposite each other on the outer wall of the combustion chamber; each set of regenerative burners includes a first regenerative burner and a second regenerative burner respectively disposed on two opposite outer walls of the combustion chamber; the combustion air inlets of the first and second regenerative burners are respectively connected to the main pipe of the combustion air fan via a first combustion air pipe and a second combustion air pipe; the fuel inlets of the first and second regenerative burners are respectively connected to the main pipe of the fuel network via a first fuel pipe and a second fuel pipe; the first regenerative burner... The flue gas outlets of the burner and the second regenerative burner are respectively connected to the first flue gas conveying pipe through the first flue gas pipe and the second flue gas pipe; a first flue gas treatment system is connected to the flue gas conveying end of the first flue gas conveying pipe; a first reversing valve is provided at the connection between the main pipe of the combustion fan and the first combustion air pipe and the second combustion air pipe; a second reversing valve is provided at the connection between the main pipe of the fuel network and the first fuel pipe and the second fuel pipe; and a third reversing valve is provided at the connection between the first flue gas conveying pipe and the first flue gas pipe and the second flue gas pipe.

[0012] Furthermore, in a preferred configuration, the first flue gas treatment system includes a first flue gas dust removal device connected to the flue gas conveying end of the first flue gas conveying pipe, a first exhaust gas fan connected to the first flue gas dust removal device, and a first chimney connected to the first exhaust gas fan.

[0013] Furthermore, a preferred structure is that a flue gas outlet is provided at the top of the preheating section; a second flue gas treatment system is connected to the flue gas outlet via a second flue gas conveying pipe; the second flue gas treatment system includes a second flue gas dust removal device connected to the second flue gas conveying pipe, a second exhaust gas fan connected to the second flue gas dust removal device, and a second chimney connected to the second exhaust gas fan.

[0014] Furthermore, a preferred structure includes a hopper located above the top of the preheating section; a discharge port located at the bottom of the hopper; a raw material discharge valve located at the discharge port; a feeding trolley located at the top of the preheating section; the feeding trolley located between the hopper and the feeding port at the top of the preheating section; and a cover located at the feeding port at the top of the preheating section.

[0015] Furthermore, a preferred structure is that an inclined bridge is provided on one side of the furnace body; a material unloading point is provided at the upper end of the inclined bridge, and a material feeding point is provided at the lower end of the inclined bridge; the material unloading point is located above the feeding port of the silo; and a material transport vehicle is provided on the inclined bridge.

[0016] As can be seen from the above technical solution, the device for producing carbon dioxide from calcined limestone provided by this utility model divides the interior of the furnace body into a preheating section, a carbon dioxide collection section, a calcination section, and a cooling section from top to bottom. A calcination tube with an outwardly expanding upper port is vertically arranged in the calcination section. Combined with the combustion chamber surrounding the outer wall of the furnace body in the calcination section and the regenerative burners arranged opposite to it on the outer wall of the combustion chamber, the limestone raw material is heated in the calcination tube by the high-temperature flue gas generated by the regenerative burners arranged opposite to it in the combustion chamber through radiation and convection. This ensures that the limestone raw material is heated evenly and stably in the calcination tube, avoiding the phenomenon of "under-burning" or "over-burning." Furthermore, the calcination tube allows for calcination of the limestone raw material without limiting the particle size, enabling the reuse of limestone with a particle size of 5mm-20mm discarded from limestone mines, thus improving the raw material utilization rate. The device also features a vertically arranged upper port in the carbon dioxide collection section... The preheating section is connected to a first feed pipe; the lower end of the first feed pipe is connected to the upper end of the calcination pipe, and a gap is provided between the outer wall of the lower end of the first feed pipe and the inner wall of the upper end of the calcination pipe. The raw material in the gap forms a first material seal. The carbon dioxide outlet on the side wall of the furnace body in the carbon dioxide collection section is connected to the process fan. The structural design of this section ensures that both the upper and lower parts of the carbon dioxide collection section form material seals, preventing carbon dioxide from contacting flue gas and ensuring the purity of carbon dioxide, so that it is not polluted by air / flue gas. It can also create a slight negative pressure in the carbon dioxide collection section. The suction force of the slight negative pressure can draw the carbon dioxide generated in the calcination pipe into the carbon dioxide collection section through the first material seal. Finally, the carbon dioxide is recovered and purified by the carbon dioxide recovery process system, and pure carbon dioxide can be collected continuously and stably. This utility model will not waste limestone raw materials during shutdown and restart, and will not produce unqualified products. Under near constant temperature conditions, the overburning rate of calcium carbonate and calcium oxide products is ≤1%. Attached Figure Description

[0017] Other objects and results of this invention will become clearer and easier to understand with reference to the following description taken in conjunction with the accompanying drawings, and with a more comprehensive understanding of the invention.

[0018] Figure 1 This is a schematic diagram of the apparatus for preparing carbon dioxide by calcining limestone according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the furnace body according to an embodiment of the present utility model;

[0020] Figure 3 for Figure 2 Schematic diagram of the structure of part AA;

[0021] Figure 4 for Figure 2Schematic diagram of the structure of the middle BB section;

[0022] Figure 5 This is a cross-sectional schematic diagram of the calcination section of the furnace body according to an embodiment of the present invention;

[0023] Figure 6 This is a schematic cross-sectional view of the calcination tube according to an embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram of the connection between the calcination tube and the first feed tube according to an embodiment of the present invention;

[0025] Figure 8 This is a schematic diagram of the connection between the calcination tube and the second feed tube according to an embodiment of the present invention.

[0026] In the attached diagram, 1-furnace body, 11-preheating section, 111-flue gas outlet, 112-second flue gas conveying pipe, 12-carbon dioxide collection section, 121-first feed pipe, 122-carbon dioxide outlet, 123-carbon dioxide conveying pipe, 124-process fan, 125-carbon dioxide recovery process system, 13-calcination section, 131-calcination pipe, 14-cooling section, 141-finished product discharge port, 142-finished product discharge valve, 143-finished product conveyor belt, 144-cooling air inlet, 145-high temperature air outlet, 15-first material seal, 16-second feed pipe, 161-support structure, 21-combustion chamber, 221-first regenerative burner, 222-second regenerative burner, 3-cooling fan, 4-high temperature fan, 51-waste heat recovery. 52-Dust removal device, 61-First combustion air duct, 62-Second combustion air duct, 63-Combustion air blower, 64-First fuel duct, 65-Second fuel duct, 66-Fuel network, 67-First flue gas duct, 68-Second flue gas duct, 69-First flue gas conveying pipe, 71-First reversing valve, 72-Second reversing valve, 73-Third reversing valve, 81-First flue gas dust removal device, 82-First exhaust gas blower, 83-First chimney, 84-Second flue gas dust removal device, 85-Second exhaust gas blower, 86-Second chimney, 91-Hopper, 911-Unloading port, 912-Raw material unloading valve, 92-Feeding car, 93-Inclined bridge, 931-Unloading point of transport car, 932-Feeding point of transport car, 94-Transport car.

[0027] In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation

[0028] In response to the aforementioned problems in the existing technology of calcining limestone in lime kilns to produce carbon dioxide, such as the inability to utilize limestone raw materials with a particle size of less than 30 mm, the low concentration of CO2 gas produced after calcining the raw materials and fuel, and the tendency for "under-burning" due to the inability to maintain a constant temperature for limestone calcination and decomposition, a device for calcining limestone to produce carbon dioxide is proposed.

[0029] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0030] To illustrate the apparatus for producing carbon dioxide by calcining limestone provided by this utility model, Figure 1 The structure of an apparatus for preparing carbon dioxide by calcining limestone according to an embodiment of the present invention is shown; Figure 2 The structure of the furnace body according to an embodiment of the present invention is shown; Figure 3 It shows Figure 2 The structure of the AA section; Figure 4 It shows Figure 2 The structure of the middle BB section; Figure 5 A cross-section of the calcination section of the furnace body according to an embodiment of the present invention is shown; Figure 6 A cross-section of the calcining tube according to an embodiment of the present invention is shown; Figure 7 The structure of the connection between the calcination tube and the first feed tube according to an embodiment of the present invention is shown; Figure 8 The structure of the connection between the calcination tube and the second feed tube according to an embodiment of the present invention is shown.

[0031] like Figures 1 to 8 As shown in the diagram, the apparatus for producing carbon dioxide by calcining limestone provided by this utility model mainly includes a furnace body 1 and a combustion mechanism; wherein,

[0032] The interior of the furnace body 1 is divided into a preheating section 11, a carbon dioxide collection section 12, a calcination section 13, and a cooling section 14 from top to bottom;

[0033] The calcination section 13 is vertically arranged with calcination pipes 131 whose upper ends flare outwards; the carbon dioxide collection section 12 is vertically arranged with a first material pipe 121 whose upper end connects to the preheating section 11; the lower end of the first material pipe 121 is connected to the upper end of the calcination pipe 131, and a gap is provided between the outer wall of the lower end of the first material pipe 121 and the inner wall of the upper end of the calcination pipe 131, forming a first material seal 15 in the gap; a carbon dioxide outlet 122 is provided on the side wall of the furnace body of the carbon dioxide collection section 12; a process fan 124 is connected to the carbon dioxide outlet 122 through a carbon dioxide conveying pipe 123; a carbon dioxide recovery process system 125 is connected to the outlet of the process fan 124; and a finished product discharge port 141 is provided at the bottom of the cooling section 14.

[0034] The combustion mechanism includes a combustion chamber 21 surrounding the outer periphery of the outer wall of the furnace body in the calcination section 13 and regenerative burners 22 arranged opposite to each other on the outer wall of the combustion chamber 21.

[0035] Specifically, the interior of the furnace body 1 is divided into a preheating section 11, a carbon dioxide collection section 12, a calcination section 13, and a cooling section 14 from top to bottom by partitions. Limestone raw material is added from the top feed port of the preheating section 11. After preheating within the preheating section 11, the preheated limestone raw material enters the first feed pipe 121 and then into the calcination pipe 131. Inside the calcination pipe 131, the preheated limestone raw material undergoes thermal decomposition, forming carbon dioxide and high-temperature lime. The carbon dioxide collection section 12, connected to a process fan 124, is under a slight negative pressure, drawing the carbon dioxide generated in the calcination pipe into the carbon dioxide collection section 12 via the first material seal 15. The heat carried by the carbon dioxide further preheats the limestone raw material in the first feed pipe 121, fully utilizing the heat generated by the decomposition of the limestone. Because the preheating section 11 and the carbon dioxide collection section 12 are connected by the first feed pipe 121, a material seal is formed between them. This prevents the preheated flue gas in the preheating section 11 from entering the interior of the carbon dioxide collection section 12. Combined with the first material seal, the purity of the carbon dioxide is greatly improved, preventing it from being contaminated by air / flue gas, and the carbon dioxide concentration can reach 99%. The limestone raw material is calcined through the calcination tube 131, with no limitation on the particle size of the limestone raw material. Limestone with a particle size of 5mm-20mm discarded from limestone mines can be reused, greatly improving the raw material utilization rate compared to existing technologies. In the calcination section 13, the high-temperature flue gas generated by the regenerative burner heats the limestone raw material in the calcination tube 131 through radiation and convection, ensuring uniform and stable heating of the limestone raw material within the calcination tube, avoiding "under-burning" and "over-burning," and improving the quality and yield of the finished lime product.

[0036] As a preferred embodiment of this utility model, a finished product unloading valve 142 is provided at the finished product unloading port 141; and a finished product conveyor belt 143 is provided below the finished product unloading port 141.

[0037] Specifically, the finished product unloading valve 142 facilitates the control of the discharge of finished lime produced in the cooling section; the finished product conveyor belt 143 transports the finished lime out.

[0038] As a preferred embodiment of this utility model, a second material pipe 16 is vertically arranged between the calcination section 13 and the cooling section 14, with its upper end connected to the lower end of the calcination pipe 131; the lower end of the second material pipe 16 is connected to the cooling section 14; and the raw material in the second material pipe 16 forms a second material seal.

[0039] Specifically, such asFigure 8 As shown, a support structure 161 is provided on the upper outer wall of the second material pipe 16, and the lower end of the calcination pipe 131 is connected to the top of the support structure 161. Through the second material sealing structure formed by the raw material in the second material pipe 16, the flue gas in the calcination section 131 is prevented from entering the cooling section 14, so that the high-temperature air generated by heat exchange in the cooling section 14 can be recovered and reused.

[0040] As a preferred embodiment of this utility model, a cooling air inlet 144 and a high-temperature air outlet 145 are respectively provided in the cooling section 14; a cooling fan 3 is connected to the cooling air inlet 144; a high-temperature fan 4 is connected to the high-temperature air outlet 145; and the air outlet of the high-temperature fan 4 is connected to the preheating air inlet of the preheating section 11.

[0041] Specifically, the cooling air inlet 144 is used to provide cold air to the cooling section 14. The high-temperature air generated after the cold air in the cooling section 14 exchanges heat with the high-temperature lime is pressurized by the high-temperature fan 4 and blown into the preheating section 11 to preheat the limestone raw material, so that the waste heat can be fully utilized.

[0042] As a preferred embodiment of this utility model, the upper end of the first feed tube 121 is in the shape of a trumpet; and / or, the calcining tube 131 is made of refractory material; the diameter of the calcining tube 131 is 100-400mm; and the wall thickness of the calcining tube 131 is 50-200mm.

[0043] Specifically, the upper end of the first feed pipe 121 is flared to facilitate the feeding of preheated limestone raw materials from the preheating section 11, ensuring smooth feeding. The calcining pipe 131 is made of refractory material, preferably but not limited to silicon carbide bricks or heat-resistant steel; the diameter of the calcining pipe 131 is preferably 100-400mm, particularly preferably 200mm, and the wall thickness of the calcining pipe 131 is preferably 50-200mm, particularly preferably 100mm, giving it the advantage of processing limestone powder smaller than 30mm.

[0044] As a preferred embodiment of this utility model, a waste heat recovery device 51 and a dust removal device 52 are sequentially connected between the carbon dioxide outlet 122 and the process fan 124 via a carbon dioxide conveying pipe 123.

[0045] Specifically, the waste heat recovery device 51 is preferably a waste heat boiler, and the dust removal device 52 is preferably a bag filter. The waste heat boiler further utilizes the heat carried by the carbon dioxide, and the carbon dioxide after being removed by the bag filter enters the carbon dioxide recovery process system.

[0046] As a preferred embodiment of this utility model, at least two sets of regenerative burners are arranged opposite each other on the outer wall of the combustion chamber 21; each set of regenerative burners includes a first regenerative burner 221 and a second regenerative burner 222 respectively disposed on two opposite outer walls of the combustion chamber 21; the combustion air inlets of the first regenerative burner 221 and the second regenerative burner 222 are respectively connected to the main pipe of the combustion air blower 63 through the first combustion air pipe 61 and the second combustion air pipe 62; the fuel inlets of the first regenerative burner 221 and the second regenerative burner 222 are respectively connected to the main pipe of the fuel network 66 through the first fuel pipe 64 and the second fuel pipe 65; The flue gas outlets of the regenerative burner 221 and the second regenerative burner 222 are respectively connected to the first flue gas conveying pipe 69 through the first flue gas duct 67 and the second flue gas duct 68; a first flue gas treatment system is connected to the flue gas conveying end of the first flue gas conveying pipe 69; a first reversing valve 71 is provided at the connection between the main pipe of the combustion fan 63 and the first combustion air duct 61 and the second combustion air duct 62; a second reversing valve 72 is provided at the connection between the main pipe of the fuel pipeline network 66 and the first fuel duct 64 and the second fuel duct 65; and a third reversing valve 73 is provided at the connection between the first flue gas conveying pipe 69 and the first flue gas duct 67 and the second flue gas duct 68.

[0047] Specifically, the fuel pipeline 66 is preferably, but not limited to, a gas pipeline. Through the above structural design, a regenerative heating method can be adopted to heat the limestone raw material inside the calcining tube 131. For example, the first regenerative burner 221 burns air and gas, and the flue gas undergoes heat storage through the second regenerative burner 222, and vice versa, thereby fully utilizing the high-temperature waste heat of the flue gas. The high-temperature flue gas, gas, and air are controlled by a reversing valve. After heat storage, the burner burns air and gas, while the burner on the opposite side performs heat storage operation, completing one cycle in the process. The high-temperature flue gas heats the limestone raw material inside the calcining tube 131 in the furnace through thermal convection and thermal radiation. The gas / air flow rate is precisely controlled by a computer to maintain the wall temperature of the calcining tube 131 in the furnace body 1 at approximately 1500K.

[0048] As a preferred embodiment of the present invention, the first flue gas treatment system includes a first flue gas dust removal device 81 connected to the flue gas conveying end of the first flue gas conveying pipe 69, a first exhaust gas fan 82 connected to the first flue gas dust removal device 81, and a first chimney 83 connected to the first exhaust gas fan 82.

[0049] Specifically, the first flue gas dust removal device 81 is preferably, but not limited to, a bag filter. The flue gas generated in the combustion section 13 is treated by the first flue gas treatment system.

[0050] As a preferred embodiment of this utility model, a flue gas outlet 111 is provided at the top of the preheating 11; a second flue gas treatment system is connected to the flue gas outlet 111 via a second flue gas conveying pipe 112; the second flue gas treatment system includes a second flue gas dust removal device 84 connected to the second flue gas conveying pipe 112, a second exhaust gas fan 85 connected to the second flue gas dust removal device 84, and a second chimney 86 connected to the second exhaust gas fan 85.

[0051] Specifically, the first and second flue gas dust removal devices 84 are preferably, but not limited to, bag filters. The second flue gas treatment system is used to treat the flue gas generated in the preheating section 11. The second and second flue gas treatment systems can be combined into a single system, thereby saving equipment.

[0052] As a preferred embodiment of this utility model, a hopper 91 is provided above the top of the preheating section 11; a discharge port 911 is provided at the bottom of the hopper 91; a raw material discharge valve 912 is provided at the discharge port 911; a feeding cart 92 is provided at the top of the preheating section 11; the feeding cart 92 is located between the hopper 91 and the feeding port at the top of the preheating section 11; and a cover (not shown in the figure) is provided at the feeding port at the top of the preheating section 11.

[0053] Specifically, the structure of the silo 91 facilitates the storage of limestone raw materials, and the feeding car 92 is used to feed the preheating section 11. After feeding, the cover is placed over the feeding port at the top of the preheating section 11 to ensure the internal pressure.

[0054] As a preferred embodiment of this utility model, an inclined bridge 93 is provided on one side of the furnace body 1; a material unloading point 931 is provided at the upper end of the inclined bridge 93, and a material feeding point 932 is provided at the lower end of the inclined bridge 93; the material unloading point 931 is located above the feeding port of the hopper 91; and a material transport vehicle 94 is provided on the inclined bridge 93.

[0055] Specifically, the above structural design facilitates the loading operation of the hopper 91.

[0056] The method for preparing carbon dioxide by calcining limestone using the apparatus for preparing carbon dioxide as described above includes the following steps:

[0057] Step S1: Add limestone raw material into preheating section 11 through the feeding port of preheating section 11, and preheat the limestone raw material in preheating section 11.

[0058] Step S2: After being preheated in the preheating section 11, the limestone raw material enters the calcination tube 131 of the calcination section 13 through the first feed pipe 121. The limestone in the calcination tube 131 is heated by the high-temperature flue gas generated by the combustion mechanism through radiation and convection and decomposes into high-temperature carbon dioxide and high-temperature lime.

[0059] Step S3: Under the action of the process fan 124, the interior of the carbon dioxide collection section 12 is in a slightly negative pressure state, so that the high-temperature carbon dioxide generated in the calcination tube 131 enters the carbon dioxide collection section 12 through the first material seal 15, and enters the carbon dioxide recovery process system 125 through the carbon dioxide conveying pipe 123 to produce carbon dioxide; and the high-temperature lime enters the cooling section 14 through the calcination tube 131, and the cooled lime is discharged from the finished product discharge port 141 to produce finished lime.

[0060] As can be seen from the above specific embodiments, the apparatus for producing carbon dioxide from calcined limestone provided by this utility model divides the interior of the furnace body into a preheating section, a carbon dioxide collection section, a calcination section, and a cooling section from top to bottom. A calcination tube with an outwardly expanding upper port is vertically arranged in the calcination section. Combined with the combustion chamber surrounding the outer wall of the furnace body in the calcination section and the regenerative burners arranged opposite to it on the outer wall of the combustion chamber, the limestone raw material is heated in the calcination tube by the high-temperature flue gas generated by the regenerative burners arranged opposite to it in the combustion chamber through radiation and convection. This ensures that the limestone raw material is heated evenly and stably in the calcination tube, avoiding the phenomenon of "under-burning" or "over-burning." Furthermore, the calcination tube allows for calcination of the limestone raw material without limiting the particle size, enabling the reuse of limestone with a particle size of 5mm-20mm discarded from limestone mines, thus improving the raw material utilization rate. The vertical arrangement of the upper port in the carbon dioxide collection section... The first feed pipe is connected to the preheating section; the lower end of the first feed pipe is connected to the upper end of the calcining tube, and a gap is provided between the outer wall of the lower end of the first feed pipe and the inner wall of the upper end of the calcining tube. The raw material in the gap forms a first material seal. The structural design of the carbon dioxide outlet on the side wall of the furnace body of the carbon dioxide collection section and the process fan are connected to the carbon dioxide collection section. This design forms material seals at both the upper and lower parts of the carbon dioxide collection section, preventing carbon dioxide from contacting the flue gas and ensuring the purity of the carbon dioxide, so that it is not polluted by air / flue gas. It can also create a slight negative pressure in the carbon dioxide collection section. The suction force of the slight negative pressure can draw the carbon dioxide generated in the calcining tube into the carbon dioxide collection section through the first material seal. Finally, the carbon dioxide is recovered and purified by the carbon dioxide recovery process system, and pure carbon dioxide can be collected continuously and stably. This utility model will not waste limestone raw materials during shutdown and restart, and will not produce unqualified products. Under near constant temperature conditions, the overburning rate of calcium carbonate and calcium oxide products is ≤1%.

[0061] The apparatus for producing carbon dioxide by calcining limestone according to the present invention has been described above by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that various modifications can be made to the apparatus for producing carbon dioxide by calcining limestone according to the present invention without departing from the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the contents of the appended claims.

Claims

1. An apparatus for producing carbon dioxide by calcining limestone, characterized in that, Includes the furnace body and combustion mechanism; among which, The interior of the furnace body is divided into a preheating section, a carbon dioxide collection section, a calcination section, and a cooling section from top to bottom. The calcination section has vertically arranged calcination pipes with outwardly expanding upper ports; the carbon dioxide collection section has vertically arranged first material pipes with upper ports connected to the preheating section; the lower port of the first material pipe is connected to the upper port of the calcination pipe, and a gap is provided between the outer wall of the lower port of the first material pipe and the inner wall of the upper port of the calcination pipe, forming a first material seal within the gap; a carbon dioxide outlet is provided on the furnace side wall of the carbon dioxide collection section; a process fan is connected to the carbon dioxide outlet via a carbon dioxide conveying pipe; a carbon dioxide recovery process system is connected to the outlet of the process fan; a finished product discharge port is provided at the bottom of the cooling section; and a finished product discharge valve is provided at the finished product discharge port. The combustion mechanism includes a combustion chamber surrounding the outer periphery of the outer wall of the furnace body in the calcination section and regenerative burners arranged opposite to each other on the outer wall of the combustion chamber.

2. The apparatus for preparing carbon dioxide by calcining limestone according to claim 1, characterized in that, A second material pipe is vertically arranged between the calcination section and the cooling section, with its upper end connected to the lower end of the calcination pipe; the lower end of the second material pipe is connected to the cooling section; the raw material inside the second material pipe forms a second material seal.

3. The apparatus for preparing carbon dioxide by calcining limestone according to claim 2, characterized in that, The cooling section is equipped with a cooling air inlet and a high-temperature air outlet. A cooling fan is connected to the cooling air inlet; A high-temperature fan is connected to the high-temperature air outlet; the air outlet of the high-temperature fan is connected to the preheating air inlet of the preheating section.

4. The apparatus for preparing carbon dioxide by calcining limestone according to claim 1, characterized in that, The upper end of the first feed tube is shaped like a trumpet.

5. The apparatus for preparing carbon dioxide by calcining limestone according to claim 1, characterized in that, A waste heat recovery device and a dust removal device are sequentially connected between the carbon dioxide outlet and the process fan via the carbon dioxide delivery pipe.

6. The apparatus for preparing carbon dioxide by calcining limestone according to claim 1, characterized in that, At least two sets of regenerative burners are arranged opposite each other on the outer wall of the combustion chamber; Each set of regenerative burners includes a first regenerative burner and a second regenerative burner respectively disposed on two opposite outer walls of the combustion chamber; The combustion air inlets of the first regenerative burner and the second regenerative burner are respectively connected to the main pipe of the combustion air fan through the first combustion air pipe and the second combustion air pipe. The fuel inlets of the first regenerative burner and the second regenerative burner are respectively connected to the main pipe of the fuel pipeline network through the first fuel pipeline and the second fuel pipeline. The flue gas outlets of the first regenerative burner and the second regenerative burner are respectively connected to the first flue gas conveying pipe through the first flue gas pipe and the second flue gas pipe; a first flue gas treatment system is connected to the flue gas conveying end of the first flue gas conveying pipe. A first reversing valve is provided at the connection between the main pipe of the combustion-supporting blower and the first and second combustion-supporting air ducts; A second reversing valve is provided at the connection between the main pipe of the fuel pipeline network and the first fuel pipeline and the second fuel pipeline; A third reversing valve is provided at the connection between the first flue gas conveying pipe and the first flue gas pipeline and the second flue gas pipeline.

7. The apparatus for preparing carbon dioxide by calcining limestone according to claim 6, characterized in that, The first flue gas treatment system includes a first flue gas dust removal device connected to the flue gas conveying end of the first flue gas conveying pipe, a first exhaust gas fan connected to the first flue gas dust removal device, and a first chimney connected to the first exhaust gas fan.

8. The apparatus for preparing carbon dioxide by calcining limestone according to claim 1, characterized in that, A flue gas outlet is provided at the top of the preheating section; A second flue gas treatment system is connected to the flue gas outlet via a second flue gas delivery pipe. The second flue gas treatment system includes a second flue gas dust removal device connected to the second flue gas conveying pipe, a second exhaust gas fan connected to the second flue gas dust removal device, and a second chimney connected to the second exhaust gas fan.

9. The apparatus for preparing carbon dioxide by calcining limestone according to claim 1, characterized in that, A hopper is provided above the top of the preheating section; a discharge port is provided at the bottom of the hopper; and a raw material discharge valve is provided at the discharge port. A feeding cart is provided at the top of the preheating section; the feeding cart is located between the hopper and the feeding port at the top of the preheating section; a cover is provided at the feeding port at the top of the preheating section.

10. The apparatus for preparing carbon dioxide by calcining limestone according to claim 9, characterized in that, An inclined bridge is provided on one side of the furnace body; a material unloading point is provided at the upper end of the inclined bridge, and a material feeding point is provided at the lower end of the inclined bridge; the material unloading point is located above the feeding port of the silo; and a material transport vehicle is provided on the inclined bridge.

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