External combustion shaft kiln

Abstract

The invention is suitable for the technical field of industrial kilns, and provides an external combustion shaft kiln which comprises a hot-blast stove and a kiln body, a burner in the kiln body is omitted, a hot air inlet is formed in the burner, high-temperature gas such as high-temperature CO2 produced by the hot-blast stove is introduced into the kiln body through the hot air inlet, and materials in the kiln body are calcined through the high-temperature gas. According to the external combustion shaft kiln and the heating device of the power plant, a combustor of a traditional shaft kiln is omitted, high-temperature CO2 is directly introduced into the shaft kiln, lime is calcined through sensible heat carried by the high-temperature CO2, pure CO2 can be produced as a byproduct, fuel of the shaft kiln is expanded, and energy reduction and efficiency improvement are facilitated.

Description

Technical Field

[0001] The present application belongs to the technical field of industrial kilns and provides a vertical kiln with external combustion. Background Art

[0002] Vertical kilns used for calcining limestone include double-chamber kilns, beam kilns, and sleeve kilns. Traditional vertical kilns ignite the limestone within the kiln chamber, where combustion flue gases mix with the carbon dioxide (CO2) produced by the thermal decomposition of the limestone. This CO2 is difficult to recycle and is released into the air along with the flue gases, hindering energy conservation and emission reduction. Summary of the Invention

[0003] In view of this, an embodiment of the present application provides a vertical kiln with external combustion to solve the technical problem that traditional vertical kilns are difficult to effectively recover and utilize CO2 produced by thermal decomposition of limestone.

[0004] The present invention provides a sleeve kiln with external combustion, comprising a hot blast furnace and a kiln body, wherein the burner in the kiln body is eliminated and a hot blast inlet is provided at the burner. A product cooling bin is provided at the bottom of the kiln body, and the gas between the product cooling bin and the kiln body is not connected.

[0005] Hot blast furnaces are used to produce high-temperature gas. The hot blast inlet is connected to the hot blast furnace's high-temperature gas outlet. The temperature of the high-temperature gas is the same as that of the material being calcined in the shaft kiln.

[0006] Specifically, the high-temperature gas discharged from the hot blast furnace is high-temperature CO2, high-temperature flue gas, high-temperature nitrogen, high-temperature oxygen-containing gas or high-temperature combustible gas.

[0007] Specifically, when the high-temperature gas is a high-temperature oxygen-containing gas, a carbon-containing substance is added to the material entering the shaft kiln. The carbon-containing substance is petroleum coke, coal powder, or coke, or a carbon-containing mixture of any two or more of these substances.

[0008] Specifically, the hot blast furnace includes two combustion chambers: an upper combustion chamber and a lower combustion chamber. Corresponding burners and regenerators are located at each end of the upper and lower combustion chambers. The upper and lower combustion chambers are each provided with a combustion exhaust gas outlet and a high-temperature gas outlet. The combustion exhaust gas outlets of the two combustion chambers are connected to corresponding regenerators.

[0009] Alternatively, the hot blast furnace includes two combustion chambers, namely a left combustion chamber and a right combustion chamber. Corresponding burners are located at each end of the left and right combustion chambers. Each of the left and right combustion chambers includes two cavities. The upper halves of the two cavities are connected, and the cavities farther from the corresponding burners are filled with a regenerator. The left and right combustion chambers are each provided with a combustion exhaust gas outlet and a high-temperature gas outlet. The combustion exhaust gas outlets of the two combustion chambers are each connected to the corresponding regenerator.

[0010] Specifically, the vertical kiln is a double-chamber kiln, and the kiln body includes kiln body A and kiln body B. A connecting passage is provided between kiln body A and kiln body B. Kiln body A and kiln body B are respectively provided with a preheating zone, a calcining zone and a cooling zone from top to bottom. The burners in kiln body A and kiln body B are eliminated, and hot air inlets are provided at the burners. The hot air inlets are connected to the high-temperature gas outlet of the hot blast furnace. Corresponding product cooling bins are provided at the bottom of kiln body A and kiln body B, respectively. The product cooling bin is connected to the corresponding kiln body A or kiln body B through a two-stage valve. Air is used to cool the lime in the product cooling bin, and the air after cooling the lime enters the burner of the hot blast furnace as a combustion-supporting gas.

[0011] Specifically, a small amount of low-temperature CO2 is introduced into the bottom of kiln body A and kiln body B.

[0012] When kiln body A is calcining and kiln body B is storing heat, a small amount of low-temperature CO2 is introduced into the top of kiln body A, and the high-temperature circulating CO2 mixed with a small amount of O2 discharged from the high-temperature gas outlet of the hot blast furnace is introduced into kiln body A through the hot air inlet. After dust removal, part of the CO2 discharged from the top of kiln body B is returned to the hot blast furnace as circulating CO2 for heating, and the other part is stored.

[0013] When kiln body B is calcining and kiln body A is storing heat, a small amount of low-temperature CO2 is introduced into the top of kiln body B, and the high-temperature circulating CO2 mixed with a small amount of O2 discharged from the high-temperature gas outlet of the hot blast furnace is introduced into kiln body B through the hot air inlet. After dust removal, part of the CO2 discharged from the top of kiln body A is returned to the hot blast furnace as circulating CO2 for heating, and the other part is stored.

[0014] Specifically, the vertical kiln is a beam-type kiln, and the kiln body is a beam-type kiln body. The beam-type kiln body is equipped with a preheating zone, a calcining zone, and a cooling zone from top to bottom. The calcining zone of the beam-type kiln body is equipped with an upper combustion beam and a lower combustion beam. An upper air intake beam is provided above the upper and lower combustion beams, and a lower air intake beam is provided below the upper and lower combustion beams. A lower cooler is provided below the lower air intake beam. The burners in the upper and lower combustion beams are eliminated, and hot air inlets are provided on the upper and lower combustion beams. The hot air inlets are connected to the high-temperature gas outlet of the hot blast furnace.

[0015] A product cooling bin is installed at the bottom of the beam kiln body. It is connected to the beam kiln body via a two-stage valve. Air is used to cool the lime in the bin, and the air after cooling the lime is used as combustion-supporting gas to enter the burner of the hot blast furnace.

[0016] Specifically, a small amount of low-temperature CO2 is introduced into the bottom of the beam kiln body through the lower cooler. This part of CO2 is discharged from the beam kiln body by the lower air intake beam and enters the shell side of the heat exchanger under the kiln.

[0017] The high-temperature circulating CO2 mixed with a small amount of O2 discharged from the high-temperature gas outlet of the hot blast furnace is introduced into the beam kiln body through the upper combustion beam and the lower combustion beam. This part of CO2 calcines the limestone material and is discharged from the beam kiln body through the upper suction beam, and then enters the shell side of the air heat exchanger.

[0018] After dust removal, part of the CO2 discharged from the shell-side outlet of the kiln heat exchanger and the air heat exchanger is returned to the hot air furnace as circulating CO2 for heating, and the other part is stored.

[0019] Thermal oil is used to cool the upper and lower combustion beams, as well as the lower air intake beam. The high-temperature thermal oil discharged from these beams is passed through a radiator, where it exchanges heat with air. The low-temperature thermal oil discharged from the radiator is returned to the upper, lower combustion beams, and lower air intake beam via a pump unit. The high-temperature air discharged from the radiator is used as combustion-supporting gas and fed into the burners of the hot air furnace.

[0020] Specifically, the vertical kiln is a sleeve kiln, and the kiln body is a sleeve kiln body. The sleeve kiln body includes an outer sleeve and an inner sleeve, with an annular material space formed between the outer sleeve and the inner sleeve. The inner sleeve is divided into an upper inner sleeve and a lower inner sleeve. The interior of the sleeve kiln body is divided into a preheating zone, a calcining zone, and a cooling zone from top to bottom. It is characterized in that the burners in the upper and lower combustion chambers of the sleeve kiln body are eliminated, and an upper hot air inlet is provided in the upper combustion chamber, and a lower hot air inlet is provided in the lower combustion chamber. The upper hot air inlet and the lower hot air inlet are connected to the high-temperature gas outlet of the hot blast furnace.

[0021] A product cooling bin is located at the bottom of the sleeve kiln. It is connected to the sleeve kiln via a two-stage valve. Air is used to cool the lime in the bin. This air, after cooling the lime, is then used as combustion-supporting gas to enter the burner of the hot blast furnace.

[0022] Air is introduced into the cooling air passages of the upper inner tube and the lower inner tube to cool the upper inner tube and the lower inner tube. The air after cooling the upper inner tube and the lower inner tube is used as combustion-supporting gas to enter the burner of the hot air furnace.

[0023] Specifically, a small amount of low-temperature CO2 cooling gas is introduced into the bottom of the sleeve kiln body.

[0024] High-temperature circulating CO2, mixed with a small amount of O2, exits the hot gas outlet of the hot blast furnace and enters the sleeve kiln body through the upper and lower hot air inlets. The high-temperature circulating CO2 entering from the upper hot air inlet flows upward along the annular material space and calcines the limestone material in the annular material space. After calcination, the limestone is converted into low-temperature CO2 and discharged from the top of the sleeve kiln body. A small portion of this high-temperature circulating CO2 enters the upper inner tube from the bottom, exits the sleeve kiln body from the top of the upper inner tube, and enters the heat exchanger, where it heats the CO2 drive gas. After heat exchange in the heat exchanger, the high-temperature drive gas and low-temperature CO2 are discharged.

[0025] Most of the high-temperature circulating CO2 entering from the lower hot air inlet flows upward along the annular material space and calcines the limestone material in the annular material space. After calcining the limestone material, it turns into low-temperature CO2 and is discharged from the top of the sleeve kiln body. The remaining high-temperature circulating CO2 entering from the lower hot air inlet is driven downward by the high-temperature driving gas and calcines the limestone material in the annular material space. It returns from the bottom of the sleeve kiln body and enters the lower inner tube. After passing through the lower inner tube, it returns to the lower hot air inlet.

[0026] The CO2 discharged from the top of the sleeve kiln is mixed with the low-temperature CO2 discharged from the heat exchanger and is divided into four parts after dust removal. The first part is returned to the hot air furnace as circulating CO2 for heating, the second part is stored, the third part is introduced into the bottom of the sleeve kiln as CO2 cooling gas, and the fourth part is pressurized by the Roots blower and used as driving gas.

[0027] The embodiment of the present application also provides a power plant boiler with external combustion, which eliminates the burner of the power plant boiler and passes the high-temperature circulating gas discharged from the hot blast furnace into the water-cooled wall of the power plant boiler.

[0028] The externally-fired vertical kiln provided in the embodiment of the present application eliminates the burner of the traditional vertical kiln, and directly introduces high-temperature gas, such as high-temperature CO2, into the sleeve kiln. The sensible heat carried by the high-temperature CO2 is used to calcine lime, which can produce pure CO2 as a by-product. In addition, the externally-fired vertical kiln provided in the embodiment of the present application expands the fuel required for calcining materials in the vertical kiln. The hot blast furnace provided outside the vertical kiln can use gas fuel, solid fuel or liquid fuel, or a mixture of any two or three of gas fuel, solid fuel and liquid fuel, which greatly expands the types and range of fuels used for calcining materials in the vertical kiln. The limestone obtained by calcining using the externally-fired sleeve kiln provided in the embodiment of the present application is of good quality, high activity, and low raw and overburned rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 This is a schematic structural diagram of a double-chamber kiln with external combustion provided in Example 1 of the present application; Figure 2 This is a schematic structural diagram of a hot blast furnace in an embodiment of the present application; Figure 3 This is a schematic structural diagram of another hot blast furnace in an embodiment of the present application; Figure 4 This is a schematic structural diagram of an externally fired beam kiln provided in Example 2 of the present application; Figure 5 This is a schematic structural diagram of an externally-fired sleeve kiln provided in Example 3 of the present application; Figure 6 This is a structural diagram of an externally-combustion power plant boiler provided in Example 4 of the present application.

[0031] Among them, 1—Kiln body A, 2—Kiln body B, 3—Connecting channel, 4—Hot air inlet, 5—Product cooling bin, 6—Two-stage valve, 7—Beam kiln body, 8—Upper combustion beam, 9—Lower combustion beam, 10—Upper air suction beam, 11—Lower air suction beam, 12—Lower cooler, 13—Heat exchanger under kiln, 14—Air heat exchanger, 15—Upper combustion chamber, 16—Lower combustion chamber, 15'left combustion chamber, 16'right combustion chamber, 17—Burners, 18—Heat storage body, 19—High temperature gas outlet, 20—Radiator, 21—Pump group, 22—Heat transfer oil tank, 23—Heat transfer oil expansion tank, 24—Outer sleeve, 25—Annular material space, 26—Upper inner sleeve, 27—Lower inner sleeve, 28—Upper hot air inlet, 29—Lower hot air inlet, 30—Heat exchanger, 31—Roots blower, 32—Power plant boiler. DETAILED DESCRIPTION

[0032] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0033] In order to illustrate the technical solution described in this application, specific embodiments are provided below. Example 1

[0034] Example 1 of the present application provides a double-chamber kiln with external combustion, which can be used to calcine limestone with a particle size of 4 cm to 8 cm. Figure 1 The structure of the double-chamber kiln in Example 1 is shown. Figure 1 As shown, the double-chamber kiln includes a hot blast furnace and a kiln body, and the kiln body consists of a kiln body A 1 and a kiln body B 2. A connecting passage 3 is provided between the kiln body A 1 and the kiln body B 2. A preheating zone, a calcining zone and a cooling zone are provided in the kiln body A 1 and the kiln body B 2 from top to bottom respectively. The burners in the kiln body A 1 and the kiln body B 2 are eliminated, and a hot air inlet 4 is provided at the original burner. Product cooling bins 5 are provided at the bottom of the kiln body A 1 and the kiln body B 2 respectively, and the gas between the product cooling bin 5 and the kiln body A 1 and the kiln body B 2 is not connected. Specifically, the product cooling bin 5 is connected to the corresponding kiln body A 1 or kiln body B 2 through a two-stage valve 6. Air is used to cool the lime in the product cooling bin 5, and the air after cooling the lime enters the burner 17 of the hot blast furnace as a combustion-supporting gas.

[0035] The hot blast furnace is used to produce high-temperature gas. The temperature of the high-temperature gas is the same as that of the materials being calcined in the twin-chamber kiln. The high-temperature gas discharged from the hot blast furnace can be high-temperature CO2, high-temperature flue gas, high-temperature nitrogen, high-temperature oxygen-containing gas, or high-temperature combustible gas. In Example 1, the hot blast furnace's high-temperature gas outlet 19 discharges high-temperature recycled CO2 mixed with a small amount of O2. The hot blast inlet 4 of the twin-chamber kiln is connected to the hot blast furnace's high-temperature gas outlet 19.

[0036] like Figure 2 As shown, the hot blast furnace includes two combustion chambers, namely a left combustion chamber 15' and a right combustion chamber 16'. Corresponding burners 17 are respectively provided at both ends of the left combustion chamber 15' and the right combustion chamber 16'. The left combustion chamber 15' and the right combustion chamber 16' each include two cavities. The upper halves of the two cavities are connected, and the cavities away from the corresponding burners 17 are filled with heat storage bodies 18. The left combustion chamber 15' and the right combustion chamber 16' are respectively provided with a combustion exhaust gas outlet and a high-temperature gas outlet 19. The combustion exhaust gas outlets of the two combustion chambers are respectively connected to the corresponding heat storage bodies 18.

[0037] The left combustion chamber 15' and the right combustion chamber 16' perform heat storage and preheating alternately. The working process is as follows: When the left combustion chamber 15' is burning with solid fuel (such as pulverized coal), the right combustion chamber 16' is not burning. The combustion exhaust gas formed by the combustion in the left combustion chamber 15' flows through the corresponding heat storage body 18 and heats the heat storage body before being discharged from the chimney. Although the right combustion chamber 16' is not burning, the heat storage body corresponding to the right combustion chamber 16' has been preheated during the previous combustion of the right combustion chamber 16'. The gas to be heated enters the heat storage body 18 corresponding to the right combustion chamber 16', and is converted into high-temperature gas after being heated by the heat storage body. The high-temperature gas is discharged from the high-temperature gas outlet 19 corresponding to the right combustion chamber 16' and transported to Figure 1 The double-chamber kiln is shown with a hot air inlet 4, thereby calcining the materials in the double-chamber kiln.

[0038] After the reversal, when the right combustion chamber 16' uses solid fuel (such as pulverized coal) to burn, the left combustion chamber 15' does not burn. The combustion exhaust gas generated by the combustion in the right combustion chamber 16' flows through the corresponding heat storage body 18 and heats the heat storage body before being discharged from the chimney. At the same time, the gas to be heated enters the heat storage body 18 corresponding to the left combustion chamber 15', and is converted into high-temperature gas after being heated by the heat storage body. The high-temperature gas is discharged from the high-temperature gas outlet 19 corresponding to the left combustion chamber 15' and is transported to the Figure 1 The double-chamber kiln is shown with a hot air inlet 4, thereby calcining the materials in the double-chamber kiln.

[0039] The hot blast furnace can use gaseous fuel, solid fuel, or liquid fuel, or a mixture of any two or three of these fuels. Regardless of the fuel or fuel mixture used by the hot blast furnace, it will not affect the calcination of the materials in the double-chamber kiln. The hot blast furnace in Example 1 of the present application uses pulverized coal as fuel. Before the hot blast furnace's combustion exhaust enters the chimney and is discharged, a CO2 separation device can be used to separate the CO2 from the exhaust gas and return it to the hot blast furnace as CO2 circulating gas for heating.

[0040] In Example 1, the high-temperature gas introduced into the twin-chamber kiln is high-temperature recycled CO2 mixed with a small amount of O2, a high-temperature oxygen-containing gas. Carbonaceous substances can be added to the calcined material (i.e., limestone) entering the twin-chamber kiln. These carbonaceous substances react with the O2 within the high-temperature kiln, releasing heat and producing CO2. The heat released by the reaction of the carbonaceous substances with O2 further increases the temperature within the kiln, facilitating the calcination of the lime. The carbonaceous substance can be petroleum coke, pulverized coal, or coke, or a carbonaceous mixture of any two or more of these. The amount of oxygen added is matched to the amount of carbonaceous substance added so that all carbon in the carbonaceous substance reacts with the high-temperature oxygen to produce CO2. Oxygen can be replaced with enriched oxygen or air.

[0041] Figure 1 The working process of the double-chamber kiln shown is as follows: While kiln body A 1 is calcining and kiln body B 2 is storing heat, high-temperature circulating CO2, mixed with a small amount of O2, is discharged from the hot gas outlet 19 of the hot blast furnace and introduced into kiln body A 1 through the hot air inlet 4. This high-temperature circulating CO2 flows downward along kiln body A 1, calcining the material in kiln body 1 before entering kiln body B 2 via connecting passage 3. A small amount of low-temperature CO2 is constantly introduced into the bottoms of kiln bodies A 1 and B 2. This low-temperature CO2 protects the steel structures at the bottoms of kiln bodies A 1 and B 2 (such as the ash discharger) from excessive temperatures, causing deformation and other problems. The CO2 introduced from the bottom of kiln body A 1 also enters kiln body B 2 via connecting passage 3. The three streams of CO2 converge in kiln body B 2, then travel upward along kiln body B together, preheating the limestone material within, before being discharged from the top of kiln body B 2. After dust removal, a portion of the CO2 discharged from the top of kiln body B is returned to the hot blast furnace as circulating CO2 for heating, while the remaining portion is stored.

[0042] While kiln body B 2 is calcining and kiln body A 1 is storing heat, high-temperature circulating CO2, mixed with a small amount of O2, is discharged from the hot gas outlet 19 of the hot blast furnace and introduced into kiln body B 2 through the hot air inlet 4. The high-temperature circulating CO2 flows downward along kiln body B 2, calcining the material therein before entering kiln body A 1 through connecting passage 3. A small amount of low-temperature CO2 is constantly introduced into the bottoms of kiln bodies A 1 and B 2. This low-temperature CO2 protects the steel structures at the bottoms of kiln bodies A 1 and B 2 (such as the ash discharger) from excessive temperatures, causing deformation and other problems. CO2 introduced from the bottom of kiln body B 2 also enters kiln body A 1 through connecting passage 3. The three streams of CO2 converge in kiln body A 1, then travel upward along kiln body A together, preheating the limestone material within kiln body A before being discharged from the top of kiln body A 1. After dust removal, a portion of the CO2 discharged from the top of kiln body A is returned to the hot blast furnace as circulating CO2 for heating, while the remaining portion is stored.

[0043] To lower the temperature of the CO2 discharged from the top of the regenerative kiln, a small amount of low-temperature CO2 can be introduced from the top of the kiln in the calcining state, thereby reducing the temperature of the limestone in the preheat zone in the calcining kiln. After the two kiln chambers are switched, the original calcining kiln chamber becomes the regenerative kiln chamber. The CO2 discharged from the top of the regenerative kiln chamber is cooled to 50°C to 100°C when passing through the preheat zone before being discharged. Example 2

[0044] Example 2 of the present application provides an externally fired beam kiln that can be used to calcine limestone with a particle size of 2 cm to 4 cm. Figure 4 The structure of the middle beam kiln in Example 2 is shown. Figure 3As shown, the kiln body of this beam-type kiln is a beam-type kiln body 7, which is equipped with a preheating zone, a calcining zone, and a cooling zone from top to bottom. The calcining zone of the beam-type kiln body 7 is equipped with an upper combustion beam 8 and a lower combustion beam 9. An upper air intake beam 10 is located above the upper and lower combustion beams 8 and 9, and a lower air intake beam 11 is located below the upper and lower combustion beams 8 and 9. A lower cooler 12 is located below the lower air intake beam 11. The burners in the upper and lower combustion beams 8 and 9 are eliminated, and hot air inlets 4 are installed on the upper and lower combustion beams 8 and 9. The hot air inlets 4 are both connected to the hot air furnace's high-temperature gas outlet 19. A product cooling bin 5 is located at the bottom of the beam-type kiln body 7 and is connected to the beam-type kiln body 7 via a two-stage valve 6. Air is used to cool the lime in the product cooling bin 5, and the cooled air is then used as a combustion-supporting gas to enter the hot air furnace's burner 17.

[0045] Figure 3 The structure of the hot blast furnace in Example 2 is shown. Figure 3 As shown, the hot blast furnace includes two combustion chambers: an upper combustion chamber 15 and a lower combustion chamber 16. A corresponding burner 17 and a heat regenerator 18 are located at each end of the upper combustion chamber 15 and the lower combustion chamber 16, respectively. The upper combustion chamber 15 and the lower combustion chamber 16 are each provided with a combustion exhaust gas outlet and a high-temperature gas outlet 19. The combustion exhaust gas outlets of the two combustion chambers are connected to the corresponding heat regenerator 18.

[0046] The upper combustion chamber 15 and the lower combustion chamber 16 perform heat storage and preheating alternately. The working process is as follows: When the upper combustion chamber 15 uses liquid or gas fuel for combustion, the lower combustion chamber 16 does not burn. The combustion exhaust gas formed by the combustion in the upper combustion chamber 15 flows through the corresponding heat storage body 18 and heats the heat storage body before being discharged from the chimney. Although the lower combustion chamber 16 does not burn, the heat storage body corresponding to the lower combustion chamber 16 has been preheated during the previous combustion of the lower combustion chamber 16. The gas to be heated enters the heat storage body 18 corresponding to the lower combustion chamber 16, and is converted into high-temperature gas after being heated by the heat storage body. The high-temperature gas is discharged from the high-temperature gas outlet 19 corresponding to the lower combustion chamber 16 and transported to the Figure 4 The hot air inlet 4 of the beam kiln is shown, so as to calcine the materials in the beam kiln.

[0047] After the reversal, when the lower combustion chamber 16 uses liquid or gas fuel for combustion, the upper combustion chamber 15 does not burn. The combustion exhaust gas formed by the combustion in the lower combustion chamber 16 flows through the corresponding heat storage body 18 and heats the heat storage body before being discharged from the chimney. At the same time, the gas to be heated enters the heat storage body 18 corresponding to the upper combustion chamber 15, and is converted into high-temperature gas after being heated by the heat storage body. The high-temperature gas is discharged from the high-temperature gas outlet 19 corresponding to the upper combustion chamber 15 and transported to Figure 4 The hot air inlet 4 of the beam kiln is shown, so as to calcine the materials in the beam kiln.

[0048] The fuel used in the hot blast furnace in Example 2 of the present application is methane.

[0049] Figure 4 The working process of the beam kiln shown is as follows: High-temperature circulating CO2, mixed with a small amount of O2, is discharged from the hot gas outlet 19 of the hot blast furnace and introduced into the beam kiln body 7 via the upper combustion beam 8 and the lower combustion beam 9. This CO2 calcines the limestone material, then exits the beam kiln body 7 via the upper air intake beam 10 and enters the shell side of the air heat exchanger 14. In the air heat exchanger 14, this CO2 exchanges heat with the air in the tube side, preheating the air before being discharged from the shell side of the air heat exchanger 14. The high-temperature air discharged from the tube side outlet of the air heat exchanger 14 is fed into the burner 17 of the hot blast furnace as supporting combustion gas.

[0050] In order to protect the steel structure devices (such as the ash discharge device) at the bottom of the beam-type kiln body 7 and avoid deformation and other problems caused by excessive temperature, a small amount of low-temperature CO2 can be introduced into the bottom of the beam-type kiln body 7. Specifically, a small amount of low-temperature CO2 can be introduced into the bottom of the beam-type kiln body 7 through the lower cooler 12. This part of CO2 is discharged from the beam-type kiln body 7 by the lower air intake beam 11 and enters the shell side of the kiln heat exchanger 13. In the kiln heat exchanger 13, this part of CO2 exchanges heat with the air in the tube side, and the air is preheated and then discharged from the shell side of the kiln heat exchanger 13. The high-temperature air discharged from the tube side outlet of the kiln heat exchanger 13 is sent to the burner 17 of the hot blast furnace to be used as combustion-supporting gas.

[0051] The CO2 discharged from the shell outlet of the kiln heat exchanger 13 is combined with the CO2 discharged from the shell outlet of the air heat exchanger 14. After dust removal, part of the CO2 is returned to the hot air furnace as circulating CO2 for heating, and the other part is stored.

[0052] Thermal oil is used to cool the upper combustion beam 8, lower combustion beam 9, and lower air intake beam 11. The high-temperature thermal oil discharged from the upper combustion beam 8, lower combustion beam 9, and lower air intake beam 11 is passed into the radiator 20, where it exchanges heat with air. The low-temperature thermal oil discharged from the radiator 20 is returned to the upper combustion beam 8, lower combustion beam 9, and lower air intake beam 11 through the pump unit 21. The high-temperature air discharged from the radiator 20 is fed into the burner 17 of the hot blast furnace as a combustion-supporting gas. Example 3

[0053] Example 3 of the present application provides a sleeve kiln with external combustion, which can be used to calcine limestone with a particle size of 2 cm to 4 cm. Figure 5 The structure of the sleeve kiln in Example 3 is shown. Figure 5As shown, the sleeve kiln body includes an outer sleeve 24 and an inner sleeve, and an annular material space 25 is formed between the outer sleeve 24 and the inner sleeve. The inner sleeve is divided into an upper inner sleeve 26 and a lower inner sleeve 27. The sleeve kiln body is divided into a preheating zone, a calcining zone and a cooling zone from top to bottom. The burners in the upper combustion chamber and the lower combustion chamber in the sleeve kiln body are eliminated, and an upper hot air inlet 28 is provided in the upper combustion chamber, and a lower hot air inlet 29 is provided in the lower combustion chamber. Both the upper hot air inlet 28 and the lower hot air inlet 29 are connected to the high-temperature gas outlet 19 of the hot blast furnace. The hot blast furnace in Example 3 has the same structure and function as the hot blast furnace in Example 1. The fuel used in the hot blast furnace in Example 3 of the present application is pulverized coal.

[0054] A product cooling bin 5 is located at the bottom of the sleeve kiln body. It is connected to the sleeve kiln body via a two-stage valve 6. Air is used to cool the lime in the product cooling bin 5. The air, after cooling the lime, serves as combustion-supporting gas and enters the burner 17 of the hot blast furnace.

[0055] Figure 5 The working process of the sleeve kiln shown is as follows: High-temperature circulating CO₂, mixed with a small amount of O₂, exits the hot gas outlet 19 of the hot blast furnace and enters the sleeve kiln body through the upper and lower hot air inlets 28 and 29. The high-temperature circulating CO₂ entering from the upper hot air inlet 28 flows upward along the annular material space 25, calcining the limestone material therein. After calcining the limestone material, it is converted into low-temperature CO₂ and discharged from the top of the sleeve kiln body. A small portion of this high-temperature circulating CO₂ enters the upper inner tube 26 from the bottom, exits the sleeve kiln body from the top, and enters the heat exchanger 30, where it heats the CO₂ driving gas. After heat exchange in the heat exchanger 30, the high-temperature driving gas and low-temperature CO₂ are discharged.

[0056] The majority of the high-temperature circulating CO2 entering through the lower hot air inlet 29 flows upward along the annular material space 25 and calcines the limestone material in the annular material space 25. After calcining the limestone material, it becomes low-temperature CO2 and is discharged from the top of the sleeve kiln body. The remaining high-temperature circulating CO2 entering through the lower hot air inlet 29 is driven downward by the high-temperature driving gas and calcines the limestone material in the annular material space 25. It then returns from the bottom of the sleeve kiln body to enter the lower inner tube 27, and then returns to the lower hot air inlet 29.

[0057] The CO2 discharged from the top of the sleeve kiln body is mixed with the low-temperature CO2 discharged from the heat exchanger 30 and is divided into four parts after dust removal. The first part is returned to the hot blast furnace as circulating CO2 for heating, the second part is stored, the third part is passed into the bottom of the sleeve kiln body as CO2 cooling gas, and the fourth part is pressurized by the Roots blower 31 and used as driving gas.

[0058] The third part of CO2 mentioned above is a small amount of low-temperature CO2 cooling gas introduced into the bottom of the sleeve kiln body. Its function is to protect the steel structure devices at the bottom of the sleeve kiln body (such as the ash discharge device) to avoid deformation and other problems caused by excessive temperature.

[0059] To protect the inner sleeve and prevent deformation caused by excessive temperature, air can be introduced into the cooling air passages of the upper inner sleeve 26 and the lower inner sleeve 27 to cool the upper inner sleeve 26 and the lower inner sleeve 27. The air after cooling the upper inner sleeve 26 and the lower inner sleeve 27 is used as a combustion-supporting gas to enter the burner 17 of the hot blast furnace.

[0060] Traditional telescopic kilns are based on the use of gaseous or liquid fuels, such as natural gas, coke oven gas, mixed coal gas, or heavy oil. my country has abundant coal resources, but lacks oil and natural gas resources, which limits the use of telescopic kilns. The externally fired telescopic kiln provided in Example 3 can use coal as fuel for the hot blast furnace, expanding the application range of telescopic kilns and reducing the cost of calcined products. Example 4

[0061] Example 4 of the present application provides a power plant boiler with external combustion. Figure 6 As shown, the high-temperature circulating gas discharged from the hot blast furnace is introduced into the heating chamber of the water-cooled wall of the power plant boiler 32. The burners in the power plant boiler 32 are eliminated, and the high-temperature circulating gas is used directly to drive the power plant boiler 32. The high-temperature circulating gas is clean CO2 gas with a temperature of 900°C to 1000°C. Using this high-temperature circulating gas protects the water-cooled wall of the power plant boiler 32 from wear and tear caused by dust-laden flue gas. Figure 6 The hot blast furnace in the invention uses liquid ammonia as fuel. In practical applications, magnesium hydride, ferrosilicon or silicon can also be used as fuel for the hot blast furnace.

[0062] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A vertical kiln with external combustion, comprising a hot blast furnace and a kiln body, characterized in that: The burner in the kiln body is removed, and a hot air inlet (4) is provided at the burner; a product cooling bin (5) is provided at the bottom of the kiln body, and the gas between the product cooling bin (5) and the kiln body is not connected; The hot blast furnace is used to produce high-temperature gas; the hot blast inlet (4) is connected to the high-temperature gas outlet (19) of the hot blast furnace; the temperature of the high-temperature gas is the same as the temperature of the calcined material in the vertical kiln.

2. The externally fired shaft kiln according to claim 1, characterized in that: The high-temperature gas discharged from the hot blast furnace is high-temperature CO2, high-temperature flue gas, high-temperature nitrogen, high-temperature oxygen-containing gas or high-temperature combustible gas.

3. The externally fired shaft kiln according to claim 2, characterized in that: When the high-temperature gas is a high-temperature oxygen-containing gas, a carbon-containing substance is added to the material entering the shaft kiln; the carbon-containing substance is petroleum coke, coal powder or coke, or the carbon-containing substance is a carbon-containing mixture composed of any two or more substances among petroleum coke, coal powder or coke.

4. The externally fired shaft kiln according to claim 3, characterized in that: The hot blast furnace comprises two combustion chambers, namely an upper combustion chamber (15) and a lower combustion chamber (16); corresponding burners (17) and heat storage bodies (18) are respectively provided at both ends of the upper combustion chamber (15) and the lower combustion chamber (16); the upper combustion chamber (15) and the lower combustion chamber (16) are respectively provided with a combustion exhaust gas outlet and a high-temperature gas outlet (19); the combustion exhaust gas outlets of the two combustion chambers are respectively communicated with the corresponding heat storage bodies (18); Alternatively, the hot blast furnace comprises two combustion chambers, namely a left combustion chamber (15') and a right combustion chamber (16'); corresponding burners (17) are respectively provided at both ends of the left combustion chamber (15') and the right combustion chamber (16'); the left combustion chamber (15') and the right combustion chamber (16') respectively comprise two cavities; the upper halves of the two cavities are connected, and the cavities of the two cavities away from the corresponding burners (17) are filled with heat storage bodies (18); the left combustion chamber (15') and the right combustion chamber (16') are respectively provided with a combustion exhaust gas outlet and a high-temperature gas outlet (19); the combustion exhaust gas outlets of the two combustion chambers are respectively connected to the corresponding heat storage bodies (18).

5. The externally fired shaft kiln according to claim 4, characterized in that: The vertical kiln is a double-chamber kiln, and the kiln body includes an A kiln body (1) and a B kiln body (2); a connecting passage (3) is provided between the A kiln body (1) and the B kiln body (2); a preheating zone, a calcining zone and a cooling zone are provided in the A kiln body (1) and the B kiln body (2) from top to bottom respectively; the burners in the A kiln body (1) and the B kiln body (2) are eliminated, and a hot air inlet (4) is provided at the burner; the hot air inlet (4) is connected to the high-temperature gas outlet (19) of the hot blast furnace; corresponding product cooling bins (5) are provided at the bottom of the A kiln body (1) and the B kiln body (2), respectively; the product cooling bins (5) are connected to the corresponding A kiln body (1) or B kiln body (2) through a two-stage valve (6); air is used to cool the lime in the product cooling bin (5), and the air after cooling the lime enters the burner of the hot blast furnace as an auxiliary gas.

6. The externally fired shaft kiln according to claim 5, characterized in that: A small amount of low-temperature CO2 is introduced into the bottom of the kiln body A (1) and the kiln body B (2); When the A kiln body (1) is calcining and the B kiln body (2) is storing heat, a small amount of low-temperature CO2 is introduced into the top of the A kiln body (1), and the high-temperature circulating CO2 mixed with a small amount of O2 discharged from the high-temperature gas outlet (19) of the hot blast furnace is introduced into the A kiln body (1) through the hot air inlet (4). After the CO2 discharged from the top of the B kiln body (2) is dusted, a part of it is returned to the hot blast furnace as circulating CO2 for heating, and the other part is stored; When the B kiln body (2) is calcining and the A kiln body (1) is storing heat, a small amount of low-temperature CO2 is introduced into the top of the B kiln body (2), and the high-temperature circulating CO2 mixed with a small amount of O2 discharged from the high-temperature gas outlet (19) of the hot blast furnace is introduced into the B kiln body (2) through the hot air inlet (4). After the CO2 discharged from the top of the A kiln body (1) is dusted, a part of it is returned to the hot blast furnace as circulating CO2 for heating, and the other part is stored.

7. The externally fired shaft kiln according to claim 4, characterized in that: The vertical kiln is a beam-type kiln, and the kiln body is a beam-type kiln body (7); a preheating zone, a calcining zone, and a cooling zone are respectively provided in the beam-type kiln body (7) from top to bottom; the calcining zone of the beam-type kiln body (7) is provided with an upper combustion beam (8) and a lower combustion beam (9), an upper air intake beam (10) is provided above the upper combustion beam (8) and the lower combustion beam (9), a lower air intake beam (11) is provided below the upper combustion beam (8) and the lower combustion beam (9), and a lower cooler (12) is provided below the lower air intake beam (11); the burners in the upper combustion beam (8) and the lower combustion beam (9) are eliminated, and hot air inlets (4) are provided on the upper combustion beam (8) and the lower combustion beam (9); the hot air inlets (4) are connected to the high-temperature gas outlet (19) of the hot blast furnace; A product cooling bin (5) is provided at the bottom of the beam kiln body (7); the product cooling bin (5) is connected to the beam kiln body (7) via a two-stage valve (6); air is used to cool the lime in the product cooling bin (5), and the air after cooling the lime is used as an auxiliary combustion gas to enter the burner of the hot blast furnace.

8. The externally fired shaft kiln according to claim 7, characterized in that: A small amount of low-temperature CO2 is introduced into the bottom of the beam-type kiln body (7) through the lower cooler (12); this part of CO2 is discharged from the beam-type kiln body (7) by the lower air intake beam (11) and then enters the shell side of the kiln lower heat exchanger (13); The high-temperature circulating CO2 mixed with a small amount of O2 discharged from the high-temperature gas outlet (19) of the hot blast furnace is introduced into the beam-type kiln body (7) through the upper combustion beam (8) and the lower combustion beam (9). This part of CO2 calcines the limestone material and then is discharged from the beam-type kiln body (7) through the upper suction beam (10), and then enters the shell side of the air heat exchanger (14); After dust removal, part of the CO2 discharged from the shell-side outlet of the kiln heat exchanger (13) and the air heat exchanger (14) is returned to the hot air furnace as circulating CO2 for heating, and the other part is stored; The upper combustion beam (8), the lower combustion beam (9) and the lower air intake beam (11) are cooled using heat transfer oil; the high-temperature heat transfer oil discharged from the upper combustion beam (8), the lower combustion beam (9) and the lower air intake beam (11) is passed into a radiator (20) and heat is exchanged with air in the radiator (20); the low-temperature heat transfer oil discharged from the radiator (20) is returned to the upper combustion beam (8), the lower combustion beam (9) and the lower air intake beam (11) after passing through a pump group (21); and the high-temperature air discharged from the radiator (20) is fed into the burner of the hot blast furnace as an auxiliary combustion gas.

9. The externally fired shaft kiln according to claim 4, wherein: The vertical kiln is a sleeve kiln, and the kiln body is a sleeve kiln body; the sleeve kiln body includes an outer sleeve (24) and an inner sleeve, and an annular material space (25) is formed between the outer sleeve (24) and the inner sleeve; the inner sleeve is divided into an upper inner sleeve (26) and a lower inner sleeve (27); the sleeve kiln body is divided into a preheating zone, a calcining zone and a cooling zone from top to bottom; it is characterized in that the burners in the upper combustion chamber and the lower combustion chamber in the sleeve kiln body are eliminated, an upper hot air inlet (28) is provided in the upper combustion chamber, and a lower hot air inlet (29) is provided in the lower combustion chamber; the upper hot air inlet (28) and the lower hot air inlet (29) are connected to the high-temperature gas outlet (19) of the hot blast furnace; A product cooling bin (5) is provided at the bottom of the sleeve kiln body; the product cooling bin (5) is connected to the sleeve kiln body via a two-stage valve (6); air is used to cool the lime in the product cooling bin (5); the air after cooling the lime is used as an auxiliary gas to enter the burner (17) of the hot blast furnace; Air is introduced into the cooling air passages of the upper inner tube (26) and the lower inner tube (27), and the air is used to cool the upper inner tube (26) and the lower inner tube (27); the air after cooling the upper inner tube (26) and the lower inner tube (27) enters the burner (17) of the hot blast furnace as an auxiliary combustion gas.

10. The externally fired shaft kiln according to claim 9, characterized in that A small amount of low-temperature CO2 cooling gas is introduced into the bottom of the sleeve kiln body; The high-temperature circulating CO2 mixed with a small amount of O2 discharged from the high-temperature gas outlet (19) of the hot blast furnace enters the sleeve kiln body through the upper hot blast inlet (28) and the lower hot blast inlet (29); the high-temperature circulating CO2 entering from the upper hot blast inlet (28) all runs upward along the annular material space (25) and calcines the limestone material in the annular material space (25), and after calcining the limestone material, it becomes low-temperature CO2 and is discharged from the top of the sleeve kiln body; a small part of this part of the high-temperature circulating CO2 enters the upper inner tube (26) from the bottom of the upper inner tube (26), and is discharged from the sleeve kiln body from the top of the upper inner tube (26) and enters the heat exchanger (30), and the driving gas composed of CO2 is heated in the heat exchanger (30), and the high-temperature driving gas and low-temperature CO2 are discharged after heat exchange in the heat exchanger (30); Most of the high-temperature circulating CO2 entering from the lower hot air inlet (29) moves upward along the annular material space (25) and calcines the limestone material in the annular material space (25), and after calcining the limestone material, it becomes low-temperature CO2 and is discharged from the top of the sleeve kiln body; the remaining high-temperature circulating CO2 entering from the lower hot air inlet (29) is driven by the high-temperature driving gas to move downward and calcine the limestone material in the annular material space (25), and then returns from the bottom of the sleeve kiln body to the lower inner tube (27), and then returns to the lower hot air inlet (29) after passing through the lower inner tube (27); The CO2 discharged from the top of the sleeve kiln body is mixed with the low-temperature CO2 discharged from the heat exchanger (30), and is divided into four parts after dust removal; the first part is returned to the hot blast furnace as circulating CO2 for heating, the second part is stored, the third part is passed into the bottom of the sleeve kiln body as CO2 cooling gas, and the fourth part is pressurized by the Roots blower (31) and used as driving gas.

11. A power plant boiler with external combustion, characterized in that: The burner of the power plant boiler is removed, and the high-temperature circulating gas discharged from the hot blast furnace is passed into the water-cooled wall of the power plant boiler (32).

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