Method for drying refractory materials in a double-hearth kiln using flue gas

Abstract

The application discloses a method for drying kiln refractory material by using flue gas of double-hearth kiln, which comprises the following steps: using a double-hearth kiln refractory material air supply device to dry the kiln refractory material, wherein the double-hearth kiln refractory material air supply device comprises a double-hearth kiln one and a double-hearth kiln two; a flue gas connecting pipe is extended from a pipeline between a chimney reversing valve of the double-hearth kiln one and a flue gas dust remover; two kiln hearth bottom discharge hoppers of the double-hearth kiln two are connected to the flue gas connecting pipe respectively; and two electric valves are arranged in front of the two discharge hoppers respectively; the drying method comprises the following steps: during production of the double-hearth kiln one, stopping a flue gas dust remover of the double-hearth kiln one, closing an inlet valve of the flue gas dust remover of the double-hearth kiln one, sending flue gas into the double-hearth kiln two, starting a flue gas dust remover of the double-hearth kiln two, and realizing flue gas extraction from the bottom of the double-hearth kiln two to dry the kiln refractory material from bottom to top. The application can solve the problem that there are a large amount of free water and combined water in the kiln refractory material of the double-hearth kiln.

Description

Technical Field

[0001] This invention relates to the field of steel manufacturing and equipment technology, and in particular to a method for drying the refractory materials of a double-chamber kiln. Background Technology

[0002] The double-chamber kiln has a chamber A (8) and a chamber B (10) connected by a central passage (9). Both chambers A and B have spray gun boxes (5) with internal spray guns at their upper parts. Both chambers have discharge hoppers (7) below their lower discharge platforms (11), with discharge gates (12) at the bottom. The air supply system includes a combustion air blower (1) connected to a combustion air release valve (2) via a pipe, which branches off to two combustion air reversing valves (3). These two valves are connected to the tops of chambers A and B respectively. The pipes connecting the two valves merge and connect to a flue gas dust collector (6) via a chimney reversing valve (4). A cooling blower (14) is connected to a cooling air release valve (13) via a pipe, which is then connected to the discharge hoppers (7) at the bottom of chambers A and B respectively. Figure 1 As shown.

[0003] In a double-chamber kiln, one chamber stores heat while the other calcines. The process reverses approximately every 14 minutes. During this reversal, hydraulic valves activate, releasing gas from the kiln chamber and simultaneously changing the position of the discharge gate 12, thus switching between the calcining and heat storage chambers. In the calcining chamber, fuel is pressurized by a compressor and fed into the chamber from a fuel injector, where it mixes with combustion air introduced from the top of the kiln for combustion. The flue gas generated during calcination flows through an annular channel and a central channel 7 to the heat storage chamber. Under the action of upward cooling air, it flows upward, storing heat on the stone material just added to the heat storage chamber. After its temperature decreases, it enters the flue gas dust collector 6. The system feeds the heat storage chamber three times per cycle. Each time the kiln is closed and the top cover is opened, the system increases the speed of the dust removal cooling fan 14 to prevent dust from being emitted. To ensure stable material levels, the finished product from calcination is precisely measured by a level gauge. A hydraulic cylinder then pushes the ash discharge device, causing lime blocks at the top of the device to fall from the edge into a small hopper at the bottom of the kiln. During reversal, the discharge gate 12 opens, allowing the finished product to enter the finished product production line.

[0004] Such an air supply system results in a relatively low flue gas temperature in the double-chamber kiln, around 100°C. The newly constructed refractory material in the double-chamber kiln contains a lot of free water and chemically bound water, which affects the service life of the refractory material. It needs to be dried to remove the free water and some of the chemically bound water from the refractory material. Summary of the Invention

[0005] The problem to be solved by the present invention is to provide a method for drying refractory materials in a double-chamber kiln using flue gas, so as to solve the problem that there is a lot of free water and chemically bound water inside the refractory materials of existing double-chamber kilns, which affects the service life.

[0006] To solve the above problems, the technical solution of the present invention is: the method for drying kiln refractory materials using double-chamber kiln flue gas includes using a double-chamber kiln refractory material air supply device to dry the kiln refractory materials;

[0007] The refractory material air supply device for the double-chamber kiln includes a double-chamber kiln I, which comprises kiln chamber A and kiln chamber B connected by an intermediate channel. Both kiln chamber A and kiln chamber B have spray gun boxes with built-in spray guns at their upper parts. Both kiln chamber A and kiln chamber B have unloading hoppers below their unloading platforms, with unloading gates at the bottom of the hoppers. A combustion air blower is connected to a combustion air release valve via a pipeline, and then branches into two sections connected to two combustion air reversing valves. Each combustion air reversing valve is connected to the top of kiln chamber A and kiln chamber B, respectively. The two combustion air reversing valves are connected... After the connecting pipes are merged, they are connected to the flue gas dust collector through the chimney reversing valve. The cooling fan is connected to the cooling air release valve through the pipe and then connected to the unloading hoppers at the bottom of kiln A and kiln B respectively. It also includes a double-chamber kiln two with the same structure as double-chamber kiln one. A flue gas connecting pipe extends from the pipe between the chimney reversing valve of double-chamber kiln one and the flue gas dust collector. After the flue gas connecting pipe branches, it is connected to the unloading hoppers at the bottom of kiln A and kiln B of double-chamber kiln two respectively. Electric valves are provided in front of the two unloading hoppers of double-chamber kiln two after the branch of the flue gas connecting pipe.

[0008] The drying method includes the following steps:

[0009] The raw materials used are those with a particle size ratio of 40-80mm or higher, accounting for more than 80%; kiln parameters are set to increase the kiln heat input to 840-880 kcal / ton of lime, adjust the combustion air coefficient to 1.15-1.25, and the cooling air coefficient to 0.75-1.0; lower the material level of the A kiln chamber to the spray gun box.

[0010] During the production process of the first double-chamber kiln, the flue gas dust removal fan of the first double-chamber kiln is shut down and its inlet valve is closed, allowing the flue gas to be sent into the second double-chamber kiln. The flue gas dust removal fan of the second double-chamber kiln is then turned on, allowing the flue gas from the first double-chamber kiln to be drawn from the bottom of the second double-chamber kiln upwards to dry the refractory materials inside the kiln. During the reversal period of the first double-chamber kiln, when the pressure inside the kiln is released, the speed of the flue gas dust removal fan of the second double-chamber kiln is reduced to 250 rpm.

[0011] A more specific solution to the above technical solution could be: a thermocouple is connected in series with the combustion air reversing valve at the top of the A and B chambers of the double-chamber kiln.

[0012] Furthermore, the combustion air blower, combustion air release valve, combustion air reversing valve, chimney reversing valve, flue gas dust collector, cooling fan, and cooling air release valve of both the first and second double-chamber kilns are connected to a control unit.

[0013] Furthermore, the electric valve and the thermocouple of the double-chamber kiln are both connected to the control unit.

[0014] Furthermore: the control unit is a PLC.

[0015] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0016] This method of drying refractory materials using flue gas from a double-chamber kiln involves branching a flue gas connection pipe from the dust collector at the inlet of the first double-chamber kiln. This connection pipe is then connected to two unloading hoppers of another double-chamber kiln via electric valves. The flue gas is used to dry the refractory materials, eliminating free and bound water and increasing the temperature of the flue gas, thus improving the overall utilization of flue gas heat energy. A thermocouple is connected in series with the two combustion air reversing valves in the second double-chamber kiln to monitor the gas temperature used for drying the refractory materials, ensuring the temperature remains above 100℃. By adjusting kiln parameters and controlling raw material particle size, the increased flue gas temperature can be further utilized.

[0017] This method utilizes the flue gas from a double-chamber kiln to dry refractory materials, achieving comprehensive utilization of the flue gas and fully leveraging its heat. By optimizing operations and increasing the flue gas temperature in the double-chamber kiln, the refractory materials can be dried, achieving the separation of free water and partially bound water from the refractory materials. By adjusting kiln parameters and controlling raw material particle size, the flue gas temperature can be further increased for utilization. Attached Figure Description

[0018] Figure 1 This is the main view of the existing technology;

[0019] Figure 2 This is a front view of an embodiment of the present invention;

[0020] Figure 3 This is a top view of the second double-chamber kiln according to an embodiment of the present invention;

[0021] The diagram shows the following components: 1. Combustion air fan; 2. Combustion air release valve; 3. Combustion air reversing valve; 4. Chimney reversing valve; 5. Spray gun box; 6. Flue gas dust collector; 7. Unloading hopper; 8. A kiln chamber; 9. Intermediate passage; 10. B kiln chamber; 11. Unloading platform; 12. Unloading gate; 13. Cooling air release valve; 14. Cooling fan; 15. Flue gas connection pipe; 16. Electric valve one; 17. Electric valve two; 18. Thermocouple one; 19. Thermocouple two; 20. Control unit. Detailed Implementation

[0022] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0023] This method for drying kiln refractory materials using flue gas from a double-chamber kiln includes using a double-chamber kiln refractory material air supply device to dry the kiln refractory materials.

[0024] Double-chamber kiln refractory material air supply device, such as Figures 2 to 3 As shown, it includes a double-chamber kiln, with kiln chamber A 8 and kiln chamber B 10 connected by an intermediate channel 9. Both kiln chamber A and kiln chamber B are equipped with spray gun boxes 5 containing spray guns in the upper part. Both kiln chamber A and kiln chamber B are equipped with unloading hoppers 7 under the unloading platform 11 at the bottom. The unloading hoppers have unloading gates 12 at the bottom. The air supply device includes a combustion air blower 1 connected to a combustion air release valve 2 via a pipeline, which then branches into two sections connected to two combustion air reversing valves 3. The two combustion air reversing valves 3 are connected to the top of kiln chamber A and kiln chamber B respectively. The pipelines connected to the two combustion air reversing valves 3 are merged and then connected to a flue gas dust collector 6 via a chimney reversing valve 4. A cooling blower 14 is connected to a cooling air release valve 13 via a pipeline and then connected to the unloading hoppers 7 at the bottom of kiln chamber A and kiln chamber B respectively.

[0025] It also includes a double-chamber kiln, such as a double-chamber kiln I. A flue gas connecting pipe 15 extends from the pipe between the chimney reversing valve 4 and the flue gas dust collector 6 of double-chamber kiln I. After branching, the flue gas connecting pipe 15 connects to the bottom unloading hoppers of kiln A and kiln B of double-chamber kiln II. Electric valves are installed before the two unloading hoppers of double-chamber kiln II after the branch of the flue gas connecting pipe 15. Electric valve 16 connects to the bottom unloading hopper of kiln A of double-chamber kiln II, and electric valve 217 connects to the bottom unloading hopper of kiln B of double-chamber kiln II. By branching off a flue gas connecting pipe 15 from the pipe of double-chamber kiln I to the flue gas dust collector 6, and connecting to the two unloading hoppers of another double-chamber kiln through electric valves, the flue gas is used to dry the refractory material of the kiln, thereby eliminating free water and chemically bound water in the refractory material and increasing the temperature of the flue gas exhaust gas of the double-chamber kiln, thus further improving the comprehensive utilization of flue gas heat energy. A thermocouple, namely thermocouple 18 and thermocouple 29, is connected in series with the combustion air reversing valve at the top of the A and B chambers of the double-chamber kiln. These thermocouples are used to detect the gas temperature of the drying refractory material in the double-chamber kiln and ensure that the temperature is above 100℃.

[0026] Combustion fan 1, combustion air release valve 2, combustion air reversing valve 3, chimney reversing valve 4, flue gas dust collector 6, cooling fan 14, and cooling air release valve 13 of double-chamber kiln one and double-chamber kiln two are all connected to a control unit 20. Electric valves and thermocouples of double-chamber kiln two are also connected to control unit 20. The control unit is a PLC.

[0027] The drying method includes the following steps:

[0028] To increase the exhaust gas temperature of the double-chamber kiln while ensuring product quality, the raw materials used have a particle size ratio of 40-80mm of over 80%, with the aim of increasing the permeability of the raw materials during calcination in the double-chamber kiln.

[0029] Set the kiln parameters to increase the kiln heat input to 840-880 kcal / ton of lime, adjust the combustion air coefficient to 1.15-1.25, and the cooling air coefficient to 0.75-1.0, with the aim of increasing the flue gas thermocouple-18 temperature to above 150℃.

[0030] Lower the material level in kiln chamber A to the top of the spray gun box 5 (the main purpose of the spray gun box is to protect the spray gun and prevent it from being washed by the material) to further increase the flue gas temperature of the double-chamber kiln.

[0031] Check the sealing strips of all valves in the double-chamber kiln to ensure that the valves inside the kiln can be reliably closed and are well sealed.

[0032] During the production process of the first double-chamber kiln, the flue gas dust removal fan 6 of the first double-chamber kiln is shut down, and the inlet valve of the flue gas dust removal fan 6 of the first double-chamber kiln is closed, so that the flue gas is sent into the second double-chamber kiln. The flue gas dust removal fan of the second double-chamber kiln is turned on, so that the flue gas of the first double-chamber kiln is drawn from the bottom of the second double-chamber kiln from bottom to top, so as to dry the refractory materials in the kiln.

[0033] During the reversal period of the first double-chamber kiln, when the pressure inside the kiln is released, the speed of the flue gas dust removal fan in the second double-chamber kiln is reduced to 250 rpm to ensure the stability of the flue gas temperature.

[0034] Electric valve 16 and electric valve 27 are used to regulate the airflow of flue gas hot air into the second chamber of the double-chamber kiln to ensure the drying effect.

[0035] By adjusting the combustion air coefficient and cooling air coefficient of the double-chamber kiln, the flue gas volume and exhaust gas temperature can be effectively controlled; that is, when the exhaust gas temperature is too high, the combustion air coefficient and cooling air coefficient can be reduced.

[0036] This method utilizes the flue gas from a double-chamber kiln to dry refractory materials, achieving comprehensive utilization of the flue gas and fully leveraging its heat. By optimizing operations and increasing the flue gas temperature in the double-chamber kiln, the refractory materials can be dried, achieving the separation of free water and partially bound water from the refractory materials. By adjusting kiln parameters and controlling raw material particle size, the flue gas temperature can be further increased for utilization.

Claims

1. A method for drying refractory materials in a double-chamber kiln using flue gas, characterized in that: This includes using a double-chamber kiln refractory material air supply device to dry the kiln refractory material; The refractory material air supply device for the double-chamber kiln includes a double-chamber kiln I, which comprises kiln chamber A and kiln chamber B connected by an intermediate channel. Both kiln chamber A and kiln chamber B have spray gun boxes with built-in spray guns at their upper parts. Both kiln chamber A and kiln chamber B have unloading hoppers under their lower unloading platforms, with unloading gates at the bottom of the hoppers. A combustion air blower is connected to a combustion air release valve via a pipeline, and then branches into two sections connected to two combustion air reversing valves. Each combustion air reversing valve is connected to the top of kiln chamber A and kiln chamber B, respectively. The two combustion air reversing valves are connected... After the pipelines are merged, they are connected to the flue gas dust collector through the chimney reversing valve. The cooling fan is connected to the cooling air release valve through the pipeline and then connected to the unloading hoppers at the bottom of kiln A and kiln B respectively. It also includes a double-chamber kiln two with the same structure as double-chamber kiln one. A flue gas connecting pipeline extends from the pipeline between the chimney reversing valve of double-chamber kiln one and the flue gas dust collector. After the flue gas connecting pipeline branches, it is connected to the unloading hoppers at the bottom of kiln A and kiln B of double-chamber kiln two respectively. Electric valves are provided in front of the two unloading hoppers of double-chamber kiln two after the flue gas connecting pipeline branches. The drying method includes the following steps: Use raw materials with a particle size ratio of 40-80mm or higher of 80%; set kiln parameters, increase kiln heat input to 840-880 kcal / ton of lime, adjust combustion air coefficient to 1.15-1.25, and cooling air coefficient to 0.75-1.0; lower the material level of kiln chamber A to the spray gun box; During the production process of the first double-chamber kiln, the flue gas dust removal fan of the first double-chamber kiln is shut down and its inlet valve is closed, allowing the flue gas to be sent into the second double-chamber kiln. The flue gas dust removal fan of the second double-chamber kiln is then turned on, allowing the flue gas from the first double-chamber kiln to be drawn from the bottom of the second double-chamber kiln upwards to dry the refractory materials inside the kiln. During the reversal period of the first double-chamber kiln, when the pressure inside the kiln is released, the speed of the flue gas dust removal fan of the second double-chamber kiln is reduced to 250 rpm.

2. The method for drying refractory materials in a double-chamber kiln using flue gas according to claim 1, characterized in that: A thermocouple is connected in series next to the combustion air reversing valve at the top of the A and B chambers of the double-chamber kiln.

3. The method for drying refractory materials in a double-chamber kiln using flue gas according to claim 2, characterized in that: The combustion air blower, combustion air release valve, combustion air reversing valve, chimney reversing valve, flue gas dust collector, cooling fan, and cooling air release valve of both the first and second double-chamber kilns are connected to a control unit.

4. The method for drying refractory materials in a double-chamber kiln using flue gas according to claim 3, characterized in that: The electric valve and the thermocouple of the double-chamber kiln are both connected to the control unit.

5. The method for drying refractory materials in a double-chamber kiln using flue gas according to claim 4, characterized in that: The control unit is a PLC.

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