Combustion-supporting air preheating device for double-hearth kiln

Abstract

The utility model discloses a combustion-supporting air preheating device for a double-chamber kiln, which belongs to the technical field of double-chamber kiln equipment and comprises a kiln chamber A and a kiln chamber B. The kiln chamber A and the kiln chamber B are respectively provided with an annular channel, a plurality of hot air pipeline branch pipes are arranged at the positions of the annular channels, hot air ring pipes are arranged on the hot air pipeline branch pipes, and the hot air ring pipe located on one side of the kiln chamber A is connected with a first hot air pipe. The hot air ring pipe located on one side of the kiln chamber B is connected with a second hot air pipe, a first hot air pipe electric valve is arranged on the first hot air pipe, a second hot air pipe electric valve is arranged on the second hot air pipe, the first hot air pipe and the second hot air pipe are converged to form a hot air pipeline, and a heat exchanger and a cooling air blending valve are sequentially installed on the pipeline. And the heat exchanger is connected with a combustion fan. Smoke heat generated during combustion of the double-chamber kiln is recycled to preheat combustion-supporting air, the problems that in winter, due to the fact that the smoke amount of the double-chamber kiln is reduced, the temperature of waste gas is low, and a cloth bag dews and hardens are solved, meanwhile, efficient utilization of heat is achieved, and energy consumption is reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of double-chamber kiln equipment, and in particular to a combustion air preheating device for a double-chamber kiln. Background Technology

[0002] The Maeltz vertical kiln has two cylinders connected by a connecting channel located between the two chambers. Its greatest advantages during calcination are co-flow and heat storage. "Co-flow" means that during calcination of the combustion cylinder, the gas, combustion air, and limestone flow downwards side-by-side, and the combustion flue gas also flows downwards, which is beneficial for producing high-quality active lime. "Heat storage" refers to the fact that the high-temperature flue gas—the fuel combustion products—enters the heat storage chamber through the connecting channel between the two kiln chambers. In the heat storage chamber, the high-temperature flue gas flows upwards, transferring heat to the limestone raw material in the preheating zone, preheating the stone to a higher temperature. Simultaneously, the high-temperature exhaust gas, after heat exchange, cools down and is discharged into the atmosphere through a flue gas bag filter.

[0003] During combustion operation, the two kiln chambers of the Maeltz kiln switch functions every 12-14 minutes, meaning that while one chamber is in calcination mode, the other is in heat storage mode. Under normal conditions, the system supplies a large amount of coal gas and combustion air to the combustion chamber to ensure normal combustion, while the flue gas dust collector ensures that the top of the heat storage chamber is in a negative pressure environment. Therefore, the pressure in the combustion chamber is always higher than that in the heat storage chamber, allowing the high-temperature flue gas to flow smoothly into the heat storage chamber, thus achieving heat storage.

[0004] After a calcination cycle is completed in the Maeltz kiln, the system enters the reversing period. The entire reversing period takes approximately 45 seconds. During the reversing period, the combustion air release valve and cooling air release valve of the Maeltz kiln open successively, releasing the pressure inside the kiln to zero, realizing the change in the position of the kiln release valve, and starting the next calcination cycle.

[0005] In the combustion chamber, the fuel burns under the influence of the downward-flowing combustion air, generating high-temperature flue gas that passes through the central channel and, together with the upward-flowing cooling air from the two chambers, preheats the aggregate in the heat storage chamber. In winter, the reduced flue gas volume in the double-chamber kiln leads to lower exhaust gas temperatures, causing condensation and caking on the filter bags. To avoid this and to better utilize the heat, it is necessary to design a combustion air preheating device for the double-chamber kiln. Utility Model Content

[0006] The main purpose of this invention is to provide a preheating device for combustion air in a double-chamber kiln. This device preheats the combustion air by recovering the heat from the flue gas generated during combustion in the double-chamber kiln, thus solving the problems of low exhaust gas temperature and condensation on the filter bags caused by the decrease in flue gas volume in winter. At the same time, it achieves efficient utilization of heat and reduces energy consumption.

[0007] To achieve the above objectives, this utility model proposes a combustion air preheating device for a double-chamber kiln. The double-chamber kiln includes a kiln chamber A and a kiln chamber B. Both kiln chamber A and kiln chamber B are provided with annular channels. Several hot air pipe branches are provided in the annular channels. Hot air ring pipes are provided on the hot air pipe branches. The hot air ring pipe located on the side of kiln chamber A is connected to a first hot air pipe, and the hot air ring pipe located on the side of kiln chamber B is connected to a second hot air pipe. A first hot air pipe electric valve is provided on the first hot air pipe, and a second hot air pipe electric valve is provided on the second hot air pipe. The first hot air pipe and the second hot air pipe converge to form a hot air pipe. A heat exchanger and a cooling air mixing valve are installed sequentially on the pipe. The heat exchanger is connected to a combustion air blower.

[0008] When combustion occurs in kiln A, the first hot air duct electric valve opens and the second hot air duct electric valve closes to recover the flue gas generated during combustion in kiln A; when combustion occurs in kiln B, the second hot air duct pneumatic valve opens and the first hot air duct pneumatic valve closes to recover the flue gas generated during combustion in kiln B. During reversal, both the second and first hot air duct electric valves are closed.

[0009] Optionally, the hot air duct branches are evenly distributed above the annular channel to ensure uniform airflow recovery within the kiln.

[0010] Optionally, the combustion fan is connected to a combustion air outlet pipe, which is connected to the B kiln chamber via the heat exchanger to exchange heat with the high-temperature flue gas passing through the hot air pipe.

[0011] Optionally, cooling fans are provided at the bottom of kiln chamber A and kiln chamber B, and the cooling fans output cooling air into kiln chamber A and kiln chamber B.

[0012] Optionally, the double-chamber kiln combustion air preheating device also includes a flue gas dust collector, which is connected to the kiln and the heat exchanger via pipelines.

[0013] Optionally, thermocouples are installed on the pipes connecting to the kiln.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. By setting up annular channels, hot air duct branches, and hot air ring pipes in kiln chambers A and B, the heat generated by the flue gas during combustion in the kiln chamber can be effectively recovered, improving energy utilization efficiency and reducing production energy consumption.

[0016] 2. The recovered flue gas heat is used to preheat the combustion air, which avoids the problem of low exhaust gas temperature and condensation on the filter bags caused by the decrease in flue gas volume in winter, thus ensuring the normal operation and service life of the equipment.

[0017] 3. The hot air duct branches are evenly distributed above the annular channel, which makes the airflow in the kiln recover evenly, improves the heat recovery effect and stability, and helps to improve the calcination quality. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of the double-chamber kiln combustion air preheating device of this utility model;

[0020] Figure 2 This is a diagram showing the layout of the annular hot air loop.

[0021] Figure 3 Detailed diagram of the layout of the annular channel hot air duct.

[0022] Explanation of icon numbers:

[0023]

[0024] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0027] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0028] This utility model proposes a combustion air preheating device for a double-chamber kiln.

[0029] Please see Figures 1-3 In one embodiment of this utility model, the double-chamber kiln combustion air preheating device includes a double-chamber kiln comprising a kiln chamber A 2 and a kiln chamber B 3.

[0030] Both kiln chamber A (2) and kiln chamber B (3) are equipped with annular channels 9, and several hot air duct branches 18 are installed in the annular channels 9. These hot air duct branches 18 are evenly distributed above the annular channels 9, and their function is to ensure that the airflow inside the kiln can be evenly recovered, thus ensuring the uniformity and stability of heat recovery.

[0031] A hot air ring pipe 19 is provided on the branch pipe 18 of the hot air duct. The hot air ring pipe 19 located on the side of kiln chamber A 2 is connected to a first hot air pipe 11, and the hot air ring pipe 19 located on the side of kiln chamber B 3 is connected to a second hot air pipe 12. A first hot air pipe electric valve 13 is provided on the first hot air pipe 11, and a second hot air pipe electric valve 14 is provided on the second hot air pipe 12. The first hot air pipe 11 and the second hot air pipe 12 converge to form a hot air duct. A heat exchanger 15 and a cooling air mixing valve 16 are installed sequentially on this hot air duct. The heat exchanger 15 is connected to a combustion fan 1.

[0032] During combustion in kiln A 2, the first hot air duct electric valve 13 is open and the second hot air duct electric valve 14 is closed, for recovering the flue gas generated during combustion in kiln A 2. During combustion in kiln B 3, the second hot air duct electric valve 14 is open and the first hot air duct electric valve 13 is closed, for recovering the flue gas generated during combustion in kiln B 3. During reversal, both the second hot air duct electric valve 14 and the first hot air duct electric valve 13 are closed to prevent flue gas from becoming disordered during the reversal process, which could affect heat recovery and system operation.

[0033] Furthermore, the combustion air blower 1 is connected to a combustion air outlet pipe 17, which connects to the B kiln chamber 3 via the heat exchanger 15. This allows the combustion air 5 to exchange heat with the high-temperature flue gas passing through the hot air pipe during its delivery to the B kiln chamber 3, thus preheating the combustion air 5. Cooling fans 10 are installed at the bottom of the A kiln chamber 2 and the B kiln chamber 3. These cooling fans 10 output cooling air 4 into the A kiln chamber 2 and the B kiln chamber 3 to cool and protect the kiln chambers, extending their service life.

[0034] The double-chamber kiln combustion air preheating device also includes a flue gas dust collector 8, which is connected to the kiln interior and the heat exchanger 15 via pipes. A thermocouple 7 is installed on the pipes connecting to the kiln interior. The thermocouple 7 is used to monitor the flue gas temperature inside the kiln in real time, providing data support for system control and regulation, and ensuring the safe and stable operation of the device.

[0035] Understandably, during combustion in kiln A 2, the second hot air duct electric valve 14 is open and the first hot air duct electric valve 13 is closed to recover the flue gas generated during combustion in kiln A 2; during combustion in kiln B 3, the first hot air duct electric valve 13 is open and the second hot air duct electric valve 14 is closed to recover the flue gas generated during combustion in kiln B 3; during the reversal period, because the airflow inside the kiln is discharged, both the second hot air duct electric valve 14 and the first hot air duct electric valve 13 are closed, and the system reduces the speed of the flue gas dust removal fan to achieve energy saving.

[0036] The heat exchanger 15 is used to reduce the temperature of the flue gas. Through heat exchange via the heat exchanger medium pipe, excess heat is recovered. The flue gas dust collector mixes the heat-exchanged flue gas with the flue gas entering from the kiln top, thereby increasing the overall temperature of the flue gas entering the dust collector 8. When the thermocouple 7 is too high, feedback is sent to the system, which reduces the opening of the first hot air pipe electric valve 13 or the second hot air pipe electric valve 14 to lower the temperature entering the dust collector 8. The hot air pipes connected to the kiln chamber are internally constructed with refractory materials and externally insulated with thermal insulation materials.

[0037] In practical application: When the double-chamber kiln starts operating, assuming that kiln chamber A 2 is initially in combustion mode, the control system controls the first hot air pipe electric valve 13 to open and the second hot air pipe electric valve 14 to close. The high-temperature flue gas generated by combustion in kiln chamber A 2 enters the hot air ring pipe 19 through the hot air pipe branch pipe 18 at the annular channel 9, and then converges into the hot air pipe through the first hot air pipe 11. The high-temperature flue gas passes sequentially through the heat exchanger 15 and the cooling air mixing valve 16 in the hot air pipe. At the heat exchanger 15, the high-temperature flue gas exchanges heat with the combustion air 5 delivered by the combustion air blower 1. The combustion air 5 is preheated through the heat exchanger 15 via the combustion air outlet pipe 17 and then delivered to kiln chamber B.

[0038] After combustion in kiln chamber A 2 for a period of time, the double-chamber kiln enters the reversal period. At this time, both the first hot air pipe electric valve 13 and the second hot air pipe electric valve 14 are closed for about 45 seconds to complete the reversal operation. After the reversal is completed, kiln chamber B 3 enters the combustion state. The control system controls the second hot air pipe electric valve 14 to open and the first hot air pipe electric valve 13 to close. The high-temperature flue gas generated by combustion in kiln chamber B 3 undergoes heat recovery and combustion air preheating according to the same process as combustion in kiln chamber A 2.

[0039] Throughout operation, the cooling fan 10 continuously outputs cooling air 4 into kiln chamber A 2 and kiln chamber B 3 to cool and protect the kiln chambers. The flue gas dust collector 8 collects the flue gas inside the kiln through pipes connected to the kiln, discharges it after dust removal, and monitors the flue gas temperature in real time via thermocouples 7 connected to the pipes inside the kiln, feeding the data back to the control system. The control system then adjusts parameters such as the flow rate of the cooling air mixing valve 16 according to the temperature to ensure stable operation of the device.

[0040] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A combustion air preheating device for a double hearth kiln comprising an A hearth and a B hearth, characterized in that, Both kiln chamber A and kiln chamber B are provided with annular channels. Several hot air duct branches are provided in the annular channels. Hot air ring pipes are provided on the hot air duct branches. The hot air ring pipe located on one side of kiln chamber A is connected to a first hot air pipe, and the hot air ring pipe located on one side of kiln chamber B is connected to a second hot air pipe. A first hot air pipe electric valve is provided on the first hot air pipe, and a second hot air pipe electric valve is provided on the second hot air pipe. The first hot air pipe and the second hot air pipe converge to form a hot air duct. A heat exchanger and a cooling air mixing valve are installed sequentially on the duct. A combustion fan is connected to the heat exchanger. When combustion occurs in kiln A, the first hot air duct electric valve opens and the second hot air duct electric valve closes to recover the flue gas generated during combustion in kiln A; when combustion occurs in kiln B, the second hot air duct pneumatic valve opens and the first hot air duct pneumatic valve closes to recover the flue gas generated during combustion in kiln B. During reversal, both the second and first hot air duct electric valves are closed.

2. The double-chamber kiln combustion air preheating device as described in claim 1, characterized in that: The hot air duct branches are evenly distributed above the annular channel to ensure uniform airflow recovery within the kiln.

3. The double-chamber kiln combustion air preheating device as described in claim 1, characterized in that: The combustion fan is connected to a combustion air outlet pipe, which is connected to the B kiln chamber via the heat exchanger to exchange heat with the high-temperature flue gas passing through the hot air pipe.

4. The double-chamber kiln combustion air preheating device as described in claim 1, characterized in that: Cooling fans are installed at the bottom of kiln chamber A and kiln chamber B, and the cooling fans output cooling air into kiln chamber A and kiln chamber B.

5. The double-chamber kiln combustion air preheating device as described in claim 1, characterized in that: The double-chamber kiln combustion air preheating device also includes a flue gas dust collector, which is connected to the kiln and the heat exchanger via pipelines.

6. The double-chamber kiln combustion air preheating device as described in claim 5, characterized in that: Thermocouples are installed on the pipes connecting to the kiln.

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