Rotary kiln tail gas treatment device and detection mechanism

Abstract

The utility model relates to a rotary kiln tail gas treatment device and a detection mechanism, the rotary kiln tail gas treatment device comprises a kiln main body, one end of the kiln main body is provided with a furnace door and a burner, and the other end of the kiln main body is connected with a tail gas treatment device through a flue gas pipeline; the tail gas treatment device comprises a settling chamber, a first flue gas cooler, a second flue gas cooler, a flue gas dust collector and a frequency conversion fan which are sequentially connected through flue gas pipelines, a sixth flue gas pipeline is arranged on the frequency conversion fan, a flue gas adjusting valve is arranged at the front end of the first flue gas pipeline, and a flue gas flow sensor is obliquely installed at the tail end, close to the settling chamber, of the first flue gas pipeline; a negative pressure sensor is vertically inserted into the top of the settling chamber; the flue gas flow sensor comprises a flow sensor and a mounting sleeve, the mounting sleeve comprises an extension pipe, a metal corrugated pipe structure is arranged at the tail of the extension pipe, and the flow sensor is arranged at the tail end of the metal corrugated pipe structure; the negative pressure sensor comprises a pressure sensor and a protective sleeve, and the protective sleeve is sleeved outside the pressure sensor. The smoke flow can be accurately controlled, and the negative pressure can be intelligently controlled.

Description

Technical Field

[0001] This utility model discloses a rotary kiln tail gas treatment device and a detection mechanism, belonging to the field of recycled lead rotary kiln smelting technology. Background Technology

[0002] In the process of smelting recycled lead in a rotary kiln, the furnace generally adopts a semi-open furnace door at one end to facilitate the feeding and opening of the furnace. The combustion of gas and oxygen is introduced through the burner and mixed and burned in the furnace to heat the smelting materials. The flue gas generated in the smelting process is driven by the negative pressure of the induced draft fan and then sent through the flue gas pipeline to the subsequent tail gas cooling, dust removal, desulfurization and denitrification treatment devices.

[0003] Traditional flue gas regulating valves and induced draft fans mostly rely on simple manual mechanical controls, making precise adjustments difficult. Over-adjustment of the regulating valve or induced draft fan results in excessive flue gas emissions, significant heat and energy loss from the furnace, and disruption to the production cycle. Under-adjustment leads to insufficient negative pressure within the furnace, causing flue gas to accumulate and escape from gaps such as the furnace door and feed inlet, creating a harsh working environment. Furthermore, the required gas and oxygen flow rates vary depending on the furnace's operating conditions, necessitating constant adjustments to the regulating valve and induced draft fan, making operation extremely inconvenient. Summary of the Invention

[0004] The purpose of this invention is to provide a rotary kiln exhaust gas treatment device and a detection mechanism to solve the problems of difficult control of flue gas flow and negative pressure in the above-mentioned background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A rotary kiln exhaust gas treatment device includes a kiln body, one end of which is provided with a kiln door and a burner, and the other end of the kiln body is connected to the exhaust gas treatment device via a flue gas duct. The exhaust gas treatment device includes a settling chamber, a flue gas cooler, a flue gas cooler, a flue gas dust collector, and a variable frequency fan connected in sequence via the flue gas duct. The variable frequency fan is provided with a flue gas duct for discharging flue gas. A flue gas regulating valve is provided at the front end of the flue gas duct. A flue gas flow sensor is detachably and inclinedly installed at the end of the flue gas duct near the settling chamber. A negative pressure sensor is vertically inserted into the top of the settling chamber.

[0007] The flue gas flow sensor includes a flow sensor and a mounting sleeve. The mounting sleeve includes an extension tube. The outer wall of the extension tube has a threaded structure that can be detachably connected to a flue gas duct. There is a heat insulation sheet structure inside the extension tube. The tail end of the extension tube has a metal corrugated pipe structure. The flow sensor is installed at the tail end of the metal corrugated pipe structure. The tail end of the flow sensor is connected to a signal line.

[0008] The negative pressure sensor includes a pressure sensor and a protective sleeve. The protective sleeve is fitted over the pressure sensor and includes a double-layer ceramic sleeve structure. The double-layer ceramic sleeve structure has a threaded structure that can be detachably connected to the top of the settling chamber. The lower part of the double-layer ceramic sleeve structure is connected to a bottom protective cone structure. The head end of the pressure sensor is placed inside the bottom protective cone structure, and the tail end of the pressure sensor is placed outside the protective sleeve. The tail end of the pressure sensor is connected to signal line two.

[0009] The insertion depth of the negative pressure sensor is 30-60mm, the bottom protective cone structure is a hollow cylindrical structure, the distance between the head of the pressure sensor and the head of the bottom protective cone structure is 2-3cm, and the angle α between the outer wall of the extension tube and the direction of the hot air blown from the flue gas duct is 30°-60°.

[0010] The flue gas regulating valve can be driven by a pneumatic or electric actuator to precisely control the amount of flue gas discharged from the furnace body through the flue gas duct.

[0011] The negative pressure sensor is a pressure sensor made of high-temperature resistant materials such as tungsten, platinum, and molybdenum, used to monitor the negative pressure of flue gas in the furnace in real time.

[0012] The flue gas flow sensor adopts a pure silicon core fiber optic flow sensor, which can withstand a high temperature of 1000℃, and is used to monitor the flue gas flow of the furnace in real time; the flue gas flow sensor adopts a pure silicon core fiber optic flow sensor, which can withstand a high temperature of 1000℃, and is used to monitor the main gas flow of the furnace in real time.

[0013] It also includes a controller for receiving signal data from negative pressure sensors and flue gas flow sensors, and for controlling the opening of flue gas regulating valves and the speed of variable frequency fans according to a preset algorithm.

[0014] A detection mechanism for a rotary kiln tail gas treatment device includes a flue gas flow sensor for real-time monitoring of the flue gas flow rate of the kiln body and a negative pressure sensor for real-time monitoring of the flue gas negative pressure of the kiln body. The flue gas flow sensor is detachably and inclinedly installed at the end of the flue gas duct near the settling chamber, and the negative pressure sensor is vertically inserted into the top of the settling chamber.

[0015] The flue gas flow sensor includes a flow sensor and a mounting sleeve. The mounting sleeve includes an extension tube. The outer wall of the extension tube has a threaded structure that can be detachably connected to a flue gas duct. There is a heat insulation sheet structure inside the extension tube. The tail end of the extension tube has a metal corrugated pipe structure. The flow sensor is installed at the tail end of the metal corrugated pipe structure. The tail end of the flow sensor is connected to a signal line.

[0016] The negative pressure sensor includes a pressure sensor and a protective sleeve. The protective sleeve is fitted over the pressure sensor and includes a double-layer ceramic sleeve structure. The double-layer ceramic sleeve structure has a threaded structure that can be detachably connected to the top of the settling chamber. The lower part of the double-layer ceramic sleeve structure is connected to a bottom protective cone structure. The head end of the pressure sensor is placed inside the bottom protective cone structure, and the tail end of the pressure sensor is placed outside the protective sleeve. The tail end of the pressure sensor is connected to signal line two.

[0017] The insertion depth of the negative pressure sensor is 30-60mm, the bottom protective cone structure is a hollow cylindrical structure, the distance between the head of the pressure sensor and the head of the bottom protective cone structure is 2-3cm, and the angle α between the outer wall of the extension tube and the direction of the hot air blown from the flue gas duct is 30°-60°.

[0018] The negative pressure sensor is a pressure sensor made of high-temperature resistant materials such as tungsten, platinum, and molybdenum, used to monitor the negative pressure of flue gas in the furnace in real time.

[0019] The flue gas flow sensor adopts a pure silicon core fiber optic flow sensor, which can withstand a high temperature of 1000℃, and is used to monitor the flue gas flow of the furnace in real time; the flue gas flow sensor adopts a pure silicon core fiber optic flow sensor, which can withstand a high temperature of 1000℃, and is used to monitor the main gas flow of the furnace in real time.

[0020] Due to the high temperature, dust, and high-flow-rate gas scouring conditions in the recycled lead rotary kiln smelting process, the control system frequently suffers from problems such as low equipment accuracy, failure, short lifespan, and cumbersome replacement, resulting in unsatisfactory control effects and hindering production control. In this invention, the flue gas flow sensor is installed at the end of the flue gas duct near the settling chamber, inserted using a sleeve-threaded structure and inclinedly connected to the outer wall of the flue gas duct. The angle α between the sensor and the direction of the hot air blowing from inside the flue gas duct is 30°-60° to avoid direct scouring by the high-flow-rate hot air. The flue gas flow sensor consists of an extension tube + alternating heat insulation sheet structure, a metal bellows structure, a flow sensor, and signal lines. The extension tube + alternating heat insulation sheet structure ensures effective physical isolation between the sensor and the high-temperature heat without affecting gas flow monitoring; the metal bellows structure ensures a flexible connection between the sensor and the flue gas duct, preventing mechanical stress from damaging the sensor. The double-layer ceramic sleeve structure outside the negative pressure sensor effectively shields the sensor from the thermal radiation of the hot air.

[0021] This invention provides an energy-saving regulating valve system for rotary kiln flue gas flow and negative pressure based on intelligent control. It solves the problem of difficult control of flue gas flow and negative pressure in the past, effectively ensures the accuracy, continuity and effectiveness of intelligent control, significantly improves combustion efficiency, reduces energy consumption in furnace smelting, and the linkage control between the variable frequency fan and the regulating valve further optimizes the system energy efficiency and reduces operating costs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of this utility model;

[0023] Figure 2 yes Figure 1 One of the magnified views of a section;

[0024] Figure 3 yes Figure 1 The second enlarged view of a part. Detailed Implementation

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

[0026] Please refer to the accompanying drawings in the abstract. The rotary kiln exhaust gas treatment device provided by this utility model includes a kiln body 1, on which a furnace door 2 and a burner 3 are provided. Flue gas ducts connect the kiln body 1 to a settling chamber 5, a flue gas cooler 6-1, a flue gas cooler 6-2, a flue gas dust collector 7, and a variable frequency fan 8. A flue gas regulating valve 9 is provided on the flue gas duct 4-1 to control the size of the exhaust port of the flue gas generated by combustion in the kiln; the flue gas regulating valve 9 can be driven by a pneumatic or electric actuator, and the valve is used to precisely control the amount of flue gas discharged from the kiln 1 passing through the flue gas duct 4-1. A flue gas flow sensor 10 is installed on flue gas duct 1-4-1 to monitor the flow rate of the discharged flue gas; a negative pressure sensor 11 is installed at the top of the settling chamber 5 to monitor the negative pressure of the discharged flue gas; the hot air flue gas in the furnace body 1 passes through flue gas duct 1-4-1, settling chamber 5, flue gas duct 2-4-2, flue gas cooler 1-6-1, flue gas duct 3-4-3, flue gas cooler 2-6-2, flue gas duct 4-4, flue gas dust collector 7, and flue gas duct 5-5 for cooling and dust collection treatment, and is discharged from the system through flue gas duct 6-6 under the gravity of the variable frequency fan 8, and enters the subsequent desulfurization and denitrification system.

[0027] The flue gas flow sensor 10, negative pressure sensor 11, flue gas regulating valve 9, and variable frequency fan 8 signal lines are all connected to the intelligent controller 12. The flue gas flow sensor 10 adopts a pure silicon core fiber optic flow sensor, which can withstand high temperatures of 1000℃ and is used for real-time monitoring of flue gas flow in the furnace. The flue gas flow sensor 10 consists of an extension tube + alternating heat insulation sheet structure 10-1, a metal corrugated pipe structure 10-2, a flow sensor 10-3, and a signal line 10-4. The negative pressure sensor 11 consists of a bottom protective cone structure 11-1, a double-layer ceramic sleeve structure 11-2, a pressure sensor 11-3, and a signal line 11-4.

[0028] The negative pressure sensor 11 is a pressure sensor made of high-temperature resistant materials such as tungsten, platinum, and molybdenum, used for real-time monitoring of the negative pressure of flue gas in the furnace. The negative pressure sensor 11 is inserted vertically from the top of the settling chamber 10, with an insertion depth of 30-60mm. The insertion method is a sleeve thread structure to ensure full contact with hot air. The negative pressure sensor 11 consists of a bottom protective cone structure 11-1, a double-layer ceramic sleeve structure 11-2, a pressure sensor 11-3, and a signal line 11-4. The bottom protective cone structure 11-1 effectively prevents the sensor 11-3 from being eroded by high-temperature hot air dust.

[0029] Working principle: This utility model provides an intelligent control-based energy-saving regulating valve system for rotary kiln flue gas flow and negative pressure. Its working principle is explained below:

[0030] 1. Put the raw materials to be smelted into the furnace 1, close the furnace door 2, and turn on the burner 3 to carry out the smelting operation;

[0031] 2. When smelting flue gas is generated in the furnace, gradually turn on the downstream flue gas cooler 6-1, flue gas cooler 6-2, flue gas dust collector 7, and variable frequency fan 8.

[0032] 3. Adjust the human-machine interface of the intelligent controller 12 to automatic control. During system operation, the intelligent controller 12 adjusts the flue gas regulating valve 9 and the variable frequency fan 8 in real time according to the feedback data of the flue gas flow sensor 10 and the negative pressure sensor 11. This ensures that the flue gas flow matches the combustion conditions in the furnace, while the negative pressure in the furnace remains stable within the set range. This ensures that the furnace is in a slightly negative pressure state, protects the working environment, reduces the extraction of excessive hot flue gas, and lowers production energy consumption.

[0033] 4. The flue gas flow sensor 10 is positioned at a 30-60° acute angle to the direction of incoming airflow on the flue gas duct 4-1, which effectively avoids direct impact and wear from the heat source of the flue gas. During production, the hot air in the flue gas duct 4-1 first passes through the extension pipe + alternating heat insulation sheet structure 10-1 before contacting the sensor 10-3, so as to avoid the high-temperature medium directly contacting the flow sensor 10-3 and affecting the test accuracy. The flue gas flow sensor 10 is equipped with a metal bellows structure 10-2 to avoid mechanical stress causing damage to the sensor 10-3 or affecting the monitoring accuracy.

[0034] 5. The flue gas negative pressure sensor 11 is equipped with a bottom protective cone structure 11-1, which is a hollow cylindrical structure. The distance between the head end of the pressure sensor 11-3 and the head end of the bottom protective cone structure 11-1 is 2-3cm to effectively prevent hot air from directly washing the sensor 11-3 and causing wear. The flue gas negative pressure sensor 11 is equipped with a double-layer ceramic sleeve structure 11-2 to shield the sensor 11-3 from heat radiation interference and improve accuracy.

[0035] 6. The intelligent controller 12 adopts polynomial fitting software compensation technology to establish a temperature-output error mathematical model for the signal received from the flue gas flow sensor 10, so as to further avoid the interference of the high temperature of hot air on the accuracy of flow; for the signal received from the negative pressure sensor 11, RTD linearization processing is adopted to further correct the interference of high temperature on the accuracy of negative pressure; thus improving the accuracy of the system in monitoring flue gas flow and negative pressure.

[0036] 7. Since the flue gas flow sensor 10 and the flue gas negative pressure sensor 11 are installed in the form of a sleeve thread structure, when dust accumulation / fault occurs, they can be directly disassembled and purged with an external compressed air pipeline or replaced with spare parts for real-time maintenance, which greatly improves maintenance efficiency.

[0037] In a preferred embodiment, the flue gas regulating valve 9, flue gas flow sensor 10, negative pressure sensor 11, and variable frequency fan 8 are all controlled by a PID control algorithm and processed at the intelligent controller 12. The function of the intelligent controller 12 is to receive signal data from the negative pressure sensor 11 and the flue gas flow sensor 10, and control the opening degree of the flue gas regulating valve 9 and the speed of the variable frequency fan 8 according to a preset algorithm to meet the expected operating conditions.

[0038] As a preferred embodiment, the intelligent controller 12 employs polynomial fitting software compensation technology to establish a temperature-output error mathematical model for the signal received from the flue gas flow sensor 10, so as to further avoid the interference of the high temperature of hot air on the accuracy of flow; and uses RTD linearization processing for the signal received from the negative pressure sensor 11 to further correct the interference of high temperature on the accuracy of negative pressure.

[0039] In a preferred embodiment, the intelligent controller 12 supports switching between manual and automatic modes, and users can set target parameters through the human-machine interface configured on the intelligent controller 12. The intelligent controller 12 can control the flue gas regulating valve 9 and the variable frequency fan 8 in conjunction, and can achieve coordinated control of flue gas flow and negative pressure in both manual and automatic modes.

[0040] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rotary kiln off-gas treatment apparatus, characterized by: The furnace body (1) is provided with a furnace door (2) and a burner (3) at one end. The other end of the furnace body (1) is connected to a tail gas treatment device via a flue gas duct (4-1). The tail gas treatment device includes a settling chamber (5), a flue gas cooler (6-1), a flue gas cooler (6-2), a flue gas dust collector (7), and a variable frequency fan (8) connected in sequence via a flue gas duct. The variable frequency fan (8) is provided with a flue gas duct (4-6) for discharging flue gas. A flue gas regulating valve (9) is provided at the front end of the flue gas duct (4-1). A flue gas flow sensor (10) is detachably and tiltedly installed at the end of the flue gas duct (4-1) near the settling chamber (5). A negative pressure sensor (11) is vertically inserted into the top of the settling chamber (5). The flue gas flow sensor (10) includes a flow sensor (10-3) and a mounting sleeve. The mounting sleeve includes an extension tube. The outer wall of the extension tube has a threaded structure that can be detachably connected to the flue gas pipe (4-1). There is a heat insulation sheet structure (10-1) inside the extension tube. There is a metal corrugated pipe structure (10-2) at the tail end of the extension tube. The flow sensor (10-3) is installed at the tail end of the metal corrugated pipe structure (10-2). The tail end of the flow sensor (10-3) is connected to a signal line (10-4). The negative pressure sensor (11) includes a pressure sensor (11-3) and a protective sleeve. The protective sleeve is fitted over the pressure sensor (11-3). The protective sleeve includes a double-layer ceramic sleeve structure (11-2). The double-layer ceramic sleeve structure (11-2) has a threaded structure that can be detachably connected to the top of the settling chamber (5). The lower part of the double-layer ceramic sleeve structure (11-2) is connected to the bottom protective cone structure (11-1). The head end of the pressure sensor (11-3) is placed inside the bottom protective cone structure (11-1), and the tail end of the pressure sensor (11-3) is placed outside the protective sleeve. The tail end of the pressure sensor (11-3) is connected to signal line two (11-4).

2. The rotary kiln off-gas treatment apparatus according to claim 1, characterized in that: The insertion depth of the negative pressure sensor (11) is 30-60mm. The bottom protective cone structure (11-1) is a hollow cylindrical structure. The distance between the head end of the pressure sensor (11-3) and the head end of the bottom protective cone structure (11-1) is 2-3cm. The angle α between the outer wall of the extension tube and the direction of the hot air blown into the flue gas pipe is 30°-60°.

3. The rotary kiln off-gas treatment apparatus as claimed in claim 1, characterized in that: The flue gas regulating valve (9) can be driven by a pneumatic or electric actuator to precisely control the amount of flue gas discharged from the furnace body (1) through the flue gas duct (4-1).

4. The rotary kiln off-gas treatment apparatus as claimed in claim 1, characterized in that: The negative pressure sensor (11) is a pressure sensor made of tungsten, platinum and molybdenum high-temperature resistant materials, used to monitor the negative pressure of flue gas in the furnace in real time.

5. The rotary kiln off-gas treatment apparatus as claimed in claim 1, characterized in that: The flue gas flow sensor (10) adopts a pure silicon core fiber optic flow sensor, which can withstand a high temperature of 1000℃ and is used to monitor the flue gas flow of the furnace in real time; the flue gas flow sensor (10) adopts a pure silicon core fiber optic flow sensor, which can withstand a high temperature of 1000℃ and is used to monitor the gas flow of the furnace body (1) in real time.

6. The rotary kiln tail gas treatment device according to claim 1, characterized in that: It also includes a controller (12) for receiving signal data from the negative pressure sensor (11) and the flue gas flow sensor (10) and controlling the opening of the flue gas regulating valve (9) and the speed of the variable frequency fan (8) according to a preset algorithm.

7. A detection mechanism characterized by: A flue gas flow sensor (10) for real-time monitoring of the flue gas flow of the main body of the furnace (1) and a negative pressure sensor (11) for real-time monitoring of the negative pressure of the flue gas in the main body of the furnace (1) are used. The flue gas flow sensor (10) is detachably and tiltedly installed at the end of the flue gas duct (4-1) near the settling chamber (5). The negative pressure sensor (11) is vertically inserted into the top of the settling chamber (5). The flue gas flow sensor (10) includes a flow sensor (10-3) and a mounting sleeve. The mounting sleeve includes an extension tube. The outer wall of the extension tube has a threaded structure that can be detachably connected to the flue gas pipe (4-1). There is a heat insulation sheet structure (10-1) inside the extension tube. There is a metal corrugated pipe structure (10-2) at the tail end of the extension tube. The flow sensor (10-3) is installed at the tail end of the metal corrugated pipe structure (10-2). The tail end of the flow sensor (10-3) is connected to a signal line (10-4). The negative pressure sensor (11) includes a pressure sensor (11-3) and a protective sleeve. The protective sleeve is fitted over the pressure sensor (11-3). The protective sleeve includes a double-layer ceramic sleeve structure (11-2). The double-layer ceramic sleeve structure (11-2) has a threaded structure that can be detachably connected to the top of the settling chamber (5). The lower part of the double-layer ceramic sleeve structure (11-2) is connected to the bottom protective cone structure (11-1). The head end of the pressure sensor (11-3) is placed inside the bottom protective cone structure (11-1), and the tail end of the pressure sensor (11-3) is placed outside the protective sleeve. The tail end of the pressure sensor (11-3) is connected to signal line two (11-4).

8. The detection mechanism of claim 7, wherein: The insertion depth of the negative pressure sensor (11) is 30-60mm. The bottom protective cone structure (11-1) is a hollow cylindrical structure. The distance between the head end of the pressure sensor (11-3) and the head end of the bottom protective cone structure (11-1) is 2-3cm. The angle α between the outer wall of the extension tube and the direction of the hot air blown into the flue gas pipe is 30°-60°.

9. The detection mechanism of claim 7, wherein: The negative pressure sensor (11) is a pressure sensor made of tungsten, platinum and molybdenum high-temperature resistant materials, used to monitor the negative pressure of flue gas in the furnace in real time.

10. The detection mechanism of claim 7, wherein: The flue gas flow sensor (10) adopts a pure silicon core fiber optic flow sensor, which can withstand a high temperature of 1000℃ and is used to monitor the flue gas flow of the furnace in real time; the flue gas flow sensor (10) adopts a pure silicon core fiber optic flow sensor, which can withstand a high temperature of 1000℃ and is used to monitor the gas flow of the furnace body (1) in real time.

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