High-temperature flue gas reverse flowing prevention system based on multi-sensor interlocking control

Abstract

The utility model relates to a high-temperature flue gas anti-backflow system based on multi-sensor interlocking control, which is suitable for the scene of conveying solid materials in high-temperature flue gas in the industries of thermal power, steel, chemical engineering and the like, and comprises an injection pipeline assembly, a flue gas stop valve, a pressure transmitter, a temperature transmitter and a PLC (Programmable Logic Controller) process control system. The injection pipeline assembly comprises a conveying pipeline and a spray gun inserted into high-temperature flue gas, the flue gas stop valve is arranged at the upstream section of the conveying pipeline, the pressure transmitter and the temperature transmitter are arranged on the conveying pipeline at the downstream of the flue gas stop valve, and the PLC process control system performs programming, processes switching quantity and analog quantity and sends out a control signal, so that the system is in a normal working state.

Description

Technical Field

[0001] This utility model belongs to the field of industrial flue gas safety control technology, and particularly relates to the scenario of conveying solid materials into high-temperature flue gas in industries such as thermal power, steel, and chemical industry using pneumatic conveying. Specifically, it relates to a high-temperature flue gas anti-backflow system based on multi-sensor interlocking control. Background Technology

[0002] In the process of conveying solid materials into high-temperature industrial flue gas, the conveying equipment injects the solid materials into the flue gas using positive pressure pneumatic conveying technology. Because the conveying pressure needs to be higher than the pressure inside the flue gas duct (typically ≥0.2MPa), when the conveying equipment stops due to air outages, power outages, or mechanical failures, the pressure inside the conveying pipeline drops sharply. Meanwhile, the flue gas duct contains high-temperature positive pressure (temperatures can reach 400℃-600℃, humidity can reach 10%-20%), acidic gases (such as SO3, HCl), and high concentrations of dust particles (concentration >50mg / m³). 3 Flue gas from the backflow may seep back into the conveying equipment, causing corrosion and blockage. Acidic gases combine with moisture to form corrosive liquids, accelerating the corrosion of metal pipes and valves. Dust particles carried in the backflow gas can deposit at spray guns and valves, leading to blockages and uneven solid material spraying. Moisture in the backflow gas can easily cause solid materials to absorb water and clump together, making material discharge difficult and even causing blockages in the conveying pipeline, requiring frequent shutdowns. The temperature of the backflow gas is typically as high as 400℃-600℃, exceeding the tolerance limits of upstream equipment and control valves. Long-term exposure will damage sealing materials and electrical components. Summary of the Invention

[0003] The purpose of this invention is to propose a high-temperature flue gas anti-backflow system based on multi-sensor interlocking control. Through a dual-parameter collaborative judgment mechanism of pressure and temperature, combined with the coordinated action of rapid shut-off valves and conveying equipment, it achieves accurate risk identification and proactive protection, significantly improving the safety and reliability of conveying solid materials in high-temperature flue gas.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] This utility model discloses a high-temperature flue gas anti-backflow system based on multi-sensor interlocking control, comprising an injection pipe assembly, a flue gas shut-off valve, a pressure transmitter, a temperature transmitter, and a PLC process control system. The injection pipe assembly includes a delivery pipe and a spray gun inserted into the high-temperature flue gas. The flue gas shut-off valve is installed on the upstream section of the delivery pipe. The pressure transmitter is installed on the delivery pipe downstream of the flue gas shut-off valve. The temperature transmitter is installed on the delivery pipe downstream of the pressure transmitter. The PLC process control system is communicatively connected to the flue gas shut-off valve, the pressure transmitter, and the temperature transmitter, and is configured to trigger interlocking control based on pressure or temperature parameters.

[0006] Preferably, the flue gas shut-off valve is a pneumatic quick-closing valve, with a pneumatic single-acting normally closed action and a fully closed action time of ≤2 seconds. In a further optimized design, the cylinder is equipped with a solenoid valve and the valve body sealing surface is made of a sealing material formed by silicon carbide and graphite composite, with a temperature resistance of ≥600℃, meeting the ANSI IV standard, and a leakage rate of <0.01%.

[0007] Preferably, the PLC process control system is programmed according to the process requirements and processes various switching and analog quantities from the system, and issues various switching and analog signals in a timely manner. The processed analog quantities include the switching signals of the flue gas shut-off valve, the pressure signals of the pressure transmitter, and the temperature signals of the temperature transmitter.

[0008] Preferably, the flue gas shut-off valve, pressure transmitter, and temperature transmitter are all communicatively connected to the PLC process control system for real-time data exchange.

[0009] Preferably, the pressure transmitter monitors the pressure parameters in the conveying pipeline in real time and is interlocked with the flue gas shut-off valve. When the pressure in the conveying pipeline exceeds the set threshold, the PLC process control system immediately triggers the flue gas shut-off valve to perform a closing action.

[0010] Preferably, the temperature transmitter monitors the temperature parameters inside the conveying pipeline in real time and is interlocked with the flue gas shut-off valve. When the temperature inside the conveying pipeline exceeds the set threshold, the PLC process control system immediately triggers the flue gas shut-off valve to perform a closing action.

[0011] The beneficial effects of this utility model are as follows:

[0012] 1. This utility model effectively distinguishes between normal operating condition fluctuations and real backlash risks by using a dual-parameter interlocking judgment of pressure transmitter and temperature transmitter, combined with a time delay mechanism, thereby reducing the false trigger rate and significantly reducing the number of unplanned shutdowns.

[0013] 2. This utility model adopts a pneumatic quick-closing flue gas shut-off valve with a full-closing action time of ≤2 seconds (traditional mechanical valve >10 seconds). It opens and closes quickly, improving the backflow flue gas blocking efficiency by more than 90%, minimizing the corrosion of high-temperature flue gas on conveying equipment, inhibiting the contact between water vapor in backflow flue gas and solid materials, preventing solid materials from absorbing water and clumping, and reducing the frequency of shutdown for cleaning.

[0014] 3. This utility model is applicable to high-temperature and highly corrosive flue gas environments in industries such as thermal power, steel, and chemical engineering. It has strong system compatibility and low cost for modification and upgrading. Attached Figure Description

[0015] Figure 1 This utility model relates to a high-temperature flue gas anti-backflow system based on multi-sensor interlocking control;

[0016] In the diagram, 1 is the flue gas shut-off valve; 2 is the pressure transmitter; 3 is the temperature transmitter; 4 is the injection pipe assembly; 41 is the conveying pipe; 42 is the spray gun; 5 is the PLC process control system; 6 is the gas supply system; 7 is the conveying equipment; and 8 is the high-temperature flue or furnace. Detailed Implementation

[0017] The present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Directional terms mentioned in the embodiments, such as up, down, front, and back, are only for reference to the directions in the accompanying drawings and are used for explanation, not for limiting the present invention.

[0018] Referring to the accompanying drawings, this utility model discloses a high-temperature flue gas anti-backflow system based on multi-sensor interlocking control, comprising a flue gas shut-off valve 1; a pressure transmitter 2; a temperature transmitter 3; an injection pipe assembly 4; and a PLC process control system 5. The conveying device 6 is connected to the spray gun 42 via the conveying pipe 41. The flue gas shut-off valve 1 is installed upstream of the conveying pipe 41. The pressure transmitter 2 and temperature transmitter 3 are installed downstream of the flue gas shut-off valve 1 on the conveying pipe 41. The conveying pipe 41 is connected to the spray gun 42. The spray gun 42 is inserted into the flue gas duct or furnace 8 to be denitrified.

[0019] Preferably, the flue gas shut-off valve 1 is a pneumatic quick-closing valve, with a pneumatic single-acting normally closed action, a fully closed action time of ≤2 seconds, a cylinder equipped with a solenoid valve, and the valve body sealing surface is made of a sealing material formed by silicon carbide and graphite composite, with a temperature resistance of ≥600℃, meeting the ANSI IV standard, and a leakage rate of <0.01%.

[0020] Preferably, the PLC process control system 5 is programmed according to the process requirements and processes various switching and analog quantities from the system, and sends out various switching and analog signals in a timely manner. The process is controlled and regulated by the pneumatic control station. The processed analog quantities include the start and stop signals of the conveying equipment 7, the switch signals of the flue gas shut-off valve 1, the pressure signals of the pressure transmitter 2, and the temperature signals of the temperature transmitter 3.

[0021] Preferably, the pressure transmitter 2 is installed 2m downstream of the flue gas shut-off valve 1, with a range of 0-2MPa and an accuracy of ±0.1%.

[0022] Preferably, the temperature transmitter 3 is a type K thermocouple, installed 2m downstream of the pressure transmitter 2, with a range of 0-800℃ and an accuracy of ±1.5℃.

[0023] The working principle of this utility model is as follows:

[0024] Before the conveying equipment 7 is put into operation, the parameters are initialized on the control panel of the PLC process control system 5. The initial values ​​P0 and T0 are set according to the actual flue gas pressure and flue gas temperature. During normal operation, the conveying pressure of the conveying equipment 7 is greater than the flue gas pressure in the high-temperature flue or furnace 8. The flue gas shut-off valve 1 is kept in the normally open state, that is, solid materials are injected into the flue gas through the conveying equipment 7, the conveying pipe 41 and the spray gun 42. If the system stops operating due to a malfunction of the conveying equipment 7, or if the conveying equipment 7 suddenly loses airflow or power, or if there is no compressed air entering the conveying pipeline 41, or if the pressure suddenly rises due to large fluctuations in the operating conditions of the industrial site equipment, causing the conveying pressure to be lower than the flue gas pressure, the high-temperature flue gas will backflow along the conveying pipeline 41. The pressure transmitter 2 and the temperature transmitter 3 transmit real-time pressure (P1) and temperature (T1) data to the PLC process control system 5. If P1≥P0 and T1≥T0 are detected, the flue gas shut-off valve 1 is immediately closed, and the PLC process control system 5 issues an early warning to prevent high-temperature flue gas from entering the conveying equipment 7. The PLC process control system 5 processes various signals sequentially according to the programming and then issues corresponding control signals to realize the above functions of the device. After the fault is cleared or the operating conditions of the industrial site equipment stabilize, the valve is reset on the control panel of the PLC process control system 5.

[0025] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Without departing from the spirit of the present utility model, any improvements and modifications made by those skilled in the art to the technical solutions of the present utility model shall fall within the protection scope defined by the claims of the present utility model.

Claims

1. A high-temperature flue gas anti-backflow system based on multi-sensor interlocking control, characterized in that, The system includes a jetting pipe assembly, a flue gas shut-off valve, a pressure transmitter, a temperature transmitter, and a PLC process control system. The jetting pipe assembly includes a delivery pipe and a spray gun inserted into the high-temperature flue gas. The flue gas shut-off valve is installed upstream of the delivery pipe. The pressure transmitter is installed downstream of the flue gas shut-off valve on the delivery pipe. The temperature transmitter is installed downstream of the pressure transmitter on the delivery pipe. The PLC process control system is communicatively connected to the flue gas shut-off valve, the pressure transmitter, and the temperature transmitter, and is configured to trigger interlock control based on pressure or temperature parameters.

2. The high-temperature flue gas anti-backflow system based on multi-sensor interlocking control according to claim 1, characterized in that, The flue gas shut-off valve is a pneumatic quick-closing valve with a full-closing action time of ≤2 seconds.

3. A high temperature flue gas anti-back-purge system based on multi-sensor interlock control according to claim 1, characterized in that, The pressure transmitter is interlocked with the flue gas shut-off valve. When the pressure in the conveying pipeline exceeds the set threshold, the PLC process control system immediately triggers the flue gas shut-off valve to close.

4. The high-temperature flue gas anti-backflow system based on multi-sensor interlocking control according to claim 1, characterized in that, The temperature transmitter is interlocked with the flue gas shut-off valve. When the temperature in the conveying pipeline exceeds the set threshold, the PLC process control system immediately triggers the flue gas shut-off valve to close.

5. A high temperature flue gas anti-back-pumping system based on multi-sensor interlock control according to claim 1, characterized in that, The PLC process control system is a programmable logic controller module that integrates pressure and temperature interlock control algorithms and interacts with flue gas shut-off valves, pressure transmitters, and temperature transmitters in real time through industrial communication protocols.

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