Overtemperature protection system of high-temperature flue gas washing cooling tower

Abstract

The utility model belongs to the technical field of chemical production, and relates to an overtemperature protection system of a high-temperature flue gas washing cooling tower, which is characterized by comprising a measuring element and an executing element which are connected through a controller, the measuring element comprises a liquid level transmitter which is arranged on the high-level water tank and is used for measuring the liquid level of the high-level water tank, and three temperature measuring elements which are arranged on the flue gas outlet pipeline of the washing cooling tower and are used for measuring the temperature of the flue gas outlet pipeline of the washing cooling tower; and the execution element comprises a switch valve arranged on a pipeline for the process water to enter the high-position water tank and a switch valve arranged on a pipeline for the process water to enter the washing cooling tower of the high-position water tank. According to the overtemperature protection system applied to the high-temperature flue gas washing cooling tower, when the temperature of the flue gas outlet pipeline of the washing cooling tower is high, the switching valve of the pipeline, entering the washing cooling tower, of the high-level water tank is automatically opened, and the washing cooling tower is forcibly cooled through cold-state process water; and when the temperature of the flue gas outlet pipeline of the washing cooling tower is low, the switching valve of the pipeline of the washing cooling tower through which the process water of the high-level water tank enters is automatically closed, so that the overtemperature protection of the washing cooling tower is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical production, and in particular relates to an over-temperature protection system applied to a high-temperature flue gas water washing and cooling tower. Background Art

[0002] In the chemical, steel, power generation and other industries, a large amount of high-temperature flue gas is generated. High-temperature flue gas generally has the characteristics of high temperature, more dust and impurities. If the flue gas needs to be discharged or reused, it needs to be cooled and dusted. The industry generally uses a water washing and cooling tower to wash and cool the high-temperature flue gas. After the high-temperature flue gas passes through the water washing and cooling tower, the temperature will be reduced, and the dust content will also be within the range that meets the production of subsequent processes. The principle of the water washing and cooling tower is that when the high-temperature flue gas flows from the bottom to the top of the water washing and cooling tower, the circulating water washing liquid flows from the top to the bottom of the water washing and cooling tower, and sprays to the high-temperature flue gas from the top to the top. The gas-liquid two-phase medium contacts at high speed and has a large contact area. After sufficient heat exchange, the flue gas temperature is reduced to a suitable range and sent to the subsequent section from the outlet of the water washing and cooling tower. When the flue gas temperature at the outlet of the water washing and cooling tower is too high, it is easy to cause irreversible damage to the equipment in the subsequent section. At present, the over-temperature protection of water washing and cooling towers in the industry is relatively simple. When over-temperature occurs, the process water in the high-level water tank is injected into the water washing and cooling tower. Automatic over-temperature injection of process water is usually not possible, and after the process water in the high-level water tank is used up, the process water cannot be automatically replenished, which has a great impact on production safety and production stability. Summary of the invention

[0003] The purpose of the utility model is to solve the above technical problems and propose an over-temperature protection system for a high-temperature flue gas water washing and cooling tower. By adding corresponding measuring elements, actuators, controllers, etc., the liquid level transmitter on the high-level water tank, the temperature on the flue gas outlet pipeline of the water washing and cooling tower, the switch valve on the pipeline of process water entering the high-level water tank, the switch valve on the pipeline of process water entering the water washing and cooling tower from the high-level water tank, etc. are interlocked and controlled, thereby realizing over-temperature protection of the high-temperature flue gas water washing and cooling tower, ensuring stable production and the safety of subsequent equipment, and ensuring the stability and safety of the production process.

[0004] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: an over-temperature protection system for a high-temperature flue gas water-washing cooling tower, characterized in that: it includes a measuring element and an actuator, and the measuring element and the actuator are connected through a controller;

[0005] The measuring elements include a level transmitter arranged on the high-level water tank for measuring the liquid level of the high-level water tank, and three temperature measuring elements arranged on the flue gas outlet pipeline of the water washing and cooling tower for measuring the temperature of the flue gas outlet pipeline of the water washing and cooling tower;

[0006] The actuator includes a switch valve arranged on the pipeline of process water entering the high-level water tank, and a switch valve on the pipeline of process water entering the high-level water tank washing and cooling tower;

[0007] The controller includes signal processors TY-101, LY-101 and logic controllers I-101, I-102;

[0008] The signal processor TY-101 is a temperature signal three-to-two calculation module, the signal processor LY-101 is a liquid level signal calculation module, and the logic controllers I-101 and I-102 are high and low level logic processing modules;

[0009] The signal processor TY-101 is connected to three temperature measuring elements and the logic controller I-101; the signal processor LY-101 is connected to the liquid level transmitter and the logic controller I-102;

[0010] The logic controller I-101 is connected to the switch valve on the pipeline where the process water from the high-level water tank enters the water washing and cooling tower, and the logic controller I-102 is connected to the switch valve on the pipeline where the process water enters the high-level water tank.

[0011] Furthermore, the liquid level transmitter is a double flange differential pressure liquid level transmitter. Since the medium in the high-level water tank is generally acidic and corrosive, the medium contact material of the transmitter is corrosion-resistant stainless steel lined with PTFE or stainless steel.

[0012] Furthermore, the temperature measuring elements are three temperature measuring elements with completely the same specifications, which are evenly distributed laterally on the flue gas outlet pipeline of the water washing and cooling tower.

[0013] Further preferably, the temperature measuring element is a Pt100 thermal resistor. Since the medium in the flue gas outlet pipeline of the water washing cooling tower is corrosive, the thermal resistor contact medium material is stainless steel lined with PTFE or stainless steel.

[0014] Furthermore, the switch valve adopts a pneumatic switch ball valve. Pneumatic valves act quickly and can quickly realize the opening and closing of the valve, so pneumatic is adopted; compared with other valve types, ball valves have lower leakage, so ball valves are adopted; because the medium in the high-level water tank is corrosive, the switch valve contact medium material adopts carbon steel lined with PTFE or stainless steel.

[0015] Furthermore, the signal processors TY-101, LY-101 and the logic controllers I-101, I-102 are connected to a distributed control system or a safety instrument system. The signal processor and the logic controller can be implemented by software configuration programming in the distributed control system or the safety instrument system.

[0016] In the system of the utility model, the signal processor TY-101 is a temperature signal three-to-two calculation module, the module input is three temperature signals, when two or more temperature signals reach the set value, the output signal is a high level, otherwise the output is a low level.

[0017] In the utility model system, the signal processor LY-101 is a liquid level signal calculation module, the module input is a liquid level signal, when the liquid level signal reaches a set value, the output signal is a high level, otherwise the output is a low level.

[0018] In the system of the present utility model, the logic controllers I-101 and I-102 are high and low level logic processing modules. When the input of the logic controllers I-101 and I-102 is low level, the output is low level; when the input of the logic controllers I-101 and I-102 is high level, the output is high level.

[0019] The utility model is applied to the over-temperature protection system of the high-temperature flue gas water-washing cooling tower. The temperature measuring element is used to measure the temperature of the flue gas outlet pipeline at the top of the water-washing cooling tower. The purpose of setting three temperature measuring elements is that, considering that the medium in the pipeline is corrosive and the working conditions are relatively bad, the temperature measuring element will have a certain probability of damage. If a single temperature measuring element is set, the signal processor TY-101 will have no signal input after damage, which will cause the protection system to fail. The purpose of the signal processor TY-101 using three-out-of-two judgment logic is that by setting three temperature measuring elements, when two or more of the temperature signals reach the set value, the signal processor TY-101 will output a high level. Even if one temperature element is damaged, it will not affect the execution of the signal processor TY-101. The purpose of setting the signal processor TY-101 to output a high level when two temperature signals reach the set value is to avoid the failure to start the signal processor TY-101 due to the different installation positions, resulting in a certain temperature element not reaching the set value.

[0020] The utility model is applied to the over-temperature protection system of the high-temperature flue gas water washing and cooling tower. When the liquid level in the high-level water tank is low, the switch valve on the pipeline of process water entering the high-level water tank is automatically opened to perform water replenishment operation; when the liquid level in the high-level water tank is high, the switch valve on the pipeline of process water entering the high-level water tank is automatically closed; thereby achieving the purpose of automatically controlling the liquid level in the high-level water tank.

[0021] The utility model is applied to the over-temperature protection system of the high-temperature flue gas water-washing and cooling tower. When the temperature of the flue gas outlet pipeline of the water-washing and cooling tower is high, the switch valve of the high-position water tank inlet pipeline of the water-washing and cooling tower is automatically opened, and the water-washing and cooling tower is forced to be cooled by cold process water; when the temperature of the flue gas outlet pipeline of the water-washing and cooling tower is low, the switch valve of the process water of the high-position water tank inlet pipeline of the water-washing and cooling tower is automatically closed, thereby realizing the over-temperature protection of the water-washing and cooling tower.

[0022] The utility model interlocks and controls the liquid level transmitter on the high-level water tank, the temperature on the flue gas outlet pipeline of the water washing and cooling tower, the switch valve on the pipeline of process water entering the high-level water tank, the switch valve on the pipeline of process water entering the water washing and cooling tower from the high-level water tank, etc. by adding corresponding measuring elements, executive elements, controllers, etc., thereby realizing over-temperature protection of the high-temperature flue gas water washing and cooling tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the connection structure of the over-temperature protection system of the high-temperature flue gas water washing and cooling tower according to an embodiment of the utility model.

[0024] In the figure: 1: process water inlet cooling tower pipeline; 2: high-temperature flue gas inlet cooling tower pipeline; 3: high-level water tank process water inlet cooling tower pipeline; 4: treated flue gas outlet cooling tower pipeline. DETAILED DESCRIPTION

[0025] The utility model is further described in detail below with reference to the accompanying drawings and embodiments. Example

[0026] The over-temperature protection system of the embodiment is applied to the high-temperature flue gas water washing cooling tower, refer to the attached Figure 1 The high-temperature flue gas enters from the lower part of the water washing and cooling tower, and the washing liquid enters from the upper part of the water washing and cooling tower. After the washing liquid is fully in contact with the high-temperature flue gas, the washing liquid is sent to the heat exchanger through a circulation pump. After heat exchange, the hot washing liquid circulates into the water washing and cooling tower.

[0027] The over-temperature protection system of the embodiment mainly comprises a measuring element, an actuator and a controller; the measuring element comprises three thermal resistors Pt100 of identical specifications installed on the treated flue gas water washing cooling tower pipeline (4), used to measure the temperature of the treated flue gas water washing cooling tower pipeline (4); three temperature elements (TE-101A / B / C) are located on the treated flue gas water washing cooling tower pipeline (4), and are arranged uniformly in the horizontal direction at a certain interval; a liquid level gauge (LT-101) arranged on the high-level water tank is used to measure the high-level The liquid level of the water tank; the actuator includes a switch valve (XV-102) arranged on the process water inlet water washing and cooling tower pipeline (1) and the process water inlet high-level water tank pipeline, which is used to open and cut off the process water entering the high-level water tank; the switch valve (XV-101) arranged on the process water inlet water washing and cooling tower pipeline (3) of the high-level water tank and the process water inlet water washing and cooling tower pipeline, which is used to open and cut off the process water entering the water washing and cooling tower; the controller includes a signal processor (TY-101, LY-101) and a logic controller (I-101, I-102).

[0028] In this embodiment, the three temperature elements are thermal resistors Pt100; because the medium in the flue gas outlet pipeline of the water washing cooling tower is highly corrosive, the thermal resistor contact medium material is stainless steel lined with PTFE.

[0029] In this embodiment, the three temperature elements are all set with high temperature alarm (80°C), high temperature high interlock (85°C), and low temperature low interlock (60°C).

[0030] In this embodiment, the high-level water tank level transmitter is a double-flange differential pressure level transmitter. Since the medium in the high-level water tank is process water, which is highly corrosive, the medium contact material of the transmitter is corrosion-resistant stainless steel lined with PTFE.

[0031] In this embodiment, the liquid level meter is provided with a liquid level high alarm (85%), a liquid level low alarm (30%), a liquid level high-high interlock (80%), and a liquid level low-low interlock (20%).

[0032] In this embodiment, the switch valve (XV-101, XV-102) adopts a pneumatic switch ball valve. Pneumatic valves act quickly and can quickly realize the opening and closing of the valve, so pneumatic is adopted; compared with other valve types, the ball valve has a lower leakage, so the ball valve is adopted; because the medium in the high-level water tank is corrosive, the switch valve contact medium material adopts carbon steel lined with PTFE or stainless steel.

[0033] In this embodiment, the signal processor TY-101 is a temperature signal three-to-two calculation module. The module input is three temperature signals. When two or more temperature signals reach the set value, the output signal is a high level, otherwise the output is a low level.

[0034] In this embodiment, the signal processor LY-101 is a liquid level signal calculation module. The module input is a liquid level signal. When the liquid level signal reaches a set value, the output signal is a high level, otherwise the output is a low level.

[0035] In this embodiment, the logic controllers I-101 and I-102 are high and low level logic processing modules. When the input of the logic controllers I-101 and I-102 is a low level, the output is a low level; when the input of the logic controllers I-101 and I-102 is a high level, the output is a high level.

[0036] In this embodiment, the signal processor (TY-101, LY-101) and the logic controller (I-101, I-102) are connected to a distributed control system or a safety instrument system.

[0037] The above-mentioned distributed control system or safety instrument system is the most commonly used instrument control system in the production process of chemical, steel and power generation industries. It is composed of hardware and software parts; signal processors and logic controllers are both basic functional modules of distributed control systems or safety instrument systems, which are conventional means in the prior art and can rely on the hardware and software implementation of distributed control systems or safety instrument systems.

[0038] In this embodiment, when two or more of the three temperature elements reach the high-high interlock value (85°C), the signal processor TY-101 determines and processes, and then outputs a high level to the logic controller I-101. When the logic controller I-101 inputs a high level, it immediately outputs a high level. After receiving the high level signal, the process water inlet water washing and cooling tower pipeline switch valve (XV-101) opens the valve, and the cold process water is sent from the high-level water tank to the water washing and cooling tower, thereby reducing the outlet pipeline of the water washing and cooling tower. The purpose of temperature; when two or more of the three temperature elements reach the low temperature interlock value (60℃), after being judged and processed by the signal processor TY-101, a low level is output to the logic controller I-101. When the input of the logic controller I-101 is a low level, a low level is output immediately. After receiving the low level signal, the process water inlet water washing and cooling tower pipeline switch valve (XV-101) closes the valve, and the cold process water stops entering the water washing and cooling tower to prevent the temperature of the water washing and cooling tower from being too low and affecting production.

[0039] In this embodiment, after a large amount of process water from the high-level water tank enters the water washing and cooling tower, the liquid level of the high-level water tank continues to decrease. When the liquid level transmitter reaches the low-low interlock (20%), after judgment and processing by the signal processor LY-101, it outputs a high level to the logic controller I-102. When the input of the logic controller I-102 is a high level, it immediately outputs a high level. After the process water enters the high-level water tank pipeline switch valve (XV-102) receives the high level signal, it opens the valve, and the process water begins to replenish the water level of the high-level water tank; when the liquid level transmitter reaches the high-high interlock (80%), after judgment and processing by the signal processor LY-101, it outputs a low level to the logic controller I-102. When the input of the logic controller I-102 is a low level, it immediately outputs a low level. After the process water enters the high-level water tank pipeline switch valve (XV-102) receives the low level signal, it closes the valve, and the liquid level of the high-level water tank reaches the water level that meets the production.

[0040] Anything not described in this embodiment is well known in the art.

Claims

1. An over-temperature protection system for a high-temperature flue gas water washing and cooling tower, characterized in that: It includes a measuring element and an executing element, and the measuring element and the executing element are connected through a controller; The measuring elements include a level transmitter arranged on the high-level water tank for measuring the liquid level of the high-level water tank, and three temperature measuring elements arranged on the flue gas outlet pipeline of the water washing and cooling tower for measuring the temperature of the flue gas outlet pipeline of the water washing and cooling tower; The actuator includes a switch valve arranged on the pipeline of process water entering the high-level water tank, and a switch valve on the pipeline of process water entering the high-level water tank washing and cooling tower; The controller includes signal processors TY-101, LY-101 and logic controllers I-101, I-102; The signal processor TY-101 is a temperature signal three-to-two calculation module, the signal processor LY-101 is a liquid level signal calculation module, and the logic controllers I-101 and I-102 are high and low level logic processing modules; The signal processor TY-101 is connected to three temperature measuring elements and the logic controller I-101; the signal processor LY-101 is connected to the liquid level transmitter and the logic controller I-102; The logic controller I-101 is connected to the switch valve on the pipeline where the process water from the high-level water tank enters the water washing and cooling tower, and the logic controller I-102 is connected to the switch valve on the pipeline where the process water enters the high-level water tank.

2. The over-temperature protection system of the high-temperature flue gas water washing and cooling tower as claimed in claim 1, characterized in that: The liquid level transmitter is a double flange differential pressure liquid level transmitter.

3. The over-temperature protection system of the high-temperature flue gas water washing and cooling tower as claimed in claim 1 is characterized in that: The temperature measuring elements are three temperature measuring elements with completely the same specifications, which are evenly distributed horizontally on the flue gas outlet pipeline of the water washing and cooling tower.

4. The over-temperature protection system of the high-temperature flue gas water washing and cooling tower as claimed in claim 1 or 3, characterized in that: The temperature measuring element is a Pt100 thermal resistor.

5. The over-temperature protection system of the high-temperature flue gas water washing and cooling tower as claimed in claim 1, characterized in that: The switch valve adopts a pneumatic switch ball valve.

6. The over-temperature protection system of the high-temperature flue gas water washing and cooling tower as claimed in claim 1, characterized in that: The signal processors TY-101, LY-101 and the logic controllers I-101, I-102 are connected to a distributed control system or a safety instrument system.

Images