Coal-fired catalyst solution adding system of circulating fluidized bed boiler
By using a PLC controller and multiple moisture sensors to detect the moisture content of coal in a circulating fluidized bed boiler, combined with a PID control valve and flow meter, precise addition of catalyst solution was achieved, solving the problem of unreasonable proportions in existing technologies, improving combustion efficiency and environmental performance, and reducing operating costs.
Patent Information
- Application Number
- CN202520487202.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2035-03-19
AI Technical Summary
Existing methods of adding catalyst solutions cannot be precisely adjusted according to the actual moisture content of coal, resulting in unreasonable proportions, affecting combustion efficiency and environmental performance, while also increasing operating costs.
The system employs a PLC controller combined with a coal moisture detection module, a belt conveyor, and a mixing and spraying module. It uses microwave and capacitive moisture sensors to detect the moisture content of the coal, and utilizes a PID control valve and flow meter to achieve precise addition of the catalyst solution, ensuring that the effective components of the catalyst can fully exert their function.
It achieves precise formulation of catalyst solution, improves boiler combustion efficiency and environmental performance, reduces equipment procurement and maintenance costs, simplifies operation procedures, and enhances system stability and ease of use.
Smart Images
Figure CN223882321U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of circulating fluidized bed boiler, especially relates to a catalyst solution precision adding system based on yard pre-detection water content. BACKGROUND
[0002] In the operation process of the circulating fluidized bed boiler, in order to improve the combustion efficiency of coal, reduce pollutant emission, usually need to add catalyst solution to coal. Catalyst solution can promote the combustion reaction of coal, improve the combustion efficiency, reduce the product of incomplete combustion, thereby reducing the emission of pollutants. However, the existing catalyst solution adding mode has some problems.
[0003] At present, most of the boilers adopt fixed proportion or experience-based adding mode when adding catalyst solution. This mode does not take into account the actual water content of coal, and the water content of coal will be greatly different due to factors such as place of origin and storage conditions. When the water content of coal is high, if the catalyst solution is still added according to the fixed proportion, it will cause too much water in the catalyst solution, dilute the effective components of the catalyst, and reduce its effect on promoting combustion; when the water content of coal is low, if the amount of catalyst solution added is insufficient, the catalyst cannot fully play its role, affecting the combustion efficiency. In addition, some existing adding systems detect the water content of coal in real time during coal conveying, but this way is easily disturbed by factors such as conveying belt vibration and uneven coal particle size, resulting in low detection accuracy, and further affecting the accuracy of catalyst solution proportioning.
[0004] Therefore, the existing catalyst solution adding mode often cannot accurately adjust according to the actual water content of coal, resulting in unreasonable proportioning of catalyst solution, affecting the combustion efficiency and environmental protection performance of the boiler, and also causing waste of catalyst and increasing the operating cost. UTILITY MODEL CONTENTS
[0005] The utility model aims at providing a circulating fluidized bed boiler coal combustion catalyst solution adding system, which solves the problem that the catalyst solution adding mode in the existing circulating fluidized bed boiler cannot accurately adjust according to the actual water content of coal, resulting in unreasonable proportioning, affecting the combustion efficiency and environmental protection performance, and increasing the operating cost.
[0006] In order to solve the above problems, the technical scheme of the utility model is as follows:
[0007] The application discloses a coal combustion catalyst solution adding system for a circulating fluidized bed boiler, which comprises a PLC controller, a coal moisture detection module, a belt conveyor and a mixing and spraying module.
[0008] Further, the coal moisture detection module is a microwave moisture sensor arranged at the feeding end of the belt conveyor.
[0009] Further, the coal moisture detection module is a plurality of capacitive moisture sensors embedded in the coal in the stockyard, and the plurality of capacitive moisture sensors form a sensor network.
[0010] Further, an ultrasonic liquid level sensor is arranged above the mixing tank, and the ultrasonic liquid level sensor is connected to the input end of the PLC controller.
[0011] Further, the liquid delivery pipeline between the liquid delivery pump and the nozzle is communicated with the mixing tank through a backflow pipe, a second PID regulating valve is arranged on the backflow pipe, and the second PID regulating valve is connected to the output end of the PLC controller.
[0012] Further, the nozzles are arranged on the conveyor in sequence at the same interval, and the spray angle of each nozzle is 60-120 degrees.
[0013] Further, the application further comprises a catalyst storage tank, the catalyst pipe is communicated with the bottom of the catalyst storage tank, a catalyst pump is arranged on the catalyst pipe, the catalyst pipe between the catalyst pump and the mixing tank is communicated with the catalyst storage tank through an overflow pipe, a third PID regulating valve is arranged on the overflow pipe, and the third PID regulating valve is connected to the output end of the PLC controller.
[0014] Further, a flow meter is arranged on each of the water pipe, the catalyst pipe and the liquid delivery pipeline, and the flow meter is connected to the input end of the PLC controller.
[0015] The application has the following beneficial effects:
[0016] 1. Precise proportioning: The utility model discloses a coal moisture detection module is used to detect the water content of coal in the stockyard in advance, and the data is transmitted to the PLC controller. According to the water content of coal and the real-time measurement of coal weight by the belt scale, the PLC controller dynamically calculates the total volume of catalyst solution and the ratio of water to catalyst, and accurately controls the flow of each pipeline through the PID regulating valve, realizing the precise addition of catalyst solution. This precise proportioning method based on pre-detection avoids the errors and disturbances of real-time detection on the belt conveyor, and can flexibly adjust the proportioning of catalyst solution according to the actual water content of coal, ensuring that the effective components of catalyst fully play a role, thereby significantly improving the combustion efficiency and environmental protection performance of the boiler.
[0017] 2. Reduce cost: The traditional catalyst solution adding system usually installs complex moisture detection equipment on the belt conveyor to monitor the water content of coal in real time. The utility model sets up a coal moisture detection module in the stockyard, reduces the moisture detection equipment on the belt conveyor, reduces the equipment procurement and maintenance cost, and also simplifies the structure of the system, improves the reliability of the system.
[0018] 3. Simple operation: The PLC controller of the utility model is connected with the touch screen through a cable, and the operator can conveniently set parameters, view real-time data and input batch information through the HMI man-machine interface. This intuitive operation mode makes the operation of the system more simple and fast, reduces the training cost and operation difficulty of the operator, and improves the usability of the system.
[0019] 4. High system stability: The utility model adopts PID control algorithm to accurately adjust the flow of water and catalyst. The PID controller can quickly and accurately adjust the opening of the regulating valve according to the real-time feedback flow data, ensuring the stability and reliability of catalyst solution addition. Even in the case of fluctuation of coal water content or change of conveying capacity, the system can automatically adjust to maintain the precise addition of catalyst solution, thereby ensuring the stability of boiler combustion.
[0020] 5. Real-time monitoring and adjustment: An ultrasonic liquid level sensor is arranged above the mixing tank, which can monitor the liquid level height of the solution in the mixing tank in real time and feed back the data to the PLC controller. The PLC controller adjusts the flow of water and catalyst in time according to the change of liquid level height, prevents the liquid level of the mixing tank from being too high or too low, and ensures the normal operation of the system. In addition, a flowmeter is installed on the liquid conveying pipeline, which can monitor the total flow of catalyst solution in real time and feed back the data to the PLC controller, forming a closed loop control. When the flow deviates, the PLC controller can adjust the flow setting value in time, further improving the accuracy and stability of the system.
[0021] 6、Equipment protection: the utility model discloses the return flow pipe is arranged on the liquid delivery pipeline between infusion pump and nozzle, and the second PID regulating valve is installed on the return flow pipe.When the infusion pump quantitative output, the belt conveyor coal weight reduces, the catalyst solution spraying quantity also reduces correspondingly, and the first PID regulating valve opening degree on the liquid delivery pipeline reduces, and the water inlet end pressure increases.At this time, the return flow pipe can carry out pressure relief to the water inlet end of the first PID regulating valve, prevents the damage of regulating valve and infusion pump because of the excessively high pressure.Meanwhile, the third PID regulating valve is installed on the catalyst pipe, is used for automatically relieving pressure when catalyst pump outlet pressure is excessively high, protects catalyst pump and valve, prolongs the service life of equipment. BRIEF DESCRIPTION OF DRAWINGS
[0022] The utility model will be further described below in combination with the drawings:
[0023] Figure 1 It is the structural schematic diagram of the utility model,
[0024] Figure 2 It is the connection relation schematic diagram between each electric device of the utility model.
[0025] In the drawing: mixing tank 1, ultrasonic liquid level sensor 2, infusion pump 3, liquid delivery pipeline 4, first PID regulating valve 5, flowmeter 6, stockyard 7, electric capacity moisture sensor 8, microwave moisture sensor 9, nozzle 10, belt scale 11, belt conveyor 12, circulating fluidized bed boiler 13, third PID regulating valve 14, catalyst pump 16, catalyst pipe 18, water pipe 19, agitator 20, second PID regulating valve 21. DETAILED DESCRIPTION
[0026] The technical scheme in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model, and obviously, the described embodiments only are a part of the embodiments of the utility model, not all the embodiments.Based on the embodiments in the utility model, all other embodiments obtained by the ordinary skill in the art without making the creative labor all belong to the range of the utility model protection.
[0027] The application discloses a circulating fluidized bed boiler coal combustion catalyst solution adding system, which comprises a PLC controller, a coal moisture detection module, a belt conveyor 12 and a mixing spraying module; the coal moisture detection module is used for detecting the water content of coal in a stockyard 7, and is connected with an input end of the PLC controller; the coal moisture detection module transmits the detected data to the PLC controller; the belt conveyor 12 is provided with a belt scale 11 and is used for conveying the coal in the stockyard 7 to a boiler 13; the belt scale 11 is used for measuring the weight in real time during the conveying of the coal and is connected with the input end of the PLC controller; the mixing spraying module comprises a water pipe 19, a catalyst pipe 18, a mixing tank 1, a liquid conveying pipeline 4, a liquid conveying pump 3 and a plurality of nozzles 10; the mixing tank 1 is provided with a stirrer 20; the bottom of the mixing tank 1 is connected with the plurality of nozzles 10 arranged above the belt conveyor 12 through the liquid conveying pipeline 4; the liquid conveying pump 3 is arranged on the liquid conveying pipeline 4; the water pipe 19 and the catalyst pipe 18 are communicated with the mixing tank 1; first PID adjusting valves 5 are arranged on the water pipe 19, the catalyst pipe 18 and the liquid conveying pipeline 4; the PLC controller is a “Siemens S7-1200” PLC controller; the PLC controller is provided with a water content-proportion mapping table; the real-time water proportion is calculated by using a linear interpolation method; the flow setting value is dynamically adjusted in combination with the weight data; each first PID adjusting valve 5, a second PID adjusting valve 21 and a third PID adjusting valve 14 are connected with the PLC controller through “Ouluo 818P” PID controllers.
[0028] The working process of the application is as follows:
[0029] S1. Coal moisture content detection:
[0030] Detection stage: when the coal is stored in the stockyard 7 or is conveyed by the belt conveyor 12, the coal moisture detection module starts to work.
[0031] Data transmission: the coal moisture detection module transmits the detected coal moisture content data to the PLC controller through a corresponding communication interface (such as RS-485, Ethernet, etc.) in a communication protocol (such as Modbus protocol). After receiving the data, the PLC controller stores the data in an internal memory for subsequent calculation and use.
[0032] S2. Coal weight measurement:
[0033] The coal is conveyed from the stockyard 7 to the belt conveyor 12, and the belt conveyor 12 starts to convey the coal to the circulating fluidized bed boiler 13. During the conveying process, the belt scale 11 arranged on the belt conveyor 12 starts to work.
[0034] Weight detection and transmission: The belt scale 11 measures the weight of coal in real time, which measures the change of pressure of the belt carrying coal. The measured coal weight information is transmitted to the PLC controller through analog signals (such as 4-20 mA) or digital communication protocols (such as Profibus DP). The PLC controller continuously receives and updates the coal weight data.
[0035] S3. Catalyst solution total volume calculation:
[0036] Parameter setting: In the PLC controller, the amount of catalyst solution required per unit of coal weight K (unit: liter / ton) is pre-set. This parameter is determined through experiments and debugging according to the combustion requirements of the boiler 13, the characteristics of the coal, and other factors.
[0037] Calculation process: The PLC controller calculates the total volume V 总 of the required catalyst solution according to the received real-time coal weight W (unit: ton) according to the formula V 总 = K * W. For example, if K = 0.5 liters / ton and the current coal weight W = 100 tons, then V 总 = 0.5 * 100 = 50 liters.
[0038] S4. Water and catalyst ratio determination:
[0039] Proportion relationship: The PLC controller stores the corresponding relationship between the water content of coal and the ratio of water and catalyst. This relationship is obtained through experimental data fitting and exists in the form of a table or a function.
[0040] For example, when the water content of coal is low, the proportion of water is relatively high; when the water content of coal is high, the proportion of water is relatively low.
[0041] Calculation process: Assuming that the current detected coal water content is ω, the water ratio r(ω) is determined according to the pre-set corresponding relationship. Then, the volume V 水 of the required water is calculated according to the formula V 总 = V 水 *r(ω), and the volume V 催化剂 of the required catalyst is calculated according to the formula V 总 = V 催化剂 × (1 - r(ω)). For example, if V 总 = 50 liters, r(ω) = 0.6, then V 水 = 50 * 0.6 = 30 liters, and V 催化剂 = 50 * (1 - 0.6) = 20 liters.
[0042] S5. Flow rate setting and PID control:
[0043] Flow conversion: the PLC controller converts the calculated volume of water and catalyst V 水 and V 催化剂 into flow set value Q 水_set and Q 催化剂_set . Since the time unit is usually second, Q 水_set = V 水 / 3600 (L / s) and Q 催化剂_set = V 催化剂 / / 3600 (L / s).
[0044] PID control: the PLC controller sends the flow set value to the "Ouluo 818P" PID controller connected to the first PID regulating valve 5 of the water pipe 19 and the catalyst pipe 18 respectively. The PID controller receives the actual flow Q 水_actual and Q 催化剂_actual fed back by the flow sensor installed on the water pipe 19 and the catalyst pipe 18 in real time, and calculates the flow error e 水 (t) = Q 水_setl -Q 水_actual and e 催化剂 (t) = Q 催化剂_set -Q 催化剂_actual . Then, according to the PID control algorithm:
[0045]
[0046] the control signal u is calculated, and the flow of water and catalyst is changed by adjusting the opening of the first PID regulating valve 5, so that the actual flow approaches the set flow.
[0047] S6. Solution mixing and spraying:
[0048] Mixing process: water and catalyst flow into the mixing tank 1 through the water pipe 19 and the catalyst pipe 18 respectively. In the mixing tank 1, the water and catalyst are fully mixed by the stirrer 20 to form a uniform catalyst solution.
[0049] The system receives the moisture content of the coal in the yard (detection accuracy ±0.3%) and real-time weight data through the PLC controller, dynamically calculates the water and catalyst ratio by linear interpolation method, realizes flow closed-loop control through the double PID regulating valve group, and the error is ≤±1%.
[0050] Spraying process: the mixed catalyst solution flows out through the liquid delivery pipeline 4, and the infusion pump 3 on the liquid delivery pipeline 4 provides power for the solution to be delivered to a plurality of nozzles 10 installed above the belt conveyor 12. The nozzles 10 uniformly spray the catalyst solution on the surface of the coal on the belt conveyor 12, and as the coal is conveyed, the catalyst solution comes into contact with the coal to improve the combustion efficiency of the coal in the circulating fluidized bed boiler 13.
[0051] Flow monitoring and adjustment: the flow sensor installed on the liquid delivery pipeline 4 monitors the total flow Q of the catalyst solution in real time 总_actual , and feeds back the data to the PLC controller. If Q 总_actual deviates from the set total flow Q 总 calculated according to V 总_set , the PLC controller will re-adjust the flow set value of water and catalyst, and further adjust the opening of the first PID regulating valve 5 through the PID controller to ensure accurate addition of the catalyst solution.
[0052] Further, the coal moisture detection module is a microwave moisture sensor 9 arranged at the feeding end of the belt conveyor 12. The microwave moisture sensor 9 is non-contact and installed above the feeding end of the belt conveyor, with a detection accuracy of ±0.3%. This structure can detect the moisture content in real time during the coal conveying process, ensuring that the system can obtain the latest data in time and make adjustments. This real-time detection method further optimizes the addition accuracy of the catalyst solution and improves the response speed of the system.
[0053] Further, the coal moisture detection module is a plurality of capacitive moisture sensors 8 buried in the coal in the stockyard 7, and the plurality of capacitive moisture sensors 8 form a sensor network. By burying a plurality of capacitive moisture sensors in the coal in the stockyard, a sensor network is formed, which can comprehensively monitor the moisture content distribution of the coal in the stockyard. This multi-point monitoring method can provide more accurate average moisture content data and avoid misjudgment caused by local moisture content differences. On the other hand, even if individual sensors fail or data are abnormal, the system can still be corrected through the data of other sensors to ensure the accuracy of the overall detection result.
[0054] Further, an ultrasonic liquid level sensor 2 is provided above the mixing tank 1, and the ultrasonic liquid level sensor 2 is connected to the input end of the PLC controller. The ultrasonic liquid level sensor 2 monitors the liquid level of the solution in the mixing tank 1 in real time. The ultrasonic liquid level sensor 2 can monitor the liquid level of the catalyst solution in the mixing tank 1 in real time and feed back the data to the PLC controller. The PLC controller adjusts the flow of water and catalyst according to the liquid level to prevent the liquid level of the mixing tank from being too high or too low, and ensures that the solution in the mixing tank always remains within the appropriate liquid level range. On the other hand, through liquid level monitoring, the system can timely discover abnormal situations (such as overflow caused by too high liquid level or pump idling caused by too low liquid level) and take corresponding measures, further improving the stability and reliability of the system.
[0055] Further, the liquid delivery pipeline 4 between the infusion pump 3 and the nozzle 10 is communicated with the mixing tank 1 through a backflow pipe, and a second PID regulating valve 21 is installed on the backflow pipe, and the second PID regulating valve 21 is connected to the output end of the PLC controller. When the infusion pump 3 outputs quantitatively and the belt conveyor 12 reduces the weight of coal, the amount of catalyst solution sprayed is also reduced accordingly, and the opening of the first PID regulating valve 5 on the liquid delivery pipeline 4 is reduced, so that the pressure at the water inlet end of the first PID regulating valve 5 is increased. This increased pressure will damage the first PID regulating valve 5 and the infusion pump 3, so the backflow pipe is added to relieve the pressure at the water inlet end of the first PID regulating valve 5. In implementation, the backflow pipe is linked with the first PID regulating valve 5 on the liquid delivery pipeline, that is, when the opening of the first PID regulating valve 5 is increased, the opening of the second PID regulating valve 21 is reduced, and when the opening of the first PID regulating valve 5 is reduced, the opening of the second PID regulating valve 21 is increased to relieve the pressure. When the discharge pressure is too high, the pressure is automatically relieved to protect the infusion pump and the valve.
[0056] Further, the nozzles 10 are arranged in sequence at the same interval above the conveyor, and the spray angle of each nozzle 10 is 60°-120°. This can ensure that the catalyst solution is uniformly sprayed on the surface of the coal on the belt conveyor. This optimized nozzle arrangement improves the uniformity of the distribution of the catalyst solution and further improves the combustion efficiency of the coal.
[0057] Further, a catalyst storage tank is further included, a catalyst pipe 18 is communicated with the bottom of the catalyst storage tank, a catalyst pump 16 is installed on the catalyst pipe 18, and the catalyst pipe 18 between the catalyst pump 16 and the mixing tank 1 is communicated with the catalyst storage tank through an overflow pipe 14, a third PID regulating valve 14 is installed on the overflow pipe 14, and the third PID regulating valve 14 is connected to the output end of the PLC controller. The third PID regulating valve 14 has the same effect as the second PID regulating valve, that is, when the outlet pressure of the catalyst pump is too high, the pressure is automatically relieved to protect the catalyst pump 16 and the valve.
[0058] Further, flow meters 6 are installed on the water pipe 19, the catalyst pipe 18 and the liquid delivery pipeline 4, and the flow meters 6 are connected to the input end of the PLC controller. The installation of the flow meters on the water pipe 19, the catalyst pipe 18 and the liquid delivery pipeline 4 can monitor the flow of each pipeline in real time and feed the data to the PLC controller. The PLC controller dynamically adjusts according to the flow data to form a closed-loop control, further improving the precision of the catalyst solution addition. On the other hand, the real-time monitoring data of the flow meters 6 can be displayed through the touch screen, and the operator can intuitively understand the running state of the system, so as to timely find out the abnormality and make adjustment, and optimize the running effect of the system.
[0059] Further, the PLC controller is connected with the touch screen through RS485 / Modbus. The operator can conveniently set parameters, view real-time data and input batch information through the HMI human-machine interface. This intuitive operation mode reduces the operation difficulty, improves the usability and operation efficiency of the system, and the visual function of the touch screen enables the operator to monitor the running state of the system in real time, timely find out and handle problems, and enhances the manageability of the system.
[0060] The content described in the embodiments of the present specification is only a list of implementation forms of the utility model concept, and the protection scope of the utility model should not be regarded as limited to the specific forms stated in the embodiments, and the protection scope of the utility model also extends to the equivalent technical means that can be thought of by those skilled in the art according to the utility model concept.
Claims
1. A circulating fluidized bed boiler coal combustion catalyst solution addition system characterized by, Including PLC controller, coal moisture detection module, belt conveyor and mixed spraying module;The coal moisture detection module is used for detecting the water content of coal in the yard;The belt conveyor has a belt scale, and the belt conveyor is used for conveying the coal in the yard to the boiler, and the belt scale is used for measuring the weight in real time during the coal conveying process;The mixed spraying module includes a water pipe, a catalyst pipe, a mixing tank, a liquid delivery pipeline, a liquid delivery pump and a plurality of nozzles, the bottom of the mixing tank is connected with the plurality of nozzles arranged above the belt conveyor through the liquid delivery pipeline, the liquid delivery pump is installed on the liquid delivery pipeline, the water pipe and the catalyst pipe are communicated with the mixing tank, the first PID regulating valve is installed on the water pipe, the catalyst pipe and the liquid delivery pipeline, the coal moisture detection module and the belt scale are connected with the input end of the PLC controller, and the first PID regulating valve is connected with the output end of the PLC controller.
2. A coal combustion catalyst solution injection system for a circulating fluidized bed boiler according to claim 1, wherein The coal moisture detection module is a microwave moisture sensor arranged at the feeding end of the belt conveyor.
3. A coal combustion catalyst solution injection system for a circulating fluidized bed boiler according to claim 1, wherein The coal moisture detection module is a plurality of capacitive moisture sensors buried in the coal in the yard, and the sensor network is composed of the plurality of capacitive moisture sensors.
4. A coal combustion catalyst solution injection system for a circulating fluidized bed boiler according to claim 1, wherein An ultrasonic liquid level sensor is arranged above the mixing tank, and the ultrasonic liquid level sensor is connected with the input end of the PLC controller.
5. A coal combustion catalyst solution injection system for a circulating fluidized bed boiler according to claim 1, wherein The liquid delivery pipeline between the liquid delivery pump and the nozzle is communicated with the mixing tank through a backflow pipe, a second PID regulating valve is installed on the backflow pipe, and the second PID regulating valve is connected with the output end of the PLC controller.
6. A coal combustion catalyst solution injection system for a circulating fluidized bed boiler according to claim 1, wherein The nozzles are arranged in sequence at the same interval above the conveyor, and the spray angle of each nozzle is 60°-120°.
7. A coal combustion catalyst solution injection system for a circulating fluidized bed boiler according to claim 1, wherein A catalyst tank is further included, the catalyst pipe is communicated with the bottom of the catalyst tank, a catalyst pump is installed on the catalyst pipe, the catalyst pipe between the catalyst pump and the mixing tank is communicated with the catalyst tank through an overflow pipe, a third PID regulating valve is installed on the overflow pipe, and the third PID regulating valve is connected with the output end of the PLC controller.
8. A coal combustion catalyst solution injection system for a circulating fluidized bed boiler according to claim 1, wherein Flow meters are installed on the water pipe, the catalyst pipe and the liquid delivery pipeline, and the flow meters are connected with the input end of the PLC controller.
9. A coal combustion catalyst solution injection system for a circulating fluidized bed boiler according to claim 1, wherein The PLC controller is connected with the touch screen through RS485 / Modbus.