Pneumatic conveying ash-gas ratio control system and method

Abstract

The invention discloses a pneumatic conveying ash-gas ratio control system and method. The pneumatic conveying ash-gas ratio control system comprises a primary gas inlet pipeline, a conveying pipeline and a control module. The primary gas inlet pipeline is provided with a pressure control device, a flow adjusting device and a flow monitoring device; the conveying pipeline is provided with a dust quality monitoring device; the pressure control device is used for adjusting the gas inlet pressure of the primary gas inlet pipeline according to a pressure set value; the dust quality monitoring device is used for monitoring the quality of dust conveyed to the conveying pipeline by the bin pump and transmitting the quality to the control module; the flow monitoring device is used for monitoring the actual gas inlet flow of the primary gas inlet pipeline and transmitting the actual gas inlet flow to the control module; the control module is used for controlling the flow adjusting device to adjust the flow of gas conveyed to the conveying pipeline according to the set ash-gas ratio, the dust quality monitored by the dust quality monitoring device and the actual gas inlet flow of the primary gas inlet pipeline. According to the invention, the wear of the conveying pipeline can be avoided while the conveying energy consumption loss is reduced, and efficient and stable operation is ensured at a lower cost.

Description

Technical Field

[0001] This invention relates to the field of material conveying technology, and in particular to a pneumatic conveying ash-to-air ratio control system and method. Background Technology

[0002] Pneumatic conveying systems utilize airflow energy to transport powdery or granular materials within closed pipelines. A specific feeding device quantitatively feeds the material into the pipeline, and positive or negative pressure gas (such as air, nitrogen, carbon dioxide, or chloromethane) is used to transport the material to a designated location. Pneumatic conveying systems are widely used in thermal power, petrochemical, steel, fine chemical, rubber, food, and pharmaceutical industries, and can achieve automatic, orderly, and safe operation through a control system.

[0003] In recent years, in an effort to reduce costs, thermal power plants have frequently used or blended coal types that deviate from their design specifications, resulting in significant variations in ash quality and quantity. This has led to insufficient ash conveying capacity in existing pneumatic conveying systems, frequently causing ash blockages. To ensure efficient ash conveying, it has become necessary to increase the gas volume and lengthen each conveying cycle, but this also results in excessive energy consumption, accelerated wear and tear on the ash conveying pipelines, and increased equipment maintenance frequency and costs. In summary, pipe blockage, pipeline wear, high gas consumption, and increasingly insufficient conveying capacity are the four major problems plaguing pneumatic ash conveying systems in coal-fired power plants.

[0004] Existing technology upgrades pneumatic conveying systems by adding pilot-operated plug valves at regular intervals along the conveying pipeline and shutting off some fluidizing gas and purging gas to reduce the pressure of the conveyed compressed air. Compared to the original system, this saves compressed air and reduces pipeline wear. However, even when the pilot-operated plug valves are not in operation, there will be a small amount of air leakage. If dozens or even hundreds of these valves are installed on a single conveying pipeline, the leakage will be significant, still resulting in a waste of conveyed compressed air. Summary of the Invention

[0005] This invention provides a pneumatic conveying ash-to-gas ratio control system and method to overcome the technical problems of high air consumption and easy pipeline wear in existing pneumatic conveying systems.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A pneumatic conveying ash-to-gas ratio control system includes: a primary gas inlet pipe, a conveying pipe connected to the primary gas inlet pipe, and a control module; the primary gas inlet pipe is equipped with a pressure control device, a flow regulating device, and a flow monitoring device; the conveying pipe is equipped with a dust quality monitoring device; the pressure control device is used to adjust the inlet pressure of the primary gas inlet pipe according to a pressure setpoint; the dust quality monitoring device is used to monitor the dust quality conveyed to the conveying pipe by the silo pump and transmit the data to the control module; the flow monitoring device is used to monitor the actual inlet flow rate of the primary gas inlet pipe and transmit the data to the control module; the control module is used to control the flow regulating device to adjust the gas flow rate conveyed to the conveying pipe according to a set ash-to-gas ratio, the dust quality monitored by the dust quality monitoring device, and the actual inlet flow rate of the primary gas inlet pipe.

[0007] Furthermore, the pneumatic conveying ash-to-gas ratio control system also includes a gas tracing pipeline connected in parallel with the primary gas inlet pipeline and a pneumatic ball valve installed in the gas tracing pipeline for controlling the opening and closing of the gas tracing pipeline; the conveying pipeline is also equipped with several burst-type pulse conveyors, one end of each burst-type pulse conveyor is connected to the gas tracing pipeline, and each burst-type pulse conveyor is equipped with a pressure transmitter; the pressure transmitter is used to monitor the pressure data at the corresponding point of the conveying pipeline and transmit it to the control module; the control module determines the pressure difference between adjacent pressure transmitters based on the received pressure data, and then opens the pneumatic ball valve according to the pressure difference, while simultaneously controlling the corresponding burst-type pulse conveyor to open to perform the unblocking operation.

[0008] Furthermore, the pressure control device is a self-regulating pressure valve.

[0009] Furthermore, the flow regulating device is a proportional flow valve.

[0010] Furthermore, the flow monitoring device is a gas flow meter.

[0011] Furthermore, the pressure setting value ranges from 0.3 to 0.35 MPa.

[0012] Furthermore, the ash-to-gas ratio ranges from 45 to 55.

[0013] A control method based on a pneumatic conveying ash-to-gas ratio control system, comprising the following steps: S1. Adjust the inlet pressure of the delivery pipeline by means of a pressure control device and according to the pressure setting value; S2. The dust quality of the dust pumped to the conveying pipeline is monitored by the dust quality monitoring device and transmitted to the control module; S3. Monitor the actual intake flow rate of the primary air intake pipe through the flow monitoring device and transmit it to the control module; S4. The control module controls the flow regulating device to adjust the gas flow rate delivered to the conveying pipeline based on the set dust-to-gas ratio, the dust quality monitored by the dust quality monitoring device, and the actual air flow rate of the primary gas inlet pipeline.

[0014] Furthermore, the control methods also include: The pressure data at the corresponding point on the delivery pipeline is monitored by a pressure transmitter and transmitted to the control module. The control module determines the pressure difference between adjacent pressure transmitters based on the received pressure data, and then opens the pneumatic ball valve according to the pressure difference, while simultaneously controlling the corresponding explosive pulse conveyor to open to perform the unblocking work.

[0015] Beneficial effects: This invention, by installing a pressure control device, a flow regulation device, and a flow monitoring device in the primary gas inlet pipeline, and a dust quality monitoring device in the conveying pipeline, allows the control module to adjust the gas flow rate delivered to the conveying pipeline based on the set dust-to-gas ratio, the dust quality monitored by the dust quality monitoring device, and the actual inlet flow rate of the primary gas inlet pipeline. This enables the entire pneumatic conveying system to operate in an optimal energy-saving manner, reducing energy loss during conveying while avoiding wear on the conveying pipeline, and ensuring efficient and stable operation at a lower cost. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the pneumatic conveying ash-to-gas ratio control system in this invention.

[0017] In the diagram: 1. Primary air intake pipe; 11. Pressure control device; 12. Flow regulating device; 13. Flow monitoring device; 2. Conveying pipelines; 21. Dust quality monitoring device; 22. Explosive pulse conveyor; 3. Gas tracing pipeline; 31. Pneumatic ball valve. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This embodiment provides a pneumatic conveying ash-to-gas ratio control system, such as... Figure 1 As shown, the system includes a primary air intake pipe 1, a delivery pipe 2 connected to the primary air intake pipe, and a control module. The primary air intake pipe 1 is equipped with a pressure control device 11, a flow regulating device 12, and a flow monitoring device 13. The delivery pipe 2 is equipped with a dust quality monitoring device 21. The pressure control device 11 is used to adjust the intake pressure of the primary air intake pipe 1 according to the pressure set value. The dust quality monitoring device 21 is used to monitor the dust quality delivered by the silo pump to the delivery pipe 2 and transmit the data to the control module. Specifically, the flow monitoring device 13 is used to monitor the actual intake flow of the primary gas intake pipe 1 and transmit it to the control module; the control module is used to control the flow regulating device to regulate the gas flow delivered to the conveying pipe 2 according to the set ash-to-gas ratio, the dust quality monitored by the dust quality monitoring device and the actual intake flow of the primary gas intake pipe.

[0020] In a specific embodiment, the pneumatic conveying ash-to-gas ratio control system further includes a gas tracing pipe connected in parallel with the conveying pipe 2 and a pneumatic ball valve 31 disposed in the gas tracing pipe 3 and used to control the opening and closing of the gas tracing pipe; The conveying pipeline 2 is also equipped with several explosive pulse conveyors 22, one end of each explosive pulse conveyor 22 is connected to the gas tracing pipeline 3, and each explosive pulse conveyor is equipped with a pressure transmitter. Specifically, in this embodiment, a gas-tracing pipe 3 is provided to supply compressed air to the blasting pulse delivery device. The pressure transmitter is used to monitor the pressure data at the corresponding point on the conveying pipeline 2 and transmit it to the control module; The control module determines the pressure difference between adjacent pressure transmitters based on the received pressure data, and then opens the pneumatic ball valve according to the pressure difference, while simultaneously controlling the corresponding explosive pulse conveyor 22 to open to perform the unblocking work.

[0021] Specifically, this embodiment uses the calculation formula for system gas consumption proposed in DL / T5142-2012 "Technical Specification for Ash Removal in Thermal Power Plants": Q=1000G / 60ρμ In the formula: Q is the standard gas consumption of the conveying system (unit: m³). 3 / min); G is the output of the conveying system (in t / h); ρ is the conveying air density under standard conditions (in kg / m³). 3 μ is the ash-to-air ratio (unit: kg / kg), which is the ratio of the mass of the material to the mass of the conveying air. As can be seen from the above formula, when the output of the conveying system is fixed, the ash-to-air ratio becomes the only variable parameter affecting air consumption, and it also determines whether the conveying process can proceed smoothly. Therefore, this embodiment adjusts the airflow into the conveying pipeline based on the ash-to-air ratio to achieve energy saving.

[0022] Specifically, in this embodiment, the conveying pressure of the entire pneumatic conveying system is first reduced to 0.3–0.35 MPa using a self-regulating pressure regulating valve to ensure that the conveying conditions are met, thereby reducing wear on the conveying pipeline. Simultaneously, only primary gas is used for conveying, and a proportional flow valve is installed on the primary gas inlet pipeline. Based on the optimal ash-to-gas ratio obtained in practice and the monitored material quality, the conveying system automatically adjusts the primary gas intake to save energy. Since this embodiment adjusts the gas flow rate by monitoring the ash-to-gas ratio in real time, while saving energy, this may also lead to blockages in certain sections of the conveying pipeline. Therefore, this embodiment also includes several explosive pulse conveyors, each equipped with a pressure transmitter for real-time monitoring of the pressure in the monitored section of the conveying pipeline. If a blockage occurs in a section of the conveying pipeline, the corresponding explosive pulse conveyor will automatically activate to clear the blockage based on the pressure transmitter's monitoring results, ensuring energy savings while smoothly conveying dust.

[0023] Specifically, due to the installation of the blasting pulse conveyor, when the conveying pipeline 2 is normal, no compressed air enters the conveying pipeline 2 from the tracing air pipeline 3, avoiding waste of compressed air. Furthermore, the opening and closing of the blasting pulse conveyor 22 is controlled by the pressure difference, ensuring stable operation and high control precision. The blasting pulse conveyor uses a sudden burst of compressed gas at extremely high speed to directly impact the blockage fault area of ​​the ash material stored in the conveying pipeline. This sudden release of the expansion impact wave overcomes the static friction of the ash material, allowing the ash material in the pipeline to resume flow. It utilizes aerodynamic principles, using compressed air as the working medium, and instantly converts air pressure energy into air jet kinetic energy, generating a powerful impact force. It is a clean, pollution-free, and low-energy-consumption ideal unblocking and ash-blowing device with significant unblocking effects. Specifically, in this embodiment, explosive pulse conveyors 22 are installed on the conveying pipeline 2 in the following manner: 2 meters for each pump room, 8 meters for each pipe gallery, and 1 meter for each bend before and after the bend. That is, one explosive pulse conveyor is installed at each location where pipe blockage is likely to occur. Each explosive pulse conveyor 22 is equipped with a pressure transmitter and a solenoid valve to participate in the precise control process of the conveying system.

[0024] In a specific embodiment, the pressure control device 11 is a self-regulating pressure valve.

[0025] In a specific embodiment, the flow regulating device 12 is a proportional flow valve.

[0026] In a specific embodiment, the flow monitoring device 13 is a gas flow meter.

[0027] In a specific embodiment, preferably, the pressure setting value is in the range of 0.3 to 0.35 MPa.

[0028] In a specific embodiment, the optimal ash-to-gas ratio is calculated based on the on-site conveying medium, the weight of the medium, the pipe size, and the conveying distance. Preferably, the ash-to-gas ratio ranges from 45 to 55.

[0029] Specifically, given the optimal ash-to-air ratio and material quality, this embodiment achieves energy saving and consumption reduction by controlling the amount of compressed air used during conveying. The optimal ash-to-air ratio can also be adjusted based on actual on-site operating conditions.

[0030] This embodiment also provides a control method based on a pneumatic conveying ash-to-gas ratio control system, the specific steps of which include: S1. Adjust the inlet pressure of the delivery pipeline by means of a pressure control device and according to the pressure setting value; S2. The dust quality of the dust pumped to the conveying pipeline is monitored by the dust quality monitoring device and transmitted to the control module; S3. Monitor the actual intake flow rate of the primary air intake pipe through the flow monitoring device and transmit it to the control module; S4. The control module controls the flow regulating device to adjust the gas flow rate delivered to the conveying pipeline based on the set ash-to-gas ratio, the dust quality monitored by the dust quality monitoring device, and the actual air flow rate of the primary gas inlet pipeline. S5. Monitor the pressure data at the corresponding point on the delivery pipeline using a pressure transmitter and transmit it to the control module; S6. The control module determines the pressure difference between adjacent pressure transmitters based on the received pressure data, and then opens the pneumatic ball valve according to the pressure difference, while simultaneously controlling the corresponding explosive pulse conveyor to open to perform the unblocking work. Specifically, this embodiment uses a dust mass flow meter installed in the conveying pipeline to accurately monitor the total mass of dust flowing through the pipeline in real time. This allows the acquisition of the material mass used to calculate the dust-to-gas ratio, and the required gas flow rate can be obtained based on the set dust-to-gas ratio, thereby controlling the proportional flow valve. Based on the set dust-to-gas ratio, the conveying system can automatically adjust the supply of compressed air during the conveying process to achieve the most economical and efficient conveying state.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pneumatic conveying ash-to-gas ratio control system, characterized in that, include: A primary air intake pipe (1), a delivery pipe (2) connected to the primary air intake pipe, and a control module; The primary air intake pipe (1) is equipped with a pressure control device (11), a flow regulation device (12) and a flow monitoring device (13). The conveying pipeline (2) is equipped with a dust quality monitoring device (21); The pressure control device (11) is used to adjust the intake pressure of the primary air intake pipe (1) according to the pressure set value; The dust quality monitoring device (21) is used to monitor the dust quality delivered by the silo pump to the conveying pipeline (2) and transmit it to the control module; The flow monitoring device (13) is used to monitor the actual intake flow of the primary air intake pipe and transmit it to the control module; The control module is used to control the flow regulating device to adjust the gas flow rate delivered to the conveying pipeline (2) according to the set ash-to-gas ratio, the dust quality monitored by the dust quality monitoring device, and the actual air flow rate of the primary gas inlet pipeline.

2. The pneumatic conveying ash-to-gas ratio control system according to claim 1, characterized in that, It also includes a gas tracing pipe (3) connected in parallel with the primary gas inlet pipe and a pneumatic ball valve (31) installed in the gas tracing pipe for controlling the opening and closing of the gas tracing pipe. The conveying pipeline (2) is also equipped with several explosive pulse conveyors (22), one end of each explosive pulse conveyor (22) is connected to the gas tracing pipeline (3), and each explosive pulse conveyor is equipped with a pressure transmitter. The pressure transmitter is used to monitor the pressure data at the corresponding point on the delivery pipeline (2) and transmit it to the control module; The control module determines the pressure difference between adjacent pressure transmitters based on the received pressure data, and then opens the pneumatic ball valve based on the pressure difference, while controlling the corresponding blasting pulse conveyor (22) to open to perform the unblocking work.

3. The pneumatic conveying ash-to-gas ratio control system according to claim 1, characterized in that, The pressure control device (11) is a self-regulating pressure valve.

4. The pneumatic conveying ash-to-gas ratio control system according to claim 1, characterized in that, The flow regulating device (12) is a proportional flow valve.

5. The pneumatic conveying ash-to-gas ratio control system according to claim 1, characterized in that, The flow monitoring device (13) is a gas flow meter.

6. The pneumatic conveying ash-to-gas ratio control system according to claim 1, characterized in that, The pressure setting value is in the range of 0.3 to 0.35 MPa.

7. The pneumatic conveying ash-to-gas ratio control system according to claim 1, characterized in that, The range of the ash-to-gas ratio is 45 to 55.

8. A control method based on the pneumatic conveying ash-to-gas ratio control system according to claim 1, characterized in that, The specific steps include: S1. Adjust the inlet pressure of the delivery pipeline by means of a pressure control device and according to the pressure setting value; S2. The dust quality of the dust pumped to the conveying pipeline is monitored by the dust quality monitoring device and transmitted to the control module; S3. Monitor the actual intake flow rate of the primary air intake pipe through the flow monitoring device and transmit it to the control module; S4. The control module controls the flow regulating device to adjust the gas flow rate delivered to the conveying pipeline based on the set dust-to-gas ratio, the dust quality monitored by the dust quality monitoring device, and the actual air flow rate of the primary gas inlet pipeline.

9. The control method according to claim 8, characterized in that, Also includes: The pressure data at the corresponding point on the delivery pipeline is monitored by a pressure transmitter and transmitted to the control module. The control module determines the pressure difference between adjacent pressure transmitters based on the received pressure data, and then opens the pneumatic ball valve according to the pressure difference, while simultaneously controlling the corresponding explosive pulse conveyor to open to perform the unblocking work.

Images