Pneumatic conveying gas volume intelligent control method and pneumatic conveying system

Abstract

The present application provides a method for intelligently controlling the air volume of pneumatic conveying and a pneumatic conveying system, which relates to the technical field of material conveying, wherein the method comprises: determining a target frequency value according to the material conveying output value, the target frequency value is used to represent the frequency of the frequency converter of the rotary feeder in the pneumatic conveying system; determining a target conveying air volume corresponding to the target frequency value based on a preset first function, wherein the first function is used to represent the relationship between the frequency of the frequency converter of the rotary feeder and the conveying air volume of the pneumatic conveying system; adjusting the opening of a flow control valve according to the target conveying air volume, the flow control valve being installed in the main conveying air intake pipe of the pneumatic conveying system, and the flow control valve being used to adjust the conveying air volume of the main conveying air intake pipe. The implementation of the technical solution provided by the present application solves the technical problem that the conveying air volume cannot be flexibly adjusted in the related art.

Description

Technical Field

[0001] The present application relates to the technical field of material conveying, and in particular to an intelligent control method for pneumatic conveying gas volume and a pneumatic conveying system. Background Art

[0002] Pneumatic conveying systems are widely used in the transportation of raw materials and powders in petroleum, chemical, metallurgy, building materials, grain and oil, pharmaceutical and other factories. Existing continuous pneumatic conveying systems are designed and selected based on the material conveying output requirements (usually t / h) proposed by users. The output requirements provided by users are usually a range according to process needs, requiring the pneumatic conveying system to continuously switch between the maximum and minimum outputs; therefore, when designing the pneumatic conveying system, the system, equipment, pipelines and air intake components are selected to meet the maximum output, and the conveying gas consumption (or simply the conveying gas volume) is also configured according to the maximum output of the system (achieved by limiting the flow through a throttling orifice or other means); usually, users It is required to consider a certain margin when selecting the system. The maximum output provided is much larger than the actual working output. Therefore, when the system is actually running, the system output is often lower than the maximum output, and in most cases it is far lower than the designed maximum output. At this time, the conveying gas consumption remains unchanged (the orifice plate is not adjusted on site with the output change, and it is still the set value at the maximum output), resulting in a lower material-gas ratio and poor economic performance. Especially when the system is running at a low load output for a long time, the problem is more prominent. The too low material-gas ratio not only causes energy waste, but also causes excessive wear of pipelines and accessories. It can be seen that the pneumatic conveying system of the related technology has the problem of energy waste due to the inability to flexibly adjust the conveying gas volume during operation.

[0003] With regard to the technical problem in the related technology that the gas delivery volume cannot be flexibly adjusted, no effective solution has been proposed so far. Summary of the invention

[0004] The present application provides a pneumatic conveying gas volume intelligent control method and a pneumatic conveying system, so as to at least solve the technical problem existing in the related art that the conveying gas volume cannot be flexibly adjusted.

[0005] In the first aspect, the present application provides an intelligent control method for pneumatic conveying gas volume, which is applied to a pneumatic conveying system, including: determining a target frequency value based on a material conveying output value, wherein the target frequency value is used to represent the frequency of a frequency converter of a rotary feeder in the pneumatic conveying system; determining a target conveying gas volume corresponding to the target frequency value based on a preset first function, wherein the first function is used to represent the relationship between the frequency of the frequency converter of the rotary feeder and the conveying gas volume of the pneumatic conveying system; adjusting the opening of a flow regulating valve according to the target conveying gas volume, wherein the flow regulating valve is installed in a main conveying air intake pipe of the pneumatic conveying system, and the flow regulating valve is used to adjust the conveying gas volume of the main conveying air intake pipe.

[0006] By adopting the above technical solution, the target frequency value is determined according to the material conveying output value, and the target frequency value represents the frequency of the frequency converter of the rotary feeder, and then the target conveying gas volume corresponding to the target frequency value is determined based on the preset first function, wherein the first function represents the functional relationship between the frequency of the frequency converter and the conveying gas volume of the pneumatic conveying system, and then the opening of the flow control valve is adjusted according to the target conveying gas volume to achieve the adjustment of the conveying gas volume in the main conveying air intake pipe of the pneumatic conveying system. The problem that the main conveying air intake pipe of the pneumatic conveying system in the related art always conveys according to the maximum output value, resulting in a decrease in the material-to-gas ratio, is avoided, and the technical problem that the pneumatic conveying system in the related art cannot flexibly adjust the conveying gas volume is solved, and the purpose of flexibly adjusting the conveying gas volume is achieved, and the effect of improving the material-to-gas ratio is achieved, thereby achieving the effect of reducing energy waste.

[0007] Optionally, adjusting the opening of the flow control valve according to the target gas delivery volume includes: determining a target opening value corresponding to the target gas delivery volume based on a preset second function, wherein the second function is used to represent the relationship between the gas delivery volume and the opening value of the pneumatic conveying system, and the second function is obtained by testing the gas delivery volume of the regulating valve of the pneumatic conveying system under different opening values ​​in advance; adjusting the current opening of the flow control valve to the target opening value.

[0008] By adopting the above technical solution, a target opening value corresponding to the target gas delivery volume is determined based on a preset second function, wherein the second function represents the functional relationship between the delivery gas volume and the opening value of the pneumatic conveying system, and then the current opening of the flow control valve is adjusted to the target opening value. The purpose of adjusting the delivery gas volume of the main delivery air inlet pipeline of the pneumatic conveying system and adjusting the opening of the flow control valve to the target opening value matching the target delivery gas volume is achieved.

[0009] Optionally, determining the target frequency value according to the material conveying output value includes: determining the target frequency value according to the material conveying output value and the following formula: Among them, A represents the material conveying output value, F0 represents the power frequency, i represents the reduction ratio of the reduction motor, and V represents the volume per revolution of the rotary feeder. It represents the material filling rate, ρ represents the material density, and M0 represents the industrial frequency speed of the reduction motor.

[0010] By adopting the above technical solution, after determining the model of the rotary feeder, the filling rate of the conveyed material, the material density, the power frequency, the power frequency speed of the reduction motor and the reduction ratio, the target frequency value corresponding to the required material conveying output value can be determined according to the above formula.

[0011] Optionally, a target conveying gas volume corresponding to a target frequency value is determined based on a preset first function, including: establishing a target configuration relationship table, wherein the target configuration relationship table records the correspondence between the frequencies of the frequency converters of multiple groups of rotary feeders and the conveying gas volumes of the pneumatic conveying system; obtaining a first function based on the target configuration relationship table; determining the target conveying gas volume based on the first function; wherein establishing the target configuration relationship table includes: obtaining N data pairs from a pneumatic conveying database, wherein the N data pairs include historical conveying data of materials, the i-th data pair includes the i-th historical conveying output value and the corresponding i-th historical conveying gas volume, the i-th data pair is any one of the N data pairs, N is a positive integer greater than or equal to 1, and i is a positive integer greater than or equal to 1 and less than or equal to N; for the i-th data pair, performing the following operations Obtain the corrected i-th data pair: determine the i-th frequency value corresponding to the i-th historical delivery output value; operate the pneumatic conveying system according to the i-th frequency value and the i-th historical delivery gas volume; adjust the flow regulating valve so that the delivery pressure at the inlet of the delivery air main pipe of the pneumatic conveying system reaches the target pressure value, and record the current delivery gas volume corresponding to the target pressure value, wherein the current delivery gas volume is measured by a flow meter, the flow meter is installed in the delivery air main pipe, and the target pressure value is within a preset pressure range; determine the current delivery gas volume as the i-th delivery gas volume correction value, and obtain the corrected i-th data pair, wherein the corrected i-th data pair includes the i-th frequency value and the i-th delivery gas volume correction value; obtain the target configuration relationship table according to the corrected N data pairs, wherein the corrected N data pairs include the corrected i-th data pair.

[0012] By adopting the above technical solution, a target configuration relationship table can be established in the above manner, specifically including: obtaining N data pairs from a pneumatic conveying database, the pneumatic conveying database includes historical conveying data of various pneumatic conveying systems under different conditions, for any data pair, such as the ith data pair, determining the ith frequency value corresponding to the ith historical conveying output value, operating the pneumatic conveying system according to the ith frequency value and the ith historical conveying gas volume, and then adjusting the flow control valve in the pneumatic conveying system so that the conveying pressure at the inlet of the conveying air main pipe of the pneumatic conveying system reaches the target pressure value, and recording the current conveying gas volume value corresponding to this time, and then determining the current conveying gas volume value as the ith conveying gas volume correction value corresponding to the ith frequency value, that is, the historical conveying data in the pneumatic conveying database are not necessarily matched, and the conveying gas volume correction value matching each frequency value is obtained through experimental adjustment, thereby obtaining the target configuration relationship table, that is, the target configuration relationship table is obtained through experimental adjustment, and the frequency value and the conveying gas volume correction value in any set of corresponding relationships in the target configuration relationship table are matched. The purpose of pre-establishing the target configuration relationship table is achieved.

[0013] Optionally, a first function is obtained based on a target configuration relationship table, including: fitting the corrected N data pairs using the least squares method to obtain a target second-order function, and determining the target second-order function as the first function, wherein the target second-order function is used to represent the functional relationship between the conveying gas volume of the pneumatic conveying system and the frequency of the frequency converter of the rotary feeder.

[0014] By adopting the above technical solution, after obtaining the corrected N data pairs, that is, after obtaining N groups of discrete values, the least squares method can be used for fitting to obtain the target second-order function, that is, to obtain the functional relationship between the delivered gas volume and the frequency value, and the target second-order function is determined as the above-mentioned first function, so that the corresponding relationship between any frequency value and the delivered gas volume can be obtained.

[0015] Optionally, the opening of the regulating valve is adjusted according to the target gas delivery volume, including: obtaining the actual gas delivery volume of the conveying air main pipe of the pneumatic conveying system; based on the actual gas delivery volume and the target gas delivery volume, a target control signal is output through a PID regulating controller, and the target control signal is used to adjust the opening of the flow regulating valve.

[0016] By adopting the above technical solution, when determining the target conveying gas volume corresponding to the target frequency value, the actual conveying gas volume of the conveying air main pipe of the pneumatic conveying system can also be obtained, and then the target control signal for controlling the flow control valve can be obtained through the PID adjustment controller, that is, the flow control valve can be controlled more accurately using the PID adjustment principle. The purpose of improving the accuracy of the flow control valve adjustment is achieved.

[0017] In the second aspect of the present application, a pneumatic conveying system is also provided, including: a silo, a manual plug-in door, a receiving pump, a feeding pump, a rotary feeder, a delivery pipe, a reduction motor, a frequency converter, a delivery air main pipe, a manual shut-off valve, an auxiliary air intake valve group, a main delivery air intake valve, a main delivery air intake pipe, a flow regulating valve, a PID regulating controller, and a flow meter, wherein the silo is used to store materials to be transported, the receiving pump is used to receive materials from the silo, the receiving pump and the feeding pump are connected through valves and pipes, and the feeding pump is used to continuously feed the materials into the rotary feeder and then into the delivery pipe; the manual plug-in door is arranged in the pipe between the silo and the receiving pump; the rotary feeder is used to continuously transport the materials output by the feeding pump through the delivery pipe; the reduction motor is used to control the rotation speed of the rotary feeder, thereby adjusting To save material delivery, the frequency converter is used to adjust the speed of the reduction motor; the receiving pump and the feeding pump are connected to the conveying air main pipe through different auxiliary air intake pipes respectively, and the conveying pipe is connected to the conveying air main pipe through the main conveying air intake pipe, wherein the conveying air main pipe is provided with a manual shut-off valve, the main conveying air intake pipe is provided with a main conveying air intake valve, and the auxiliary air intake pipe is provided with an auxiliary air intake valve group; the flow meter is installed in the conveying air main pipe to measure the actual conveying air volume of the pneumatic conveying system; the flow regulating valve is installed in the main conveying air intake pipe to adjust the air flow of the main conveying air intake pipe; the PID regulating controller is respectively connected to the flow meter and the flow regulating valve to obtain the actual conveying air volume, and control the flow regulating valve based on the actual conveying air volume and the target conveying air volume.

[0018] By adopting the above technical solution, a flow meter is installed in the conveying air main pipe of the traditional pneumatic conveying system, a flow regulating valve is installed in the main conveying air intake duct, and a PID regulating controller is added. The flow meter is used to measure the actual conveying air volume of the conveying air main pipe in real time, and the PID regulating controller controls the flow regulating valve based on the actual conveying air volume and the target conveying air volume.

[0019] Optionally, the target conveying gas volume is obtained by the PID adjustment controller in the following manner: determining a target frequency value based on the material conveying output value, wherein the target frequency value is used to represent the frequency of the frequency converter; determining a target conveying gas volume corresponding to the target frequency value based on a preset first function, wherein the first function is used to represent the relationship between the frequency of the frequency converter and the conveying gas volume of the pneumatic conveying system.

[0020] By adopting the above technical scheme, the target frequency value can be determined first according to the material conveying output value, and the target frequency value represents the frequency of the inverter of the rotary feeder, and then the target conveying gas volume corresponding to the target frequency value can be determined based on the preset first function. On this basis, the PID regulation controller can control the flow control valve based on the actual conveying gas volume and the target conveying gas volume.

[0021] In a third aspect of the present application, an electronic device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the program, any of the above method steps is implemented.

[0022] In a fourth aspect of the present application, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores instructions, and when the instructions are executed, any of the above method steps is performed.

[0023] In summary, one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0024] 1. It avoids the problem that the gas volume of the main conveying air intake pipe of the pneumatic conveying system in the related technology is always conveyed according to the maximum output value, resulting in a decrease in the material-gas ratio, and solves the technical problem that the pneumatic conveying system in the related technology cannot flexibly adjust the conveying gas volume, thereby achieving the purpose of flexibly adjusting the conveying gas volume, achieving the effect of improving the material-gas ratio, and thus achieving the effect of reducing energy waste.

[0025] 2. The purpose of regulating the conveying gas volume of the main conveying air inlet pipeline of the pneumatic conveying system and adjusting the opening of the flow control valve to a target opening value matching the target conveying gas volume is achieved.

[0026] 3. The target control signal for controlling the flow control valve is obtained by using the PID adjustment controller, that is, the flow control valve is controlled more accurately using the PID adjustment principle, thereby achieving the purpose of improving the accuracy of the flow control valve adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of a method for intelligently controlling the gas volume of pneumatic conveying provided in an embodiment of the present application;

[0028] Figure 2 It is a structural diagram of a pneumatic conveying system in the related art;

[0029] Figure 3 It is a structural diagram of a pneumatic conveying system provided in an embodiment of the present application.

[0030] Description of reference numerals:

[0031] 1- Silo; 2- Manual plug-in door; 3- Receiving pump; 4- Feeding pump; 5- Rotary feeder; 6- Feeding pipe; 7- Reduction motor; 8- Frequency converter; 9- Delivery air main pipe; 10- Manual shut-off valve; 11- Auxiliary air intake valve group; 12- Main delivery air intake valve; 13- Main delivery air intake pipeline; 14- Flow control valve; 15- PID control controller; 16- Flow meter. DETAILED DESCRIPTION

[0032] In order to enable technicians in this field to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments.

[0033] In the description of the embodiments of the present application, words such as "for example" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "for example" or "for example" is intended to present related concepts in a specific way.

[0034] In the description of the embodiments of the present application, the meaning of the term "multiple" refers to two or more. For example, multiple systems refer to two or more systems, and multiple screen terminals refer to two or more screen terminals. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. The terms "include", "comprise", "have" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0035] The present application provides a pneumatic conveying gas volume intelligent control method, which is applied to a pneumatic conveying system. Figure 1 , Figure 1 It is a flow chart of a pneumatic conveying gas volume intelligent control method provided by an embodiment of the present application, comprising the following steps: Step S101, determining a target frequency value according to a material conveying output value, wherein the target frequency value is used to represent the frequency of a frequency converter of a rotary feeder in a pneumatic conveying system;

[0036] Step S102, determining a target conveying gas volume corresponding to a target frequency value based on a preset first function, wherein the first function is used to represent a relationship between a frequency converter frequency of a rotary feeder and a conveying gas volume of a pneumatic conveying system;

[0037] Step S103, adjusting the opening of the flow control valve according to the target gas delivery volume, wherein the flow control valve is installed in the main delivery air intake pipeline of the pneumatic conveying system, and the flow control valve is used to adjust the delivery gas volume of the main delivery air intake pipeline.

[0038] The execution body of the above steps may be the above-mentioned pneumatic conveying system, or a controller, etc., but is not limited thereto.

[0039] In the above embodiment, the target frequency value is determined according to the material conveying output value, and the target frequency value represents the frequency of the frequency converter of the rotary feeder. The rotary feeder is driven by a reduction motor, and the frequency converter is used to adjust the speed of the reduction motor. Then, the target conveying gas volume corresponding to the target frequency value is determined based on a preset first function, wherein the first function represents the functional relationship between the frequency of the frequency converter and the conveying gas volume of the pneumatic conveying system. For example, the frequency is 50 Hz, 40 Hz (or other frequencies), and the corresponding conveying gas volume is 50m 3 / min、45m 3 / min (or other gas volume value); then, the opening of the flow control valve is adjusted according to the target gas delivery volume, so that the actual gas delivery volume is equal to the target gas delivery volume, or the error between the two is less than the preset error threshold, so as to adjust the gas delivery volume in the main delivery air intake pipeline of the pneumatic conveying system. For example, the opening corresponding to the maximum output is 80% (or 75, or other), taking the maximum output of 50t / h (tons / hour) as an example, assuming that the gas delivery volume corresponding to the maximum output is 50m 3 / min, the maximum output can be understood as full load, then at low load (such as 30t / h), it may only need to deliver 35m 3 / min (or other), so the opening of the flow control valve can be reduced to 60%, which is only an example here. The above data can be adjusted for different materials or different pneumatic conveying systems. Through this embodiment, the problem that the gas volume of the main conveying air intake pipeline of the pneumatic conveying system in the related art is always conveyed according to the maximum output value, resulting in a decrease in the material-to-gas ratio is avoided, and the technical problem that the pneumatic conveying system in the related art cannot flexibly adjust the conveying gas volume is solved, the purpose of flexibly adjusting the conveying gas volume is achieved, and the effect of improving the material-to-gas ratio is achieved, thereby achieving the effect of reducing energy waste.

[0040] In an optional embodiment, adjusting the opening of the flow control valve according to the target gas delivery volume includes: determining a target opening value corresponding to the target gas delivery volume based on a preset second function, wherein the second function is used to represent the relationship between the gas delivery volume and the opening value of the pneumatic conveying system, and the second function is obtained by testing the gas delivery volume of the regulating valve of the pneumatic conveying system under different opening values ​​in advance; adjusting the current opening of the flow control valve to the target opening value.

[0041] In the above embodiment, the target opening value corresponding to the target gas delivery volume is determined based on the preset second function, wherein the second function represents the functional relationship between the gas delivery volume and the opening value of the pneumatic conveying system. For example, the gas delivery volume is 50m 3 / min, the corresponding target opening value is 80% (or other), and the gas delivery volume is 40m 3 / min, the corresponding target opening value is 70% (or other), and so on; in practical applications, the second function of the flow control valve can be provided by the manufacturer, and the second function represents the change curve between the conveying gas volume and the opening; then the current opening of the flow control valve is adjusted to the target opening value. The purpose of adjusting the conveying gas volume of the main conveying air intake pipeline of the pneumatic conveying system and adjusting the opening of the flow control valve to the target opening value matching the target conveying gas volume is achieved.

[0042] In an optional embodiment, determining the target frequency value according to the material conveying output value includes: determining the target frequency value according to the material conveying output value and in accordance with the following formula: Among them, A represents the material conveying output value, F0 represents the power frequency, i represents the reduction ratio of the reduction motor, and V represents the volume per revolution of the rotary feeder. It represents the material filling rate, ρ represents the material density, and M0 represents the industrial frequency speed of the reduction motor.

[0043] In the above embodiment, the model of the rotary feeder is determined, and the filling rate (or filling efficiency) of the conveyed material, the material density, the power frequency, the power frequency speed of the reduction motor and the reduction ratio are determined. The model of the rotary feeder is determined, that is, the volume per revolution is determined, and the target frequency value corresponding to the required material conveying output value can be determined according to the above formula.

[0044] In an optional embodiment, a target conveying gas volume corresponding to a target frequency value is determined based on a preset first function, including: establishing a target configuration relationship table, wherein the target configuration relationship table records the correspondence between the frequencies of the frequency converters of multiple groups of rotary feeders and the conveying gas volumes of the pneumatic conveying system; obtaining a first function based on the target configuration relationship table; determining the target conveying gas volume based on the first function; wherein establishing the target configuration relationship table includes: obtaining N data pairs from a pneumatic conveying database, wherein the N data pairs include historical conveying data of the material, the i-th data pair includes the i-th historical conveying output value and the corresponding i-th historical conveying gas volume, the i-th data pair is any one of the N data pairs, N is a positive integer greater than or equal to 1, and i is a positive integer greater than or equal to 1 and less than or equal to N; for the i-th data pair, executing The following operations obtain the corrected i-th data pair: determine the i-th frequency value corresponding to the i-th historical delivery output value; operate the pneumatic conveying system according to the i-th frequency value and the i-th historical delivery gas volume; adjust the flow control valve so that the delivery pressure at the inlet of the delivery air main pipe of the pneumatic conveying system reaches the target pressure value, and record the current delivery gas volume corresponding to the target pressure value, wherein the current delivery gas volume is measured by a flow meter, the flow meter is installed in the delivery air main pipe, and the target pressure value is within a preset pressure range; determine the current delivery gas volume as the i-th delivery gas volume correction value, and obtain the corrected i-th data pair, wherein the corrected i-th data pair includes the i-th frequency value and the i-th delivery gas volume correction value; obtain the target configuration relationship table according to the corrected N data pairs, wherein the corrected N data pairs include the corrected i-th data pair.

[0045] In the above embodiment, a target configuration relationship table can be established in the above manner, specifically including: obtaining N data pairs from a pneumatic conveying database, the pneumatic conveying database including historical conveying data of various pneumatic conveying systems under different conditions, for any data pair, such as the ith data pair, determining the ith frequency value corresponding to the ith historical conveying output value, operating the pneumatic conveying system according to the ith frequency value and the ith historical conveying gas volume, and then adjusting the flow control valve in the pneumatic conveying system so that the conveying pressure at the inlet of the conveying air main pipe of the pneumatic conveying system reaches the target pressure value, and recording the corresponding pressure value at this time. The current gas delivery volume value is determined as the i-th gas delivery volume correction value corresponding to the i-th frequency value, that is, the historical delivery data in the pneumatic delivery database is not necessarily matched, and the gas delivery volume correction value matching each frequency value is obtained through test adjustment. The same method is also used to test and adjust other data pairs in the N data pairs to obtain matching gas delivery volume correction values, thereby obtaining the target configuration relationship table, that is, the target configuration relationship table is obtained through test adjustment, and the frequency value and gas delivery volume correction value in any set of corresponding relationships in the target configuration relationship table are matched. The purpose of pre-establishing the target configuration relationship table is achieved.

[0046] In an optional embodiment, a first function is obtained based on a target configuration relationship table, including: fitting the corrected N data pairs using the least squares method to obtain a target second-order function, and determining the target second-order function as the first function, wherein the target second-order function is used to represent the functional relationship between the conveying gas volume of the pneumatic conveying system and the frequency of the frequency converter of the rotary feeder.

[0047] In the above embodiment, after obtaining the corrected N data pairs, that is, after obtaining N groups of discrete values, the least squares method can be used for fitting to obtain the target second-order function, that is, to obtain the functional relationship between the delivered gas volume and the frequency value, and the target second-order function is determined as the above-mentioned first function, so that the corresponding relationship between any frequency value and the delivered gas volume can be obtained. In practical applications, the target delivered gas volume corresponding to the target frequency value can also be directly determined according to the above-mentioned first function. For example, the corresponding N frequency values ​​can be obtained according to the above-mentioned N data pairs, and the delivered gas volume corresponding to other frequency values ​​other than the above-mentioned N frequency values ​​can also be obtained according to the target second-order function.

[0048] In an optional embodiment, the opening of the regulating valve is adjusted according to the target gas delivery volume, including: obtaining the actual gas delivery volume of the conveying air main pipe of the pneumatic conveying system; based on the actual gas delivery volume and the target gas delivery volume, a target control signal is output through a PID regulating controller, and the target control signal is used to adjust the opening of the flow regulating valve.

[0049] In the above embodiment, when the target air delivery volume corresponding to the target frequency value is determined, the actual air delivery volume of the air delivery main pipe of the pneumatic conveying system can also be obtained, and then the target control signal for controlling the flow control valve is obtained through the PID adjustment controller. For example, the control signal is obtained according to the error between the target air delivery volume and the actual air delivery volume using the PID adjustment principle to adjust the flow control valve, and then the adjusted actual air delivery volume is obtained, and then compared with the target air delivery volume, and so on, that is, the flow control valve is controlled more accurately using the PID adjustment principle. The purpose of improving the accuracy of the flow control valve adjustment is achieved.

[0050] Figure 2 It is a structural diagram of a pneumatic conveying system in the related art. The pneumatic conveying system includes: a silo 1, a manual plug-in door 2, a receiving pump 3, a feeding pump 4, a rotary feeder 5, a conveying pipe 6, a reduction motor 7, a frequency converter 8, a conveying air main pipe 9, a manual shut-off valve 10, an auxiliary air intake valve group 11, a main conveying air intake valve 12, and a main conveying air intake pipe 13. The connection relationship is as follows Figure 2 As shown, in the related art, the pneumatic conveying system is designed to meet the maximum output. However, in actual operation, the system output is lower than the maximum output in most cases, but the conveyed gas volume is still the value at the maximum output, that is, Figure 2 The gas flow rate of the middle main transport air intake pipe 13 remains unchanged, which easily leads to a too low material-gas ratio, thus causing energy waste, poor economic efficiency and other problems.

[0051] The present application also provides a pneumatic conveying system for executing the method of any of the above embodiments, such as Figure 3 As shown, Figure 3 1 is a structural diagram of a pneumatic conveying system provided in an embodiment of the present application, the system comprising: a silo 1, a manual plug-in door 2, a receiving pump 3, a feeding pump 4, a rotary feeder 5, a conveying pipe 6, a reduction motor 7, a frequency converter 8, a conveying air main pipe 9, a manual shut-off valve 10, an auxiliary air intake valve group 11, a main conveying air intake valve 12, a main conveying air intake pipeline 13, a flow regulating valve 14, a PID regulating controller 15, and a flow meter 16, wherein the silo 1 is used to store materials to be conveyed, the receiving pump 3 is used to receive materials from the silo 1, the receiving pump 3 is connected to the feeding pump 4 through valves and pipelines, and the feeding pump 4 is used to continuously feed materials into the rotary feeder 5 and then into the conveying pipe 6;

[0052] The manual plug-in door 2 is arranged in the pipeline between the silo 1 and the receiving pump 3;

[0053] The rotary feeder 5 is used to continuously convey the material output by the feed pump 4 through the feed pipe 6;

[0054] The reduction motor 7 is used to control the rotation speed of the rotary feeder 5, thereby adjusting the conveying amount of the material, and the frequency converter 8 is used to adjust the rotation speed of the reduction motor 7;

[0055] The receiving pump 3 and the feeding pump 4 are connected to the conveying air main pipe 9 through different auxiliary air intake pipes, respectively, and the conveying pipe 6 is connected to the conveying air main pipe 9 through the main conveying air intake pipe 13, wherein the conveying air main pipe 9 is provided with a manual shut-off valve 10, the main conveying air intake pipe 13 is provided with a main conveying air intake valve 12, and the auxiliary air intake pipe is provided with an auxiliary air intake valve group 11;

[0056] The flow meter 16 is installed in the conveying air main pipe 9 to measure the actual conveying air volume of the pneumatic conveying system;

[0057] The flow regulating valve 14 is installed in the main air delivery intake pipe 13, and is used to adjust the air flow of the main air delivery intake pipe 13; the PID regulation controller 15 is respectively connected to the flow meter 16 and the flow regulating valve 14, and is used to obtain the actual air delivery volume, and control the flow regulating valve 14 based on the actual air delivery volume and the target air delivery volume.

[0058] Through the pneumatic conveying system of this embodiment, a flow meter is installed in the conveying air main pipe of the traditional pneumatic conveying system, a flow regulating valve is installed in the main conveying air intake duct, and a PID regulating controller is added. The flow meter is used to measure the actual conveying air volume of the conveying air main pipe in real time, and the PID regulating controller controls the flow regulating valve based on the actual conveying air volume and the target conveying air volume.

[0059] and Figure 2 In comparison, the pneumatic conveying system provided in the embodiment of the present application has a flow meter 16 installed in the conveying air main pipe 9, a flow regulating valve 14 installed in the main conveying air intake pipe 13, and an additional PID regulating controller 15.

[0060] In an optional embodiment, the target conveying gas volume is obtained by the PID adjustment controller in the following manner: determining a target frequency value based on the material conveying output value, wherein the target frequency value is used to represent the frequency of the frequency converter; determining a target conveying gas volume corresponding to the target frequency value based on a preset first function, wherein the first function is used to represent the relationship between the frequency of the frequency converter and the conveying gas volume of the pneumatic conveying system.

[0061] By adopting the above technical scheme, the target frequency value can be determined first according to the material conveying output value, and the target frequency value represents the frequency of the inverter of the rotary feeder, and then the target conveying gas volume corresponding to the target frequency value can be determined based on the preset first function. On this basis, the PID regulation controller can control the flow control valve based on the actual conveying gas volume and the target conveying gas volume.

[0062] It should be noted that the above-described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application will be described in detail below in conjunction with specific embodiments.

[0063] In order to solve the problem of excessive gas consumption of continuous pneumatic conveying system when running at low load, the present application is based on the original conveying system (such as Figure 2 As shown in the figure, a flow meter 16 is added to the conveying air main pipe 9, a flow regulating valve 14 is added to the main conveying air intake pipe 13, and a PID regulating controller 15 (or intelligent gas volume controller) is added at the same time. First, the functional relationship between the system conveying output and the frequency of the frequency converter 8 corresponding to the rotary feeder 5 is calculated. After field testing, a second-order functional relationship between the frequency of the frequency converter 8 and the conveying gas volume is fitted, so that the frequency value of the frequency converter 8 is input into the PID regulating controller 15 (or intelligent gas volume controller) as a control signal. The input value is calibrated through the feedback signal of the flow meter 16, and the opening of the flow regulating valve 14 is adjusted to match the conveying gas volume with the system conveying output. The present application can greatly reduce the conveying gas consumption under low-load conditions of the system, thereby saving electric energy and enhancing the economic efficiency of the system operation; at the same time, the material conveying speed is reduced, the wear of the pipeline and accessories is reduced, and the service life is increased.

[0064] The specific method is as follows:

[0065] (1) According to the material characteristics (including material name, material density, material particle size, moisture content, etc.) of the existing system, the conveying distance (including horizontal section, vertical section, elbow angle and number) and the conveying pipeline specifications (including the number of pipeline diameter changes and diameter change points, pipeline distributor type and number, etc.), historical data with similar characteristics are selected from the pneumatic conveying database, and the historical data are processed and calculated by the difference method to obtain the approximate gas consumption corresponding to different output conditions of the existing system (multi-point discrete value).

[0066] (2) For the given conditions in (1), the relationship between the real-time output of the conveyed material and the frequency converter frequency is calculated by using the frequency converter frequency of the rotary feeder 5, the speed of the reduction motor 7, the reduction ratio of the reduction motor 7, etc. The specific process is as follows: 1) It is known that the volume per revolution V (m 3 / rev), material filling efficiency φ, material density ρ (kg / m 3 ) then the weight output per revolution is A R =V×φ×ρ(kg / rev);

[0067] 2) It is known that: the power frequency speed of the selected reduction motor 7 is M0 (rpm), the reduction ratio of the reduction motor 7 is i, then the power frequency speed of the rotary feeder 5 is R0 = M0 / i (rpm);

[0068] 3) It is known that: the power frequency is F0 (Hz), the actual operating frequency of the frequency converter is F (Hz), then the actual speed of the rotary feeder 5 is R = F / F0 × R0 = F / F0 × M0 / i (rpm);

[0069] 4) The actual output of the system: A = A R ×R×60=V×φ×ρ×F / F0×M0 / i×60(kg / h), so A=β×F, where the coefficient β=V×φ×ρ / F0×M0 / i×60 is a constant under given conditions; that is, the system output is proportional to the actual frequency of the motor inverter; the given conditions here refer to the selected rotary feeder model, the filling efficiency of the conveyed material (related to the material properties), the material density, the power frequency, the power frequency speed of the selected reduction motor and the reduction ratio of the reduction motor.

[0070] (3) Carry out physical tests under actual working conditions on site, calibrate the calculated value in (1), and obtain the optimal gas consumption data under different outputs. The specific process is as follows:

[0071] 1) According to the estimated relationship between the conveying output and the gas consumption in (1), the conveying output value of each point is selected one by one, and the corresponding frequency is calculated and set on the frequency converter 8 according to the relationship formula between the conveying output and the frequency converter frequency of the rotary feeder 5 in (2), and then the required gas consumption value is obtained by adjusting the aperture of the throttling orifice plate of the air inlet pipeline, and a real material conveying test is carried out;

[0072] 2) By observing the value of the pressure monitoring instrument installed at the inlet of the conveying pipeline, the stability and efficiency of the conveying process can be understood; if the conveying pressure is too high, it means that the conveying speed is slow, the pipe is prone to blockage, and the stability is poor. The aperture of the throttle orifice plate of the air inlet pipeline should be increased; on the contrary, if the conveying pressure is too low, it means that the conveying gas volume is too large and the conveying efficiency is low. At this time, the aperture of the throttle orifice plate of the air inlet pipeline should be reduced; usually, according to the different distances of the conveying pipeline, the optimal conveying pressure should be maintained at 0.10-0.20MPa;

[0073] 3) After the above adjustment test, the optimal gas consumption data under different conveying outputs are obtained, as shown in Table 1 below. 3 / min is the unit of gas flow rate, and N refers to standard operating conditions (i.e., a standard atmospheric pressure and a temperature of 0°C).

[0074] Table 1

[0075] Output A(t / h) A1 A2 A3 A4 A5 … Inverter frequency F(Hz) F1 F2 F3 F4 F5 … <![CDATA[Gas consumption Q (Nm 3 / min)]]> Q1 Q2 Q3 Q4 Q5 …

[0076] (4) The discrete point values ​​of the inverter frequency F and the gas consumption Q are fitted by the "least square method" to obtain the relationship function (second-order function) between the inverter frequency and the gas consumption, that is, Q = a × F 2 +b×F+c, where a, b, c are constants.

[0077] (5) A flow meter 16 is installed on the main air delivery pipe 9, a flow control valve 14 is installed on the main air delivery pipe 13, and an intelligent air volume controller is added (corresponding to the aforementioned PID control controller 15, which can be installed locally or remotely). During actual operation, the material delivery output value required by the process (or other process parameters, such as the SO2 content in the flue gas at the outlet of the desulfurization system) is converted into a frequency value of the inverter 8. After this value is input into the intelligent air volume controller, the required air volume value is calculated in the controller according to the fitting calculation formula. At the same time, the actual air consumption value measured by the flow meter 16 on the air pipeline is also input into the intelligent air volume controller. The flow control valve opening is controlled through PID (Proportional-Integral-Derivative) adjustment output to obtain the required optimal air consumption value.

[0078] In the embodiment of the present application, the best matching relationship between different outputs and gas consumption is found through a combination of calculation and experiment; by adding a flow control valve and a flow meter, the optimal gas volume is matched according to the actual output of the system, and the optimal gas consumption value is obtained through PID adjustment.

[0079] The pneumatic conveying gas volume intelligent control method and pneumatic conveying system provided in the embodiments of the present application have a conveying output that is less than the designed maximum value under most working conditions. The gas consumption is greatly reduced during low-load operation, and the power consumption and pipeline wear are reduced, thereby improving economy. Therefore, the system output is tracked in real time to adjust the gas consumption, which is significantly reduced compared to the gas consumption that is always configured according to the maximum output, thereby ensuring the stable operation of the air compressor station, saving power consumption, reducing the wear of pipelines and pipeline accessories, and improving the economic benefits of users.

[0080] The above is only an exemplary embodiment of the present disclosure and cannot be used to limit the scope of the present disclosure. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the disclosure of the specification and the truth of practice, those skilled in the art will easily think of other embodiments of the present disclosure.

[0081] This application is intended to cover any modifications, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary technical means in the technical field not recorded in the present disclosure.

Claims

1. A method for intelligently controlling the amount of pneumatic conveying gas, characterized in that: Applied in pneumatic conveying systems, including: Determine a target frequency value according to the material conveying output value, wherein the target frequency value is used to represent the frequency of the frequency converter of the rotary feeder in the pneumatic conveying system; Determine a target conveying gas volume corresponding to the target frequency value based on a preset first function, wherein the first function is used to represent the relationship between the frequency of the frequency converter of the rotary feeder and the conveying gas volume of the pneumatic conveying system; Adjusting the opening of a flow control valve according to the target gas delivery volume, wherein the flow control valve is installed in the main delivery air intake pipeline of the pneumatic conveying system, and the flow control valve is used to adjust the delivery gas volume of the main delivery air intake pipeline; Wherein, determining the target conveying gas volume corresponding to the target frequency value based on a preset first function includes: establishing a target configuration relationship table, wherein the target configuration relationship table records the correspondence between multiple groups of frequencies of the frequency converter of the rotary feeder and the conveying gas volume of the pneumatic conveying system; obtaining the first function based on the target configuration relationship table; determining the target conveying gas volume based on the first function; wherein, establishing the target configuration relationship table includes: obtaining N data pairs from a pneumatic conveying database, wherein the N data pairs include historical conveying data of the material, the i-th data pair includes the i-th historical conveying output value and the corresponding i-th historical conveying gas volume, the i-th data pair is any one of the N data pairs, N is a positive integer greater than or equal to 1, and i is a positive integer greater than or equal to 1 and less than or equal to N; for the i-th data pair, performing the following operations to obtain the corrected the i-th data pair: determining the i-th frequency value corresponding to the i-th historical delivery output value; operating the pneumatic conveying system according to the i-th frequency value and the i-th historical delivery gas volume; adjusting the flow regulating valve so that the delivery pressure at the inlet of the delivery air main pipe of the pneumatic conveying system reaches the target pressure value, and recording the current delivery gas volume corresponding to the target pressure value, wherein the current delivery gas volume is measured by a flow meter, the flow meter is installed in the delivery air main pipe, and the target pressure value is within a preset pressure range; determining the current delivery gas volume as the i-th delivery gas volume correction value, and obtaining the corrected i-th data pair, wherein the corrected i-th data pair includes the i-th frequency value and the i-th delivery gas volume correction value; obtaining the target configuration relationship table according to the corrected N data pairs, wherein the corrected N data pairs include the corrected i-th data pair.

2. The method according to claim 1, characterized in that Adjusting the opening of the flow control valve according to the target gas delivery volume includes: Determine a target opening value corresponding to the target gas delivery volume based on a preset second function, wherein the second function is used to represent the relationship between the gas delivery volume and the opening value of the pneumatic conveying system, and the second function is obtained by testing the gas delivery volume of the regulating valve of the pneumatic conveying system under different opening values ​​in advance; The current opening of the flow control valve is adjusted to the target opening value.

3. The method according to claim 1, characterized in that Determine the target frequency value based on the material conveying output value, including: The target frequency value is determined according to the material conveying output value and the following formula: Wherein, A represents the material conveying output value, F0 represents the power frequency, i represents the reduction ratio of the reduction motor, V represents the volume per revolution of the rotary feeder, represents the material filling rate, ρ represents the material density, and M0 represents the industrial frequency speed of the reduction motor.

4. The method according to claim 1, characterized in that Obtaining the first function based on the target configuration relationship table includes: The modified N data pairs are fitted using the least squares method to obtain a target second-order function, and the target second-order function is determined as the first function, wherein the target second-order function is used to represent the functional relationship between the conveying gas volume of the pneumatic conveying system and the frequency of the frequency converter of the rotary feeder.

5. The method according to claim 1, characterized in that Adjusting the opening of the regulating valve according to the target gas delivery volume includes: Obtaining the actual conveying air volume of the conveying air main pipe of the pneumatic conveying system; Based on the actual gas delivery volume and the target gas delivery volume, a target control signal is output through a PID adjustment controller, and the target control signal is used to adjust the opening of the flow control valve.

6. A pneumatic conveying system, characterized in that: The method for executing any one of claims 1 to 5 comprises: a silo (1), a manual gate (2), a receiving pump (3), a feeding pump (4), a rotary feeder (5), a feeding pipe (6), a reduction motor (7), a frequency converter (8), a conveying air main pipe (9), a manual shut-off valve (10), an auxiliary air intake valve group (11), a main air intake valve (12), a main air intake pipeline (13), a flow regulating valve (14), a PID regulating controller (15), and a flow meter (16), wherein: The silo (1) is used to store materials to be transported, the receiving pump (3) is used to receive the materials from the silo (1), the receiving pump (3) is connected to the feeding pump (4) through a valve and a pipeline, and the feeding pump (4) is used to continuously feed the materials into the rotary feeder (5) and then into the conveying pipe (6); The manual plug-in door (2) is arranged in the pipeline between the silo (1) and the material receiving pump (3); The rotary feeder (5) is used to continuously transport the material output by the feed pump (4) through the feed pipe (6); The reduction motor (7) is used to control the rotation speed of the rotary feeder (5), thereby adjusting the conveying amount of the material, and the frequency converter (8) is used to adjust the rotation speed of the reduction motor (7); The receiving pump (3) and the feeding pump (4) are respectively connected to the conveying air main pipe (9) through different auxiliary air intake pipes, and the conveying pipe (6) is connected to the conveying air main pipe (9) through the main conveying air intake pipe (13), wherein a manual shut-off valve (10) is provided in the conveying air main pipe (9), the main conveying air intake pipe (13) is provided with the main conveying air intake valve (12), and the auxiliary air intake pipe is provided with the auxiliary air intake valve group (11); The flow meter (16) is installed in the conveying air main pipe (9) and is used to measure the actual conveying air volume of the pneumatic conveying system; The flow regulating valve (14) is installed in the main air delivery intake pipeline (13) and is used to regulate the air flow of the main air delivery intake pipeline (13); The PID regulating controller (15) is connected to the flow meter (16) and the flow regulating valve (14) respectively, and is used to obtain the actual gas delivery volume, and control the flow regulating valve (14) based on the actual gas delivery volume and the target gas delivery volume.

7. The system according to claim 6, characterized in that The target gas delivery volume is obtained by the PID adjustment controller (15) in the following manner: Determining a target frequency value according to the material conveying output value, wherein the target frequency value is used to represent the frequency of the frequency converter (8); The target conveying gas volume corresponding to the target frequency value is determined based on a preset first function, wherein the first function is used to represent the relationship between the frequency of the frequency converter (8) and the conveying gas volume of the pneumatic conveying system.

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