A gas flow accurate regulation device for preparing formaldehyde

Abstract

The utility model discloses a kind of gas flow accurate regulation and control device of preparation formaldehyde, including gas main pipe and downstream passage connected with formaldehyde synthesis reactor, flow regulation and control unit is equipped between gas main pipe and downstream passage, flow regulation and control unit and downstream passage between being equipped with the pipeline connection component for the pipe line of gas convergence and distribution is merged and distributed.The utility model is in cooperation with the collaborative architecture of integrated flow temperature sensor, pressure sensor and electric regulating valve, can synchronously collect gas flow, temperature, pressure parameter and realize dynamic adjustment, effectively shorten adjustment response time, improve flow control precision, prolong catalyst service life, significantly improve flow regulation and control precision and response speed;Main flow regulation module and spare flow regulation module are connected in parallel, and quick switching is realized by electromagnetic reversing valve;When main branch fault, system can automatically switch to spare branch, reduce production interruption, improve the reliability of device operation.

Description

Technical Field

[0001] This utility model belongs to the technical field of auxiliary equipment for formaldehyde production, specifically relating to a device for precise control of gas flow rate in formaldehyde production. Background Technology

[0002] In the industrial production of formaldehyde, the formaldehyde synthesis reaction has extremely high requirements for the flow rate ratio and pressure stability of the raw material gas. Excessive deviation in the raw material gas ratio can lead to decreased catalyst activity, increased by-products, and even safety hazards such as local overheating of the reactor.

[0003] In existing technologies, flow control often employs a simple closed-loop structure consisting of a single controller, flow meter, and regulating valve. For example, the flow control scheme in the feeding mechanism of a formaldehyde storage tank (publication number CN214004048U) only uses a single flow control valve to achieve basic flow regulation. This type of scheme has significant drawbacks when applied to formaldehyde preparation:

[0004] 1. Insufficient control precision: The lack of a temperature and pressure coordinated compensation mechanism results in a large deviation in flow metering when the pressure or temperature of the gas main changes, which fails to meet the ratio requirements for formaldehyde synthesis.

[0005] 2. Response lag: The single closed-loop control link is long and the valve adjustment response is slow. When faced with instantaneous flow fluctuations, it is easy to overshoot or undershoot, resulting in an imbalance of the inlet gas ratio of the reactor.

[0006] 3. Poor reliability: There is no backup regulating branch. When the regulating valve or flow meter fails, the machine needs to be shut down for maintenance, causing production interruption and significant economic losses.

[0007] Therefore, designing a flow control device with high precision, high reliability, and dynamic compensation to meet the special process requirements of formaldehyde preparation has become the key to improving production efficiency and product quality. Utility Model Content

[0008] The purpose of this invention is to provide a precise flow rate control device for the preparation of formaldehyde, so as to solve the technical defects of existing flow rate control devices, such as insufficient control accuracy, delayed response, and poor reliability.

[0009] To achieve the above objectives, this utility model provides the following technical solution:

[0010] A device for precise control of gas flow rate in formaldehyde preparation includes a gas main pipe and a downstream passage connected to a formaldehyde synthesis reactor. A flow control unit is provided between the gas main pipe and the downstream passage, and a pipeline connection assembly for merging and distributing gas is provided between the flow control unit and the downstream passage.

[0011] The flow control unit includes a main flow control module and a backup flow control module, which are connected in parallel between the gas main and the pipeline connection assembly.

[0012] Both the main flow control module and the backup flow control module include branches, an integrated flow and temperature sensor, and an electric regulating valve. The two branches are divided into a main branch and a backup branch. The gas main pipe is connected to the input end of each of the two branches, and the output end of each branch is connected to the pipeline connection assembly. The integrated flow and temperature sensor and the electric regulating valve are installed on the branches.

[0013] As a further embodiment of this utility model, the two electric regulating valves are divided into a three-way electric regulating valve and a two-way electric regulating valve. The input end of the three-way electric regulating valve is connected to the main branch, the first output end is connected to the pipeline connection assembly, and the second output end is connected to a bypass pipeline. The input end of the two-way electric regulating valve is connected to the spare branch, and the output end is connected to the pipeline connection assembly.

[0014] As a further embodiment of this utility model, a pressure sensor is also installed on the branch line. The pressure sensor is located between the integrated flow and temperature sensor and the electric regulating valve, and is used to correct the preset flow parameters.

[0015] As a further embodiment of this utility model, the pipeline connection assembly includes a Y-shaped pipe and a tee pipe. The two input ends of the Y-shaped pipe are respectively connected to two branches, the output end of the Y-shaped pipe is connected to the tee pipe, and the downstream passage is connected to one of the output ends of the tee pipe.

[0016] As a further embodiment of this invention, a calibration module is also included, which is connected to the other output end of the tee tube.

[0017] The calibration module includes a calibration pipeline, a calibration valve, a standard flow generator, and a recovery main. The input end of the calibration pipeline is connected to the calibration valve, the calibration valve is connected to the other output end of the tee, the output end of the calibration pipeline is connected to the standard flow generator, and the output end of the standard flow generator is connected to the recovery main.

[0018] As a further embodiment of this utility model, the output end of the gas main is connected to an electromagnetic reversing valve for switching between the main and backup branches, and the two branches are respectively connected to the output end of the electromagnetic reversing valve.

[0019] As a further embodiment of this utility model, the electric regulating valve on the main flow regulating module diverts the flow to the recovery main pipe through a bypass pipeline, and a one-way valve is installed at the connection point of the bypass pipeline and the calibration pipeline to the recovery main pipe.

[0020] As a further embodiment of this utility model, a bypass valve is installed on the bypass pipeline, and a process valve is installed on the downstream passage.

[0021] Compared with existing technologies, the gas flow rate precision control device for formaldehyde preparation provided by this utility model has the following advantages:

[0022] 1. The device adopts an integrated flow and temperature sensor, pressure sensor and electric regulating valve collaborative architecture, which can simultaneously collect gas flow, temperature and pressure parameters and realize dynamic adjustment, effectively shorten the adjustment response time, improve the flow control accuracy, meet the stringent requirements of formaldehyde synthesis on the raw material gas ratio, extend the catalyst service life, and significantly improve the flow control accuracy and response speed.

[0023] 2. The main flow regulation module and the backup flow regulation module are connected in parallel in this device and can be quickly switched through an electromagnetic reversing valve; when the main branch fails, the system can automatically switch to the backup branch, reducing production interruption and improving the reliability of the device operation.

[0024] 3. The pressure sensor and temperature sensor work together in this device to sense gas pressure and temperature fluctuations in real time and correct flow deviations through structural design; the three-way electric regulating valve of the main branch diverts overpressure gas through the bypass pipeline, and the one-way valve design of the recovery main pipe prevents gas backflow and improves the safety of system operation. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only examples of embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0027] Figure 2 This is a partial structural diagram of an embodiment of the present utility model. Figure 1 ;

[0028] Figure 3 This is a partial structural diagram of an embodiment of the present utility model. Figure 2 .

[0029] Figure label:

[0030] 100. Gas main pipe;

[0031] 200. Main flow regulation module;

[0032] 300. Backup flow regulation module; 10. Branch line; 20. Integrated flow and temperature sensor; 30. Electric regulating valve; 40. Bypass pipeline; 50. Pressure sensor;

[0033] 400. Pipe connection assembly; 410. Y-type pipe; 420. T-shaped pipe;

[0034] 500, downstream channels;

[0035] 600. Calibration module; 610. Calibration piping; 620. Calibration valve; 630. Standard flow generator; 640. Recovery main;

[0036] 700. Electromagnetic directional valve. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0038] In the description of the embodiments of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model.

[0039] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to the internal connection of two components; they can refer to a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of this utility model can be understood according to the specific circumstances.

[0040] See appendix Figures 1-3 As shown in the figure, an embodiment of the present invention provides a gas flow rate precision control device for the preparation of formaldehyde, including a gas main pipe 100 and a downstream passage 500 connected to a formaldehyde synthesis reactor. A flow rate control unit is provided between the gas main pipe 100 and the downstream passage 500, and a pipeline connection assembly 400 for merging and distributing gas is provided between the flow rate control unit and the downstream passage 500.

[0041] The flow control unit includes a main flow control module 200 and a backup flow control module 300, which are connected in parallel between the gas main pipe 100 and the pipeline connection assembly 400. Both the main flow control module 200 and the backup flow control module 300 include a branch 10, an integrated flow and temperature sensor 20, and an electric regulating valve 30. The two branches 10 are divided into a main branch and a backup branch. The gas main pipe 10 is connected to the input ends of the two branches 10 respectively, and the output ends of the two branches 10 are connected to the pipeline connection assembly 400. The integrated flow and temperature sensor 20 and the electric regulating valve 30 are both installed on the branch 10 through flanges.

[0042] This embodiment of the invention also includes a first controller and a second controller, which are communicatively connected. An integrated flow and temperature sensor 20 is electrically connected to the first controller, and an electric regulating valve 30 is electrically connected to the second controller, forming a dual closed-loop control. Both the first and second controllers are PLC controllers, and they interact with each other via an industrial Ethernet network. The first controller has a built-in flow prediction algorithm module, which is used to adjust the pre-opening degree of the electric regulating valve 30 based on historical data. The invention constructs a basic architecture for detection, control, and execution, and achieves redundancy design through parallel connection of main and backup modules. The dual closed-loop control provides hardware support for high-precision regulation, solving the problems of low reliability and insufficient regulation accuracy of single-branch systems in existing technologies, and meeting the continuous production requirements of formaldehyde preparation.

[0043] When using the gas flow rate precision control device for formaldehyde preparation described above:

[0044] Normal production conditions: The raw material gas flows sequentially through the main gas pipe 100, the electromagnetic reversing valve 700, the main branch, the integrated flow and temperature sensor 20, the pressure sensor 50, the three-way electric regulating valve, the Y-type pipe 410, the three-way pipe 420, and the downstream passage 500 to the formaldehyde synthesis reactor.

[0045] Control logic: The first controller receives flow, temperature, and pressure signals, calculates correction values ​​based on preset flow parameters, and transmits the corrected adjustment command to the second controller; the second controller drives the opening of the three-way electric regulating valve to stabilize the actual flow within the target value range; at the same time, the flow prediction algorithm of the first controller predicts the flow trend based on historical data, guides the second controller to pre-adjust the valve, and reduces overshoot.

[0046] Main branch circuit fault condition: The trigger condition is when the three-way electric regulating valve fails or the data of each sensor in the main branch circuit exceeds the threshold, the second controller determines that the main branch circuit is faulty.

[0047] Switching logic: The second controller drives the solenoid reversing valve 700 to switch to the backup branch, while closing the relevant valves of the main branch; the raw material gas passes through the backup branch, the integrated flow and temperature sensor 20, the pressure sensor 50, the two-way electric regulating valve, the Y-tube 410 and the downstream passage 500 in sequence to ensure the stability of the gas ratio at the reactor inlet.

[0048] Calibration condition: The calibration process is automatically started when the first controller detects that the cumulative flow deviation exceeds the limit.

[0049] Calibration logic: The second controller closes the process valve of the downstream passage 500 and opens the calibration valve 620 of the calibration module 600; the gas passes through the three-way pipe 420, the calibration pipeline 610, the standard flow generator 630 and the recovery main pipe 640 in sequence; the first controller compares the detection value of the integrated flow and temperature sensor 20 of the main branch with the standard flow value, automatically corrects the coefficient of the integrated flow and temperature sensor 20, and switches back to normal production conditions after calibration is completed.

[0050] Overpressure protection condition: The trigger condition is when the pressure sensor 50 detects that the pressure of the main branch exceeds the safety threshold, the first controller sends a pressure reduction command to the second controller.

[0051] Control logic: The second controller drives the bypass line 40 of the three-way electric regulating valve to open. Some gas passes through the bypass line 40, the check valve and the recovery main line 640 in sequence until the pressure drops to a safe range. The check valve of the bypass line 40 prevents gas backflow in the recovery main line 640 and ensures the pressure of the main branch line is stable.

[0052] The two electric regulating valves 30 are a three-way electric regulating valve and a two-way electric regulating valve. The input end of the three-way electric regulating valve is connected to the main branch, the first output end is connected to the pipeline connection assembly 400, and the second output end is connected to the bypass pipeline 40. The input end of the two-way electric regulating valve is connected to the standby branch, and the output end is connected to the pipeline connection assembly 400. The main branch realizes the dual function of main passage and bypass diversion through the three-way electric regulating valve to cope with overpressure conditions. The standby branch uses a two-way electric regulating valve to reduce costs while ensuring flow stability during switching, taking into account both functionality and economy.

[0053] A pressure sensor 50 is also installed on branch 10 via a flange. The pressure sensor 50 is electrically connected to the first controller. The pressure sensor 50 is located between the integrated flow and temperature sensor 20 and the electric regulating valve 30. It is used to correct the preset flow parameters and collect gas pressure data in real time. The first controller can dynamically compensate for the measurement deviation caused by pressure fluctuations based on the pressure and flow correction model, improve the flow control accuracy, and solve the problem of decreased accuracy caused by the lack of pressure compensation in the existing technology.

[0054] The pipeline connection assembly 400 includes a Y-shaped pipe 410 and a tee pipe 420. The two input ends of the Y-shaped pipe 410 are connected to two branches 10 through flanges, and the output end of the Y-shaped pipe 410 is connected to the tee pipe 420 through a flange. The downstream passage 500 is connected to one of the output ends of the tee pipe 420 through a flange. The Y-shaped pipe 410 efficiently merges the gas from the main and backup branches, and the tee pipe 420 realizes the flow separation between the downstream passage 500 and the calibration module 600. The structure is compact and the flow field is stable, avoiding flow measurement errors caused by gas turbulence.

[0055] This embodiment of the invention also includes a calibration module 600, which is connected to another output terminal of the three-way tube 420.

[0056] The calibration module 600 includes a calibration pipeline 610, a calibration valve 620, a standard flow generator 630, and a recovery main pipe 640. The input end of the calibration pipeline 610 is connected to the calibration valve 620 via a flange, and the calibration valve 620 is connected to the other output end of the tee pipe 420 via a flange. The output end of the calibration pipeline 610 is connected to the standard flow generator 630, and the output end of the standard flow generator 630 is connected to the recovery main pipe 640. The calibration valve 620 is electrically connected to the first controller. It can perform online accuracy calibration of the integrated flow and temperature sensor 20 without disassembly. The standard flow generator 630 provides a reference value to ensure that the flow measurement deviation is within a reasonable range during long-term operation, solving the problems of existing technologies that require shutdown for calibration and have high maintenance costs.

[0057] The output end of the gas main 100 is connected to an electromagnetic directional valve 700 for switching between the main and backup branches. The two branches 10 are respectively connected to the output end of the electromagnetic directional valve 700. The electromagnetic directional valve 700 is electrically connected to the second controller. This enables rapid switching between the main and backup branches, reduces flow fluctuations during the switching process, avoids production interruptions caused by branch failures, and improves the system's resilience.

[0058] The electric regulating valve 30 on the main flow regulating module 200 diverts the flow to the recovery main pipe 640 through the bypass pipe 40. A one-way valve is installed at the connection point of the bypass pipe 40 and the calibration pipe 610 in the recovery main pipe 640 to prevent the gas in the recovery main pipe 640 from flowing back to the main branch or the calibration module 600, thereby avoiding contamination of the sensor and affecting the calibration accuracy, and ensuring the stability of system operation.

[0059] A bypass valve is installed on the bypass line 40, and a process valve is installed on the downstream passage 500. The bypass valve and the process valve are electrically connected to the second controller. The bypass valve can accurately control the diversion flow rate and adapt to different overpressure conditions. The process valve enables the rapid opening and closing of the downstream passage 500. When used in conjunction with the calibration module 600, it can isolate the process system, ensure calibration accuracy, and improve operational safety.

[0060] The integrated flow and temperature sensor 20 can be an MF5700 series mass flow sensor with a built-in PT100 temperature sensor, supporting simultaneous output of flow and temperature signals to meet the requirements of coordinated flow and temperature detection in formaldehyde preparation. The pressure sensor 50 can be a PX409-1.0KG5V pressure sensor, which can capture pipeline pressure fluctuations in real time and provide data support for flow correction. It is recommended that all sensors be made of 316 stainless steel. The first controller can be a Siemens S7-1214C PLC controller, which supports industrial Ethernet communication and can access flow, temperature, and pressure sensor signals. The built-in PID control module can run flow prediction algorithms (pre-adjustment logic based on historical data). The second controller can be a Mitsubishi FX5-32MT PLC controller, which can drive actuators such as the electric regulating valve 30 and the solenoid directional valve 700. It interacts with the first controller via Ethernet to form a dual closed-loop control link.

[0061] In summary, the present invention provides a gas flow rate precision control device for formaldehyde preparation, which adopts a collaborative architecture of an integrated flow and temperature sensor 20, a pressure sensor 50, and an electric regulating valve 30. It can simultaneously collect gas flow rate, temperature, and pressure parameters and achieve dynamic adjustment, effectively shortening the adjustment response time, improving flow control accuracy, meeting the stringent requirements of formaldehyde synthesis for raw material gas ratio, extending catalyst life, and significantly improving flow control accuracy and response speed.

[0062] In a gas flow rate precision control device for formaldehyde preparation according to an embodiment of this utility model, the main flow rate control module 200 and the backup flow rate control module 300 are connected in parallel and quickly switched by an electromagnetic reversing valve 700; when the main branch fails, the system can automatically switch to the backup branch, reducing production interruptions and improving the reliability of the device operation.

[0063] The pressure sensor 50 and the integrated flow and temperature sensor 20 work together to sense gas pressure and temperature fluctuations in real time and correct flow deviations through structural design. The three-way electric regulating valve of the main branch diverts overpressure gas through the bypass pipeline, and the one-way valve design of the recovery main pipe 640 prevents gas backflow and improves the safety of system operation.

[0064] The foregoing has shown and described the basic principles of the present invention. The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. The above embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Any modifications, equivalent substitutions, and improvements made within the scope of the present invention without departing from the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for precisely controlling the gas flow rate in the preparation of formaldehyde, characterized in that: It includes a gas main (100) and a downstream passage (500) connected to the formaldehyde synthesis reactor. A flow control unit is provided between the gas main (100) and the downstream passage (500). A pipeline connection assembly (400) for merging and distributing gas is provided between the flow control unit and the downstream passage (500). The flow control unit includes a main flow control module (200) and a backup flow control module (300), which are connected in parallel between the gas main pipe (100) and the pipeline connection assembly (400). Both the main flow regulating module (200) and the backup flow regulating module (300) include a branch (10), an integrated flow and temperature sensor (20), and an electric regulating valve (30). The two branches (10) are divided into a main branch and a backup branch. The gas main pipe (100) is connected to the input end of the two branches (10) respectively. The output end of the two branches (10) is connected to the pipeline connection assembly (400). The integrated flow and temperature sensor (20) and the electric regulating valve (30) are both installed on the branch (10).

2. The device for precisely controlling the gas flow rate in the preparation of formaldehyde according to claim 1, characterized in that: The two electric regulating valves (30) are divided into a three-way electric regulating valve and a two-way electric regulating valve. The input end of the three-way electric regulating valve is connected to the main branch, the first output end is connected to the pipeline connection assembly (400), and the second output end is connected to the bypass pipeline (40). The input end of the two-way electric regulating valve is connected to the spare branch, and the output end is connected to the pipeline connection assembly (400).

3. The device for precisely controlling the gas flow rate in the preparation of formaldehyde according to claim 2, characterized in that: A pressure sensor (50) is also installed on the branch (10). The pressure sensor (50) is located between the integrated flow and temperature sensor (20) and the electric regulating valve (30) and is used to correct the preset flow parameters.

4. The device for precisely controlling the gas flow rate in the preparation of formaldehyde according to claim 3, characterized in that: The pipeline connection assembly (400) includes a Y-shaped pipe (410) and a tee pipe (420). The two input ends of the Y-shaped pipe (410) are respectively connected to two branches (10), and the output end of the Y-shaped pipe (410) is connected to the tee pipe (420). The downstream passage (500) is connected to one of the output ends of the tee pipe (420).

5. The device for precisely controlling the gas flow rate in the preparation of formaldehyde according to claim 4, characterized in that: It also includes a calibration module (600), which is connected to the other output of the tee (420); The calibration module (600) includes a calibration pipeline (610), a calibration valve (620), a standard flow generator (630), and a recovery main pipe (640). The input end of the calibration pipeline (610) is connected to the calibration valve (620), the calibration valve (620) is connected to the other output end of the tee pipe (420), the output end of the calibration pipeline (610) is connected to the standard flow generator (630), and the output end of the standard flow generator (630) is connected to the recovery main pipe (640).

6. The device for precisely controlling the gas flow rate in the preparation of formaldehyde according to claim 5, characterized in that: The output end of the gas main (100) is connected to an electromagnetic reversing valve (700) for switching between the main and backup branches, and the two branches (10) are respectively connected to the output end of the electromagnetic reversing valve (700).

7. The device for precisely controlling the gas flow rate in the preparation of formaldehyde according to claim 6, characterized in that: The electric regulating valve (30) on the main flow regulating module (200) is diverted to the recovery main pipe (640) through the bypass pipe (40). The bypass pipe (40) and the calibration pipe (610) are equipped with a one-way valve at the connection point of the recovery main pipe (640).

8. The device for precisely controlling the gas flow rate in the preparation of formaldehyde according to claim 7, characterized in that: A bypass valve is installed on the bypass pipeline (40), and a process valve is installed on the downstream passage (500).

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