PLC-based microwave constant temperature control device for microchannel reactor

Abstract

The utility model relates to the technical field of reactor temperature control, in particular to a PLC (programmable logic controller)-based microwave constant-temperature control device for a micro-channel reactor, which is characterized in that a microwave generator is mounted on a reaction cavity of the micro-channel reactor and adopts a magnetron; then a constant temperature control unit for controlling the power of the magnetron to change is optimized and improved, a temperature sensor and a PLC constant temperature control circuit are used for controlling the microwave generation frequency of the magnetron, and a solid-state voltage regulator and the like are introduced into the PLC constant temperature control circuit, so that the constant temperature control difficulty in the micro-channel reactor is reduced, and the microwave generation frequency of the magnetron is controlled. The temperature change of the magnetron is intelligently controlled in real time according to the temperature change condition in the micro-channel reactor, and the temperature control difficulty is reduced.

Description

Technical Field

[0001] This utility model relates to the field of reactor temperature control technology, and in particular to a PLC-based microwave constant temperature control device for microchannel reactors. Background Technology

[0002] Intelligent microchannel heating and temperature control technology is an enhancement technology for chemical reaction processes and will become one of the key technologies for achieving efficient, safe, and environmentally friendly chemical production. Microwave reactors are reactors that use microwaves for heating, while microchannel reactors are reactors manufactured using precision machining technology, achieving fluid channel sizes at the micrometer level, thereby enhancing the chemical reaction process. Adding microwave heating to a microchannel reactor results in a microwave-heated microchannel reactor. However, due to the extremely small size of the fluid channels in the microchannel reactor, temperature control during microwave heating is challenging, leading to significant temperature fluctuations and limiting the heating rate of the chemical reaction. Therefore, how to control the temperature during microwave heating has become a pressing technical problem for those skilled in the art, attracting widespread attention and leading to relevant research.

[0003] For example, patent number 201910370172.0 discloses a constant temperature control system for a batch microwave reactor. This constant temperature control system sets up a microwave reflector in the batch microwave reactor. By controlling the reflection direction of the microwave reflector, the microwave heating point in the batch microwave reactor can be moved, effectively spreading energy to the entire reactor. At the same time, through excellent and optimized PLC dual-module control and PID fuzzy control, the system receives and processes the difference between at least three temperature detection signals and the temperature setpoint, and adjusts the power of the microwave transmitter, the speed of the stirring spindle motor, and the speed of the motor connected to the microwave reflector to achieve precise temperature control in the heating field.

[0004] For example, patent number 201820972283.X discloses a microwave chemical constant temperature control system, which includes a heating cavity with a microwave feed device, a microwave chemical reactor disposed in the heating cavity, and a PLC heat exchange control device. The PLC heat exchange control device includes a PLC controller, a heat exchange device electrically connected to the PLC controller for exchanging heat with the microwave chemical reactor, and a temperature detection element electrically connected to the PLC controller for detecting the temperature of the microwave chemical reactor, thereby realizing real-time temperature acquisition and output signal control of the heat exchange device to perform constant temperature regulation.

[0005] For example, patent number 202123174291.0 discloses a high-voltage drive circuit for a medical microwave magnetron, including a drive transformer, a half-bridge converter, a step-up transformer, a voltage doubler rectifier circuit, and a sampling module. The drive transformer with dual secondary windings amplifies the small pulse signal from the microcontroller and alternately inputs it into the half-bridge converter to form a high-quality AC signal, which is then input into the step-up transformer with secondary slotted windings and the voltage doubler rectifier circuit. Three sampling modules are then used to detect the circuit output status in a timely manner to ensure stable circuit output.

[0006] In view of this, based on our long-term research on temperature control of microchannel reactors, our research team applied the magnetron as a microwave generating unit to the microchannel reactor. Furthermore, in order to meet the practical application requirements of microwave heating of microchannel reactors, we improved and optimized the microwave constant temperature control system, which enhanced the intelligence and convenience of microwave heating control of microchannel reactors and reduced the difficulty of constant temperature control. Utility Model Content

[0007] To address the aforementioned technical issues, this invention provides a PLC-based microwave constant temperature control device for microchannel reactors.

[0008] The specific technical solution is as follows:

[0009] A PLC-based microwave thermostat control device for a microchannel reactor includes a reaction chamber, a transformer, and a temperature transmitter PT100. A temperature sensor is installed inside the reaction chamber, and a microwave generator is installed on the reaction chamber. The microwave generator contains a magnetron and also includes a thermostat control unit. The temperature transmitter PT100 is installed on the reaction chamber. The temperature sensor is electrically connected to the thermostat control unit via the temperature transmitter PT100. The thermostat control unit is connected to the magnetron via the transformer. The thermostat control unit includes a PLC thermostat control circuit and a power supply for powering the PLC thermostat control circuit.

[0010] A microwave generator, which uses a magnetron, is installed on the reaction chamber of a microchannel reactor. The temperature control unit that controls the power of the magnetron is then optimized and improved. A temperature sensor and a PLC temperature control circuit are used to control the microwave generation frequency of the magnetron. A solid-state voltage regulator is introduced into the PLC temperature control circuit to reduce the difficulty of temperature control in the microchannel reactor. This enables intelligent control of the magnetron temperature based on the temperature changes inside the microchannel reactor, thus reducing the difficulty of temperature control.

[0011] The PLC constant temperature control circuit used in this invention includes a PLC controller and a solid-state voltage regulator. An EM AM06 module is installed on the PLC controller. The temperature transmitter PT100 is connected to the input terminal of the EM AM06 module, and the solid-state voltage regulator is connected to the output terminal of the EM AM06 module. The power supply is wired to the input terminal of the PLC controller. This enables real-time monitoring of the temperature inside the microchannel reactor. Based on the monitoring results, the power of the microwaves generated by the magnetron is adjusted using the voltage regulation function of the solid-state voltage regulator, thereby achieving temperature control and realizing intelligent temperature control.

[0012] For ease of operation, the PLC controller described in this invention is equipped with a human-machine interface (HMI) via a wire connection. The PLC controller is a Siemens S7-200SMART SR20. This PLC controller is a self-programmable controller.

[0013] To protect the PLC constant temperature control circuit and accurately control the heating and cooling process of the magnetron inside the microwave generator, while also controlling the magnetron's power output to achieve constant temperature control within the reaction chamber, the PLC constant temperature control circuit preferably includes the primary coil L1 of the transformer, a cooling fan, relays KA2 and KA3, short-circuit protection S3, a temperature controller ST, and a fuse FU. The fuse FU is installed in the connection circuit between the power supply and the PLC controller; the power supply is connected to the temperature controller ST via the fuse FU, and the power supply is also connected to the short-circuit protection S3 via the temperature controller ST. The power supply is connected to the relay KA3 via the temperature controller ST. The power supply is connected to the solid-state voltage regulator and relay KA2 via relay KA3. The power supply is connected to the cooling fan via relay KA2. The power supply is connected to the primary coil L1 via the solid-state voltage regulator. The input terminals I0.0, I0.1, I0.2, I0.3, and I0.4 of the PLC controller are respectively connected to start SB1, stop SB2, reset SB3, short circuit protection S3, and temperature controller ST. The output terminals Q0.1 and Q0.2 of the PLC controller are respectively connected to relay KA2 and relay KA3.

[0014] To ensure the lighting requirements of the reaction chamber, the PLC constant temperature control circuit preferably includes a relay KA1 and a lighting lamp. The power supply is connected to the relay KA1 through the temperature controller ST, and the power supply is connected to the lighting lamp through the relay KA1. The output terminal Q0.0 of the PLC controller is connected to the relay KA1.

[0015] To improve safety, preferably, the PLC constant temperature control circuit further includes a door lock switch S1, a door lock switch S2, and a buzzer. The power supply is connected to the wires of the door lock switch S1 and the door lock switch S2, and the power supply is also connected to the wire of the buzzer. The output terminal Q0.3 of the PLC controller is connected to the buzzer, and the input terminals I0.5 and I0.6 of the PLC controller are connected to the door lock switch S1 and the door lock switch S2, respectively.

[0016] In order to ensure accurate temperature monitoring within the reaction chamber, timely feedback of the reaction temperature within the reaction chamber to the PLC control, timely control of the frequency of microwaves generated by the magnetron, and improve the accuracy of constant temperature control, preferably, the reaction chamber is provided with a fluid inlet and a fluid outlet, and at least three temperature sensors are respectively installed at the fluid inlet, the fluid outlet, and the midpoint between the fluid inlet and the fluid outlet.

[0017] The reaction chamber in this invention can be a microchannel reactor or a microchannel reactor can be installed inside the reaction chamber. When setting the temperature sensor, it is respectively placed at the inlet, outlet, and midway between the inlet and outlet of the fluid flow channel in the microchannel reactor. This helps to improve the accuracy of temperature control within the microchannel reactor and reduces the difficulty of temperature control.

[0018] Compared with the prior art, the technical effects of this invention are reflected in:

[0019] This invention utilizes a constant temperature control unit to adjust the power input frequency of the magnetron to indirectly regulate the output power of the magnetron, thereby adjusting the frequency of microwave generation by the magnetron. Combined with a temperature sensor to collect real-time temperature and feed the real-time temperature back to the constant temperature control unit, the magnetron's microwave output power is adjusted by comparing the target temperature set within the constant temperature control unit, thus reducing the difficulty of constant temperature control in microchannel reactors.

[0020] In order to avoid the direct heating of the temperature sensor by microwaves, which would cause errors in temperature acquisition, this invention uses a temperature sensor that does not absorb microwaves, such as a thermocouple temperature sensor or a resistance temperature sensor.

[0021] This invention has a simple structure, is easy to operate and improve, and can effectively reduce the difficulty of temperature control within the microchannel structure of a microchannel reactor. Attached Figure Description

[0022] In order to enable those skilled in the art to fully understand the technical solution of the present invention, the following description is made in conjunction with the technical solution content and the accompanying drawings.

[0023] Figure 1 This invention provides a schematic diagram of the principle framework of a PLC-based microwave constant temperature control device.

[0024] Figure 2 The schematic diagram of the main circuit of the PLC-based microwave constant temperature control device for this invention is shown.

[0025] Figure 3 for Figure 2 PLC wiring diagram.

[0026] 1-Reaction chamber 2-Microwave generator 3-Solid-state voltage regulator 4-PLC controller 5-Human-machine interface 6-Temperature sensor 7-Power supply 8-PLC constant temperature control circuit 9-Magnetron 10-Lighting lamp 11-Cooling fan 12-Buzzer 13-Primary coil L1. Detailed Implementation

[0027] To facilitate a correct understanding of the present invention by those skilled in the art, and to enable them to fully understand the technical content of the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. However, this description does not limit the scope of protection claimed by the present invention. Those skilled in the art should not limit the scope of protection of the present invention to the following description. Any equivalent substitutions or changes made by those skilled in the art or those familiar with the art based on the present invention, and based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0028] like Figure 1 and Figure 2 As shown, in some embodiments, the microchannel reactor uses a PLC-based microwave thermostat control device, including a reaction chamber 1, a transformer, and a temperature transmitter PT100, a temperature sensor 6 installed inside the reaction chamber 1, and a microwave generator 2 installed on the reaction chamber 1. The microwave generator 2 has a magnetron 9 inside. The device is characterized by further including a thermostat control unit. The temperature transmitter PT100 is installed on the reaction chamber 1, and the temperature sensor 6 is electrically connected to the thermostat control unit via the temperature transmitter PT100. The thermostat control unit is connected to the magnetron 9 via the transformer. The thermostat control unit includes a PLC thermostat control circuit 8 and a power supply 7 for supplying power to the PLC thermostat control circuit 8. A PLC constant temperature control circuit 8 is used as the control system. By connecting the PLC constant temperature control circuit 8 with the temperature sensor 6, the real-time temperature collected by the temperature sensor 6 is compared with the set temperature in the PLC constant temperature control circuit 8. Based on the comparison result, the output microwave power of the magnetron 9 is adjusted and controlled to achieve the purpose of constant temperature control and regulation, thus reducing the difficulty of constant temperature control in the microchannel reactor.

[0029] like Figure 2 and Figure 3 As shown, in some embodiments, the PLC constant temperature control circuit includes a PLC controller 4 and a solid-state voltage regulator 3. An EM AM06 module is installed on the PLC controller 4. The temperature transmitter PT100 is connected to the input terminal of the EM AM06 module, and the solid-state voltage regulator 3 is connected to the output terminal of the EM AM06 module. The power supply 7 is wired to the input terminal of the PLC controller 4. By constructing a closed-loop control circuit using the programmable PLC controller, the solid-state voltage regulator SSVR, the temperature sensor 6, and the magnetron 9, the microwave output power of the magnetron 9 can be automatically adjusted, thereby achieving automatic constant temperature control and reducing the difficulty of constant temperature control within the microchannel reactor. In the actual research process of this invention, the PLC controller 4 used is a Siemens S7-200SMART SR20. The EM AM06 analog module can control the solid-state voltage regulator SSVR with signals. Combined with the self-programmed target temperature value set by the PLC controller 4 and the temperature collected by the temperature sensor 6, the PLC controller 4 is fed back. The PLC controller performs PID calculation on the real-time temperature collected by the temperature sensor 6 and the set target temperature, and outputs a control signal to the solid-state voltage regulator SSVR, thereby controlling the power of the magnetron to generate microwaves.

[0030] like Figure 2 and Figure 3As shown, in some embodiments, the PLC constant temperature control circuit further includes the primary coil L113 of the transformer, a cooling fan 11, relays KA2 and KA3, short-circuit protection S3, a temperature controller ST, and a fuse FU. The fuse FU is installed in the connection circuit between the power supply 7 and the PLC controller 4. The power supply 7 is connected to the temperature controller ST through the fuse FU, to the short-circuit protection S3 through the temperature controller ST, and to the relay KA3 through the temperature controller ST. The power supply 7 is connected to the solid-state voltage regulator 3 and the relay KA2 via the relay KA3. The power supply 7 is connected to the cooling fan 11 via the relay KA2. The power supply 7 is connected to the primary coil L113 via the solid-state voltage regulator 3. The input terminals I0.0, I0.1, I0.2, I0.3, and I0.4 of the PLC controller 4 are respectively connected to start SB1, stop SB2, reset SB3, short circuit protection S3, and temperature controller ST. The output terminals Q0.1 and Q0.2 of the PLC controller 4 are respectively connected to relay KA2 and relay KA3. The temperature controller ST has two sets of normally closed contacts. One set is connected to the main circuit, and the other set is connected to I0.4 of the PLC controller 4. When I0.4 is on, the temperature control is normal. When the temperature controller ST detects that the temperature of the magnetron 9 is too high, for example, when the temperature limit of the magnetron 9 detected by the temperature controller ST is 120℃, the temperature controller ST will disconnect when the temperature exceeds 120℃, the main circuit will be de-energized, the I0.4 signal point will become "0", the protection will be activated, and a message will be displayed that "the temperature of the magnetron 9 is too high, use with caution" to improve safety.

[0031] like Figure 2 and Figure 3 As shown, in some embodiments, the PLC constant temperature control circuit further includes a relay KA1 and a lighting lamp 10. The power supply 7 is connected to the relay KA1 through the temperature controller ST, and the power supply 7 is connected to the lighting lamp 10 through the relay KA1. The output terminal Q0.0 of the PLC controller 4 is connected to the relay KA1. This satisfies the lighting requirements.

[0032] like Figure 2 and Figure 3As shown, in some embodiments, the PLC constant temperature control circuit further includes door lock switches S1 and S2 and a buzzer 12. The power supply 7 is wired to door lock switches S1 and S2 respectively, and the power supply 7 is wired to the buzzer 12. The output terminal Q0.3 of the PLC controller 4 is connected to the buzzer 12, and the input terminals I0.5 and I0.6 of the PLC controller 4 are connected to door lock switches S1 and S2 respectively. This ensures that before the PLC constant temperature control circuit starts working and controls the magnetron 9 to generate microwaves, it can detect whether the door lock on the microchannel reactor or the reaction chamber containing the microchannel reactor is closed. If it is not closed or not closed properly, a warning is issued through the buzzer 12, for example, giving a warning message such as "Door lock not closed, please close," and the microwave generating unit 2 cannot be started normally to generate microwaves, thus prompting and alerting the microchannel reactor operators and improving safety.

[0033] like Figure 1 and Figure 3 As shown, the PLC controller 4 of this invention is equipped with a human-machine interface 5 via a wire. The reaction chamber 1 has a fluid inlet and a fluid outlet, and at least three temperature sensors 6 are installed at the fluid inlet, the fluid outlet, and the midpoint between the fluid inlet and the fluid outlet. This allows for timely adjustment and control of the microwave power generated by the magnetron 9 based on the temperature at the fluid inlet, the fluid outlet, and the midpoint between the fluid inlet and the fluid outlet, reducing the difficulty of constant temperature control and improving the accuracy of constant temperature control within the microchannel reactor. For example, the temperature collected by the temperature sensor 6 at the fluid inlet is T1, the temperature collected by the temperature sensor 6 at the fluid outlet is T3, and the temperature collected at the midpoint between the fluid inlet and the fluid outlet is T2. Alarm values ​​are set for these three temperature values ​​(T1, T2, and T3) in the PLC controller 4, and these three temperature values ​​can be monitored by... Figure 3The temperature transmitter PT100 shown feeds back to the PLC controller 4. When the actual temperature exceeds the alarm value, the system will alarm and issue a warning, and will force a shutdown when one of the temperature values ​​exceeds the alarm value. In this invention, temperature value T3 is used as the real-time temperature, and the two real-time acquired temperature values ​​T2 and T1 are used as auxiliary feedback temperature values. After PID calculation processing using T3 as the real-time acquired temperature value and the target temperature value set on the PLC controller 4, a control signal is output to the solid-state voltage regulator SSVR to control the working power of the magnetron 9. At this time, temperature sensor 6, which acquires the temperature value of T3, is the feedback element; temperature sensors 6, which acquire the temperature values ​​of T2 and T1, are the auxiliary feedback elements; the PLC controller is the judgment and data processing element; the SSVR is the control element; and the magnetron 9 is the execution element. This realizes that the PLC controller 4 outputs a changing signal to the SSVR, thereby controlling the magnetron to output microwaves of different powers, so that the error between the actual temperature value and the target temperature value set by the PLC controller 4 is close to infinitesimal, achieving the effect of constant temperature control heating.

[0034] This invention employs dual magnetron overheat protection in the constant temperature control unit. By directly connecting to the power supply and feeding the signal back to the PLC controller, and then using the solid-state voltage regulator (SSVR), the microwave power generated by the magnetron 9 is adjusted and controlled, thereby improving the constant temperature control effect and reducing the difficulty of constant temperature control.

[0035] For any other matters not covered in this invention, they can be implemented by referring to existing technology or common knowledge known to those skilled in the art, and by conventional technical means. For example, the magnetron 9 driving circuit diagram used in this invention is shown below. Figure 2 The circuit diagram shown or other existing circuit diagrams are acceptable.

Claims

1. A PLC-based microwave constant temperature control device for a microchannel reactor, comprising a reaction chamber (1), a transformer and a temperature transmitter PT100, a temperature sensor (6) installed inside the reaction chamber (1) and a microwave generator (2) installed on the reaction chamber (1), wherein a magnetron (9) is provided inside the microwave generator (2), characterized in that, It also includes a constant temperature control unit, wherein the temperature transmitter PT100 is installed on the reaction chamber (1), and the temperature sensor (6) is connected to the constant temperature control unit via the temperature transmitter PT100 through an electrical signal; the constant temperature control unit is connected to the magnetron (9) through the transformer; the constant temperature control unit includes a PLC constant temperature control circuit (8) and a power supply (7) for supplying power to the PLC constant temperature control circuit (8).

2. The PLC-based microwave constant temperature control device for the microchannel reactor according to claim 1, characterized in that, The PLC constant temperature control circuit includes a PLC controller (4) and a solid voltage regulator (3). An EMAM06 module is installed on the PLC controller (4). The temperature transmitter PT100 is connected to the input terminal of the EMAM06 module, and the solid voltage regulator (3) is connected to the output terminal of the EMAM06 module. The power supply (7) is wired to the input terminal of the PLC controller (4).

3. The PLC-based microwave constant temperature control device for the microchannel reactor according to claim 2, characterized in that, The PLC constant temperature control circuit also includes the primary coil L1 (13) of the transformer, a cooling fan (11), relays KA2 and KA3, short circuit protection S3, a temperature controller ST, and a fuse FU. The fuse FU is installed in the connection circuit between the power supply (7) and the PLC controller (4). The power supply (7) is connected to the temperature controller ST through the fuse FU. The power supply (7) is connected to the short circuit protection S3 through the temperature controller ST. The power supply (7) is connected to the relay KA3 through the temperature controller ST. The power supply (7) is connected to the relay KA3 through the relay KA3. The device KA3 is connected to the solid-state voltage regulator (3) and the relay KA2. The power supply (7) is connected to the cooling fan (11) through the relay KA2. The power supply (7) is connected to the primary coil L1 (13) through the solid-state voltage regulator (3). The input terminals I0.0, I0.1, I0.2, I0.3, and I0.4 of the PLC controller (4) are respectively connected to start SB1, stop SB2, reset SB3, short circuit protection S3, and temperature controller ST. The output terminals Q0.1 and Q0.2 of the PLC controller (4) are respectively connected to relay KA2 and relay KA3.

4. The PLC-based microwave constant temperature control device for the microchannel reactor according to claim 3, characterized in that, The PLC constant temperature control circuit also includes a relay KA1 and a lighting lamp (10). The power supply (7) is connected to the relay KA1 through the temperature controller ST. The power supply (7) is connected to the lighting lamp (10) through the relay KA1. The output terminal Q0.0 of the PLC controller (4) is connected to the relay KA1.

5. The PLC-based microwave constant temperature control device for the microchannel reactor according to claim 2 or 3, characterized in that, The PLC constant temperature control circuit also includes door lock switch S1, door lock switch S2 and buzzer (12). The power supply (7) is connected to the door lock switch S1 and door lock switch S2 by wires respectively, and the power supply (7) is connected to the buzzer (12) by wires respectively. The output terminal Q0.3 of the PLC controller (4) is connected to the buzzer (12), and the input terminals I0.5 and I0.6 of the PLC controller (4) are connected to the door lock switch S1 and door lock switch S2 respectively.

6. The PLC-based microwave constant temperature control device for the microchannel reactor according to claim 2 or 3, characterized in that, The PLC controller (4) is a Siemens S7-200SMARTSR20.

7. The PLC-based microwave constant temperature control device for the microchannel reactor according to claim 1, 2, or 3, characterized in that, The power supply (7) is AC220V.

8. The PLC-based microwave constant temperature control device for the microchannel reactor according to claim 2 or 3, characterized in that, The PLC controller (4) is equipped with a human-machine interface (5) via a wire number.

9. The PLC-based microwave constant temperature control device for the microchannel reactor according to claim 8, characterized in that, The reaction chamber (1) is provided with a fluid inlet and a fluid outlet, and there are at least three temperature sensors (6), which are respectively installed at the fluid inlet, the fluid outlet and the midpoint between the fluid inlet and the fluid outlet.

Images