Heating system based on back pressure and temperature cooperative control

Abstract

The utility model discloses a kind of heating system based on back pressure and temperature collaborative control, it is related to oil and gas storage and transportation automation technical field.The utility model aims at solving the technical problem that current single temperature control cannot reflect medium viscosity change in time, leading to heating lag even pipe coagulation.The system includes PLC controller, analog quantity extension module, touch screen and temperature transmitter and pressure transmitter installed on pipeline;The transmitter transmits the analog quantity signal collected in field to analog quantity extension module by shielded cable, and PLC controller controls the on-off of heating execution circuit according to real-time temperature and back pressure data.The utility model can forcibly start heating when its back pressure is abnormally high, effectively prevent pipeline blockage, improve delivery safety.

Description

Technical Field

[0001] This utility model belongs to the field of oil and gas storage and transportation automation technology, specifically relating to a heating system based on back pressure and temperature coordinated control. Background Technology

[0002] In the process of oil and gas gathering and transportation, in order to prevent crude oil from waxing or solidifying due to temperature drop, it is usually necessary to heat the pipeline. Existing pipeline heating control systems mostly adopt a single temperature control strategy, that is, to detect the temperature of the pipe wall or medium through temperature sensors, start the heater when the temperature is lower than the set value, and stop heating when it is higher than the set value.

[0003] However, in actual production, relying solely on temperature parameters for control has significant limitations. Due to the complex properties of crude oil, its fluidity depends not only on temperature but also on water content, emulsification degree, and wax content. Under certain special operating conditions, although the pipeline temperature may be within the theoretically acceptable range, severe emulsification or localized wax precipitation can lead to a sharp increase in crude oil viscosity and increased flow resistance (i.e., increased back pressure). If the system fails to activate heating under these conditions because the temperature is "acceptable," the pipeline back pressure will continue to rise, easily causing severe pipe blockage accidents or even pipeline rupture. Therefore, a hardware system capable of collaboratively monitoring and controlling both pipeline back pressure and temperature—two key physical quantities—is urgently needed to address these safety hazards. Utility Model Content

[0004] The purpose of this invention is to address the deficiencies mentioned in the background art by proposing a heating system based on the coordinated control of back pressure and temperature.

[0005] The technical solution adopted in this utility model is as follows: This utility model provides a heating system based on the coordinated control of back pressure and temperature, including... The main control unit includes a PLC controller, which integrates a CPU module and a communication interface. The data acquisition unit includes an analog quantity expansion module that is communicatively connected to the PLC controller; A human-machine interaction unit, the human-machine interaction unit including a touch screen, the touch screen being connected to the PLC controller; A sensing and detection unit is installed on the oil and gas transmission pipeline, including a temperature transmitter for detecting the temperature of the pipeline medium and a pressure transmitter for detecting the pipeline back pressure. The power supply unit includes a DC switching power supply that provides DC operating voltage to the system; a heating execution circuit whose input terminal is connected to the output terminal of the PLC controller, and whose output terminal is used to control the on / off state of the heating equipment; wherein the signal output terminals of the temperature transmitter and the pressure transmitter are respectively connected to the analog input channel of the analog expansion module; the PLC controller is configured to coordinately control the operation of the heating execution circuit based on the temperature data and back pressure data collected by the analog expansion module.

[0006] As a preferred technical solution of this utility model: the analog quantity expansion module is configured as a multi-channel analog quantity input module, wherein the first channel is electrically connected to the temperature transmitter and the second channel is electrically connected to the pressure transmitter; both the temperature transmitter and the pressure transmitter are 4-20mA current signal output type sensors.

[0007] As a preferred technical solution of this utility model: the cables connecting the temperature transmitter, the pressure transmitter and the analog quantity expansion module are all twisted-pair shielded cables; each analog input channel of the analog quantity expansion module is provided with a common grounding terminal, and the shielding layer of the twisted-pair shielded cable is connected to the common grounding terminal.

[0008] As a preferred technical solution of this utility model: the PLC controller is further extended with an RS485 communication board, and the touch screen is connected to the network port of the PLC controller via an Ethernet cable, or connected to the RS485 communication board via a twisted pair cable.

[0009] As a preferred technical solution of this utility model: the heating execution circuit includes an intermediate relay and an AC contactor; the digital output port of the PLC controller is electrically connected to the coil of the intermediate relay, the normally open contact of the intermediate relay is connected in series in the control circuit of the AC contactor, and the main contact of the AC contactor is connected in series in the power supply circuit of the heating equipment.

[0010] As a preferred technical solution of this utility model: the output terminal of the DC switching power supply is divided into two paths. The first path is connected to the power input terminal of the PLC controller and the touch screen, and the second path is connected to the power supply terminal of the analog expansion module and the power supply terminal of each transmitter.

[0011] This invention integrates an analog signal extension module into a PLC control system and simultaneously connects to temperature and pressure transmitters, enabling dual monitoring of oil and gas pipeline temperature and back pressure. When the system detects an abnormal increase in pipeline back pressure, even if the temperature is within the normal range, the PLC controller can force the heating circuit to operate, using the increased temperature to reduce the viscosity of the medium. This effectively solves the pipeline blockage problem caused by the inability of single temperature control to respond promptly to changes in medium viscosity, significantly improving the safety and reliability of the oil and gas gathering and transportation process. Attached Figure Description

[0012] Figure 1 This is a block diagram of the overall hardware structure of an embodiment of the present utility model.

[0013] Figure 2 This is a wiring diagram of the analog quantity expansion module and the sensor in an embodiment of this utility model.

[0014] 1. PLC controller; 11. RS485 communication board; 2. Analog expansion module; 3. Touch screen; 4. Temperature transmitter; 5. Pressure transmitter; 6. DC switching power supply. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0016] See Figure 1 , Figure 1 This is an overall hardware structure block diagram of one embodiment of the present invention. The present invention provides a heating system based on the coordinated control of back pressure and temperature, which is mainly applied in oil and gas gathering and transportation pipelines. From a macroscopic architecture perspective, the system mainly consists of a main control unit, a data acquisition unit, a human-machine interface unit, a sensing and detection unit, and a power supply unit.

[0017] Specifically, the power supply unit includes a DC switching power supply 6, which converts the 220V AC power on site into 24V DC power to provide a stable operating voltage for the low-voltage equipment within the system. The core of the main control unit is the PLC controller 1, which is the logic processing center of the entire system. The data acquisition unit includes an analog signal expansion module 2, which is physically mounted on the side of the PLC controller 1 to expand the input channels for analog signals. The human-machine interface unit includes a touchscreen 3 (HMI) for visual display of data and parameter setting. The sensing and detection unit includes temperature transmitters 4 and pressure transmitters 5 installed on the field pipelines to sense changes in the physical environment in real time.

[0018] The following is combined Figure 1 and Figure 2 Please describe in detail the circuit connection relationship and the selection of core components of this system.

[0019] In a preferred embodiment, the PLC controller 1 is a Siemens S7-200SMART series, specifically model CPUST30 (order number 6ES7288-1ST30-0AA1). This controller integrates a high-performance CPU and an Ethernet communication interface. Figure 1 As shown, the PLC controller 1 can also be optionally equipped with an RS485 communication board 11 (model 6ES7288-5CM01-0AA0) to expand the serial communication capability for subsequent connection to third-party smart instruments or host computer SCADA systems.

[0020] The touch screen 3 is a TPC7022Ew model, which is directly connected to the RJ45 Ethernet port integrated in the PLC controller 1 via a network cable (industrial Ethernet cable) to establish a high-speed data communication link and realize human-machine interface interaction.

[0021] Analog expansion module 2 is model EMAE08 (order number 6ES7288-3AE08-0AA0). This module is connected to the right side of PLC controller 1 via the backplane bus. Figure 2 As shown, the module is configured with 8 channels of analog input for receiving standard 4-20mA current signals.

[0022] The specific wiring path for the sensor is as follows (see Figure 2 ): 1. Power supply circuit: The output of the DC switching power supply 6 is divided into multiple circuits, which are respectively connected to the power input terminal of the PLC controller 1, the power supply terminal of the touch screen 3, and the power supply terminals (L+, M) of the analog expansion module 2.

[0023] 2. Temperature Monitoring Loop: The signal output line of temperature transmitter 4 is connected to the first channel (AI1) of analog expansion module 2. Specifically, the positive terminal of temperature transmitter 4 is connected to the AI1+ terminal of the module, and the negative terminal is connected to the AI1- terminal. This channel is configured to monitor "1# Temperature Monitoring Access".

[0024] 3. Back pressure monitoring loop: The signal output line of pressure transmitter 5 is connected to the second channel (AI2) of analog expansion module 2. Specifically, the positive terminal of pressure transmitter 5 is connected to the AI2+ terminal of the module, and the negative terminal is connected to the AI2- terminal. This channel is configured to monitor "No. 2 pipeline pressure monitoring access".

[0025] 4. Backup circuit: Figure 2The AI3 and AI4 channels shown are reserved for backup monitoring access (3# and 3# backup), and are also configured with 4-20mA input mode for future expansion (such as flow meter or level meter access).

[0026] To ensure system stability in industrial environments with strong electromagnetic interference, this embodiment employs rigorous anti-interference and signal transmission design: see [link to relevant documentation]. Figure 2 The signal cables connecting temperature transmitter 4, pressure transmitter 5, and analog expansion module 2 are all strictly twisted-pair shielded cables. The twisted-pair structure effectively cancels common-mode noise induced in the conductors by external alternating magnetic fields. More importantly, each group of analog input channels in analog expansion module 2 is equipped with a common ground terminal E. When wiring, the metal shielding layer of the shielded cable must be grounded at one end, i.e., connected to this common ground terminal E, and then connected to the earth through the system grounding bus. This design utilizes the Faraday cage principle to directly conduct induced electrostatic interference and high-frequency electromagnetic interference to the earth, preventing interference signals from being superimposed on the weak 4-20mA measurement signal, thereby ensuring the accuracy of the PLC data reading.

[0027] The working principle and control logic of this system are as follows: This system uses the dual physical quantities of "back pressure" and "temperature" to coordinate the control of heating equipment, aiming to solve the problems of heating lag or energy waste caused by traditional single temperature control.

[0028] 1. Signal Acquisition and Conversion: During operation, temperature transmitter 4 converts the physical quantity of crude oil temperature in the pipeline into a 4-20mA current signal; pressure transmitter 5 converts the physical quantity of pipeline back pressure (i.e., flow resistance) into a 4-20mA current signal. The high-precision A / D converter inside analog expansion module 2 converts the above analog current signals into digital quantities (e.g., integers from 0-27648) and transmits them to the CPU of PLC controller 1 via the bus.

[0029] 2. Data Processing and Logic Judgment: The PLC controller 1 runs a PID control program or a comparison logic program. The CPU compares the collected real-time temperature value with the preset "start-up heating temperature threshold", and at the same time compares the collected real-time back pressure value with the preset "high-pressure alarm threshold".

[0030] Operating Condition 1 (Low Temperature Trigger): When the pipeline temperature is detected to be lower than the set value, regardless of whether the back pressure is normal, it is determined that there is a risk of condensation in the medium, and the PLC outputs a heating command.

[0031] Operating Condition 2 (High Pressure Trigger): This is the core innovation of this utility model. Even if the pipeline temperature is within the acceptable range, if an abnormal increase in back pressure is detected (indicating severe crude oil emulsification or high wax content leading to increased viscosity and poor fluidity), PLC controller 1 will also determine that heating is required to reduce viscosity and output a heating command.

[0032] 3. Execution output: When any of the above triggering conditions are met, the digital output terminal (DO) of PLC controller 1 outputs a high level, driving the external intermediate relay to close, thereby turning on the AC contactor and connecting the power supply of the high-power heating equipment (such as electric heating rods or skin tracing systems) to heat the pipeline.

[0033] 4. Feedback Regulation: As heating progresses, the pipeline temperature rises, the medium viscosity decreases, and the back pressure drops accordingly. When the temperature exceeds the stop threshold and the back pressure returns to normal, PLC controller 1 stops outputting, and heating ends.

[0034] Through the above hardware architecture and logic coordination, this utility model realizes intelligent and precise closed-loop control of the oil and gas pipeline heating process.

[0035] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0036] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A heating system based on coordinated control of back pressure and temperature, characterized in that, include: The main control unit includes a PLC controller (1), which integrates a CPU module and a communication interface; The data acquisition unit includes an analog quantity expansion module (2) that is communicatively connected to the PLC controller (1). The human-machine interaction unit includes a touch screen (3) and the touch screen (3) is connected to the PLC controller (1); The sensing and detection unit is installed on the oil and gas transmission pipeline and includes a temperature transmitter (4) for detecting the temperature of the pipeline medium and a pressure transmitter (5) for detecting the back pressure of the pipeline. The power supply unit includes a DC switching power supply (6) that provides DC operating voltage to the system; a heating execution circuit whose input terminal is connected to the output terminal of the PLC controller (1), and whose output terminal is used to control the on / off state of the heating equipment; wherein the signal output terminals of the temperature transmitter (4) and the pressure transmitter (5) are respectively connected to the analog input channel of the analog expansion module (2); the PLC controller (1) is configured to coordinately control the operation of the heating execution circuit based on the temperature data and back pressure data collected by the analog expansion module (2).

2. The heating system based on the coordinated control of back pressure and temperature according to claim 1, characterized in that, The analog quantity expansion module (2) is configured as a multi-channel analog quantity input module, wherein the first channel (AI1) is electrically connected to the temperature transmitter (4), and the second channel (AI2) is electrically connected to the pressure transmitter (5); the temperature transmitter (4) and the pressure transmitter (5) are both 4-20mA current signal output type sensors.

3. A heating system based on coordinated control of back pressure and temperature according to claim 2, characterized in that, The cables connecting the temperature transmitter (4), pressure transmitter (5) and analog expansion module (2) are all twisted-pair shielded cables; each analog input channel of the analog expansion module (2) is provided with a common ground terminal (E), and the shielding layer of the twisted-pair shielded cable is connected to the common ground terminal (E).

4. A heating system based on coordinated control of back pressure and temperature according to claim 1, characterized in that, The PLC controller (1) is further extended with an RS485 communication board (11). The touch screen (3) is connected to the network port of the PLC controller (1) via an Ethernet cable or to the RS485 communication board (11) via a twisted pair cable.

5. A heating system based on coordinated control of back pressure and temperature according to claim 1, characterized in that, The heating execution circuit includes an intermediate relay and an AC contactor; the digital output port of the PLC controller (1) is electrically connected to the coil of the intermediate relay, the normally open contact of the intermediate relay is connected in series in the control circuit of the AC contactor, and the main contact of the AC contactor is connected in series in the power supply circuit of the heating equipment.

6. A heating system based on coordinated control of back pressure and temperature according to claim 1, characterized in that, The output of the DC switching power supply (6) is divided into two paths. The first path is connected to the power input of the PLC controller (1) and the touch screen (3), and the second path is connected to the power supply of the analog expansion module (2) and the power supply of each transmitter.

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