Comprehensive protection system and method for instrument flange pressure sampling in asphalt media

Abstract

A comprehensive protection system and method for instrument flange pressure sampling of asphalt media includes a radiator, an electric heating cable, and a sampling tube temperature detection instrument installed on the instrument flange pressure sampling pipeline, as well as a field thermostat. The sampling tube temperature detection instrument is connected to the temperature acquisition terminal of the field thermostat, and the two output contacts of the field thermostat are respectively connected to a radiator fan and an electric heating cable. The field thermostat controls the start and stop of the radiator fan and the electric heating cable according to the sampling tube temperature. This invention effectively avoids the aforementioned problems and ensures the continuous, stable, and accurate operation of a system using a remote flange pressure transmitter for asphalt media measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of tar processing technology and high-temperature asphalt chemical production technology, and in particular to a comprehensive protection system and method for pressure sampling of an instrument flange for asphalt media. Background Art

[0002] In technical fields such as tar processing and high-temperature asphalt chemical production, medium-temperature asphalt with a softening point of 75°C to 90°C is heated in an asphalt reactor. The asphalt undergoes further thermal polymerization and condensation reactions, forming higher-molecular-weight aromatic hydrocarbons. Some low-boiling-point substances are evaporated, raising the asphalt's softening point and producing high-temperature asphalt. The temperature within the asphalt reactor is maintained between 350°C and 390°C, and in extreme cases can reach over 400°C. The temperature within asphalt pipelines is generally controlled between 210°C and 280°C to ensure fluidity. However, due to varying operating conditions, the asphalt temperature can sometimes fall outside this range, making instrumentation difficult to adapt to these conditions. Traditional asphalt reactor level measurement uses radiometric methods, which offer high accuracy but high investment costs and require professional maintenance. Radiation exposure can also cause personal injury and safety incidents, making this method less popular. Furthermore, traditional asphalt flow measurement uses high-temperature ultrasonic flowmeters, which are expensive, require high maintenance, and are prone to damage. Therefore, from the perspective of safety and economy, the level measurement, flow measurement and pressure measurement of asphalt media are often measured using the remote flange pressure method, that is, a remote flange liquid level transmitter is used to measure the liquid level, a wedge flowmeter is used to measure the flow, and a pressure transmitter is used to measure the pressure. Since the temperature of the asphalt medium is sometimes as high as 350°C or above, and the high-temperature silicone oil used in the remote flange transmitter has a maximum temperature resistance of 310°C, the instrument flange pressure sampling system must use a radiator to ensure that the temperature is reduced to below 310°C. At the same time, since the softening point of high-temperature asphalt is above 150°C or even higher, to ensure the fluidity of the asphalt medium, the temperature needs to be controlled above 210°C. Therefore, the temperature of the asphalt pressure system must be strictly controlled between 210°C and 310°C. This is the only way to ensure that the measurement using the remote flange pressure transmitter is continuous, stable and accurate. The pressure system of the traditional remote flange pressure transmitter uses a radiator to dissipate heat, and the choice of the radiator is based on the external temperature and medium conditions. There are the following problems with this pressure sampling method:

[0003] 1. When the ambient temperature or the medium temperature changes, the heat dissipation efficiency of the radiator changes, and it cannot be guaranteed that the temperature of the asphalt medium measurement and pressure system is strictly controlled between 210℃ and 310℃.

[0004] 2. When the asphalt medium passes through the heat exchanger, if the heat exchanger does not work properly, the temperature of the asphalt medium may remain high, causing the medium temperature to exceed 310°C. The temperature of the asphalt medium measurement and pressure taking system cannot be strictly controlled to be below 310°C, causing the silicone oil filled in the remote flange pressure taking device to vaporize and the instrument to be completely damaged.

[0005] 3. When the asphalt reactor is operated in intermittent mode, there will be low temperatures. At this time, the asphalt medium will be too cold to solidify in the sampling tube of the pressure taking system and on the flange diaphragm of the measuring instrument, making the instrument unable to work normally when it is put into normal operation.

[0006] 4. When the process is under maintenance, the temperature of the asphalt medium will drop, and the measurement and pressure taking system is easily seriously blocked by the asphalt medium with poor fluidity, causing damage to the sampling valve and instrument. Summary of the Invention

[0007] In order to solve the technical problems raised by the background technology, the present invention provides a comprehensive protection system and method for instrument flange pressure sampling of asphalt media, which can effectively avoid the occurrence of the above-mentioned problems and ensure the continuous, stable and accurate operation of the system using a remote flange pressure transmitter for asphalt medium measurement.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A comprehensive protection system for instrument flange pressure sampling of asphalt media includes a radiator, an electric heating tape and a sampling tube temperature detection instrument arranged on the instrument flange pressure sampling pipeline, and also includes a field temperature controller; the sampling tube temperature detection instrument is connected to the temperature acquisition end of the field temperature controller, and the two output contacts of the field temperature controller are respectively connected to the radiator fan and the electric heating tape, and the field temperature controller controls the start and stop of the radiator fan and the electric heating tape according to the sampling tube temperature.

[0010] Furthermore, it also includes a manual switch SW2 for bypassing the on-site thermostat of the electric heating circuit and a manual switch SW3 for the electric heating circuit. The output contact of the on-site thermostat connected to the electric heating tape is SW1. The manual switch SW2 for bypassing the on-site thermostat of the electric heating circuit and the output contact SW1 for connecting the electric heating tape in the on-site thermostat are connected in parallel and then connected in series with the manual switch SW3 for the electric heating circuit and the electric heating tape and connected to the power supply end.

[0011] Furthermore, it also includes a heat exchange fan circuit field thermostat bypass switch manual SW5 and a heat exchange fan circuit manual switch SW6. The output contact of the radiator fan connected to the field thermostat is SW4. The heat exchange fan circuit field thermostat bypass switch manual SW5 and the output contact of the radiator fan connected to the field thermostat is SW4. The heat exchange fan circuit field thermostat bypass switch manual SW5 is connected in parallel with the heat exchange fan circuit manual switch SW6 and the radiator fan and connected to the power supply end.

[0012] The method of the comprehensive protection system for instrument flange pressure sampling in asphalt media includes the following:

[0013] 1) Sampling tube temperature TRSA01 high processing procedure

[0014] When TRSA01>THH, the TRSA01 temperature is in an extremely high state, and the comprehensive protection program is processed as follows:

[0015] High temperature electric heating automatic control: OFF, set switch SW1: OFF;

[0016] Heat exchange fan automatic control: ON, set switch SW4: ON;

[0017] The on-site temperature controller exchanges data with the DCS to realize remote alarm and promptly notify manual processing to close the gate valve;

[0018] The on-site thermostat output is maintained, the program stops, and it waits for manual maintenance and reset;

[0019] 2) Sampling tube temperature TRSA01 high temperature processing procedure

[0020] When TRSA01<=THH and TRSA01>TH, the temperature of TRSA01 is high and the integrated protection procedure is as follows:

[0021] High temperature electric heating automatic control: OFF, set switch SW1: OFF;

[0022] Heat exchange fan automatic control: ON, set switch SW4: ON;

[0023] On-site temperature controller exchanges data with DCS to realize remote alarm;

[0024] The on-site thermostat maintains output for a duration of t, and returns to the on-site thermostat automatic control cycle program after waiting for the operation effect of the comprehensive protection;

[0025] 3) Sampling tube temperature TRSA01 low temperature processing procedure

[0026] When TRSA01<=TLL, the temperature of TRSA01 is in an ultra-low state, and the comprehensive protection program is processed as follows:

[0027] High temperature electric heating automatic control: ON, set switch SW1: ON;

[0028] Heat exchange fan automatic control: 0FF, set switch SW4: OFF;

[0029] The on-site temperature controller exchanges data with the DCS to realize remote alarm and promptly notify manual processing to close the gate valve;

[0030] The on-site thermostat output is maintained, the program stops, and it waits for manual maintenance and reset;

[0031] 4) Sampling tube temperature TRSA01 low temperature processing procedure

[0032] When TRSA01<=TL and TRSA01>TLL, the TRSA01 temperature is in a low state, and the integrated protection program is processed as follows:

[0033] High temperature electric heating automatic control: ON, set switch SW1: ON;

[0034] Heat exchange fan automatic control: 0FF, set switch SW4: OFF;

[0035] On-site temperature controller exchanges data with DCS to realize remote alarm;

[0036] The on-site thermostat maintains output for a duration of t, and returns to the on-site thermostat automatic control cycle program after waiting for the operation effect of the comprehensive protection;

[0037] 5) Sampling tube temperature TRSA01 normal temperature processing procedure

[0038] When TRSA01>TL and TRSA01<=TH, the TRSA01 temperature is in normal state, and the comprehensive protection program is processed as follows:

[0039] High temperature electric heating automatic control: OFF, set switch SW1: OFF;

[0040] Heat exchange fan automatic control: 0FF, set switch SW4: OFF;

[0041] On-site temperature controller exchanges data with DCS to achieve remote monitoring;

[0042] Return to the on-site temperature controller to automatically control the cycle program;

[0043] TLL: The temperature value at the sampling tube is the minimum limit that can ensure the normal operation of the instrument;

[0044] The THH temperature value is the maximum limit of the jacket sampling tube to ensure the normal operation of the instrument;

[0045] TL: The temperature value is the lower limit of the ideal temperature at the sampling tube to ensure the normal operation of the instrument;

[0046] TH: The temperature value is the ideal upper temperature limit at the sampling tube to ensure the normal operation of the instrument;

[0047] t: The reaction time of the integrated protection system after controlling and switching protection.

[0048] The method of a comprehensive protection system for instrument flange pressure sampling in asphalt media also includes a method for calculating the length of the high-temperature electric heating cable used in the comprehensive protection system:

[0049] Calculation of heat consumption of electric heating belt:

[0050] Ф=KlQ (1)

[0051] Where: Ф——heat consumption of electric belt, W

[0052] K——compensation coefficient, generally 1.3~1.5

[0053] l——the length of the sampling tube, m

[0054] Q——heat dissipation per unit length of sampling tube, W / m

[0055]

[0056] Where: t g ——Temperature of medium in pipe, ℃

[0057] t a ——Temperature of the surrounding air, ℃

[0058] τ——Thermal conductivity of insulation material, W / (m·K)

[0059] d1——Outer diameter of the insulation layer of the sampling tube, m

[0060] d0——External diameter of sampling tube, m

[0061] α——Surface heat transfer coefficient between the insulation layer surface and the surrounding air, W / (m2·K)

[0062]

[0063] Where: P——Power of the electric heating belt, W

[0064] η——Efficiency of electric heating belt, generally taken as 0.85.

[0065]

[0066] Where: σ——electric heating power per unit length, W

[0067] L——Length of heating tape, m.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] 1) The use of this system can completely solve the problem of using a radiator to dissipate heat in the pressure sampling system of the traditional remote flange pressure transmitter. When the ambient temperature changes, or the production conditions change, causing the medium temperature to change, the heat dissipation efficiency of the pressure sampling system radiator changes. The comprehensive protection method of the instrument flange pressure sampling system of the present invention can ensure that the temperature of the instrument flange pressure sampling system is strictly controlled between 210°C and 260°C, ensuring the continuous and stable operation of the instrument under normal working conditions, improving the measurement accuracy of the instrument, extending the service life of the instrument, and laying a solid foundation for the stable and continuous production of the process.

[0070] 2) The comprehensive protection method of the present invention employs multiple methods to dissipate heat and insulate the instrument flange pressure sampling system. This system utilizes a high-temperature electric heating control circuit and a heat exchange fan control circuit to implement insulation and heat dissipation control, respectively. These two circuits are completely independent, enabling multiple combined comprehensive protection solutions, resulting in more precise temperature control of the sampling tubes in the instrument flange pressure sampling system.

[0071] 3) The comprehensive protection method of the present invention is automatically implemented via an on-site thermostat. The operator inputs the setpoint and upper and lower limit values ​​for the sampling tube temperature into the on-site thermostat, and the comprehensive protection program automatically executes within the on-site thermostat. This system is simple to maintain, efficient to operate, and easy to implement.

[0072] 4) The comprehensive protection method of the present invention adopts manual mode and automatic mode control. The operator manually controls the working mode of the comprehensive protection system based on the understanding of the on-site conditions and maintenance experience. The operation mode is flexible, the control means of the comprehensive protection system are more abundant, the degree of automation is higher, and the system adaptability is better.

[0073] 5) In the comprehensive protection method of the present invention, all the working status information of the on-site temperature controller is sent to the asphalt process DCS system to realize remote online monitoring of the comprehensive protection, achieve the purpose of unmanned on-site maintenance, and improve the management and control level of the comprehensive protection of the instrument.

[0074] 6) The comprehensive protection method of the present invention adopts online detection of the sampling tube temperature, monitors the temperature at the sampling tube in real time, and controls the operation of the comprehensive protection program in real time according to the temperature value, realizing fully automatic interlocking control of the high-temperature electric heating circuit and the heat exchange fan circuit.

[0075] 7) The present invention provides a method for calculating the length of the high-temperature electric heating cable of the instrument flange pressure sampling system, optimizes the design of the high-temperature electric heating control circuit, can effectively solve the insulation and heating control of the sampling tube at low temperatures, maximize energy conservation, and improve the application effect of the comprehensive protection system.

[0076] 8) The comprehensive protection method of the present invention can be applied to measurements using instrument flange pressure sampling systems in asphalt process flows, including level measurement in asphalt reactors and asphalt upgrading towers using dual-flange level transmitters, pressure measurement in asphalt reactors and asphalt upgrading towers using single-flange remote pressure transmitters, and wedge flowmeters in asphalt pipelines using dual-flange level transmitters. The comprehensive protection method of the present invention is highly practical and has a wide range of applications.

[0077] 9) The application method of this system can be simply expanded to be used in other chemical fields with high temperature and viscous media pressure, flow and liquid level measurement instrument systems, and has strong promotion potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 This is a schematic structural diagram of the comprehensive protection system for pressure sampling of instrument flanges in asphalt media according to the present invention;

[0079] Figure 2 This is a control circuit diagram of the comprehensive protection system for instrument flange pressure sampling in asphalt media of the present invention;

[0080] Figure 3 This is a program implementation block diagram of the comprehensive protection method for the asphalt medium instrument flange pressure sampling system of the present invention.

[0081] In the figure: 1- pressure pipe 2- gate valve 3- radiator 4- sampling pipe drain valve 5- sampling pipe 6- remote transmission flange of pressure transmitter 7- remote transmission flange pressure transmitter 8- sampling pipe temperature detection instrument TRSA01 9- electric heating cable 10- radiator fan 11- on-site thermostat;

[0082] 21- Comprehensive protection manual control mode 22- Comprehensive protection automatic mode manual switch setting 23- Comprehensive protection automatic mode data acquisition module 24- Sampling tube temperature automatic judgment module 25- TRSA01 over-high temperature processing program 26- TRSA01 high temperature processing program 27- TRSA01 over-low temperature processing program 28- TRSA01 low temperature processing program 29- TRSA01 normal temperature processing program. DETAILED DESCRIPTION

[0083] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0084] like Figure 1-2 As shown, the instrument flange pressure sampling system for asphalt medium comprises a pressure sampling pipe (1), a gate valve (2), a sampling pipe (5), a remote transmission flange of a pressure transmitter (6), a remote transmission flange pressure transmitter (7) and a sampling pipe drain valve (4).

[0085] The invention discloses a comprehensive protection system for pressure sampling of an instrument flange for asphalt medium, comprising a radiator (3), an electric heating tape (9), and a sampling tube temperature detection instrument (8) arranged on the instrument flange pressure sampling pipeline, and also comprising a field temperature controller (11); the sampling tube temperature detection instrument (8) is connected to the temperature acquisition end of the field temperature controller (11), and the two output contacts SW4 and SW1 of the field temperature controller (11) are respectively connected to the radiator fan (10) and the electric heating tape (9), and the field temperature controller (11) controls the start and stop of the radiator fan (10) and the electric heating tape (9) according to the sampling tube temperature. An online temperature detection instrument TRSA01 (8) is arranged at the tail end of the sampling tube (5), and the instrument adopts a dual-branch thermal resistance instrument, one of which is sent to the field temperature controller (11) for comprehensive protection control interlocking, and the other is sent to the asphalt process DCS control system for real-time monitoring. The comprehensive protection system includes a sampling tube high-temperature electric heating control circuit and a heat exchange fan control circuit. The two control circuits are independently controlled by a field temperature controller (11) according to the instrument TRSA01 (8) value detected online, thereby realizing comprehensive protection of the instrument flange pressure sampling system.

[0086] The high-temperature electric heating control circuit also includes a manual switch SW2 for bypassing the electric heating circuit on-site temperature controller and a manual switch SW3 for bypassing the electric heating circuit. The output contact of the electric heating tape in the on-site temperature controller is SW1. The manual switch SW2 for bypassing the electric heating circuit on-site temperature controller and the output contact of the electric heating tape in the on-site temperature controller are connected in parallel to SW1, and then connected in series with the manual switch SW3 for bypassing the electric heating circuit and the electric heating tape (9) and connected to the power supply end.

[0087] The heat exchange fan control circuit includes a heat exchange fan circuit field thermostat bypass switch manual SW5 and a heat exchange fan circuit manual switch SW6, an output contact of the field thermostat connected to the radiator fan is SW4, the heat exchange fan circuit field thermostat bypass switch manual SW5 and the output contact of the field thermostat connected to the radiator fan is SW4, and then connected in parallel with the heat exchange fan circuit manual switch SW6 and the radiator fan (10) and connected in series to the power supply end.

[0088] 1. Process thermal parameters:

[0089] Asphalt medium parameters: normal temperature 380℃, upper limit temperature 420℃, lower limit temperature 350℃, density 1253kg / m3, dynamic viscosity 3.43mPa·s.

[0090] 2. Measurement using instrument flange pressure sampling system

[0091] The main occasions for measuring with instrument flange pressure sampling system in asphalt process are:

[0092] a) The liquid level measurement of asphalt reactor and asphalt modification tower adopts double flange liquid level transmitter;

[0093] b) Pressure measurement of asphalt reactor and asphalt reforming tower adopts single flange remote pressure transmitter;

[0094] c) Asphalt medium pipeline flow measurement uses a wedge flowmeter and a double flange differential pressure transmitter;

[0095] d) Asphalt medium pipeline pressure measurement uses a single flange remote pressure transmitter;

[0096] Silicone oil parameters of the transmitter instrument: The instrument adopts a remote flange pressure transmitter, and the silicone oil filled is high-temperature silicone oil with a maximum temperature tolerance of 310°C.

[0097] 3. Composition of instrument flange pressure sampling system

[0098] In order to ensure the normal operation of the measuring instrument, the temperature of the asphalt instrument flange pressure sampling system is strictly controlled between 210℃ and 310℃. The instrument flange pressure sampling system uses a radiator to dissipate heat to cool the temperature of the high-temperature asphalt medium. At the same time, it uses a sampling tube with high-temperature electric heating control, a high-temperature resistant gate valve and a sampling tube drain valve.

[0099] 4. Radiator selection requirements

[0100] During the design, the length and style of the radiator are calculated based on the process conditions, external temperature parameters, and correction results. It is required that the temperature of the sampling medium in the sampling tube be maintained within the range of 210°C to 260°C after passing through the high-temperature gate valve and radiator. It can be seen that after the length and type of the radiator are fixed, the heat dissipation effect will change with the changes in process parameters and external conditions. In extreme cases, such as when the medium temperature is too high or too low, the ambient temperature is too high or too low, and process operation changes, the heat dissipation effect of the radiator will be affected. It is difficult to ensure that the temperature at the sampling tube of the asphalt instrument flange pressure sampling system is between 210°C and 260°C. Therefore, the flange pressure sampling system that only uses a radiator is a feedforward protection method with poor adaptability.

[0101] 5. Comprehensive protection measures for instrument flange pressure sampling system

[0102] a) High-temperature electric heating circuits are used in the sampling tubes: When process parameters and external conditions change, resulting in low sampling tube temperatures, the asphalt medium's fluidity deteriorates, seriously affecting the measurement results of the remote flange instrument. If the temperature drops even lower, the medium solidifies, potentially damaging the remote flange instrument. To prevent this, high-temperature heating cables are wrapped around the sampling tubes to provide auxiliary heating when the medium temperature is low, ensuring that the medium's temperature is controlled within a reasonable range.

[0103] The following is a method for calculating the length of the high-temperature electric heating cable used in the comprehensive protection system of the present invention:

[0104] Calculation of heat consumption of electric heating belt:

[0105] Ф=KlQ (1)

[0106] Where: Ф——heat consumption of electric belt, W

[0107] K——compensation coefficient, generally 1.3~1.5

[0108] l——the length of the sampling tube, m

[0109] Q——heat dissipation per unit length of sampling tube, W / m

[0110]

[0111] Where: t g ——Temperature of medium in pipe, ℃

[0112] t a ——Temperature of the surrounding air, ℃

[0113] τ——Thermal conductivity of insulation material, W / (m·K)

[0114] d1——Outer diameter of the insulation layer of the sampling tube, m

[0115] d0——External diameter of sampling tube, m

[0116] α——Surface heat transfer coefficient between the insulation layer surface and the surrounding air, W / (m2·K)

[0117]

[0118] Where: P——Power of the electric heating belt, W

[0119] η——Efficiency of electric heating belt, generally taken as 0.85.

[0120]

[0121] Where: σ——electric heating power per unit length, W

[0122] L——Length of heating tape, m

[0123] The length of the high-temperature heating cable can be calculated using formulas (1) to (4). The above formulas are theoretical calculation formulas. In practical applications, the length of the high-temperature heating cable can also be estimated using empirical methods. During construction, the high-temperature heating cable should be evenly wound around the sampling tube.

[0124] b) A heat exchange fan circuit is used in the flange pressure sampling system: when the process parameters and external conditions change, the radiator cannot reduce the temperature of the medium to a normal temperature, causing the sampling tube temperature to be too high, which will cause the silicone oil in the remote flange instrument to vaporize, causing damage to the remote flange instrument. In addition, since the comprehensive protection system of the present invention adopts a high-temperature electric heating circuit at the sampling tube, the high-temperature electric heating tape needs to be wrapped around the sampling tube, and the temperature tolerance of the high-temperature electric heating tape is limited. Generally, the upper limit temperature of the high-temperature electric heating tape is about 260°C. In order to ensure the normal use of the high-temperature electric heating tape, the temperature needs to be controlled below the upper limit temperature tolerance of the high-temperature electric heating tape. Combining the above two situations, the present invention adopts heat exchange fan circuit control to increase the heat dissipation of the instrument flange pressure sampling system, thereby controlling the temperature of the instrument flange pressure sampling system within a normal temperature range.

[0125] 6. Instrument detection of integrated protection system

[0126] An online temperature detection instrument TRSA01 is installed at the tail end of the sampling pipe. The instrument adopts a double-branch thermal resistance instrument, one of which sends data to the on-site temperature controller for comprehensive protection control interlocking, and the other sends data to the asphalt process DCS control system for remote real-time monitoring of the operation effect of the comprehensive protection of the instrument flange pressure sampling system.

[0127] 7. Configuration of on-site thermostat

[0128] The field thermostat consists of a 220V AC power supply, a high-temperature electric heating circuit switch SW1 digital output module, a heat exchange fan circuit switch SW4 digital output module, a temperature detection instrument TRSA01 analog input module, a DCS data communication module, and a temperature control calculation module. The field thermostat is configured and programmed using its programmer. The setpoint range, upper limit, upper-upper limit, lower limit, and lower-lower limit data for the pressure sampling tube temperature are input into the field thermostat's calculation module. The field thermostat's integrated protection program runs continuously. The field thermostat transmits the equipment's operating status and results, along with configuration data, to the asphalt process DCS control system in real-time.

[0129] 8. Implementation of comprehensive protection system for instrument flange pressure sampling system

[0130] To better ensure the adaptability of the instrument flange pressure sampling system and the proper operation of the instrument, this invention employs an active defense approach to provide comprehensive protection for the instrument flange pressure sampling system. This system utilizes a high-temperature electric heating circuit for auxiliary heating and a heat exchange fan circuit for auxiliary cooling. Based on the temperature measurement of the sampling tube, this circuit automatically interlocks and controls the operation of the high-temperature electric heating control circuit and the heat exchange fan control circuit, strictly controlling the temperature of the asphalt instrument flange pressure sampling system between 210°C and 260°C. The program implementation of this comprehensive protection system is primarily implemented within the field controller via the built-in CPU. Simultaneously, the operating status of the comprehensive protection system is remotely monitored on the asphalt process DCS system, providing timely alarms and maintenance recommendations.

[0131] Description of comprehensive protection system setting parameters:

[0132] TLL: The temperature value is the minimum limit at the sampling tube to ensure the normal operation of the instrument, which is generally 210°C. The TLL of modified asphalt media of different qualities is inconsistent. Generally, the better the quality of the asphalt, the higher the TLL. The operator can set it on the on-site temperature controller.

[0133] The THH temperature value is the maximum limit at the jacketed sampling tube that ensures the instrument operates normally. The upper temperature limit of the high-temperature silicone oil used in the transmitter is 310°C. To be on the safe side, the THH temperature is set below 310°C. Here, 260°C is selected. The temperature control requirement below 260°C fully considers the upper temperature limit of the high-temperature electric heating cable. If the temperature resistance of the high-temperature electric heating cable changes, the THH will also change. The operator can set this setting on the on-site thermostat.

[0134] TL: The temperature value is the ideal lower limit of temperature at the sampling tube to ensure the normal operation of the instrument, which is generally 220℃. The TL of modified asphalt media of different qualities is inconsistent. Generally, the better the quality of the asphalt, the higher the TL. The operator can set it on the on-site temperature controller.

[0135] TH: The temperature value is the ideal upper temperature limit at the sampling tube to ensure the normal operation of the instrument, which is generally 250°C. If the temperature resistance value of the high-temperature electric heating cable changes, TH will change accordingly. The operator can set it on the on-site temperature controller.

[0136] t: The integrated protection system's reaction time after switching control. This time is typically set to 30 minutes or longer. This is to prevent frequent starts and stops in the high-temperature electric heating and heat exchange fan control circuits near temperature limits, which could affect the integrated protection system's effectiveness. Operators can set this time on the on-site thermostat.

[0137] like Figure 3 As shown, the operation modes of the comprehensive protection program are divided into: automatic mode and manual mode

[0138] 1) Comprehensive protection manual control mode (21)

[0139] Manual mode allows maintenance personnel to manually activate and deactivate the high-temperature electric heating circuit and heat exchange fan circuit based on the operating conditions of the field instrument flange pressure sampling system and their experience. In principle, when the sampling tube temperature is high, the heat exchange fan circuit is activated to cool it down; when the sampling tube temperature is low, the high-temperature electric heating cable circuit is activated to heat it up; and when the sampling tube temperature is within the normal range, the heat exchange fan circuit and the high-temperature electric heating circuit are deactivated.

[0140] 2) Data acquisition module in comprehensive protection automatic mode (23)

[0141] a) TRSA01 collects data from the on-site temperature controller.

[0142] b) TRSA01 collects data to the DCS control system.

[0143] 3) Automatic determination module of sampling tube temperature (24)

[0144] The real-time data collected from the on-site temperature controller TRSA01 is compared with the set temperature limit, and the working status of the instrument flange pressure sampling system is automatically determined. The control plan for comprehensive protection is determined according to the working status.

[0145] 4) TRSA01 Over-temperature Processing Procedure (25)

[0146] When TRSA01>THH, the TRSA01 temperature is in an extremely high state, and the comprehensive protection program is processed as follows:

[0147] a) High temperature electric heating automatic control: OFF, set switch SW1: OFF.

[0148] b) Heat exchange fan automatic control: ON, set switch SW4: ON.

[0149] c) The on-site temperature controller exchanges data with the DCS to implement remote alarms and promptly notify manual processing to close the gate valve.

[0150] d) The on-site temperature controller output is maintained, the program stops, and waits for manual maintenance and reset.

[0151] 5) TRSA01 High Temperature Processing Program (26)

[0152] When TRSA01<=THH and TRSA01>TH, the temperature of TRSA01 is high and the integrated protection procedure is as follows:

[0153] a) High temperature electric heating automatic control: OFF, set switch SW1: OFF.

[0154] b) Heat exchange fan automatic control: ON, set switch SW4: ON.

[0155] c) The on-site temperature controller exchanges data with DCS to realize remote alarm.

[0156] d) The on-site thermostat maintains output for a duration of t, and returns to the on-site thermostat automatic control cycle program after waiting for the operation effect of the comprehensive protection.

[0157] 6) TRSA01 Ultra-low Temperature Processing Procedure (27)

[0158] When TRSA01<=TLL, the temperature of TRSA01 is in an ultra-low state, and the comprehensive protection program is processed as follows:

[0159] a) High temperature electric heating automatic control: ON, set switch SW1: ON.

[0160] b) Heat exchange fan automatic control: 0FF, set switch SW4: OFF.

[0161] c) The on-site temperature controller exchanges data with the DCS to implement remote alarms and promptly notify manual processing to close the gate valve.

[0162] d) The on-site temperature controller output is maintained, the program stops, and waits for manual maintenance and reset.

[0163] 7) TRSA01 Low Temperature Processing Procedure (28)

[0164] When TRSA01<=TL and TRSA01>TLL, the TRSA01 temperature is in a low state, and the integrated protection program is processed as follows:

[0165] a) High temperature electric heating automatic control: ON, set switch SW1: ON.

[0166] b) Heat exchange fan automatic control: 0FF, set switch SW4: OFF.

[0167] c) The on-site temperature controller exchanges data with DCS to realize remote alarm.

[0168] d) The on-site thermostat maintains output for a duration of t, and returns to the on-site thermostat automatic control cycle program after waiting for the operation effect of the comprehensive protection.

[0169] 8) TRSA01 Temperature Normal Processing Procedure (29)

[0170] When TRSA01>TL and TRSA01<=TH, the TRSA01 temperature is in normal state, and the comprehensive protection program is processed as follows:

[0171] a) High temperature electric heating automatic control: OFF, set switch SW1: OFF.

[0172] b) Heat exchange fan automatic control: 0FF, set switch SW4: OFF.

[0173] c) The on-site temperature controller exchanges data with DCS to achieve remote monitoring.

[0174] d) Return to the on-site temperature controller to automatically control the cycle program.

[0175] The comprehensive protection method for the instrument flange pressure sampling system of asphalt medium is given for a set of instrument pressure sampling systems, which can be directly applied to the pressure instrument measurement of asphalt medium. For the occasions of using wedge flowmeter for asphalt flow measurement and double flange differential pressure transmitter for liquid level measurement, two sets of comprehensive protection systems are required, which are independently set and controlled. The on-site temperature controller can be selected into one-to-one configuration and one-to-two configuration according to actual needs.

[0176] High temperature electric heating control circuit

[0177] It is composed of a high-temperature electric heating cable (9), a 220V AC power supply, a high-temperature electric heating circuit manual switch SW3, a high-temperature electric heating circuit on-site thermostat bypass manual switch SW2, and a local thermostat automatic control high-temperature electric heating circuit switch contact SW1. The explosion-proof grade of the high-temperature electric heating cable (9), the high-temperature electric heating circuit manual switch SW3, and the high-temperature electric heating circuit on-site thermostat bypass manual switch SW2 is selected according to the explosion-proof area division requirements of the installation site, and the protection grade is selected to be IP65 or above.

[0178] The high temperature electric heating control circuit working modes are divided into:

[0179] Manual Mode: The operator, based on their understanding of the site and maintenance experience, manually controls the status of the various switches in the high-temperature electric heating control circuit to start and stop the circuit. This requires turning ON the high-temperature electric heating circuit's on-site thermostat bypass manual switch SW2. To start the circuit, turn ON the high-temperature electric heating circuit's manual switch SW3; to stop the circuit, turn OFF the high-temperature electric heating circuit's manual switch SW3.

[0180] Automatic mode: In automatic mode, the manual switch SW3 of the high-temperature electric heating circuit needs to be set to the ON state, and the manual switch SW2 of the high-temperature electric heating circuit field thermostat bypass needs to be set to the OFF state. The field thermostat (11) implements program control based on the detection data of the online temperature detection instrument TRSA01 (8). The automatic interlock field thermostat automatically controls the switch contact SW1 of the high-temperature electric heating circuit. When the switch contact SW1 of the high-temperature electric heating circuit is set to ON, the high-temperature electric heating control circuit starts working. When the switch contact SW1 of the high-temperature electric heating circuit is set to OFF, the high-temperature electric heating control circuit stops working.

[0181] Heat exchange fan control circuit

[0182] The heat exchange fan circuit is composed of a radiator fan (10), a 220V AC power supply, a heat exchange fan circuit manual switch SW6, a heat exchange fan circuit field thermostat bypass manual switch SW5, and a field thermostat automatic control heat exchange fan circuit switch contact SW4. The explosion-proof grade of the heat exchange fan, the heat exchange fan circuit manual switch SW6, and the heat exchange fan circuit field thermostat bypass manual switch SW5 is selected according to the explosion-proof area division requirements of the installation site, and the protection grade is selected to be IP65 or above.

[0183] The heat exchange fan control circuit working modes are divided into:

[0184] Manual Mode: Based on their understanding of the site and maintenance experience, the operator manually controls the status of the various switches in the heat exchange fan control circuit to start and stop the circuit. The operator turns on and off the heat exchange fan circuit's on-site thermostat bypass manual switch SW5. To start the circuit, turn on the heat exchange fan circuit manual switch SW6; to stop the circuit, turn off the heat exchange fan circuit manual switch SW6.

[0185] Automatic mode: In automatic mode, the heat exchange fan circuit manual switch SW6 needs to be turned on, and the heat exchange fan circuit field thermostat bypass manual switch SW5 needs to be turned off. The field thermostat (11) implements program control based on the detection data of the online temperature detection instrument TRSA01 (8). The automatic interlock field thermostat automatically controls the heat exchange fan circuit switch contact SW4. When the heat exchange fan circuit switch SW4 is turned on, the heat exchange fan control circuit starts working. When the heat exchange fan circuit switch contact SW4 is turned off, the heat exchange fan control circuit stops working.

[0186] On-site thermostat (11)

[0187] It is composed of a 220V AC power supply, a high-temperature electric heating circuit switch SW1 switch output module, a heat exchange fan circuit switch SW4 switch output contact, a temperature detection instrument TRSA01 (8) Pt100 analog input module, and a DCS data communication module. The temperature setting value range, upper limit, upper upper limit, lower limit, and lower lower limit data are input into the field temperature controller (11). The field temperature controller transmits the equipment operating status and operating results and configuration data to the asphalt process DCS control system in real time through communication, realizing remote monitoring in the central control room.

[0188] Temperature detection instrument TRSA01(8)

[0189] An online temperature detection instrument TRSA01(8) is installed at the end of the sampling tube. The instrument uses a dual-branch thermal resistance instrument, one of which is sent to the on-site temperature controller for comprehensive protection control interlocking. The explosion-proof grade of the online temperature detection instrument TRSA01(8) is selected according to the explosion-proof area division requirements of the installation site, and the protection grade is selected to be IP65 or above.

[0190] The above embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the above embodiments. The methods used in the above embodiments are conventional methods unless otherwise specified.

Claims

1. A method for a comprehensive protection system for instrument flange pressure sampling in asphalt media, characterized in that: The comprehensive protection system includes a radiator, an electric heating tape, and a sampling tube temperature detection instrument arranged on the instrument flange pressure sampling pipeline, and also includes a field thermostat; the sampling tube temperature detection instrument is connected to the temperature acquisition end of the field thermostat, and the two output contacts of the field thermostat are respectively connected to the radiator fan and the electric heating tape, and the field thermostat controls the start and stop of the radiator fan and the electric heating tape according to the sampling tube temperature; It also includes a manual switch SW2 for bypassing the on-site thermostat of the electric heating circuit and a manual switch SW3 for the electric heating circuit. The output contact of the on-site thermostat connected to the electric heating tape is SW1. The manual switch SW2 for bypassing the on-site thermostat of the electric heating circuit and the output contact SW1 for connecting the electric heating tape in the on-site thermostat are connected in parallel, and then connected in series with the manual switch SW3 for bypassing the electric heating circuit and the electric heating tape, and then connected to the power supply terminal. It also includes a heat exchange fan circuit field thermostat bypass switch manual SW5 and a heat exchange fan circuit manual switch SW6. The output contact of the radiator fan in the field thermostat is SW4. The heat exchange fan circuit field thermostat bypass switch manual SW5 and the output contact of the radiator fan in the field thermostat are connected in parallel, and then connected in series with the heat exchange fan circuit manual switch SW6 and the radiator fan and connected to the power supply end. The method of the comprehensive protection system includes the following: 1) Sampling tube temperature TRSA01 high processing procedure When TRSA01>THH, the TRSA01 temperature is in an extremely high state, and the comprehensive protection program is processed as follows: High temperature electric heating automatic control: OFF, set output contact SW1: OFF; Heat exchange fan automatic control: ON, set output contact SW4: ON; The on-site temperature controller exchanges data with the DCS to realize remote alarm and promptly notify manual processing to close the gate valve; The on-site thermostat output is maintained, the program stops, and it waits for manual maintenance and reset; 2) Sampling tube temperature TRSA01 high temperature processing procedure When TRSA01<=THH and TRSA01>TH, the temperature of TRSA01 is high and the integrated protection procedure is as follows: High temperature electric heating automatic control: OFF, set output contact SW1: OFF; Heat exchange fan automatic control: ON, set output contact SW4: ON; On-site temperature controller exchanges data with DCS to realize remote alarm; The on-site thermostat maintains output for a duration of t, and returns to the on-site thermostat automatic control cycle program after waiting for the operation effect of the comprehensive protection; 3) Sampling tube temperature TRSA01 low temperature processing procedure When TRSA01<=TLL, the temperature of TRSA01 is in an ultra-low state, and the comprehensive protection program is processed as follows: High temperature electric heating automatic control: ON, set output contact SW1: ON; Heat exchange fan automatic control: 0FF, set output contact SW4: OFF; The on-site temperature controller exchanges data with the DCS to realize remote alarm and promptly notify manual processing to close the gate valve; The on-site thermostat output is maintained, the program stops, and it waits for manual maintenance and reset; 4) Sampling tube temperature TRSA01 low temperature processing procedure When TRSA01<=TL and TRSA01>TLL, the TRSA01 temperature is in a low state, and the integrated protection program is processed as follows: High temperature electric heating automatic control: ON, set output contact SW1: ON; Heat exchange fan automatic control: 0FF, set output contact SW4: OFF; On-site temperature controller exchanges data with DCS to realize remote alarm; The on-site thermostat maintains output for a duration of t, and returns to the on-site thermostat automatic control cycle program after waiting for the operation effect of the comprehensive protection; 5) Sampling tube temperature TRSA01 normal temperature processing procedure When TRSA01>TL and TRSA01<=TH, the TRSA01 temperature is in normal state, and the comprehensive protection program is processed as follows: High temperature electric heating automatic control: OFF, set output contact SW1: OFF; Heat exchange fan automatic control: 0FF, set output contact SW4: OFF; On-site temperature controller exchanges data with DCS to achieve remote monitoring; Return to the on-site temperature controller to automatically control the cycle program; TLL: The temperature value at the sampling tube is the minimum limit that can ensure the normal operation of the instrument; THH: The temperature value is the maximum limit of the jacketed sampling tube to ensure the normal operation of the instrument; TL: The temperature value is the lower limit of the ideal temperature at the sampling tube to ensure the normal operation of the instrument; TH: The temperature value is the ideal upper temperature limit at the sampling tube to ensure the normal operation of the instrument; t: The reaction time of the integrated protection system after controlling and switching protection.

2. The method of a comprehensive protection system for instrument flange pressure sampling in asphalt media according to claim 1, characterized in that: Also included is the calculation method for the length of high-temperature heating cables used in integrated protection systems: Calculation of heat consumption of electric heating belt: Ф=KlQ (1) Where: Ф——heat consumption of electric belt, W K——compensation coefficient, generally 1.3~1.5 l——the length of the sampling tube, m Q——heat dissipation per unit length of sampling tube, W / m Where: t g ——Temperature of medium in pipe, ℃ t a ——Temperature of the surrounding air, ℃ τ——Thermal conductivity of insulation material, W / (m·K) d1——Outer diameter of the insulation layer of the sampling tube, m d0——External diameter of sampling tube, m α——Surface heat transfer coefficient between the insulation layer surface and the surrounding air, W / (m2·K) Where: P——Power of the electric heating belt, W η——Efficiency of electric heating belt, generally taken as 0.85 Where: σ——electric heating power per unit length, W L——Length of heating tape, m.

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