Pipeline tetrahydrothiophene odorant concentration on-line injection control method

Abstract

The invention discloses a pipeline tetrahydrothiophene odorant concentration on-line injection control method, which comprises the following steps of: extracting fuel gas in a fuel gas pipeline through a gas inlet pump, conveying the fuel gas into a detection cavity, and starting a refrigerator to quickly refrigerate the fuel gas in the detection cavity to cause nonlinear ring-down characteristics; and continuously recording and collecting time tau 1 and tau 2 from temperature ring-down to an initial value T0.1 / e and from pressure ring-down to an initial value P0.1 / e in the detection cavity through a pressure sensor, a temperature sensor, a moisture sensor and a timer in the detection cavity, and calculating a tetrahydrothiophene concentration value corrected by combining with inversion by combining with a Claberron equation. Compared with the prior art, the method has the beneficial effects that nondestructive testing is carried out by utilizing specific physical characteristics in pipeline gas, real-time automatic detection can be realized, so that the filling of the odorization station is regulated and controlled in real time, the concentration value of tetrahydrothiophene is controlled within a reasonable range, and then the extracted gas is sent back into the pipeline, so that the detection efficiency is improved. A large amount of gas waste and possible potential safety hazards caused by sampling are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of gas detection control, in particular to an online filling control method for concentration of tetrahydrothiophene odorant in a pipeline. Background Art

[0002] Tetrahydrothiophene odorant is mainly used as an odorant for fuel gases such as city gas, liquefied petroleum gas, and natural liquefied gas to increase the detectability of gas leaks. Since it does not produce habitual dulling of the human sense of smell and is non-corrosive to materials such as gas equipment and transportation pipeline gaskets, it is widely used as an odorant for fuel gas, replacing the original odorants such as ethyl mercaptan. Tetrahydrothiophene's colorless, transparent, volatile liquid characteristics, as well as its stable and non-dispersible odor, make it an ideal fuel gas odorant. In addition, tetrahydrothiophene also has an anesthetic effect and can be used as medicine, pesticides, and organic synthesis raw materials.

[0003] Tetrahydrothiophene is a commonly added ingredient in odorizers for warning of pipeline gas leaks. It is of great significance for discovering, detecting, processing and warning of gas leaks. The concentration of tetrahydrothiophene added needs to be controlled, otherwise it will lose its warning effect or cause unnecessary waste. At present, the concentration of tetrahydrothiophene odorizer in gas pipelines is mainly controlled by on-site sampling and brought back to the laboratory for testing. After the concentration of tetrahydrothiophene odorizer is detected, the gas station adjusts the concentration of tetrahydrothiophene odorizer according to the detected concentration. Not only is the operation cumbersome for terminal staff, but it is also impossible to achieve real-time detection and real-time regulation, and it is not timely. In addition, there are certain safety hazards in the process of manual sampling and testing. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem of low efficiency in the existing method of controlling the concentration of tetrahydrothiophene odorant in a gas pipeline, which mainly relies on on-site sampling and taking it back to a laboratory for testing. In the traditional method, after the concentration of the tetrahydrothiophene odorant is detected, the gas station then adjusts the concentration of the tetrahydrothiophene odorant according to the detected concentration. Not only is the operation cumbersome for terminal staff, but real-time detection and real-time regulation cannot be achieved, and the timeliness is not high, and there are certain safety hazards in the process of manual sampling and testing. The present invention provides a method for online filling control of the concentration of tetrahydrothiophene odorant in a pipeline.

[0005] The purpose of the present invention is achieved through the following technical solutions: A method for controlling the concentration of tetrahydrothiophene odorant in a pipeline online, comprising: S1. Sampling: extracting the gas in the gas pipeline through an intake air pump and transporting it to a detection cavity;

[0006] S2. Seal the detection cavity: turn off the air intake pump in S1, seal the detection cavity, collect the pressure in the cavity through the pressure sensor as the initial pressure value P0, and collect the initial temperature value T0 in the cavity through the temperature sensor;

[0007] S3. Rapid refrigeration: Turn on the refrigerator to rapidly refrigerate the gas in the detection chamber. Due to the condensation of tetrahydrothiophene, the nonlinear ring-down characteristics are caused, and the time τ1 and τ2 for the temperature in the detection chamber to decay to the initial value T0·1 / e and the pressure to decay to the initial value P0·1 / e are continuously recorded and collected through the pressure sensor, temperature sensor, moisture sensor and timer in the detection chamber; S4. Calculate the concentration of tetrahydrothiophene odorant: According to τ1 and τ2 detected in S3, combined with the Clapeyron equation PV=nRT, P represents pressure, V represents gas volume, n represents amount of substance, T represents absolute temperature, and R represents gas constant, the concentration value of tetrahydrothiophene can be deduced and corrected by inversion;

[0008] S5. Exhaust recovery: The exhaust gas after the test is recovered into the gas pipeline through the exhaust gas pump;

[0009] S6. Send data: upload the tetrahydrothiophene concentration value calculated by S4 to the remote control system through the 4G communication module;

[0010] S7. Adjusting the concentration: The odorant filling station controls the filling amount of tetrahydrothiophene odorant according to the tetrahydrothiophene concentration value in S5.

[0011] A further technical solution is that solenoid valves are installed at both the air inlet and air outlet ends of the detection cavity in S1, and the two sets of solenoid valves are installed at the air outlet end of the air intake air pump and the air intake end of the exhaust air pump respectively.

[0012] A further technical solution is that a PLC controller is installed on the detection cavity, and the PLC controller is responsible for controlling the opening and closing of the solenoid valve, air pump, pressure sensor, temperature sensor, moisture sensor and timer. The PLC controller exchanges information with the remote control system through a 4G communication module.

[0013] A further technical solution is that the PLC controller can regularly control the opening and closing of the solenoid valve, air pump, pressure sensor, temperature sensor, moisture sensor and timer to achieve regular periodic detection of the gas pipeline.

[0014] A further technical solution is that the PLC controller can control the device to enter a low-power sleep state, waiting for the next task to wake up.

[0015] A further technical solution is that the 4G communication module in the S6 can upload the number, time, longitude and latitude, and ambient temperature and humidity of the extracted gas pipeline to the remote control system.

[0016] The present invention has the following advantages: the present invention utilizes the unique physical properties of pipeline gas for nondestructive testing, thereby avoiding the cumbersome operation caused by frequent sampling by staff, and has real-time automatic detection, so as to perform real-time regulation on the filling of the odorization station, so that the concentration value of tetrahydrothiophene is controlled within a reasonable range, and then the extracted gas is sent back to the inside of the pipeline, thereby reducing a large amount of gas waste and possible safety hazards caused by sampling. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown can be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0020] It should be noted that like reference numerals and letters denote similar items, and thus, once an item is defined, further definition and explanation thereof are unnecessary.

[0021] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate the orientation or positional relationship that the product of the invention is usually placed in when in use, or the orientation or positional relationship that is commonly understood by those skilled in the art, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The purpose of the present invention is achieved through the following technical solutions: A method for controlling the concentration of tetrahydrothiophene odorant in a pipeline online, comprising: S1. Sampling: extracting the gas in the gas pipeline through an intake air pump and transporting it to a detection cavity;

[0024] S2. Seal the detection cavity: turn off the air intake pump in S1, seal the detection cavity, collect the pressure in the cavity through the pressure sensor as the initial pressure value P0, and collect the initial temperature value T0 in the cavity through the temperature sensor;

[0025] S3. Rapid refrigeration: Turn on the refrigerator to rapidly refrigerate the gas in the detection chamber. Due to the condensation of tetrahydrothiophene, the nonlinear ring-down characteristics are caused, and the time τ1 and τ2 for the temperature in the detection chamber to decay to the initial value T0·1 / e and the pressure to decay to the initial value P0·1 / e are continuously recorded and collected through the pressure sensor, temperature sensor, moisture sensor and timer in the detection chamber; S4. Calculate the concentration of tetrahydrothiophene odorant: According to τ1 and τ2 detected in S3, combined with the Clapeyron equation PV=nRT, P represents pressure, V represents gas volume, n represents amount of substance, T represents absolute temperature, and R represents gas constant, the concentration value of tetrahydrothiophene can be deduced and corrected by inversion;

[0026] The specific components of pipeline gas include methane, ethane, propane, isobutane, n-butane, isopentane, n-pentane, etc. Among them, the content of methane is the highest, reaching 80-98%, and the content of other hydrocarbon components is lower. In addition, pipeline gas also contains a small amount of nitrogen and carbon dioxide.

[0027] When tetrahydrothiophene is not added, the pipeline gas is cooled, and the pressure P changes linearly with the temperature T. When tetrahydrothiophene exists in the pipeline gas, the sealed cavity is cooled, and tetrahydrothiophene has a partial condensation effect, which causes a phase change of tetrahydrothiophene. The degree of phase change is a related quantity to the concentration of tetrahydrothiophene, so the concentration of tetrahydrothiophene is inverted through the nonlinear change of pressure P and temperature T.

[0028] S5. Exhaust recovery: The exhaust gas after the test is recovered into the gas pipeline through the exhaust gas pump;

[0029] S6. Send data: upload the tetrahydrothiophene concentration value calculated by S4 to the remote control system through the 4G communication module;

[0030] S7. Adjusting the concentration: The odorant filling station controls the filling amount of tetrahydrothiophene odorant according to the tetrahydrothiophene concentration value in S5.

[0031] A further technical solution is that solenoid valves are installed at both the air inlet and air outlet ends of the detection cavity in S1, and the two sets of solenoid valves are installed at the air outlet end of the air intake air pump and the air intake end of the exhaust air pump respectively.

[0032] A further technical solution is that a PLC controller is installed on the detection cavity, and the PLC controller is responsible for controlling the opening and closing of the solenoid valve, air pump, pressure sensor, temperature sensor, moisture sensor and timer. The PLC controller exchanges information with the remote control system through a 4G communication module.

[0033] A further technical solution is that the PLC controller can regularly control the opening and closing of the solenoid valve, air pump, pressure sensor, temperature sensor, moisture sensor and timer to achieve regular periodic detection of the gas pipeline.

[0034] A further technical solution is that the PLC controller can control the device to enter a low-power sleep state, waiting for the next task to wake up.

[0035] A further technical solution is that the 4G communication module in the S6 can upload the number, time, longitude and latitude, and ambient temperature and humidity of the read device to the remote control system.

[0036] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the concentration of tetrahydrothiophene odorant in pipelines online, characterized in that: include: S1. Sampling: The gas in the gas pipeline is extracted by the air intake pump and transported to the detection chamber; S2. Seal the detection cavity: turn off the air intake pump in S1, seal the detection cavity, collect the pressure in the cavity through the pressure sensor as the initial pressure value P0, and collect the initial temperature value T0 in the cavity through the temperature sensor; S3. Rapid refrigeration: Turn on the refrigerator to rapidly refrigerate the gas in the detection chamber. The nonlinear ring-down characteristics caused by the condensation of tetrahydrothiophene are recorded and collected through the pressure sensor, temperature sensor, moisture sensor and timer in the detection chamber. The time τ1 and τ2 of the temperature ring-down to the initial value T0·1 / e and the pressure ring-down to the initial value P0·1 / e in the detection chamber are continuously recorded and collected; S4. Calculate the concentration of tetrahydrothiophene odorant: Based on τ1 and τ2 detected in S3, combined with the Clapeyron equation PV=nRT, P represents pressure, V represents gas volume, n represents the amount of substance, T represents absolute temperature, and R represents gas constant, the concentration value of tetrahydrothiophene can be calculated and corrected by inversion; S5. Exhaust recovery: The exhaust gas after the test is recovered into the gas pipeline through the exhaust gas pump; S6. Send data: upload the tetrahydrothiophene concentration value calculated by S4 to the remote control system through the 4G communication module; S7. Adjusting the concentration: The odorant filling station controls the filling amount of tetrahydrothiophene odorant according to the tetrahydrothiophene concentration value in S5.

2. The method for controlling the concentration of tetrahydrothiophene odorant in pipelines according to claim 1, characterized in that: The air inlet and air outlet ends of the detection cavity in S1 are both installed with solenoid valves, and the two sets of solenoid valves are respectively installed at the air outlet end of the air intake air pump and the air inlet end of the exhaust air pump.

3. A method for controlling the concentration of tetrahydrothiophene odorant in pipelines online according to claim 2, characterized in that: A PLC controller is installed on the detection cavity, and the PLC controller is responsible for controlling the opening and closing of the solenoid valve, air pump, pressure sensor, temperature sensor, moisture sensor and timer. The PLC controller exchanges information with the remote control system through a 4G communication module.

4. A method for controlling the concentration of tetrahydrothiophene odorant in pipelines online according to claim 3, characterized in that: The PLC controller can control the opening and closing of the solenoid valve, the air pump, the pressure sensor, the temperature sensor, the moisture sensor and the timer at a regular time, so as to realize the regular periodic detection of the gas pipeline.

5. The method for controlling the concentration of tetrahydrothiophene odorant in pipelines online according to claim 3, characterized in that: The PLC controller can control the device to enter a low-power sleep state, waiting for the next task to wake up.

6. The method for controlling the concentration of tetrahydrothiophene odorant in pipelines according to claim 1, characterized in that: The 4G communication module in the S6 can upload the number, time, longitude and latitude, and ambient temperature and humidity of the read device to the remote control system.