Flow mode control system and method for natural gas accumulation sampling system

Abstract

The invention discloses a natural gas accumulation sampling system flow mode control system and method, and relates to the technical field of natural gas analysis. Comprising the following steps: reading instantaneous flow data of a station control system, and selecting a flow mode control signal type of a natural gas accumulation sampling system; when the flow mode control signal is a pulse voltage signal, instantaneous flow data are read and accumulated, when an accumulated flow value reaches a preset flow value, the pulse voltage signal is output, and a sampling pump of an accumulated sampling system is controlled and triggered to perform primary sampling; when the flow mode control signal is an analog current signal, instantaneous flow data are read and converted into the analog current signal, instantaneous flow is calculated and accumulated through an accumulation sampling system control module, and a sampling pump performs primary sampling when a preset flow value is reached; after one-time sampling is completed, accumulation is carried out again until the sampling frequency reaches a preset value; flow mode control of the natural gas accumulation sampling system is achieved, and the natural gas accumulation sampling system has the advantages of being high in universality, independent, portable, simple and easy to achieve.

Description

Technical Field

[0001] This invention relates to the field of natural gas analysis technology, specifically to a flow pattern control system and method for a natural gas cumulative sampling system. Background Technology

[0002] Cumulative sampling systems, as a crucial means of determining calorific value in natural gas energy metering, play a vital role in ensuring the fairness and impartiality of natural gas trade transactions. Natural gas cumulative sampling systems operate in two modes: a time-proportional mode and a flow-proportional mode. Each mode has its advantages. In time mode, the cumulative sampling system samples at set time intervals, making it simple and easy to implement, suitable for operating conditions with relatively stable gas composition and flow rate. In flow-proportional mode, the cumulative sampling system samples according to a preset flow rate value, suitable not only for conditions with relatively stable gas composition and flow rate but also for operating conditions with large fluctuations in gas composition and flow rate. However, this mode requires connection to a flow rate computer to convert the flow signal into a pulse voltage or analog current signal and transmit it to the cumulative sampling system control module, thereby controlling the system to sample according to the flow rate ratio.

[0003] The current implementation method of the flow mode of the cumulative sampling system at natural gas transmission stations is as follows: ① Prepare relevant hardware modules according to the trigger signal of the cumulative sampling system; ② Write software programs for flow reading, cumulative calculation, and trigger signal issuance according to the type of station control system; ③ When the station temporarily shuts down, embed the software program into the station control system to read the flow data, perform software debugging, and test the control function of the output flow control signal on the cumulative sampling system.

[0004] The existing method has three main problems: First, it easily disrupts normal production at the plant and is difficult to implement. Embedding the flow mode control program into the station control system requires a temporary shutdown of the plant, which is challenging and can also affect data transmission from other online equipment. Second, the software program has limited applicability and lacks versatility. Because different station control systems read and transmit flow data differently, when the cumulative sampling system is used at a different plant, the software control program needs to be rewritten and debugged, increasing the workload of operators and making it difficult to promote. Third, the flow control signal output is singular. The current method can only generate a specific trigger signal to control the cumulative sampler. When the type of cumulative sampler is changed at the plant, the hardware and software need to be redesigned, making it incompatible with all cumulative sampling systems.

[0005] Therefore, there is a need to design a flow pattern control system and method that is easy to operate, applicable to different flow trigger signals, and meets the needs of different station control systems in various gas transmission stations. Summary of the Invention

[0006] This invention addresses the technical problems of current natural gas cumulative sampling systems, which require station gas shutdown to embed the control program, resulting in high implementation difficulty, limited versatility, and inability to meet the needs of different trigger signals and different types of station control systems. The aim is to provide a flow mode control system and method for natural gas cumulative sampling systems that is applicable to cumulative sampling systems with different trigger signals and can be associated with different station control systems without shutting down the gas supply at the station. This enables flow mode control of the natural gas cumulative sampling system and features strong versatility, independent portability, and ease of implementation.

[0007] This invention is achieved through the following technical solution:

[0008] The first objective of this invention is to provide a flow pattern control method for a natural gas cumulative sampling system, comprising the following steps:

[0009] The controller reads the instantaneous flow data from the gas transmission station control system and selects the flow mode control signal type for the natural gas cumulative sampling system.

[0010] When the flow mode control signal is a pulse voltage signal, the controller performs cumulative calculation based on the instantaneous flow data read. When the cumulative flow value reaches the preset flow value, it outputs a pulse voltage signal, which is transmitted to the control module of the cumulative sampling system to trigger the sampling pump to perform one sampling. The sampling count is incremented by 1, the cumulative flow value is reset to zero, and the flow data is read again for cumulative calculation until the sampling count reaches the preset value, at which point sampling stops.

[0011] When the flow mode control signal is an analog current signal, the controller converts the instantaneous flow data it reads into an analog current signal and transmits it to the control module of the cumulative sampling system to calculate the instantaneous flow and accumulate it. When the preset flow value is reached, the sampling pump is triggered to perform a sampling, the sampling count is incremented by 1, the cumulative flow value is reset to zero, the flow data is read again and accumulated, until the sampling count reaches the preset value, and then sampling stops.

[0012] Furthermore, when the flow mode control signal type of the natural gas cumulative sampling system is pulse voltage, a 5-24V pulse voltage signal is output when the cumulative flow value reaches the preset flow value.

[0013] Furthermore, when the flow mode control signal type of the natural gas cumulative sampling system is analog current, the instantaneous flow data read will be converted into a 4-20mA analog current signal.

[0014] A second objective of this invention is to provide a flow pattern control system for a natural gas cumulative sampling system, characterized in that it comprises:

[0015] The cumulative sampling system is installed on the gas transmission pipeline;

[0016] The gas transmission station control system is connected to the cumulative sampling system;

[0017] The controller is used to read the instantaneous flow data of the gas transmission station control system and simultaneously select the flow mode control signal type of the cumulative sampling system.

[0018] The pulse voltage output module transmits the pulse voltage signal output by the controller to the cumulative sampling system control module;

[0019] The analog current output module transmits the analog current signal output by the controller to the cumulative sampling system control module;

[0020] When the flow mode control signal of the cumulative sampling system is a pulse voltage signal, the controller performs cumulative calculation based on the instantaneous flow data read. When the cumulative flow value reaches the preset flow value, the pulse voltage output module outputs a pulse voltage signal to the cumulative sampling system control module to trigger the sampling pump to perform sampling.

[0021] When the flow mode control signal of the cumulative sampling system is an analog current signal, the controller converts the instantaneous flow data it reads into an analog current signal and transmits it to the control module of the cumulative sampling system through the analog current output module. The cumulative sampling system calculates the instantaneous flow and accumulates it. When the preset flow value is reached, the sampling pump is triggered to sample.

[0022] Furthermore, the gas transmission station control system is connected to a network switch, and the controller is connected to the network switch of the gas transmission station control system via a network cable.

[0023] Furthermore, it also includes a relay connected between the pulse voltage output module and the cumulative sampling system control module.

[0024] Furthermore, it also includes a surge protector connected between the analog current output module and the cumulative sampling system control module.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] This invention provides a flow mode control system and method for a natural gas cumulative sampling system. Firstly, the system is independent and portable, requiring only a network cable connection to the network switch of the gas transmission station control system for flow reading and control. This makes operation simple and easy to implement, solving the problem of the difficulty in embedding flow mode control programs into the station control system due to the need for gas shutdown. Secondly, the system is highly versatile and can be used in different types of gas transmission station control systems, facilitating large-scale application. Thirdly, it can simultaneously implement flow mode functions for cumulative sampling systems with different trigger signals, meeting the usage requirements of different types of cumulative sampling systems in various gas transmission stations. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0028] Figure 1 This is a flowchart illustrating the flow pattern control system of the natural gas cumulative sampling system of the present invention.

[0029] Figure 2 This is a schematic diagram of the flow mode control system of the natural gas cumulative sampling system of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0031] The following detailed description of an embodiment of a flow pattern control system and method for a natural gas cumulative sampling system, with appropriate reference to the accompanying drawings, illustrates the present invention. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art.

[0032] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0033] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0034] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0035] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0036] It should be noted that the specific structural composition of the cumulative sampling system is existing technology, and the flow pattern control system of the present invention is applicable to any type of cumulative sampling system in the prior art.

[0037] Example 1

[0038] A flow pattern control method for a natural gas cumulative sampling system, such as Figure 1 As shown, it includes the following steps:

[0039] The controller reads the instantaneous flow data of the pipeline where the cumulative sampling system is installed through the IP address of the station control system, and selects the flow mode control signal type of the natural gas cumulative sampling system; the controller can be an FPGA, MCU, PLC and CPLD, etc.

[0040] When the flow mode control signal is a pulse voltage signal, the controller performs cumulative calculation based on the instantaneous flow data read. When the cumulative flow value reaches the preset flow value, it outputs a 5-24V pulse voltage signal, which is transmitted to the cumulative sampling system control module through the pulse voltage output module and the relay. This triggers the sampling pump of the cumulative sampling system to perform one sampling. The sampling count is incremented by 1, the cumulative flow value is reset to zero, and the flow data is read again for cumulative calculation until the sampling count reaches the preset value, at which point sampling stops.

[0041] When the flow mode control signal is an analog current signal, the controller converts the instantaneous flow data into a 4-20mA analog current signal. Through the analog current output module and surge protector, the analog current signal is transmitted in real time to the cumulative sampling system control module. The calculation module built into the cumulative sampling system calculates the instantaneous flow based on the correspondence between current and flow and accumulates it. When the preset flow value is reached, the sampling pump of the cumulative sampling system is triggered to perform a sampling, the sampling count is incremented by 1, the cumulative flow value is reset to zero, and the flow data is read again for accumulation calculation until the sampling count reaches the preset value, at which point sampling stops.

[0042] Example 2

[0043] A flow pattern control system for a natural gas cumulative sampling system, such as Figure 2 As shown, it includes:

[0044] The cumulative sampling system is installed on the gas transmission pipeline;

[0045] The gas transmission station control system is connected to the cumulative sampling system, and the gas transmission station control system is connected to a network switch.

[0046] The controller is used to read the instantaneous flow data of the gas transmission station control system and determine the control signal type of the cumulative sampling system. The controller is connected to the network switch of the gas transmission station control system via a network cable.

[0047] The pulse voltage output module transmits the pulse voltage signal output by the controller to the cumulative sampling system control module; a relay is connected between the pulse voltage output module and the cumulative sampling system controller.

[0048] An analog current output module transmits the analog current signal output by the controller to the cumulative sampling system control module; a surge protector is connected between the analog current output module and the cumulative sampling system controller.

[0049] When the flow mode control signal of the cumulative sampling system is a pulse voltage signal, the controller performs cumulative calculation based on the instantaneous flow data read. When the cumulative flow value reaches the preset flow value, the pulse voltage output module outputs a pulse voltage signal to the control module of the cumulative sampling system to trigger the sampling pump of the cumulative sampling system to perform sampling.

[0050] When the flow mode control signal of the cumulative sampling system is an analog current signal, the controller converts the instantaneous flow data it reads into an analog current signal and transmits it to the control module of the cumulative sampling system through the analog current output module. The cumulative sampling system calculates the instantaneous flow and accumulates it. When the preset flow value is reached, the sampling pump of the cumulative sampling system is triggered to sample.

[0051] The cumulative sampling system has a built-in calculation module. When the analog current signal is transmitted to the cumulative sampling system controller, the built-in calculation module calculates the instantaneous flow rate and accumulates it based on the correspondence between the received analog current signal and the flow rate.

[0052] The overall system of this invention is powered by an external power supply module and is equipped with a touch screen display module to display and set parameters such as instantaneous flow rate, real-time cumulative flow rate, number of samplings, preset cumulative flow rate, sampling bottle volume, and single sampling amount, so as to realize that the cumulative sampling system samples according to the flow rate ratio.

[0053] Application Example 1

[0054] Taking a cumulative sampling system installed at a gas transmission station, which uses pulse signals as the flow mode control signal, as an example, the system is implemented in the field. The preset cumulative flow value and sampling frequency are calculated and determined based on the sampling bottle capacity, sampling cycle, and historical flow data of the cumulative sampling system.

[0055] Assuming a sampling bottle volume of 500 mL, a sampling volume of 400 mL (80% full), and a single sampling pump volume of 0.4 mL, the required number of sampling operations is calculated to be 1000. Assume the station's daily natural gas flow rate is 5 million m³. 3 The cumulative sampling period is set to 1 month, and the preset cumulative flow rate is calculated to be 150,000 m³. 3 That is, every time it accumulates to 150,000 m 3 The sampling pump operates once per cycle.

[0056] Based on this, a flow mode control method for a natural gas cumulative sampling system includes the following steps:

[0057] (1) The programmable logic controller reads the instantaneous flow data of the gas transmission station control system, selects the control signal as a pulse signal, and thus selects the corresponding process;

[0058] (2) The programmable logic controller reads the instantaneous flow data of the gas transmission field pipeline where the cumulative sampling system is installed in real time through the IP address of the gas transmission field control system and performs cumulative calculation.

[0059] (3) When the cumulative flow reaches 150,000 m³ 3 At this time, a 24V voltage pulse signal is output and transmitted to the cumulative sampling system controller through a relay and cable, and the sampling pump of the cumulative sampling system performs one operation;

[0060] (4) After the cumulative flow value reaches zero, continue reading the flow data for cumulative calculation until it reaches 150,000 m³ again. 3 At that time, output the next 24V voltage pulse signal;

[0061] (5) Sampling will stop when the number of samplings reaches the preset 1000.

[0062] Application Example 2

[0063] Taking a cumulative sampling system installed at a gas transmission station, which uses analog current signals as the flow mode control signal, as an example, the system is implemented in the field. The preset cumulative flow value and sampling frequency are calculated and determined based on the sampling bottle capacity, sampling cycle, and historical flow data of the cumulative sampling system.

[0064] Assuming a sampling bottle volume of 500 mL, a sampling volume of 400 mL (80% full), and a single sampling pump volume of 0.4 mL, the required number of sampling operations is calculated to be 1000. Assume the station's daily natural gas flow rate is 5 million m³. 3 The cumulative sampling period is set to 1 month, and the preset cumulative flow rate is calculated to be 150,000 m³. 3 That is, every time it accumulates to 150,000 m 3 The sampling pump operates once per cycle.

[0065] Based on this, a flow mode control method for a natural gas cumulative sampling system includes the following steps:

[0066] (1) The programmable logic controller reads the instantaneous flow data of the gas transmission station control system, selects the analog current signal as the control signal, and then selects the corresponding process;

[0067] (2) The programmable logic controller reads the instantaneous flow data of the gas transmission field pipeline where the cumulative sampling system is installed in real time through the IP address of the gas transmission field control system, performs cumulative calculation, and converts the instantaneous flow data into an analog current signal and transmits it to the control module of the cumulative sampling system.

[0068] (3) The calculation module built into the cumulative sampling system performs calculations based on the received analog current signal. When the preset flow rate value of 150,000 m³ is reached... 3 When the time is right, the sampling pump of the cumulative sampling system is triggered to take a sample once;

[0069] (4) The flow data accumulated by the programmable logic controller reaches the preset flow value of 150,000 m³. 3 When the sampling time is reached, the sampling count is incremented by 1;

[0070] (5) Sampling will stop when the number of samplings reaches the preset 1000.

[0071] Finally, it should be noted that the above specific embodiments are only used to describe the purpose, technical solution, and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation of the present invention and is not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the foregoing specific embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions or improvements can be made to some or all of the technical features. These modifications, equivalent substitutions, and improvements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A flow mode control method for a natural gas cumulative sampling system, characterized in that, Includes the following steps: The controller reads the instantaneous flow data from the gas transmission station control system and selects the flow mode control signal type for the natural gas cumulative sampling system. When the flow mode control signal is a pulse voltage signal, the controller performs cumulative calculation based on the instantaneous flow data read. When the cumulative flow value reaches the preset flow value, it outputs a pulse voltage signal, which is transmitted to the control module of the cumulative sampling system to trigger the sampling pump to perform one sampling. The sampling count is incremented by 1, the cumulative flow value is reset to zero, and the flow data is read again for cumulative calculation until the sampling count reaches the preset value, at which point sampling stops. When the flow mode control signal is an analog current signal, the controller converts the instantaneous flow data it reads into an analog current signal and transmits it to the control module of the cumulative sampling system to calculate the instantaneous flow and accumulate it. When the preset flow value is reached, the sampling pump is triggered to perform a sampling, the sampling count is incremented by 1, the cumulative flow value is reset to zero, the flow data is read again and accumulated, until the sampling count reaches the preset value, and then sampling stops.

2. The flow mode control method for a natural gas cumulative sampling system according to claim 1, characterized in that, When the flow mode control signal type of the natural gas cumulative sampling system is pulse voltage, a 5-24V pulse voltage signal is output when the cumulative flow value reaches the preset flow value.

3. The flow mode control method for a natural gas cumulative sampling system according to claim 1, characterized in that, When the flow mode control signal type of the natural gas cumulative sampling system is analog current, the instantaneous flow data read will be converted into a 4-20mA analog current signal.

4. A flow mode control system for a natural gas cumulative sampling system, characterized in that, include: The cumulative sampling system is installed on the gas transmission pipeline; The gas transmission station control system is connected to the cumulative sampling system; The controller is used to read the instantaneous flow data of the gas transmission station control system and simultaneously select the flow mode control signal type of the cumulative sampling system. The pulse voltage output module transmits the pulse voltage signal output by the controller to the cumulative sampling system control module; The analog current output module transmits the analog current signal output by the controller to the cumulative sampling system control module; When the flow mode control signal of the cumulative sampling system is a pulse voltage signal, the controller performs cumulative calculation based on the instantaneous flow data read. When the cumulative flow value reaches the preset flow value, the pulse voltage output module outputs a pulse voltage signal to the cumulative sampling system control module to trigger the sampling pump to perform sampling. When the flow mode control signal of the cumulative sampling system is an analog current signal, the controller converts the instantaneous flow data it reads into an analog current signal and transmits it to the control module of the cumulative sampling system through the analog current output module. The cumulative sampling system calculates the instantaneous flow and accumulates it. When the preset flow value is reached, the sampling pump is triggered to sample.

5. The flow mode control system for a natural gas cumulative sampling system according to claim 4, characterized in that, The gas transmission station control system is connected to a network switch, and the controller is connected to the network switch of the gas transmission station control system via a network cable.

6. The flow mode control system for a natural gas cumulative sampling system according to claim 4, characterized in that, It also includes a relay, which is connected between the pulse voltage output module and the cumulative sampling system control module.

7. The flow mode control system for a natural gas cumulative sampling system according to claim 4, characterized in that, It also includes a surge protector connected between the analog current output module and the cumulative sampling system control module.

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