A monitoring system for source odorization of a natural gas pipeline

Abstract

The present application relates to natural gas odorization monitoring technical field, disclose a kind of natural gas pipeline source head odorization monitoring system, including dosing pump, medicine storage tank, pressure sensor, liquid level sensor, natural gas flowmeter and controller.Pulse pressure is monitored in dosing pump outlet by pressure sensor, and actual working frequency is obtained by controller recording pulse pressure, and actual working frequency is compared with target working frequency of associated flow data, and dosing pump working frequency state is obtained.Liquid level sensor monitors liquid level drop in medicine storage tank, and controller calculates actual odorization consumption, and actual odorization consumption is compared with target odorization total amount of associated natural gas total volume, and odorization total amount state is obtained.The present application completes frequency and volume dimension double comparison by pipeline source head end, constructs closed loop check logic, avoids the defect that control instruction lacks dosing pump action confirmation, eliminates the data lag error caused by end detection affected by pipe storage natural gas.

Description

Technical Field

[0001] This invention relates to the field of natural gas odorization monitoring technology, specifically a monitoring system for odorization at the source of natural gas pipelines. Background Technology

[0002] According to the specifications of "Urban Gas Odor Addition Devices" and "Technical Regulations for Urban Gas Odor Addition," the odorization device controller has manual and automatic operation modes, receives signals from the gas flow meter, and transmits operational monitoring data to the host computer. Currently available odorization controllers only have the function of outputting control signals and lack a feedback loop for the dosing pump's actions. When the controller issues an action command, the system cannot confirm whether the dosing pump has performed the dosing action according to the set operating frequency.

[0003] When a mechanical failure of the dosing pump reduces the amount of odorization added in a single cycle, the total amount of odorization added within a specific period decreases simultaneously, and the controller cannot monitor or provide feedback on the changes in the total amount of odorization. The lack of action confirmation and odorization total monitoring feedback loops easily leads to insufficient natural gas odorization concentration, which is a significant hidden danger in gas operation.

[0004] Existing natural gas odorization control methods typically employ either periodic end-point detection or real-time end-point monitoring. However, natural gas remains stored between the odorization source and the end-point detection point in the pipeline. This storage means that the odorization concentration data detected at the end reflects the odorization activity at the source over a past period. The time lag between the odorization operation at the source and the data feedback at the end results in data delays in natural gas odorization control. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a monitoring system for odorization at the source of natural gas pipelines. This system solves the problem that existing natural gas odorization control methods are limited by periodic end-point detection management, resulting in detection lags due to the presence of stored natural gas in the pipeline between the odorization source and the end point.

[0006] To achieve the above objectives, the present invention provides a monitoring system for odorization at the source of natural gas pipelines, including a dosing pump and a storage tank connected to the dosing pump, and also includes a pressure sensor, a level sensor, a natural gas flow meter at the station and a station control system or controller, wherein the pressure sensor, the level sensor and the natural gas flow meter at the station are respectively connected to the station control system or controller.

[0007] A pressure sensor is installed at the outlet of the dosing pump and monitors the pulse pressure, transmitting the pulse pressure to the station control system or controller. The station control system or controller records the pulse pressure to obtain the actual operating frequency. The target operating frequency is calculated based on the pre-defined formula data of the ratio of gas flow rate and odor addition amount. The actual operating frequency is compared with the target operating frequency to determine whether the dosing pump frequency is normal or abnormal.

[0008] A liquid level sensor is installed in the storage tank to monitor the liquid level data. The station control system or controller calculates the total amount of natural gas to be transmitted and calculates the target total amount of odorization. The actual odorization consumption is calculated based on the amount of liquid level drop in the storage tank. The target total amount of odorization is compared with the actual odorization consumption to determine whether the odorization amount is normal or abnormal.

[0009] Preferably, the station control system includes an analog input module, a central processing unit (CPU), a communication module, a switch, and a host computer. Pressure sensors, level sensors, and the station's natural gas flow meter are all connected to the analog input module. The analog input module receives analog signals and converts them into digital signals. The CPU scans and stores the digital signals at a fixed frequency, performs calculations and comparisons on the digital signals, obtains the comparison results, and sends the corresponding alarm status information to the communication module. The communication module outputs the alarm status information to the switch, which then transmits the alarm status information to the host computer via a network line. The host computer uses configuration software to monitor, classify, store, and compare the received alarm status information and corresponding digital signals in real time.

[0010] Preferably, the central processing unit (CPU) extracts the flow rate digital value from its internal registers and converts it into instantaneous natural gas flow rate. The CPU simultaneously verifies whether the single rated dosing amount is greater than zero. If the single rated dosing amount is greater than zero, the CPU performs calculations based on the instantaneous natural gas flow rate, the specified concentration requirements, and the single rated dosing amount. The CPU calculates the target operating frequency that the dosing pump needs to perform, reflecting the dosing action rate matched to the current pipeline gas transmission status.

[0011] Preferably, the central processing unit (CPU) has internal filtering threshold conditions, with the lower and upper limits set to 1.2 and 1.5 times the working pressure of the natural gas pipeline, respectively. The CPU performs amplitude filtering on continuously read pressure values, filtering out pressure values ​​with amplitudes lower than 1.2 times the working pressure of the natural gas pipeline and pressure values ​​with amplitudes higher than 1.5 times the working pressure of the natural gas pipeline, retaining pressure values ​​with amplitudes between 1.2 and 1.5 times the working pressure of the natural gas pipeline, and determining the retained pressure values ​​as valid pulses. The CPU accumulates the total number of valid pulses generated within a 1-minute statistical time window and calculates the actual operating frequency based on the total number of pulses.

[0012] Preferably, the central processing unit (CPU) synchronously extracts the calculated target operating frequency and the statistically obtained actual operating frequency, and performs a comparison operation between the target operating frequency and the actual operating frequency. When the CPU finds that the target operating frequency and the actual operating frequency are inconsistent and the difference exceeds the 5% warning band for three consecutive sampling cycles, it excludes the single misjudgment interference caused by transient fluctuations in the natural gas pipeline and determines that the current odorization frequency of the dosing pump is abnormal. The CPU modifies the status word bound to the odorization frequency node in its internal register to the abnormal bit and generates alarm status information specific to the odorization frequency abnormality. It then encapsulates the alarm status information specific to the odorization frequency abnormality into a standard network data packet and sends it to the switch.

[0013] Preferably, the central processing unit (CPU) has a fixed calculation cycle time axis, and the length of the calculation cycle is fixed at one hour. Within the hourly calculation cycle, the CPU continuously reads the flow rate data and converts the read flow rate data into instantaneous natural gas flow rate. It performs an accumulation operation on the instantaneous natural gas flow rate within the same calculation cycle to calculate the total natural gas transmission volume within the same cycle. The CPU extracts the total natural gas transmission volume within the same cycle and the pre-written specified concentration requirement, multiplies the total natural gas transmission volume within the same cycle with the specified concentration requirement, and obtains the target total odorization volume based on the result of the multiplication operation.

[0014] Preferably, the internal storage area of ​​the central processing unit (CPU) contains a tank level-volume lookup table that includes discrete liquid level height nodes and odorant mass nodes bound to each liquid level height node. The CPU reads the initial liquid level data at the start time and the final liquid level data at the end time through the analog input module, substitutes them into the tank level-volume lookup table to find the upper and lower liquid level height nodes that envelop the initial liquid level data. The CPU simultaneously extracts the upper odorant mass node associated with the upper liquid level height node and the lower odorant mass node associated with the lower liquid level height node, and uses a linear interpolation algorithm based on the slope of the line connecting the two points to convert the initial liquid level data and the final liquid level data into initial mass data and final mass data, respectively. The initial mass data is subtracted from the final mass data to convert the liquid level drop into the actual odorant consumption in the mass dimension.

[0015] Preferably, the central processing unit (CPU) synchronously reads the calculated target total odorization amount and the interpolated actual odorization consumption amount, and performs a consistency comparison operation on the value of the target total odorization amount and the value of the actual odorization consumption amount. When the CPU finds that the value of the target total odorization amount and the value of the actual odorization consumption amount are inconsistent, it determines that there is a deviation in the total odorization amount discharged by the dosing pump within the calculation cycle. The CPU modifies the status word bound to the cycle odorization amount node in the internal register to the abnormal bit and generates alarm status information specifically for cycle total odorization abnormality. The alarm status information specifically for cycle total odorization abnormality is forwarded to the host computer via the communication module and the switch.

[0016] Preferably, the configuration software running inside the host computer performs unpacking operations on standard network data packets, extracts alarm status information, and sends a front-end display reconstruction command to the HMI (Human Machine Interface). This forces the display attribute of the status indicator control to switch from a normal display state to a red flashing state, and automatically generates an independent alarm prompt box at the top level of the HMI. The configuration software synchronously reads the current time data inside the host computer and sets it as a timestamp. It continuously extracts various comparison values ​​and performs horizontal alignment verification based on the same time axis with the alarm status information. After confirming that the time offset of the data source is within the allowable tolerance range, the configuration software binds and combines the data with the timestamp to generate fault data packets with time stamp attributes, and directly writes the fault data packets into the host computer's internal hard disk database.

[0017] Preferably, the dosing pump is equipped with a dosing pipeline, on which a dosing valve, a check valve, and a vaporizer valve are sequentially installed, and the dosing pipeline is connected to the main natural gas pipeline; a pressure sensor, a pressure gauge, and a calibrator are installed in parallel on the pipeline between the dosing pump outlet and the dosing valve, for directly sensing the instantaneous pulse pressure formed inside the dosing pipeline when the dosing pump discharges the odorant; a return pipeline is led out from the front end of the dosing valve on the dosing pipeline, a return valve is installed on the return pipeline, and the end of the return pipeline is connected to the top of the storage tank.

[0018] This invention provides a monitoring system for odorization at the source of natural gas pipelines. It has the following beneficial effects:

[0019] 1. This invention installs a pressure sensor at the outlet of the dosing pump to monitor pulse pressure within 1.2 to 1.5 times the operating pressure of the natural gas pipeline. The station control system or controller records the pulse pressure to obtain the actual operating frequency. The actual operating frequency is then compared with the target operating frequency calculated by combining the instantaneous natural gas flow rate. This enables feedback monitoring of the dosing pump's operating status and solves the shortcomings of the original system, which could only output control commands in one direction and lacked confirmation of the actual operation of the dosing pump.

[0020] 2. This invention installs a liquid level sensor on the storage tank and uses the station control system or controller to read the liquid level drop within a fixed calculation cycle. The liquid level drop is converted into the actual odorization consumption. Simultaneously, the target total odorization amount associated with the total natural gas transmission volume within the same cycle is extracted. The target total odorization amount is compared with the actual odorization consumption in terms of volume dimension, thus constructing a closed-loop verification logic for the total odorization amount. This avoids the hidden danger of the total odorization amount not meeting the standard due to mechanical failure of the dosing pump causing a reduction in the single discharge volume.

[0021] 3. This invention integrates the pulse pressure data collected by the pressure sensor, the liquid level data collected by the liquid level sensor, and the flow rate data collected by the natural gas flow meter at the station into the station control system or controller. Combined with the preset calculation formula, it directly completes double cross-checking and abnormal alarm at the source of the natural gas pipeline. The source data comparison architecture replaces the periodic detection and management mode at the end, eliminating the data monitoring lag error caused by the natural gas stored in the pipeline between the source and the end of the natural gas pipeline. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the pipeline connection and hardware deployment for odorization at the source of the natural gas pipeline according to the present invention.

[0023] Figure 2 This is a block diagram of the data flow and control architecture of the natural gas pipeline source odorization monitoring system of the present invention;

[0024] Figure 3 This is a flowchart illustrating the dual monitoring logic for adding odor to the source of natural gas pipelines according to the present invention.

[0025] Figure 4 This is a schematic diagram illustrating the dynamic monitoring and comparison of the working frequency following the instantaneous natural gas flow rate during the chemical dosing operation of the present invention;

[0026] Figure 5 This is a line graph showing the monitoring of total odor addition during different accounting periods according to the present invention. Detailed Implementation

[0027] 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 described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] See attached document Figure 1 -Appendix Figure 3This invention provides a monitoring system for odorization at the source of a natural gas pipeline, including a dosing pump connected to a storage tank. The invention also includes a pressure sensor, a level sensor, a natural gas flow meter at the site, a site control system, and a controller. The pressure sensor is installed at the outlet of the dosing pump, the level sensor is installed in the storage tank, and the pressure sensor, level sensor, and natural gas flow meter at the site are respectively connected to the site control system or the controller.

[0029] Existing natural gas odorization control methods are limited by periodic end-point inspections, which are delayed due to the presence of stored natural gas in the pipeline between the odorization source and the end point. To overcome this delay, this invention employs dual monitoring at the natural gas pipeline source: monitoring the operation of the dosing pump and the level drop in the storage tank. By integrating data from pressure sensors, level sensors, and the station's natural gas flow meter, it achieves intelligent monitoring of the odorization quality at the natural gas pipeline source.

[0030] The pressure sensor monitors the pulse pressure at the outlet of the dosing pump and transmits it to the site control system or controller. The site control system or controller records the pulse pressure to determine the actual operating frequency. It then calculates the target operating frequency using pre-defined formulas for the ratio of gas flow rate to odorization volume. The actual operating frequency is compared with the target frequency to determine whether the dosing pump frequency is normal or abnormal. If the site control system or controller finds a discrepancy between the actual and target operating frequencies, it determines that the odorization frequency is abnormal and sends an alarm to the associated HMI (Human Machine Interface).

[0031] The liquid level sensor monitors the liquid level data of the chemical storage tank and transmits the data to the station control system or controller. The station control system or controller calculates the total natural gas transmission volume hourly, calculates the target total odorization volume based on the pre-defined ratio of gas flow rate to odorization volume, and calculates the actual odorization consumption based on the liquid level drop in the chemical storage tank using a pre-written liquid level-volume comparison table. The target total odorization volume is compared with the actual odorization consumption to determine whether the odorization volume is normal or abnormal. When the station control system or controller finds a discrepancy between the target total odorization volume and the actual odorization consumption, it determines that the odorization volume is abnormal and pushes an odorization volume abnormality alarm to the associated HMI (Human Machine Interface).

[0032] See attached document Figure 2 To enable monitoring data processing and judgment, this invention establishes a hardware connection directly integrated with the station control system. A pressure sensor collects pressure data from the dosing pump outlet and outputs an analog pressure signal; a level sensor collects level data from the storage tank and outputs an analog level signal; and a station natural gas flow meter collects flow data from the station and outputs an analog flow signal. The pressure sensor, level sensor, and station natural gas flow meter are all connected to the analog input module within the station control system.

[0033] The analog input module synchronously receives analog pressure, level, and flow signals. It then converts all these signals into digital signals. The station control system also includes a central processing unit (CPU), a communication module, a switch, and a host computer. The CPU, connected to the analog input module, cyclically scans and stores the digital signals at a fixed frequency, performs calculations and comparisons on the digital signals, obtains the comparison results, and sends the corresponding alarm status information to the communication module.

[0034] The communication module is connected to the central processing unit (CPU) and also to the switch, outputting alarm status information to the switch. The switch then transmits the alarm status information to the host computer via a network line. The host computer contains configuration software that performs real-time monitoring, classification, storage, and comparative analysis of the received alarm status information and corresponding digital values. Data from pressure sensors, level sensors, and the station's natural gas flow meter are sequentially transmitted through the analog input module, CPU, communication module, and switch, and then aggregated and displayed on the host computer of the station control system.

[0035] In addition to the direct data connection to the station control system, this invention provides a controller-based cascade architecture. The analog pressure signal output from the pressure sensor, the analog level signal output from the level sensor, and the analog flow signal output from the station's natural gas flow meter are all connected to the controller.

[0036] The controller internally performs the conversion of analog signals to digital signals, performs calculations and comparisons on the digital signals to obtain comparison results, generates corresponding alarm status information based on the comparison results, establishes a communication connection with the site control system, and pushes the alarm status information to the site control system.

[0037] The station control system receives alarm status information from the controller. The switch within the station control system transmits the alarm status information to the host computer. The host computer uses configuration software to perform real-time monitoring, classification, storage, and comparative analysis of the received alarm status information. The core principle of this invention remains unchanged compared to the method of data access to the station control system and data access to the controller.

[0038] This invention establishes specific pipeline connections and hardware deployment at the source execution end. The storage tank contains odorizing agent, and its top is equipped with a breather valve, an emptying valve, and a feeding valve. The bottom discharge area of ​​the storage tank is connected to a discharge valve and a filter via pipelines. The filter's output is connected to the inlet of the dosing pump. A separate drain valve is also located at the bottom of the storage tank. The dosing pump is equipped with an explosion-proof switch, which is connected to the power supply. The dosing pump is connected to a dosing pipeline, on which a dosing valve, a check valve, and a vaporizer valve are sequentially installed. The dosing pipeline is connected to the main natural gas pipeline.

[0039] The pressure sensor is explosion-proof. The pressure sensor, pressure gauge, and calibrator are installed in parallel on the pipeline between the dosing pump outlet and the dosing valve. The pressure sensor directly senses the instantaneous pulse pressure formed inside the dosing pipeline when the dosing pump discharges the odorant, obtaining the data source corresponding to each actual pressurization action of the dosing pump. A return pipeline is led out from the front end of the dosing valve on the dosing pipeline, and a return valve is installed on the return pipeline. The end of the return pipeline connects to the top of the storage tank.

[0040] The liquid level sensor is installed on the outside of the side wall of the storage tank. The sensing probe is fixed vertically along the tank to sense the height of the odorant liquid level inside and convert it into real-time liquid level change data. The controller receives power from the power supply and also receives the input flow signal. The analog signals collected by the liquid level sensor and the pressure sensor are electrically connected to the controller or the site control system via a control cable.

[0041] The level sensor, pressure sensor, and natural gas flow meter at the station generate continuous analog signals for level, pressure, and flow, respectively, at the data acquisition end. These signals are connected to the analog input module via control cables. All three analog signals are transmitted unidirectionally to the analog input module via the control cables.

[0042] The analog input module is equipped with a multi-channel analog-to-digital converter circuit that simultaneously receives analog signals of liquid level, pressure, and flow rate. It performs analog-to-digital conversion on continuously changing analog signals of liquid level, pressure, and flow rate, converting them into discrete digital quantities.

[0043] The central processing unit has a fixed time cycle. It establishes a data communication network with the analog input module and sends read commands to the analog input module according to the fixed time cycle. It obtains the digital values ​​of liquid level, pressure and flow generated by the analog input module, stores them in internal registers, and continuously refreshes the digital values ​​of liquid level, pressure and flow in the registers according to the fixed time cycle. It then uses the continuously refreshed digital values ​​to perform subsequent comparison calculations.

[0044] The communication module connects to the central processing unit (CPU) via an internal data bus, reads digital values ​​and alarm status information stored in the CPU in real time, packages the read digital values ​​and alarm status information into standard network data packets, and sends them to the switch. The switch is configured with a fixed communication routing address. The switch receives the standard network data packets and forwards them to the host computer according to the communication routing address.

[0045] The host computer's hardware port continuously receives standard network data packets forwarded by the switch. The host computer uses internally installed configuration software to unpack and extract these standard network data packets. The configuration software extracts the digital values ​​of liquid level, pressure, and flow rate, as well as alarm status information contained within the standard network data packets. The configuration software pre-designs an HMI (Human-Machine Interface), directly binding and mapping the digital values ​​of liquid level, pressure, and flow rate to the corresponding data display controls within the HMI to refresh the values. The configuration software also associates and maps the alarm status information to the status indicator controls within the HMI. When the alarm status information extracted by the configuration software is determined to be abnormal, the configuration software drives the status indicator controls to change their display color and generates an independent alarm prompt box on the HMI to complete the terminal's visual monitoring.

[0046] Before generating alarm status information, the central processing unit performs calculations on the extracted digital values. Internally, it pre-stores the ratio formula data between gas flow rate and odorization amount, and has fixed odorization concentration requirements written into the natural gas pipeline source, with the specified concentration requirement set at 20 mg / Nm³. 3 Simultaneously, the rated dosage of the dosing pump is set to 200mg per cycle. When multiple dosing pumps are connected and their rated dosages are different, the host computer sends a data switching command to the central processing unit. The central processing unit receives the data switching command and replaces the value corresponding to the rated dosage.

[0047] See attached document Figure 3In this embodiment, to ensure the stability of core operations and prevent crashes due to configuration data loss, the central processing unit (CPU) extracts the flow rate digital value from its internal registers and converts it into instantaneous natural gas flow rate. Simultaneously, it verifies whether the single-use rated dosing quantity is greater than zero. If the single-use rated dosing quantity is greater than zero, it calculates the target operating frequency required by the dosing pump based on the instantaneous natural gas flow rate, the specified concentration requirement, and the single-use rated dosing quantity. This reflects the dosing action rate matched to the current pipeline gas transmission status. The formula for calculating the target operating frequency is:

[0048] ;

[0049] In the formula: Represents the frequency of target work; Represents instantaneous natural gas flow rate; This represents the specified concentration requirement; This represents the single rated dosage; 60 in the formula is the conversion factor from hours to minutes.

[0050] After calculating the target operating frequency, the central processing unit (CPU) simultaneously acquires the actual operating frequency. When the dosing pump discharges odorant into the main natural gas pipeline, the output discharge pressure is greater than the operating pressure of the natural gas pipeline inside the main pipeline. The dosing outlet pipeline experiences transient pulse pressure due to the discharge pressure. The pressure sensor continuously acquires these pulse pressures and converts them into digital pressure values ​​via an analog input module. The CPU continuously reads these digital pressure values ​​from its registers.

[0051] As a preferred approach, the central processing unit (CPU) has internally set filtering threshold conditions. These conditions are based on the premise that the liquid flow discharged from the dosing pump must overcome the pressure within the pipeline network and the resistance of the one-way valve spring, inevitably creating a water hammer wave significantly higher than the background pressure within the dosing pipeline. The lower limit of the filtering threshold condition is set to 1.2 times the operating pressure of the natural gas pipeline, and the upper limit is set to 1.5 times the operating pressure of the natural gas pipeline. The CPU performs amplitude filtering on continuously read pressure values, filtering out pressure values ​​with amplitudes lower than 1.2 times the operating pressure of the natural gas pipeline and pressure values ​​with amplitudes higher than 1.5 times the operating pressure of the natural gas pipeline. Pressure values ​​with amplitudes within the range of 1.2 to 1.5 times the operating pressure of the natural gas pipeline are retained and considered valid pulses.

[0052] The central processing unit (CPU) has a 1-minute statistical time window. The total number of valid pulses generated within this 1-minute window is accumulated, and the actual operating frequency is calculated based on this total. The formula for calculating the actual operating frequency is:

[0053] ;

[0054] In the formula: Represents actual work frequency; This represents the total number of valid pulses generated within a 1-minute statistical time window.

[0055] The central processing unit synchronously extracts the target operating frequency generated by calculation and the actual operating frequency obtained by statistics, performs a comparison operation on the value of the target operating frequency and the value of the actual operating frequency, and generates corresponding alarm status information based on the comparison operation result.

[0056] When the central processing unit compares and finds that the target operating frequency value is consistent with the actual operating frequency value, it determines that the current operating frequency of the dosing pump is normal, generates alarm status information corresponding to the normal state, and writes the alarm status information corresponding to the normal state into the internal register.

[0057] In addition to outputting alarm status information, the central processing unit (CPU) simultaneously performs periodic data calculations. The CPU has a fixed calculation cycle timeline, with the cycle length set to one hour. Within each hourly calculation cycle, the CPU continuously reads the flow rate data, converts it into instantaneous natural gas flow rates, and performs an accumulation operation on the instantaneous natural gas flow rates within the same calculation cycle to calculate the total natural gas transmission volume for that cycle.

[0058] The central processing unit internally retrieves the pre-written concentration requirement, which is set to 20 mg / Nm³. 3 Simultaneously, the total natural gas transmission volume and the specified concentration requirement within the same cycle are extracted. The total natural gas transmission volume within the same cycle is multiplied by the specified concentration requirement, and the target odorization volume is calculated based on the result of the multiplication. The formula for calculating the target odorization volume is:

[0059] ;

[0060] In the formula: Represents the total amount of odor plus the target; Represents the total amount of natural gas transmitted within the same cycle; This indicates the specified concentration requirement.

[0061] The central processing unit (CPU) simultaneously monitors the liquid level changes inside the storage tank while calculating the target total odorization amount. At the beginning of each hourly calculation cycle, the CPU reads the digital liquid level value generated by the liquid level sensor through the analog input module, and saves the initial liquid level value as the starting liquid level data in the internal storage area to complete the first-end data latch. At the end of each hourly calculation cycle, the CPU reads the liquid level value again, and saves the ending liquid level value as the ending liquid level data in the internal storage area to complete the last-end data latch. The geometric difference between the initial liquid level data and the ending liquid level data is calculated to determine the corresponding liquid level drop.

[0062] The central processing unit (CPU) has a pre-loaded liquid level-volume lookup table for the drug storage tanks in its internal storage area. This table contains a series of discrete liquid level height nodes and corresponding odorant mass nodes. The CPU extracts the initial liquid level data and compares it with the liquid level-volume lookup table to identify the upper and lower liquid level height nodes that envelop the initial liquid level data. Simultaneously, it extracts the upper odorant mass nodes associated with the upper liquid level height nodes and the lower odorant mass nodes associated with the lower liquid level height nodes.

[0063] Under the premise that the values ​​of the upper and lower liquid level nodes are not equal, the central processing unit performs a linear interpolation algorithm by calculating the slope of the line connecting the two points using the upper and lower liquid level nodes, the upper odorant mass node, and the lower odorant mass node. Based on the slope calculation, the initial liquid level data is converted into initial mass data. Based on the identical nodes, the final liquid level data is converted into final mass data by finding and calculating the slope of the line. The initial mass data is subtracted from the final mass data to convert the liquid level drop into the actual odorant consumption in the mass dimension.

[0064] The central processing unit synchronously reads the calculated target total odorization amount and the interpolated actual odorization consumption amount, performs a consistency comparison operation on the value of the target total odorization amount and the value of the actual odorization consumption amount, and generates corresponding alarm status information based on the result of the consistency comparison operation.

[0065] When the central processing unit compares and finds that the target total odorization amount is consistent with the actual odorization consumption amount, it determines that the total odorization amount discharged by the dosing pump within the calculation cycle is in a normal state. Simultaneously, it confirms that the single odorization amount at the source of the dosing pump has reached the preset sufficient standard, generates alarm status information corresponding to the normal total odorization amount, and writes the alarm status information corresponding to the normal total odorization amount into the internal register for storage.

[0066] When the central processing unit (CPU) determines that the target operating frequency is inconsistent with the actual operating frequency, and the difference exceeds the 5% warning threshold for three consecutive sampling cycles, it excludes single-time misjudgment interference caused by transient fluctuations in the natural gas pipeline, classifies the dosing pump's current odorization frequency as abnormal, modifies the status word bound to the odorization frequency node in the internal register to the abnormal bit, and generates alarm status information specific to the odorization frequency abnormality. The communication module continuously scans and reads the CPU's internal register to obtain the status word in the abnormal bit and the alarm status information, encapsulates the alarm status information specific to the odorization frequency abnormality into a standard network data packet, and sends it to the switch. The switch forwards the standard network data packet to the host computer. The configuration software running on the host computer performs real-time unpacking and calculation of the standard network data packet, extracts the alarm status information specific to the odorization frequency abnormality, and sends a front-end display reconfiguration command to the HMI (Human Machine Interface).

[0067] Within the HMI (Human Machine Interface), the status indicator control for the corresponding odorization frequency monitoring node receives a front-end display reconfiguration command, forcibly switching its display attribute from the normal display state to a flashing red state. The configuration software simultaneously extracts the target operating frequency and the actual operating frequency values ​​from standard network data packets, automatically generating a dedicated independent alarm prompt box for the odorization frequency at the top level of the HMI, and simultaneously binding and displaying both the target and actual operating frequency values ​​within this independent alarm prompt box. The host computer utilizes the flashing red status indicator control and the independent alarm prompt box containing the frequency comparison values ​​to push visual abnormality alarms to the display end.

[0068] When the central processing unit (CPU) finds a discrepancy between the target total odorization amount and the actual odorization consumption, it determines that the total odorization amount discharged by the dosing pump within the calculation cycle has deviated. This simultaneously confirms an abnormal situation where the single odorization amount at the dosing pump source is insufficient or excessive. The CPU then modifies the status word bound to the cycle odorization total node in its internal register to an abnormal bit and generates a specific alarm status message for the cycle total abnormality. The communication module continuously reads the CPU's internal register to obtain the status word in the abnormal bit and the alarm status information, and encapsulates the status word in the abnormal bit and the alarm status information into a standard network data packet before sending it to the switch.

[0069] The switch receives standard network data packets and forwards them to the host computer. The configuration software running on the host computer unpacks the standard network data packets, extracts alarm status information specific to periodic total abnormalities, and sends a front-end display reconstruction command to the HMI (Human-Machine Interface). The status indicator control of the corresponding periodic odorization total monitoring node in the HMI receives the front-end display reconstruction command, and its display attribute is forcibly switched from the normal display state to a flashing red state. The configuration software simultaneously extracts the target odorization total value and the actual odorization consumption value from the standard network data packets, automatically generating a dedicated independent alarm prompt box for the odorization total value at the top level of the HMI, and simultaneously binding and displaying both values ​​within the independent alarm prompt box. The host computer uses the flashing red state of the status indicator control and the independent alarm prompt box containing the total comparison value to complete the visual abnormality alarm push on the display end, thus completing the data loop of the defense line.

[0070] While pushing abnormal alarms to the HMI (Human Machine Interface), the configuration software simultaneously reads the current time data from the host computer and sets it as a timestamp. It continuously extracts the target operating frequency, the actual operating frequency, the target total odor addition, the actual odor addition consumption, and the corresponding alarm status information. It performs horizontal alignment verification based on the same time axis on each extracted value. After confirming that the time offset of the data source is within the allowable tolerance range, it binds and combines them with the timestamp to generate a fault data packet with a timestamp attribute. The fault data packet is then directly written into the host computer's internal hard disk database.

[0071] The configuration software displays historical trend curve controls and a safety management record table on the preset access page of the HMI (Human Machine Interface). The software continuously reads fault data packets stored in the host computer's internal hard disk database, extracts values ​​from these packets based on timestamp order, and converts the target operating frequency, actual operating frequency, target total odor addition, and actual odor consumption values ​​into two-dimensional coordinate points within the historical trend curve control. Adjacent coordinate points are connected to generate independent historical trend curves. Simultaneously, alarm status information from the fault data packets, along with their associated timestamps, is entered into the safety management record table in reverse chronological order. The host computer provides the retained internal hard disk database and safety management record table for external access terminals to perform data traceability queries.

[0072] Specific application examples:

[0073] Based on the specific odorization operation nodes of the natural gas transmission and distribution pipeline network at the site, the constants and initial parameters set by the system are as follows:

[0074] The specified concentration requirement is set at 20.0 mg / Nm³. 3The single rated dosage is set to 200.0 mg; the lower limit of the filtering threshold condition is set to 1.2 times the working pressure of the natural gas pipeline; the upper limit of the filtering threshold condition is set to 1.5 times the working pressure of the natural gas pipeline.

[0075] During the system's frequency calculation, the central processing unit (CPU) retrieves the flow rate digital value from its internal registers and converts it into instantaneous natural gas flow rate. At a certain monitoring moment, the CPU retrieves an instantaneous natural gas flow rate of 18000.0 Nm³. 3 / h. The central processing unit verifies the condition that the single rated dosage is greater than zero, simultaneously extracts the specified concentration requirement and the single rated dosage, and substitutes the data into the proportional formula to calculate the target operating frequency that the dosing pump needs to perform:

[0076] ;

[0077] The central processing unit will use the calculated 30.0 times / min as the target operating frequency to objectively reflect the matching dosing action rate under the current gas transmission status of the pipeline network.

[0078] During the system's periodic data calculation, the central processing unit (CPU) performs an accumulation calculation on the instantaneous natural gas flow rate within the same calculation cycle. At the end of a certain calculation cycle, the CPU calculates the total natural gas transmission volume for that cycle to be 15000.0 Nm³. 3 The central processing unit synchronously retrieves the pre-written concentration requirements and substitutes them into the formula to calculate the target total amount of odor addition: ,

[0079] ;

[0080] The central processing unit converts the calculated 300,000.0 mg into 300.0 g, and uses 300.0 g as the target total amount of odorization for this accounting cycle. This is then used in subsequent conversion processes to perform consistency comparison calculations with the actual amount of odorization consumed.

[0081] Actual operation tests were conducted and data were compared. Specific verification results are detailed in the appendix. Figure 4 and attached Figure 5 The experiment compared the operating data of the traditional end-of-pipe detection and control system and the system of this invention under the same initial operating conditions at the same natural gas station and natural gas pipeline working pressure. The experimental data records are shown in Table 1.

[0082] Table 1. Comparison of Operational Data between Traditional End-of-Line Detection and Control Systems and the System of the Invention

[0083] See attached document Figure 4 And Table 1, Appendix Figure 4 This diagram illustrates the dynamic monitoring and comparison of operating frequency during chemical dosing operations in relation to instantaneous natural gas flow. The horizontal axis represents system operating time in minutes, ranging from 0 to 60. The vertical axis represents operating frequency in cycles per minute, also ranging from 0 to 60. The diagram includes the target operating frequency curve, the actual operating frequency curve of the traditional system, and the actual operating frequency curve of this invention.

[0084] When the system had been running for approximately 20 minutes, downstream gas consumption surged, and the instantaneous natural gas flow rate increased synchronously. The target operating frequency curve showed that the target operating frequency increased from 30.0 times / min to 45.0 times / min. Traditional end-point detection and control systems do not establish specific hardware connections at the source of the natural gas pipeline, and the operating frequency of the dosing pump fails to automatically match the instantaneous changes in natural gas flow rate. The actual operating frequency curve of the traditional system stagnates below 30.0 times / min and exhibits significant deviation. The system of this invention calculates the target operating frequency through sequential transmission between the analog input module and the central processing unit, and then issues commands to drive the dosing pump. (See attached...) Figure 4 The demonstration shows that the actual operating frequency curve of this invention initially aligns with the target operating frequency curve. After the target operating frequency curve first shows an upward inflection point, the central processing unit generates an alarm handling command, simultaneously generating an alarm handling status indicator at the actual upward inflection point position of the actual operating frequency curve of this invention. Upon receiving the alarm handling command, the actual operating frequency curve of this invention exhibits an upward trend, ultimately reaching the same level as the target operating frequency curve and maintaining the same frequency overlap. The system maintains the actual operating frequency at approximately 45.0 times / min within a 20-40 minute runtime, eliminating single-time misjudgment interference caused by transient fluctuations in the natural gas pipeline, and reducing the terminal concentration fluctuation amplitude from 7 mg / Nm³ in traditional terminal detection and control systems. 3 Reduced to 1.5 mg / Nm³ in the system of this invention. 3 .

[0085] See attached document Figure 5 And Table 1, Appendix Figure 5 This diagram illustrates the monitoring of liquid level decline conversion quality and total quantity in the drug storage tank across different accounting cycles. The horizontal axis represents the accounting cycle number, dimensionless, with values ​​ranging from 1 to 8. The vertical axis represents the total odorization amount added during the cycle, in grams, with values ​​ranging from 0 to 500. The diagram includes a target total odorization amount line, a line showing the actual odorization consumption of the traditional system, and a line showing the actual odorization consumption of the present invention.

[0086] When the accounting cycle reached its fifth cycle, a minor internal leakage fault occurred in the one-way valve at the dosing pump outlet, resulting in a substantial reduction in the effective odorant discharged by the dosing pump per pressurization. The actual odorant consumption curve of the traditional system was limited by periodic end-point monitoring and management, failing to monitor the dosing pump's operation and the drop in the storage tank level. This caused the actual odorant consumption in subsequent cycles to continuously deviate from the target total odorant consumption curve, resulting in a cumulative odorant shortage of 15.6 kg.

[0087] This invention's system latches initial and final liquid level data using a liquid level sensor, converting a drop in liquid level into actual odorization consumption in terms of mass. When the actual odorization consumption curve deviates and drops to its lowest point in the fifth cycle, the central processing unit immediately determines that the target total odorization amount is inconsistent with the actual odorization consumption amount. An abnormal odorization alarm is pushed to the associated HMI (Human-Machine Interface), and an alarm handling status indicator is simultaneously generated at the lowest point of the actual odorization consumption curve. After the alarm handling information is processed, the system performs fault repairs and restores the equipment to operation. This ensures that the actual odorization consumption curve immediately returns to the target total odorization value at a right angle after the alarm is handled, preventing continuous abnormal operating losses.

Claims

1. A monitoring system for odorization at the source of a natural gas pipeline, characterized in that, It includes a dosing pump and a storage tank connected to the dosing pump, and also includes a pressure sensor, a level sensor, a station natural gas flow meter and a station control system or controller, wherein the pressure sensor, the level sensor and the station natural gas flow meter are respectively connected to the station control system or controller; The pressure sensor is installed at the outlet of the dosing pump and monitors the pulse pressure, transmitting the pulse pressure to the station control system or controller. The station control system or controller records the pulse pressure to obtain the actual operating frequency. It calculates the target operating frequency based on the pre-defined formula data of the ratio of gas flow rate and odor addition amount. The actual operating frequency is compared with the target operating frequency to determine whether the dosing pump frequency is normal or abnormal. The liquid level sensor is installed in the storage tank and monitors the liquid level data. The station control system or controller calculates the total amount of natural gas transmission and calculates the target total amount of odorization. The actual odorization consumption is calculated based on the amount of liquid level drop in the storage tank. The target total amount of odorization is compared with the actual odorization consumption to determine whether the odorization amount is normal or abnormal.

2. The monitoring system for odorization at the source of a natural gas pipeline according to claim 1, characterized in that, The station control system or controller includes an analog input module, a central processing unit, a communication module, a switch, and a host computer. The pressure sensor, the liquid level sensor, and the station natural gas flow meter are all connected to the analog input module. The analog input module receives analog signals and converts them into digital signals. The central processing unit scans and stores the digital signals at a fixed frequency, performs calculations and comparisons on the digital signals, obtains comparison results, and sends the alarm status information corresponding to the comparison results to the communication module. The communication module outputs the alarm status information to the switch, and the switch transmits the alarm status information to the host computer via the network line. The host computer uses configuration software to monitor, classify, store, and compare the received alarm status information and the corresponding digital quantity in real time.

3. A monitoring system for odorization at the source of a natural gas pipeline according to claim 2, characterized in that, The central processing unit extracts the flow rate digital value from its internal registers and converts the flow rate digital value into instantaneous natural gas flow rate; The calculation is performed based on the instantaneous natural gas flow rate, the specified concentration requirement, and the single rated dosage. The central processing unit calculates the target operating frequency that the dosing pump needs to perform, reflecting the matching dosing action rate under the current gas transmission status of the pipeline network.

4. A monitoring system for odorization at the source of a natural gas pipeline according to claim 3, characterized in that, The central processing unit has a filter threshold condition set internally, and the lower limit and upper limit of the filter threshold condition are set to 1.2 times and 1.5 times the working pressure of the natural gas pipeline, respectively. The central processing unit performs amplitude filtering on the continuously read pressure digital values, filtering out pressure digital values ​​with amplitudes lower than 1.2 times the working pressure value of the natural gas pipeline and pressure digital values ​​with amplitudes higher than 1.5 times the working pressure value of the natural gas pipeline, retaining pressure digital values ​​with amplitudes in the range of 1.2 to 1.5 times the working pressure value of the natural gas pipeline, and determining the retained pressure digital values ​​as valid pulses; The central processing unit accumulates the total number of valid pulses generated within a 1-minute statistical time window, and calculates the actual operating frequency based on the total number of pulses.

5. A monitoring system for odorization at the source of a natural gas pipeline according to claim 4, characterized in that, The central processing unit synchronously extracts the calculated target operating frequency and the statistically derived actual operating frequency, and performs a comparison operation between the value of the target operating frequency and the value of the actual operating frequency. When the central processing unit compares and finds that the value of the target operating frequency is inconsistent with the value of the actual operating frequency and the difference exceeds the warning band of 5% for three consecutive sampling cycles, it excludes the single misjudgment interference caused by the transient fluctuation of the natural gas pipeline and determines that the current odorization frequency of the dosing pump is abnormal. The central processing unit modifies the status word bound to the odorization frequency node in its internal register to an abnormal bit and generates alarm status information specific to the odorization frequency abnormality. It then encapsulates the alarm status information specific to the odorization frequency abnormality into a standard network data packet and sends it to the switch.

6. A monitoring system for odorization at the source of a natural gas pipeline according to claim 2, characterized in that, The central processing unit has a fixed calculation cycle time axis, and the length of the calculation cycle is fixed at one hour. The station's natural gas flow meter continuously reads the flow rate data within the hourly calculation cycle and continuously converts the read flow rate data into instantaneous natural gas flow rate. It performs an accumulation operation on the instantaneous natural gas flow rate within the same calculation cycle to calculate the total natural gas transmission volume within the same cycle. The central processing unit extracts the total amount of natural gas transported in the same cycle and the pre-written specified concentration requirement, multiplies the total amount of natural gas transported in the same cycle with the specified concentration requirement, and obtains the target total amount of odorization based on the result of the multiplication operation.

7. A monitoring system for odorization at the source of a natural gas pipeline according to claim 6, characterized in that, The internal storage area of ​​the central processing unit contains a table of liquid level and volume of the drug storage tank, which includes discrete liquid level height nodes and odorant mass nodes that are respectively bound to each liquid level height node. The central processing unit reads the initial liquid level data at the start time and the final liquid level data at the end time through the analog input module, and substitutes them into the liquid level volume lookup table of the medicine storage tank to find the upper liquid level height node and the lower liquid level height node that enclose the initial liquid level data. The central processing unit synchronously extracts the upper odorant mass node associated with the upper liquid level height node and the lower odorant mass node associated with the lower liquid level height node. Using the slope of the line connecting the two points, a linear interpolation algorithm is used to convert the initial liquid level data and the final liquid level data into initial mass data and final mass data, respectively. The initial mass data is subtracted from the final mass data to convert the liquid level drop into the actual odorant consumption in the mass dimension.

8. A monitoring system for odorization at the source of a natural gas pipeline according to claim 7, characterized in that, The central processing unit synchronously reads the calculated target total odorization amount and the interpolated actual odorization consumption amount, and performs a consistency comparison operation on the value of the target total odorization amount and the value of the actual odorization consumption amount; When the central processing unit compares and finds that the value of the target total amount of odorization is inconsistent with the value of the actual amount of odorization consumed, it determines that there is a deviation in the total amount of odorization discharged by the dosing pump within the calculation cycle; The central processing unit modifies the status word bound to the periodic total odor node in its internal register to an abnormal bit and generates alarm status information specific to periodic total odor abnormality. The alarm status information specific to periodic total odor abnormality is forwarded to the host computer via the communication module and the switch.

9. A monitoring system for odorization at the source of a natural gas pipeline according to claim 8, characterized in that, The configuration software running inside the host computer performs unpacking operations on standard network data packets, extracts the alarm status information, and sends a front-end display reconstruction command to the HMI human-machine interface, driving the display attribute of the status indicator control to be forcibly switched from the normal display state to the red flashing state, and automatically generating an independent alarm prompt box at the top level of the HMI human-machine interface. The configuration software synchronously reads the current time data inside the host computer and sets it as a timestamp, continuously extracts various comparison values ​​and performs horizontal alignment verification based on the same time axis with the alarm status information; After the configuration software confirms that the time offset of the data source is within the allowable tolerance range, it binds and combines the data with the timestamp to generate a fault data packet with a timestamp attribute, and then writes the fault data packet directly into the internal hard disk database of the host computer.

10. A monitoring system for odorization at the source of a natural gas pipeline according to claim 1, characterized in that, The dosing pump is equipped with a dosing pipeline, on which a dosing valve, a check valve and a vaporizer valve are sequentially installed, and the dosing pipeline is connected to the main natural gas pipeline. The pressure sensor, pressure gauge, and calibrator are installed in parallel on the pipeline between the outlet of the dosing pump and the dosing valve to directly sense the instantaneous pulse pressure formed inside the dosing pipeline when the dosing pump discharges the odorant. A return pipeline is led out from the front end of the dosing valve on the dosing pipeline. A return valve is installed on the return pipeline, and the end of the return pipeline is connected to the top of the storage tank.

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