Natural gas pipeline hydrogen-doped cascade ratio control device

Abstract

The utility model relates to a natural gas pipeline hydrogen-doped cascade ratio control device which comprises a hydrogen pipeline, a natural gas pipeline, a static mixer and a hydrogen-doped natural gas pipeline, the natural gas pipeline is connected with a first input end of the static mixer, and the hydrogen pipeline is connected with a second input end of the static mixer. A first pressure regulating device, a first filter and a natural gas turbine flowmeter are sequentially arranged on a natural gas pipeline in the flowing direction of natural gas, and the natural gas turbine flowmeter is provided with a temperature compensation instrument and a pressure compensation instrument. A second pressure regulating device, a second filter, a gas mass flowmeter and a regulating valve are sequentially arranged on the hydrogen pipeline in the hydrogen flowing direction, the output end of the static mixer is connected with a hydrogen-doped natural gas pipeline, a hydrogen concentration monitoring device is arranged on the hydrogen-doped natural gas pipeline, and the hydrogen concentration monitoring device is in communication connection with a main controller; the natural gas turbine flowmeter and the gas mass flowmeter are in communication connection with the auxiliary controller, and the main controller is in communication connection with the auxiliary controller.

Description

Technical Field

[0001] The utility model relates to a natural gas pipeline hydrogen blending control technology, in particular to a natural gas pipeline hydrogen blending cascade ratio control device. Background Art

[0002] Natural gas hydrogen blending technology involves adding hydrogen to natural gas at a specific volume ratio to create hydrogen-blended natural gas, which can be transported through existing natural gas pipelines and directly replace natural gas. Both natural gas and hydrogen offer green, low-carbon benefits that distinguish them from other fossil fuels. Their combination can significantly enhance the green, low-carbon soft power of natural gas.

[0003] The process flow is as follows: natural gas and hydrogen enter the static mixer and then enter the hydrogen-blended natural gas pipeline in a certain proportion. The control of the hydrogen blending ratio is related to whether the production can operate stably, production efficiency and equipment safety. The hydrogen blending process requires that the hydrogen content be maintained within a certain range when the natural gas flow fluctuates, while ensuring the accuracy after blending. Traditional control adopts a natural gas and hydrogen ratio control system, that is, a control scheme that controls the amount of hydrogen added by controlling the ratio of the natural gas flow to the hydrogen flow before mixing. Since the measurement control time constant and pure lag of the hydrogen content are large, and the natural gas flow fluctuates frequently, the ordinary ratio control scheme cannot meet the blending control requirements.

[0004] CN217635103U discloses a device for precisely controlling the ratio of hydrogen blended with natural gas. The device includes a hydrogen pipeline, a natural gas pipeline, a hydrogen pipeline regulating module, a natural gas pipeline regulating module, a static mixer, and a PLC controller. The hydrogen pipeline regulating module is mounted on the hydrogen pipeline, while the natural gas pipeline regulating module is mounted on the natural gas pipeline. The PLC controller is connected to the hydrogen and natural gas pipeline regulating modules, respectively. The static mixer has two inlets connected to the hydrogen and natural gas pipelines, respectively. A disadvantage of this technology is that the control method is relatively complex, requiring simultaneous control of the hydrogen and natural gas pipeline regulating valves. Utility Model Content

[0005] This utility model builds on the traditional natural gas and hydrogen ratio control system by incorporating the hydrogen content after blending to automatically set the ratio, thus forming a cascade ratio control system. The hydrogen content controller serves as the primary controller, while the ratio control of the hydrogen flow rate to the natural gas flow rate forms the secondary loop. This system uses the hydrogen content signal measured by the hydrogen analyzer to correct the blending ratio. If the blended hydrogen content deviates, the hydrogen content is restored to normal by adjusting the hydrogen flow rate, thereby changing the hydrogen-to-natural gas ratio.

[0006] The process flow of the utility model is as follows: natural gas from the main pipeline enters the static mixer through a flow meter, and hydrogen from the hydrogen pipeline enters the static mixer through a flow meter and a regulating valve. The two media are mixed in the static mixer and then output to the natural gas main pipeline.

[0007] The utility model discloses a natural gas pipeline hydrogen blending cascade ratio control device comprising a hydrogen pipeline, a natural gas pipeline, a static mixer, a hydrogen blending natural gas pipeline,

[0008] The natural gas pipeline is connected to the first input end of the static mixer, and the hydrogen pipeline is connected to the second input end of the static mixer. A first pressure regulating device, a first filter (for filtering impurities in the natural gas) and a natural gas turbine flowmeter are sequentially arranged on the natural gas pipeline along the natural gas flow direction. The natural gas turbine flowmeter is equipped with a temperature compensation instrument and a pressure compensation instrument (for correcting the measured natural gas flow).

[0009] A second pressure regulating device, a second filter (for filtering impurities in hydrogen), a gas mass flow meter, and a regulating valve are sequentially arranged on the hydrogen pipeline along the flow direction of hydrogen. A first pressure monitoring device (arranged between the second filter and the gas mass flow meter) and a first temperature monitoring device (arranged between the regulating valve and the gas mass flow meter) are also arranged on the hydrogen pipeline.

[0010] The output end of the static mixer is connected to the hydrogen-blended natural gas pipeline, on which a hydrogen concentration monitoring device is installed.

[0011] The hydrogen concentration monitoring device is communicatively connected to the main controller, the natural gas turbine flowmeter and the gas mass flowmeter are communicatively connected to the sub-controller, and the main controller is communicatively connected to the sub-controller.

[0012] In addition, a second pressure monitoring device and a second temperature monitoring device may be provided on the hydrogen-blended natural gas pipeline.

[0013] The gas mass flow meter may be a gas thermal mass flow meter, and the regulating valve may be a pneumatic regulating valve.

[0014] The cascade ratio control technology for hydrogen blending in natural gas pipelines includes a cascade control loop for hydrogen content after blending and a control loop for the ratio of natural gas pipeline flow to hydrogen pipeline flow before blending. The cascade control loop for hydrogen content after blending includes a main controller (proportional integral differential) PID loop and a sub-controller (proportional integral differential) PID loop, and the ratio signal of the natural gas pipeline flow to hydrogen pipeline flow before blending is introduced into the sub-controller (proportional integral differential) PID loop as an intermediate controlled variable.

[0015] The content of hydrogen after blending is measured and transmitted by a main measuring and transmitting device (thermal mass flowmeter), and the measurement result is used as the input signal of the main controller (proportional integral differential) PID loop of the cascade control loop of the content of hydrogen after blending.

[0016] The main controller (proportional integral differential) PID loop of the cascade control loop for the hydrogen content after blending receives the measurement signal of the hydrogen content after blending and the main set value signal of the hydrogen content after blending and performs PID calculation based on them, and transmits the calculation result to the sub-controller (proportional integral differential) PID loop.

[0017] The sub-controller (proportional integral differential) PID loop receives the calculation results from the main controller (proportional integral differential) PID loop and the ratio signal of the natural gas pipeline flow rate to the hydrogen pipeline flow rate before blending, and performs PID calculation based on this. The calculated results are output to control the regulating valve of the hydrogen pipeline before blending, thereby adjusting the hydrogen supply.

[0018] The utility model realizes automatic control of the hydrogen blending ratio by combining cascade control with proportion control, so as to achieve the purpose of controlling the hydrogen content after blending to a target value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a cascade ratio control device for hydrogen blending in a natural gas pipeline according to the present invention;

[0020] Figure 2 for Figure 1 Block diagram of the principle of controlling the cascade ratio of hydrogen blending in natural gas pipelines.

[0021] Reference numerals:

[0022] L1, hydrogen pipeline; L2, natural gas pipeline; M1, static mixer; L3, hydrogen-blended natural gas pipeline; first pressure regulating device TY01, first filter GL01, and natural gas turbine flowmeter FT01, which comes with a temperature compensation instrument TT01 and a pressure compensation instrument PT01;

[0023] TY02, second pressure regulating device; GL02, second filter; FT02, gas mass flow meter; FV02, regulating valve;

[0024] PT02, first pressure monitoring device; TT02, first temperature monitoring device; AT01, hydrogen concentration monitoring device; AIC01, main controller; FY1, sub-controller; PT03, second pressure monitoring device; TT03, second temperature monitoring device. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] like Figure 1 As shown, the natural gas pipeline hydrogen blending cascade ratio control device includes a hydrogen pipeline L1, a natural gas pipeline L2, a static mixer M1, and a hydrogen blending natural gas pipeline L3.

[0027] The natural gas pipeline is connected to the first input end of the static mixer M1, and the hydrogen pipeline is connected to the second input end of the static mixer M1. The first pressure regulating device TY01, the first filter GL01 and the natural gas turbine flowmeter FT01 are sequentially arranged along the natural gas flow direction on the natural gas pipeline. The natural gas turbine flowmeter FT01 is equipped with a temperature compensation instrument TT01 and a pressure compensation instrument PT01.

[0028] A second pressure regulating device TY02, a second filter GL02, a gas mass flow meter FT02, and a regulating valve FV02 are sequentially arranged on the hydrogen pipeline along the flow direction of hydrogen. A first pressure monitoring device PT02 (arranged between the second filter GL02 and the gas mass flow meter FT02) and a first temperature monitoring device TT02 (arranged between the regulating valve FV02 and the gas mass flow meter FT02) are also arranged on the hydrogen pipeline.

[0029] The output end of the static mixer M1 is connected to the hydrogen-blended natural gas pipeline L3, on which a hydrogen concentration monitoring device AT01 is installed.

[0030] The hydrogen concentration monitoring device AT01 is communicatively connected to the main controller AIC01, the natural gas turbine flowmeter FT01 and the gas mass flowmeter FT02 are communicatively connected to the sub-controller FY1, and the main controller AIC01 is communicatively connected to the sub-controller FY1.

[0031] In addition, a second pressure monitoring device PT03 and a second temperature monitoring device TT03 may be provided on the hydrogen-blended natural gas pipeline to monitor the pressure and temperature of the hydrogen-blended natural gas in the hydrogen-blended natural gas pipeline.

[0032] The gas mass flowmeter FT02 may be a gas thermal mass flowmeter, and the control valve FV02 may be a pneumatic control valve.

[0033] The natural gas from the main pipeline enters the static mixer through the turbine flowmeter, and the hydrogen from the hydrogen pipeline enters the static mixer through the gas thermal mass flowmeter and the pneumatic control valve. The flow signal is transmitted to the sub-controller via a 4~20mA signal. The control valve receives the 4~20mA control signal from the control system. The two media are mixed in the static mixer and output to the natural gas main pipeline.

[0034] The hydrogen content after blending is measured and transmitted by the main measurement and transmission equipment (hydrogen content analyzer), and the hydrogen content is transmitted to the main controller through a 4~20mA signal. The control system calculates and uses the measurement result as the input signal of the main controller (proportional integral differential) PID loop of the cascade control loop of the hydrogen content after blending.

[0035] The main controller (proportional integral differential) PID loop of the cascade control loop for the hydrogen content after blending receives the measurement signal of the hydrogen content after blending and the main set value signal of the hydrogen content after blending and performs PID calculation based on them, and transmits the calculation result to the sub-controller (proportional integral differential) PID loop.

[0036] The sub-controller (proportional integral differential) PID loop receives the calculation results from the main controller (proportional integral differential) PID loop and the ratio signal of the natural gas pipeline flow rate to the hydrogen pipeline flow rate before blending, and performs PID calculation accordingly, and outputs the calculated results to control the hydrogen pipeline regulating valve before blending.

[0037] The cascade ratio control device for hydrogen blending in natural gas pipelines of the present invention operates as follows:

[0038] Both the main and auxiliary controllers utilize a programmable logic controller (PLC). The natural gas turbine flowmeter FT01 transmits the calculated flow rate value, after compensation by the temperature compensator TT01 and the pressure compensator PT01, to the PLC via analog signals, enabling flow indication, accumulation, and control functions within the control system. The hydrogen mass flowmeter FT02 also transmits flow rate value to the PLC via analog signals, enabling flow indication, accumulation, and control functions within the control system. The hydrogen pipeline pressure monitoring device PT02 and temperature monitoring device TT02 transmit analog signals to the PLC, enabling hydrogen temperature and pressure indication. The real-time flow detection values of the natural gas turbine flowmeter FT01 and the hydrogen gas mass flowmeter FT02 are divided in the control system PLC, and the calculation result is used as the input of the sub-controller. The hydrogen concentration detection device AT01 connected to the static mixer output pipe transmits the concentration detection value to the main controller AIC01 through an analog signal, realizing the indication and control functions in the control system. The hydrogen concentration detection value is used as the input of the main controller. The main controller compares the measured value with the set value (adjustable) of the hydrogen concentration to obtain the concentration deviation, and performs PID operation on this deviation and uses the output value as the set value of the sub-controller. The sub-controller compares the calculated result of the ratio of hydrogen flow rate to natural gas flow rate with the set value of the sub-controller to obtain the deviation value, and performs PID operation on this deviation and outputs a 4~20mA control signal to the hydrogen pipeline regulating valve FV02, causing its opening to change to control the amount of hydrogen entering the static mixer.

[0039] Combine Figure 2The principle is as follows: the main controller sets the set value 1 of the hydrogen content in the natural gas pipeline after the static mixer; the measured value of the hydrogen content in the natural gas pipeline after the static mixer is input into the main controller AIC01, and PID operation is performed with the set value, and the result is transmitted to the sub-controller FY1; the gas mass flowmeter FT02 measures the flow value 3 of the hydrogen pipeline before the static mixer, and the natural gas turbine flowmeter FT01 measures the flow value 4 of the natural gas pipeline before the static mixer. The measured values are transmitted to the ratiometer to output the ratio signal, which is transmitted to the sub-controller FY1 as the ratio 5 of the hydrogen pipeline flow before the static mixer to the natural gas pipeline flow. The calculation result transmitted by the main controller and the ratio signal of the natural gas pipeline flow before mixing to the hydrogen pipeline flow are received by the sub-controller, and PID operation is performed accordingly. The calculated result is output to control the regulating valve of the hydrogen pipeline before mixing, and the hydrogen pipeline flow before the static mixer is adjusted 6, so that the hydrogen content 7 of the natural gas pipeline after the static mixer meets the set value 1 of the hydrogen content after mixing.

[0040] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A natural gas pipeline hydrogen blending cascade ratio control device, characterized in that: It includes hydrogen pipeline (L1), natural gas pipeline (L2), static mixer (M1), hydrogen-blended natural gas pipeline (L3), A natural gas pipeline is connected to the first input end of the static mixer (M1), and a hydrogen pipeline is connected to the second input end of the static mixer (M1). A first pressure regulating device (TY01), a first filter (GL01), and a natural gas turbine flowmeter (FT01) are sequentially arranged on the natural gas pipeline along the natural gas flow direction. The natural gas turbine flowmeter (FT01) is equipped with a temperature compensation instrument (TT01) and a pressure compensation instrument (PT01). A second pressure regulating device (TY02), a second filter (GL02), a gas mass flow meter (FT02) and a regulating valve (FV02) are sequentially arranged on the hydrogen pipeline along the flow direction of hydrogen. A first pressure monitoring device (PT02) and a first temperature monitoring device (TT02) are also arranged on the hydrogen pipeline. The output end of the static mixer (M1) is connected to the hydrogen-blended natural gas pipeline (L3), and a hydrogen concentration monitoring device (AT01) is installed on the hydrogen-blended natural gas pipeline (L3). The hydrogen concentration monitoring device (AT01) is communicated with the main controller (AIC01), the natural gas turbine flowmeter (FT01) and the gas mass flowmeter (FT02) are communicated with the sub-controller (FY1), and the main controller (AIC01) is communicated with the sub-controller (FY1).

2. The natural gas pipeline hydrogen blending cascade ratio control device according to claim 1, characterized in that: A second pressure monitoring device (PT03) and a second temperature monitoring device (TT03) are also installed on the hydrogen-blended natural gas pipeline.

3. The natural gas pipeline hydrogen blending cascade ratio control device according to claim 1, characterized in that: The gas mass flow meter (FT02) is a gas thermal mass flow meter.

4. The natural gas pipeline hydrogen blending cascade ratio control device according to claim 1, characterized in that: The regulating valve (FV02) is a pneumatic regulating valve.

5. The natural gas pipeline hydrogen blending cascade ratio control device according to claim 1, characterized in that: The first pressure monitoring device (PT02) is arranged between the second filter (GL02) and the gas mass flow meter (FT02), and the first temperature monitoring device (TT02) is arranged between the regulating valve (FV02) and the gas mass flow meter (FT02).

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