阅读说明：本技术 一种基于绿氢掺氧预防掺氢天然气管道氢脆的系统及方法 (System and method for preventing hydrogen embrittlement of hydrogen-doped natural gas pipeline based on hydrogen-green doping and oxygen-doping ) 是由 邢百汇 郑津洋 花争立 顾超华 尚娟 李奇楠 魏皓天 于 2021-08-02 设计创作，主要内容包括：本发明涉及掺氢天然气管网运输领域,旨在提供一种基于绿氢掺氧预防掺氢天然气管道氢脆的系统及方法。该方法包括：按体积比例0.05％～0.5％将氧气掺入氢气中,得到掺氧氢气；将掺氧氢气掺入天然气中,得到掺氢天然气；掺氧氢气在掺氢天然气中的体积百分比为1％～20％。本发明利用特定量氧气对氢气在管材中氢脆有抑制作用的机理,通过掺氧抑制天然气管道氢脆现象,保障掺氢天然气管道安全输送；本发明使用可再生能源制氢系统,可以同时获得的氢气和氧气,能够最大程度降低生产、运输成本,可实现综合效益最大化。(The invention relates to the field of pipeline transportation of hydrogen-doped natural gas, and aims to provide a system and a method for preventing hydrogen embrittlement of a hydrogen-doped natural gas pipeline based on hydrogen-green doping and oxygen doping. The method comprises the following steps: mixing oxygen into hydrogen according to the volume ratio of 0.05-0.5% to obtain oxygen-doped hydrogen; doping the oxygen-doped hydrogen into natural gas to obtain hydrogen-doped natural gas; the volume percentage of the oxygen-doped hydrogen in the hydrogen-doped natural gas is 1 to 20 percent. The mechanism that a specific amount of oxygen has an inhibiting effect on hydrogen embrittlement of hydrogen in the pipe is utilized, and the hydrogen embrittlement phenomenon of the natural gas pipeline is inhibited through oxygen doping, so that the safe transportation of the hydrogen-doped natural gas pipeline is guaranteed; the invention uses the renewable energy hydrogen production system, can simultaneously obtain hydrogen and oxygen, can reduce the production and transportation cost to the maximum extent, and can realize the maximization of comprehensive benefits.)

1. A method for preventing hydrogen embrittlement of a hydrogen-doped natural gas pipeline based on hydrogen-green oxygen doping is characterized by comprising the following steps:

(1) mixing oxygen into hydrogen according to the volume ratio of 0.05-0.5% to obtain oxygen-doped hydrogen;

(2) doping the oxygen-doped hydrogen into natural gas to obtain hydrogen-doped natural gas; the volume percentage of the oxygen-doped hydrogen in the hydrogen-doped natural gas is 1 to 20 percent.

2. The method of claim 1, wherein the hydrogen is derived from a wind, hydroelectric, or solar hydrogen production system and has a purity greater than 99%.

3. The method of claim 1, wherein the temperature difference between the gas before and after mixing is not more than 20 ℃ by controlling the mixing speed and the mixing pressure when the oxygen is mixed into the hydrogen; and controlling the pressure of the mixed oxygen-doped hydrogen gas to be 1-15 MPa.

4. The method of claim 1, wherein the temperature of the oxygen-doped hydrogen gas is controlled to be within ± 10 ℃ of the temperature range of the natural gas when the oxygen-doped hydrogen gas is doped into the natural gas.

5. The method of claim 1, wherein the hydrogen is derived from a renewable energy hydrogen production system, and is any one of a wind power hydrogen production system, a hydroelectric hydrogen production system, or a solar hydrogen production system.

6. A system for preventing hydrogen embrittlement of a hydrogen-doped natural gas pipeline based on green hydrogen doping and oxygen doping for realizing the method of claim 1 is characterized by comprising a renewable energy hydrogen production system, an oxygen-hydrogen mixing system, a pressure and temperature control system, a concentration balance control system, a hydrogen-doped natural gas conveying system and an integrated terminal control system;

the hydrogen and oxygen mixing system comprises hydrogen and oxygen mixing equipment which is respectively connected with a hydrogen production outlet and an oxygen production outlet in the renewable energy hydrogen production system through pipelines; the oxygen-doped hydrogen discharge port of the hydrogen-oxygen mixing system is also connected to a hydrogen-doped natural gas conveying system through a pipeline;

the pressure and temperature control system comprises a temperature monitoring element and a pressure detection element which are arranged on the renewable energy hydrogen production system, the hydrogen-oxygen mixing system, the hydrogen-doped natural gas conveying system and each connecting pipeline and is electrically connected to the integrated terminal control system in a wired or wireless communication mode;

the concentration balance control system comprises concentration monitors arranged on a renewable energy hydrogen production system, an oxyhydrogen mixing system, a hydrogen-doped natural gas conveying system and each connecting pipeline, and is electrically connected to the integrated terminal control system in a wired or wireless communication mode;

the integrated terminal control system is provided with a control platform arranged locally or at the cloud, and the control platform is connected with valves arranged in each system or on each connecting pipeline in a wired or wireless communication mode so as to control the production and the transportation of the oxygen-doped hydrogen and the hydrogen-doped natural gas.

7. The system of claim 6, wherein the renewable energy hydrogen production system is any one of a wind, hydro or solar hydrogen production system.

8. The system of claim 6, wherein the hydrogen loaded natural gas delivery system further comprises a natural gas delivery transfer tank and a user terminal connected by a delivery line.

Technical Field

The invention belongs to the field of pipeline transportation of hydrogen-doped natural gas, and particularly relates to a system and a method for preventing hydrogen embrittlement of a hydrogen-doped natural gas pipeline based on hydrogen-green doping and oxygen doping.

Background

Green hydrogen takes renewable energy sources (such as wind power, hydropower, solar energy and the like) as energy sources of a hydrogen production device, and no carbon is discharged in the hydrogen production process. The carbon peak reaching and carbon neutralization have great requirements on energy consumption structure change, and hydrogen energy is used as clean energy with various sources, convenient storage and transportation and high efficiency, and is an important means for realizing double-carbon target and renewable energy large-scale energy storage. Safe and economic transportation is one of the key links of hydrogen energy development. The natural gas pipe network in China has wide distribution range and large construction scale, and the hydrogen energy is conveyed by utilizing the natural gas pipe network in service or newly built natural gas pipe network, which is considered as the best mode for realizing large-scale hydrogen conveying and utilization at present.

But the compatibility problem of the in-service or newly-built natural gas pipe and the hydrogen/hydrogen-doped natural gas is still not negligible. The physical and chemical properties of hydrogen/hydrogen-doped natural gas are special, and the hydrogen/hydrogen-doped natural gas has a degradation effect on the performance of the pipeline material, which may cause premature failure of the pipeline and cause major safety accidents, so that the research on the compatibility of the pipe and the hydrogen/hydrogen-doped natural gas is insufficient, and the application thereof faces a serious challenge.

A plurality of organizations at home and abroad research the aspect. In-situ test research on material performance in pure hydrogen/simulated hydrogen-doped natural gas environment has been carried out by both the Saint Asia national laboratory and the Korean Standard science research institute, and the evolution law of the mechanical properties of the material is analyzed; the construction of a metal compatibility experiment database of hydrogen and pipes of domestic natural gas pipelines and the like are developed at Zhejiang university in China.

Representative achievements in the related field currently are: the invention patent 202011477933.1 'a hydrogen-doped natural gas transportation separation system and a control method thereof', the invention patent 202011634936.1 'a pure hydrogen transportation distribution pipe network system and a control method thereof', the invention patent 202011191416.8 'a medium and low pressure gas distribution pipe network modeling method of hydrogen-doped natural gas', and the like, but the pure hydrogen/hydrogen-doped natural gas transportation methods are designed only on the aspects of transportation distribution and transportation methods, and the problem that hydrogen causes damage (hydrogen embrittlement) to a natural gas pipeline is not considered.

Therefore, the transportation of the hydrogen-doped natural gas through an in-service natural gas pipeline network or a newly-built natural gas pipeline is an important way for reducing the hydrogen transportation cost, but the problem of hydrogen compatibility between hydrogen and steel for the natural gas pipeline network needs to be solved urgently, and a system and a method for preventing hydrogen embrittlement of the hydrogen-doped natural gas pipeline based on hydrogen-doped oxygen are established.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a system and a method for preventing hydrogen embrittlement of a hydrogen-doped natural gas pipeline based on hydrogen-green doping and oxygen doping.

In order to solve the technical problem, the solution of the invention is as follows:

the method for preventing hydrogen embrittlement of the hydrogen-doped natural gas pipeline based on hydrogen-green oxygen doping comprises the following steps:

(1) mixing oxygen into hydrogen according to the volume ratio of 0.05-0.5% to obtain oxygen-doped hydrogen;

(2) doping the oxygen-doped hydrogen into natural gas to obtain hydrogen-doped natural gas; the volume percentage of the oxygen-doped hydrogen in the hydrogen-doped natural gas is 1 to 20 percent.

Preferably, the hydrogen is derived from a wind power, hydroelectric power or solar hydrogen production system, and the purity is more than 99%.

Preferably, when oxygen is doped into hydrogen, the temperature difference between gases before and after mixing is not more than 20 ℃ by controlling the mixing speed and the mixing pressure; and controlling the pressure of the mixed oxygen-doped hydrogen gas to be 1-15 MPa.

Preferably, when the oxygen-doped hydrogen gas is doped into the natural gas, the temperature of the oxygen-doped hydrogen gas is controlled within +/-10 ℃ of the temperature range of the natural gas.

Preferably, the hydrogen is derived from a renewable energy hydrogen production system, and is any one of a wind power hydrogen production system, a hydroelectric hydrogen production system or a solar hydrogen production system.

The invention further provides a system for preventing hydrogen embrittlement of a hydrogen-doped natural gas pipeline based on green hydrogen-doped oxygen for realizing the method, which comprises a renewable energy hydrogen production system, an oxygen-hydrogen mixing system, a pressure and temperature control system, a concentration balance control system, a hydrogen-doped natural gas conveying system and an integrated terminal control system;

the hydrogen and oxygen mixing system comprises hydrogen and oxygen mixing equipment which is respectively connected with a hydrogen production outlet and an oxygen production outlet in the renewable energy hydrogen production system through pipelines; the oxygen-doped hydrogen discharge port of the hydrogen-oxygen mixing system is also connected to a hydrogen-doped natural gas conveying system through a pipeline;

the pressure and temperature control system comprises a temperature monitoring element and a pressure detection element which are arranged on the renewable energy hydrogen production system, the hydrogen-oxygen mixing system, the hydrogen-doped natural gas conveying system and each connecting pipeline and is electrically connected to the integrated terminal control system in a wired or wireless communication mode;

the concentration balance control system comprises concentration monitors arranged on a renewable energy hydrogen production system, an oxyhydrogen mixing system, a hydrogen-doped natural gas conveying system and each connecting pipeline, and is electrically connected to the integrated terminal control system in a wired or wireless communication mode;

the integrated terminal control system is provided with a control platform arranged locally or at the cloud, and the control platform is connected with valves arranged in each system or on each connecting pipeline in a wired or wireless communication mode so as to control the production and the transportation of the oxygen-doped hydrogen and the hydrogen-doped natural gas.

Preferably, the renewable energy hydrogen production system is any one of a wind power hydrogen production system, a hydroelectric hydrogen production system or a solar hydrogen production system.

Preferably, the hydrogen-loaded natural gas conveying system further comprises a natural gas conveying and transferring storage tank and a user terminal which are connected through a conveying pipeline.

Description of the inventive principles:

most natural gas conveying pipelines are pipeline steel, and when hydrogen is doped into natural gas, the pipeline steel is in a high-pressure hydrogen-rich environment, and the pipeline steel generates a high-pressure hydrogen embrittlement phenomenon. In the metal loading process, hydrogen molecules are adsorbed on the surface of the metal, and the processes of hydrogen molecule dissociation, permeation, diffusion, segregation and the like are carried out, so that the plasticity and toughness of the metal material are damaged or the plastic fracture is caused by hydrogen. In a material mechanics test, the high-pressure hydrogen embrittlement has little influence on the yield strength and the tensile strength of high-strength pipeline steel, but can reduce the plasticity and the fatigue performance of the pipeline, so that the material fails early to cause serious accidents.

The applicant's group of inventors has found, through intensive studies, that some mixtures of hydrogen and X (X ═ an additional gas) promote or inhibit the hydrogen embrittlement effect. Among them, oxygen is one of the strongest inhibitors, and has a stronger electronegativity and higher reactivity with most metals than hydrogen. Hydrogen embrittlement occurs, and firstly, hydrogen is required to be adsorbed and dissociated on the surface of the metal, and oxygen is adsorbed and dissociated before the hydrogen, so that a thin oxide layer is formed on the surface of the metal, and the adsorption and dissociation of hydrogen molecules on the surface of the metal are prevented. And researches show that under certain conditions, the higher the oxygen content is, the stronger the inhibition effect on hydrogen embrittlement is. However, the hydrogen embrittlement in the process can only be inhibited but not eliminated, firstly, the oxygen content in the hydrogen is not high enough, otherwise, the explosion risk exists; secondly because oxygen cannot block all hydrogen dissociation sites.

The volume fraction of oxygen in hydrogen in a hydrogen system is regulated by the national standard GB4962-2008 'hydrogen use safety technical code' to be not more than 0.5%. However, the regulations and other related documents describing the results of research on the presence of trace oxygen in hydrogen gas have been studied in view of the hydrogen explosion safety range, and the data of the safety range is not related to the inhibition effect of high-pressure hydrogen embrittlement. Therefore, the specification is completely different from the technical starting point of the technical solution of the present invention.

The largest byproduct in the production of the green hydrogen is oxygen which is non-toxic and harmless. Therefore, according to the two inventive principles, a certain amount of oxygen is mixed into the hydrogen to form a mixed gas; and then the mixed gas is doped into a hydrogen-doped natural gas pipeline for transporting the hydrogen-doped natural gas, so that the hydrogen embrittlement of the natural gas pipeline can be inhibited to a certain extent, and the safe and low-cost transportation of the hydrogen-doped natural gas is ensured.

Compared with the prior art, the invention has the beneficial effects that:

1. the mechanism that a specific amount of oxygen has an inhibiting effect on hydrogen embrittlement of hydrogen in the pipe is utilized, and the hydrogen embrittlement phenomenon of the natural gas pipeline can be inhibited through oxygen doping on the basis of effectively reducing the hydrogen transportation cost, so that the safe transportation of the hydrogen-doped natural gas pipeline is guaranteed;

2. according to the invention, the concentration of hydrogen and oxygen can be strictly monitored in real time through the concentration balance control system and the pressure temperature control system, so that the hydrogen-oxygen ratio in the hydrogen-oxygen mixing system can be dynamically adjusted through feedback, and the natural gas from different sources can be adaptively doped under the condition of multiple components; meanwhile, temperature change and pressure transmission in the mixing device can be controlled through the pressure and temperature control system, and mixing safety is guaranteed.

3. The hydrogen source of the invention is a hydrogen production system using renewable energy sources such as wind power, hydropower or solar energy, and the like, and the hydrogen can simultaneously obtain a byproduct of oxygen, thereby reducing the production and transportation costs to the maximum extent and realizing the maximization of comprehensive benefits.

Drawings

FIG. 1 is a schematic block diagram of the overall system and method of the present invention.

Detailed Description

The invention designs a system and a method for preventing hydrogen embrittlement of a hydrogen-doped natural gas pipeline based on green hydrogen-doped oxygen by utilizing a mechanism that a certain amount of oxygen has an inhibiting effect on hydrogen embrittlement of hydrogen in a pipe, so that the problem that hydrogen embrittlement of a natural gas pipeline material is caused by hydrogen can be solved, and the risk index of hydrogen-doped natural gas transportation is reduced.

Firstly, the invention is verified by designing corresponding experiments: the hydrogen doped with oxygen with specific content has inhibition effect on hydrogen embrittlement in the pipe; furthermore, the hydrogen gas containing a specific content of oxygen is mixed into the natural gas, and the hydrogen embrittlement in the pipe is also inhibited. The method comprises the following specific steps:

verification experiment I: the hydrogen doped with oxygen with specific content has the function of inhibiting the hydrogen brittleness of the pipe.

And (3) performing mechanical property experiments on the pipeline steel fatigue test sample in a high-pressure hydrogen environment with different concentration gradient oxygen contents at 1-15 MPa, and analyzing the hydrogen embrittlement sensitivity index and the fatigue life. The pressure values are selected on the basis of: the design pressure of a pipeline for conveying natural gas between a producing area and a town gate station after the natural gas passes through a gas field gathering and conveying pipeline is usually between 4.2MPa and 13.9MPa, so that the relevant performance of a pipe in the pressure interval is mainly tested.

Considering that the explosion range of hydrogen is 4.0-75.6% (volume concentration), GB4962-2008 "safety technical code for hydrogen use" stipulates that the volume fraction of oxygen in hydrogen in a hydrogen system should not exceed 0.5%, so experiments were set up to incorporate oxygen into hydrogen at a volume ratio of 0.05-0.5%, above which there is an explosion risk. The experimental results show that: in the high-pressure hydrogen environment, with the increase of the content of doped oxygen, the hydrogen brittleness sensitivity of the material is reduced, and the fatigue performance is improved; meanwhile, when the amount of oxygen doped is less than this range, the effect of suppressing hydrogen embrittlement is not significant. The oxygen is mixed with the hydrogen according to the volume ratio of 0.05-0.5 percent, which is the optimal selection range of the oxygen-mixed hydrogen.

And (5) verifying an experiment II: the hydrogen containing oxygen with specific content is mixed into natural gas, so that the hydrogen embrittlement effect of the pipe is inhibited.

And (3) performing mechanical property experiments on the pipeline steel fatigue samples in a natural gas environment containing different concentration gradient oxygen-doped hydrogen at 1-15 MPa, and analyzing the hydrogen embrittlement sensitivity index and the fatigue life.

Considering that the recommended range of the national relevant regulations on the hydrogen-loading concentration of the hydrogen-loaded natural gas is 5-20%, the hydrogen carrying capacity below the range is small, and the safety of the pipe is at risk above the range. Therefore, the experiment is set to mix the oxygen-doped hydrogen into the natural gas pipe network according to the volume proportion of 1-20%. The experimental results show that: in a pressure environment of pipeline natural gas transportation, the concentration of oxygen-doped hydrogen doped into natural gas is kept unchanged, and as the oxygen content in the hydrogen is increased, the hydrogen brittleness sensitivity of pipeline steel is reduced, and the fatigue performance is improved; keeping the content of oxygen doped in the hydrogen unchanged, and increasing the concentration of the oxygen doped hydrogen mixed in the natural gas, the sensitivity of the pipeline steel to hydrogen embrittlement is increased, and the fatigue performance is reduced. Therefore, the volume percentage of the oxygen-doped hydrogen gas is 1-20% which is the optimal selection range of the doping proportion in the hydrogen-doped natural gas.

Embodiments of the present invention are described in further detail below with reference to schematic block diagrams of general systems and methods of the invention.

A preferred schematic block diagram of the overall system and method of the present example is shown in fig. 1, but the form of the technique to which the present invention relates may be implemented in other similar implementations and is not limited solely to the schematic framework shown in fig. 1. More precisely, the implementation flow given by the invention is a better way to fully understand the technical route of the invention in the technical field related to the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the summary of the invention and the accompanying drawings is for the purpose of better describing the steps performed in the technical process of the invention and is not intended to be limited to the terminology so described.

The invention provides a method for preventing hydrogen embrittlement of a hydrogen-doped natural gas pipeline based on hydrogen-green doping and oxygen doping, which comprises the following steps:

(1) mixing oxygen into hydrogen according to the volume ratio of 0.05-0.5% to obtain oxygen-doped hydrogen; when oxygen is doped into hydrogen, the temperature difference between gases before and after mixing is not more than 20 ℃ by controlling the mixing speed and the mixing pressure; and controlling the pressure of the mixed oxygen-doped hydrogen gas to be 1-15 MPa. The hydrogen is green hydrogen from a wind power, hydroelectric power or solar hydrogen production system; carbon emission is completely avoided in the hydrogen production process, and the method belongs to renewable energy sources; the purity of the hydrogen used should be greater than 99%.

(2) Doping the oxygen-doped hydrogen into natural gas to obtain hydrogen-doped natural gas; the volume percentage of the oxygen-doped hydrogen in the hydrogen-doped natural gas is 1 to 20 percent. When the oxygen-doped hydrogen is doped into the natural gas, the temperature of the oxygen-doped hydrogen is controlled within +/-10 ℃ of the temperature range of the natural gas. The hydrogen-doped natural gas basically meets the requirement that the oxygen component content is less than or equal to 0.1 percent in the national standard GB _ T37124-2018 'gas quality requirement for entering a natural gas long-distance pipeline'.

The invention provides a system for preventing hydrogen embrittlement of a hydrogen-loaded natural gas pipeline based on hydrogen-green loading and oxygen loading, and a schematic block diagram of the system is shown in figure 1. The system comprises a renewable energy hydrogen production system, an oxyhydrogen mixing system, a pressure temperature control system, a concentration balance control system, a hydrogen-doped natural gas conveying system and an integrated terminal control system; wherein, the renewable energy hydrogen production system is any one of a wind power hydrogen production system, a hydroelectric hydrogen production system or a solar hydrogen production system. The hydrogen-oxygen mixing system comprises hydrogen-oxygen mixing equipment which is respectively connected with a hydrogen production outlet and an oxygen production outlet in the renewable energy hydrogen production system through pipelines; the oxygen-doped hydrogen discharge port of the hydrogen-oxygen mixing system is also connected to a hydrogen-doped natural gas conveying system through a pipeline; the hydrogen-loaded natural gas conveying system also comprises a natural gas conveying and transferring storage tank and a user terminal which are connected through a conveying pipeline. The pressure and temperature control system comprises a temperature monitoring element and a pressure detection element which are arranged on the renewable energy hydrogen production system, the hydrogen and oxygen mixing system, the hydrogen-doped natural gas conveying system and each connecting pipeline and is electrically connected to the integrated terminal control system in a wired or wireless communication mode; the concentration balance control system comprises concentration monitors arranged on a renewable energy hydrogen production system, an oxyhydrogen mixing system, a hydrogen-doped natural gas conveying system and each connecting pipeline, and is electrically connected to the integrated terminal control system in a wired or wireless communication mode; the integrated terminal control system is provided with a control platform arranged locally or at the cloud, and the control platform is connected with valves arranged in each system or on each connecting pipeline in a wired or wireless communication mode so as to control the production and the transportation of the oxygen-doped hydrogen and the hydrogen-doped natural gas.

The regulation of pressure, temperature and concentration in the system is realized by controlling valves arranged in each system or on each connecting pipeline in a wired or wireless communication mode through the integrated terminal control system, and finally the production and the transportation of the oxygen-doped hydrogen and the hydrogen-doped natural gas can be controlled.

More specific implementation contents based on the system comprise:

the hydrogen and oxygen mixing system is used for mixing and controlling oxygen and hydrogen generated by hydrogen production from renewable energy sources (such as wind energy in northwest region, hydrogen production from water electrolysis by light energy and the like) in a proportion range of 0.05-0.5%, wherein the purity of the hydrogen is required to be more than 99%, and the concentrations of the oxygen and the hydrogen are respectively monitored by a concentration monitor 1 and a concentration monitor 2. Because the hydrogen and oxygen mixing has a heat exchange process, the hydrogen and oxygen mixing system is monitored by the pressure and temperature control system; meanwhile, because the hydrogen and oxygen mixing system controls the hydrogen and oxygen mixing, the hydrogen and oxygen mixing system needs to receive a concentration signal from concentration monitoring feedback for control, and the hydrogen and oxygen mixing system is monitored by the concentration balance control system.

The pressure and temperature control system comprises an oxyhydrogen mixing system, a pressure transmitting element and a temperature monitoring element. The hydrogen-oxygen mixing system is monitored by a pressure and temperature control system because hydrogen-oxygen mixing can generate heat exchange, and the mixing temperature difference is controlled not to exceed 20 ℃ through the mixing speed and the mixing pressure; the pressure transmitting element transmits the monitored data into a pressure and temperature control system by regulating and monitoring the pressure of the hydrogen-oxygen mixed gas to reach 1-15 MPa; the temperature monitoring element is responsible for monitoring the temperature of the mixed gas of hydrogen and oxygen immediately before entering the natural gas pipeline, the temperature range is controlled within +/-10 ℃ of the natural gas temperature range, so that the hydrogen loading safety of the natural gas pipeline is prevented from being threatened by overhigh/low temperature or overlarge temperature difference, and the temperature monitoring element feeds back the monitored temperature data to the pressure temperature control system.

The concentration balance control system comprises a concentration monitor 1, a concentration monitor 2, a concentration monitor 3, a concentration monitor 4 and an oxyhydrogen mixing system. The concentration monitor 1 and the concentration monitor 2 respectively control the amount of hydrogen and oxygen before mixing of the hydrogen production product of the electrolyzed water, the concentration monitor 3 is responsible for monitoring the actual hydrogen-oxygen mixing ratio after mixing of hydrogen and oxygen, and the concentration monitor 4 is responsible for monitoring the content of hydrogen and oxygen in the hydrogen-blended natural gas conveying pipeline. The concentration balance control system controls the proportion and the content of hydrogen and oxygen mixed in the hydrogen and oxygen mixing system through monitoring data of the four concentration monitors.

In the invention, the hydrogen-oxygen mixing system is simultaneously regulated and controlled by the pressure-temperature control system and the concentration balance control system, the temperature change generated by hydrogen-oxygen mixing is monitored by the pressure-temperature control system, and the concentration balance control system receives feedback and simultaneously acts on the hydrogen-oxygen mixing system so as to regulate and control the mixing proportion of the hydrogen-oxygen mixing system. The integrated control system performs cloud computer integrated control and processing on the pressure and temperature control system, the hydrogen-doped natural gas conveying system and the concentration balance control system (the hydrogen-oxygen mixing system is controlled by the concentration balance control system).

If the proportion and the content of the hydrogen and the oxygen input before the hydrogen and the oxygen are mixed are not in the specified range, the hydrogen and oxygen mixing system receives the data fed back by the concentration monitor 1 and the concentration monitor 2 in the concentration balance control system, so that the proportion and the content of the mixed gas in the mixing system are adjusted to the specified range; if the concentration monitor 3 monitors that the proportion and the content of the mixed hydrogen-oxygen gas mixture are not in the specified range, the hydrogen-oxygen mixing system receives the data fed back by the concentration monitor 3 in the concentration balance control system, so that the proportion and the content of the mixed gas in the mixing system are adjusted to the specified range; if the concentration monitor 4 in the natural gas hydrogen-loading pipeline monitors that the hydrogen-oxygen ratio and the hydrogen-oxygen content are not in the specified range in the actual conveying process, the hydrogen-oxygen mixing system can receive the data fed back by the concentration monitor 4 in the concentration balance control system, and therefore the ratio and the content of the mixed gas in the mixing system are adjusted to the specified range. The process forms a concentration balance control system, and can carry out adaptive doping on natural gas from different sources under complex components.

The specific control process comprises the following steps:

mixing oxygen and hydrogen generated by hydrogen production from renewable energy sources by a hydrogen-oxygen mixing system, monitoring the concentrations of the hydrogen and the oxygen by a concentration monitor 1 and a concentration monitor 2 before mixing, and transmitting data to a concentration balance control system; the concentration of the mixed gas is controlled by a concentration monitor 3, and the data is transmitted to a concentration balance control system; the mixed gas is processed by a pressure transmitting element and a temperature monitoring element in a pressure temperature control system in an integrated way, and data is transmitted to the integrated control system by the pressure temperature control system; the mixed gas with qualified concentration, temperature and pressure enters a hydrogen-doped natural gas conveying system, a concentration monitor 4 monitors the content of oxygen and hydrogen in a hydrogen-doped natural gas conveying pipeline, and data is transmitted to a concentration balance control system; the integrated terminal control system analyzes all data, judges whether the data meet the specified range, and adjusts each system if the data do not meet the specified range.

As an example of comprehensive utilization of green energy, the hydrogen-doped natural gas conveying system comprises a natural gas conveying and transferring storage tank for providing natural gas, a conveying pipeline, a hydrogen-doped natural gas conveying pipeline and a user terminal. The hydrogen and the oxygen in the hydrogen-oxygen mixing system are generated by electrolyzing water to produce hydrogen by not utilizing peak wind power, photoelectricity and the like. The concentration monitor 4 monitors the components of hydrogen and oxygen of the final hydrogen-doped natural gas conveying pipeline, can take the trace hydrogen and oxygen contained in the original natural gas into consideration, feeds a concentration signal back to the hydrogen-oxygen mixing system through the concentration balance control system, realizes the cooperative control of the concentration monitor, and ensures that the concentration range of hydrogen doping and oxygen doping is controlled within the range specified by national standards.

Although the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention are still within the technical scope of the present invention, unless the content of the technical solution of the present invention is departed from.