CN116399680B - Gas transportation method with pipeline hydrogen embrittlement protection function - Google Patents

Abstract

The invention belongs to the technical field of pipeline transportation, and provides a gas transportation method with a pipeline hydrogen embrittlement protection function, which comprises the following steps: determining the pressure and the hydrogen loading ratio of the gas to be transported; pre-charging protective gas under preset pressure according to the pressure and the hydrogen loading ratio of the gas to be transported, and stopping pre-charging after lasting the first preset time period; after the pre-completion is finished, the pipeline conveys the gas to be conveyed, and conveying is stopped after the second time is continuously preset; according to the first preset time length and the second preset time length, the pipeline alternately performs pre-charging of protective gas and transportation of gas to be transported; according to the first preset duration of pre-filling the protective gas and the second preset duration of transporting the gas, the pipeline alternately performs pre-filling of the protective gas and transporting the gas to be transported, so that the purpose of inhibiting the hydrogen embrittlement of the pipeline is achieved, the probability of failure of the pipeline due to the hydrogen embrittlement is reduced, the problem of directly adding the additional protective gas into the gas is avoided, and the purity of the transporting gas is ensured.

Description

A gas transportation method with pipeline hydrogen embrittlement protection

Technical field

The invention belongs to the technical field of pipeline transportation, and in particular relates to a gas transportation method with a pipeline hydrogen embrittlement protection function.

Background technique

Hydrogen energy is a clean and low-carbon energy and an important means of the current global energy technology revolution and industrial transformation. Currently, in order to reduce the transportation cost of hydrogen, hydrogen is usually transported through existing natural gas pipelines in the form of pure hydrogen or hydrogen-mixed natural gas. Hydrogen embrittlement of metal pipes is an important factor limiting the development of hydrogen pipelines: in a hydrogen environment, hydrogen molecules will be adsorbed on the surface of metal pipes and penetrate into the pipes in the form of atoms, reducing their mechanical properties and threatening the safety of pipeline operations. Therefore, hydrogen embrittlement protection of pure hydrogen or hydrogen-doped natural gas pipelines is of great significance to the safe operation of pure hydrogen or hydrogen-doped natural gas pipelines.

In existing research, a method has been disclosed to prevent pipeline hydrogen embrittlement by adding carbon monoxide gas to hydrogen transmission pipelines or mixed hydrogen transmission pipelines. This method can effectively inhibit pipeline steel without reducing the total pressure and high hydrogen partial pressure. Hydrogen-induced failure occurs to avoid catastrophic accidents caused by hydrogen-induced brittle explosion. Also disclosed is a system and method for preventing hydrogen embrittlement of hydrogen-doped natural gas pipelines based on green hydrogen doping with oxygen. This method mixes oxygen into hydrogen at a volume ratio of 0.05% to 0.5% to obtain oxygen-doped hydrogen, and then mixes the oxygen-doped hydrogen with Into natural gas, hydrogen-doped natural gas is obtained, which utilizes the mechanism that a specific amount of oxygen can inhibit the hydrogen embrittlement of hydrogen in pipes, and suppresses the hydrogen embrittlement phenomenon in natural gas pipelines by adding oxygen.

The inventor found that the existing hydrogen embrittlement protection technology for pure hydrogen or hydrogen-mixed natural gas pipelines requires mixing a certain amount of additional gas into the pipeline, which will cause the purity of the transported pure hydrogen or hydrogen-mixed natural gas to decrease, which is not conducive to pure hydrogen. /Subsequent sales and processing of hydrogen-doped natural gas.

Contents of the invention

In order to solve the above problems, the present invention proposes a gas transportation method with a hydrogen embrittlement protection function for pipelines. The present invention relies on the competitive adsorption characteristics of hydrogen on the surface of pipeline steel by protective gases such as carbon monoxide, by adding pure hydrogen/hydrogen-doped natural gas pipelines. The method of pre-charging protective gas maximizes the protection against hydrogen embrittlement of pure hydrogen/hydrogen-doped natural gas pipeline steel.

In order to achieve the above objects, the present invention is achieved through the following technical solutions:

The invention provides a gas transportation method with pipeline hydrogen embrittlement protection, including:

Determine the pressure and hydrogen doping ratio of the gas to be transported;

Based on the pressure and hydrogen doping ratio of the gas to be transported, the protective gas is precharged under a preset pressure, and the prefilling stops after continuing for a first preset time;

After the pre-completion is completed, the pipeline will transport the gas to be transported, and the transportation will stop after the preset second time;

According to the first preset time length and the second preset time length, the pipeline alternately performs pre-charging of the protective gas and transportation of the gas to be transported.

Further, when the gas to be transported is pure hydrogen, determine the pressure of pure hydrogen.

Further, when the gas to be transported is hydrogen-doped natural gas, the pressure and hydrogen-doping ratio of the hydrogen-doped natural gas are determined.

Further, during the gas transportation process, the time for the pipeline's adsorbed hydrogen concentration to increase to the critical adsorbed hydrogen concentration is used as the second preset time length.

Further, gas with a critical pressure and a critical hydrogen doping ratio is charged into the pipeline, and the surface adsorbed hydrogen concentration of the pipeline at this time is calculated as the critical adsorbed hydrogen concentration.

Further, in gas environments with different pressures and different hydrogen doping ratios, the cross-sectional shrinkage of the pipeline is measured, the hydrogen embrittlement index is calculated, and the critical pressure and critical hydrogen doping ratio that make the hydrogen embrittlement index of the pipeline sample reach the preset value are determined.

Further, prepare a pipeline sample, and fill the autoclave of the high-pressure in-situ stretching machine with pure hydrogen at different pressures or hydrogen-doped natural gas with different pressures and different hydrogen-doping ratios;

In the environment of pure hydrogen at different pressures or hydrogen-doped natural gas environments with different pressures and different hydrogen doping ratios, tensile experiments are conducted on pipeline samples, the section shrinkage of the pipeline samples is measured, the hydrogen embrittlement index is calculated, and the hydrogen embrittlement of the pipeline samples is determined. The index is the critical pure hydrogen pressure or critical hydrogen-doped natural gas pressure and hydrogen doping ratio of 35%.

Further, a hydrogen permeation electrolytic cell with a high-pressure gas phase reactor is filled with a protective gas of a preset pressure, and the pipeline sample is left standing in the protective gas for a preset time of the first preset time.

Further, the protective gas is carbon monoxide.

Further, the protective gas is carbon monoxide and oxygen.

Compared with the prior art, the beneficial effects of the present invention are:

1. The present invention determines the pre-charging of protective gas under a preset pressure based on the pressure of the gas to be transported and the hydrogen doping ratio; based on the first pre-set duration of pre-charging the protective gas and the length of the transport gas. During the second preset time, the pipeline alternately pre-charges the protective gas and transports the gas to be transported, achieving the purpose of suppressing hydrogen embrittlement in the pipeline, reducing the probability of pipeline failure due to hydrogen embrittlement, and avoiding directly adding additional protection to the gas. Solve the problem of sexual gas and ensure the purity of the transported gas;

2. The present invention utilizes the characteristic that the adsorption amount of hydrogen molecules decreases on the surface of pipeline steel that has pre-adsorbed protective gas. By alternately transporting hydrogen embrittlement protective gas and pure hydrogen or hydrogen-doped natural gas into the pipeline, it inhibits pure hydrogen or hydrogen-doped natural gas pipelines. Hydrogen embrittlement, which reduces the probability of failure of pure hydrogen or hydrogen-doped natural gas pipelines due to hydrogen embrittlement;

3. The present invention alternately transports hydrogen embrittlement protective gas and pure hydrogen or hydrogen-doped natural gas in the pipeline, avoiding the mixing of impurity gases into pure hydrogen or hydrogen-doped natural gas, and ensuring the purity of pure hydrogen or hydrogen-doped natural gas;

4. The protective gas transported alternately in the present invention can be recycled, which reduces the industrial cost of the method;

5. In the present invention, by calculating the effective hydrogen embrittlement protection time, the alternating transportation time of pure hydrogen or hydrogen-doped natural gas and protective gas can be reasonably arranged, which can minimize the occurrence of hydrogen embrittlement and maximize the protective effect of the protective gas.

Description of drawings

The description drawings that form a part of this embodiment are used to provide further understanding of this embodiment. The schematic embodiments and their descriptions of this embodiment are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

Figure 1 is a flow chart of Embodiment 1 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meanings commonly understood by one of ordinary skill in the art to which this application belongs.

Example 1:

As recorded in the background art, during the process of pipeline gas transportation, the hydrogen embrittlement protection methods currently used for pure hydrogen or hydrogen-doped natural gas pipelines require a certain amount of additional protective gas to be mixed into the pipeline, resulting in a decrease in the purity of the transported gas. It is not conducive to the sales and processing of gas after transportation. In response to the above problems, this embodiment provides a gas transportation method with pipeline hydrogen embrittlement protection, including:

Determine the pressure and hydrogen doping ratio of the gas to be transported; based on the pressure and hydrogen doping ratio of the gas to be transported, pre-charge the protective gas under the preset pressure. The pre-charging will stop after the first pre-set time; Then, the pipeline transports the gas to be transported, and continues to stop the transport after the second preset time; according to the first preset time length and the second preset time length, the pipeline alternately prefills the protective gas and transports the gas to be transported. In this embodiment, based on the first preset duration of pre-charging the protective gas and the second preset duration of the transport gas, the pipeline alternately pre-charges the protective gas and transports the gas to be transported, thereby achieving the purpose of suppressing hydrogen embrittlement in the pipeline and avoiding It eliminates the problem of adding additional protective gas directly into the gas and ensures the purity of the transported gas. In this embodiment, the main steps of the gas transportation method with pipeline hydrogen embrittlement protection are:

S1. Fill the autoclave of the high-pressure in-situ stretching machine with pure hydrogen at different pressures or hydrogen-doped natural gas with different pressures and different hydrogen-doping ratios;

S2. Conduct tensile experiments on pipeline samples in pure hydrogen at different pressures or hydrogen-doped natural gas environments with different pressures and hydrogen doping ratios, measure the section shrinkage of the samples, calculate the hydrogen embrittlement index, and determine whether the pipeline samples will be hydrogen embrittled. The index is 35% pure hydrogen pressure or hydrogen-doped natural gas pressure and hydrogen doping ratio; the pipeline sample is a pipeline steel pipe sample, and X52 steel can be used; the calculation of the hydrogen embrittlement index can be achieved by conventional methods and will not be detailed here;

S3. In the hydrogen permeation electrolytic cell with a high-pressure gas phase reactor, fill pure hydrogen or hydrogen-doped natural gas so that the hydrogen embrittlement index of the pipeline sample is 35%; calculate the critical adsorbed hydrogen concentration of the pipeline sample at this time;

S4. Fill the hydrogen permeation electrolytic cell with a high-pressure gas phase reactor with 2MPa carbon monoxide, and let the pipeline sample stand in the 2MPa carbon monoxide for one day;

S5. Empty 2MPa carbon monoxide and fill 4MPa pure hydrogen into the hydrogen permeation electrolytic cell with a high-pressure gas phase reactor. Measure the change of the adsorbed hydrogen concentration of the pipeline sample in the 4MPa pure hydrogen environment with time. When the adsorbed hydrogen concentration of the pipeline sample in the 4MPa pure hydrogen environment increases to the critical adsorbed hydrogen concentration, it is the effective protection under this condition. time;

S6. Transport 2MPa carbon monoxide into X52 steel pure hydrogen or hydrogen-mixed natural gas pipelines, and the transport time is one day;

S7. Transport 4MPa pure hydrogen into X52 steel pure hydrogen or hydrogen-doped natural gas pipelines. The transport time is equal to the effective protection time obtained from the experiment;

S8. Re-transport 2MPa carbon monoxide into the X52 steel pure hydrogen/hydrogen-doped natural gas pipeline. The transportation time is one day. After the transportation is completed, transport 4MPa pure hydrogen. The transportation time is equal to the effective protection time obtained from the experiment; the subsequent process repeats steps S6 and S7.

In some embodiments, an experimental method for calculating the critical adsorbed hydrogen concentration that does not cause hydrogen embrittlement for pipeline steel in a pure hydrogen or hydrogen-doped natural gas environment based on gas-phase hydrogen permeability parameter measurement is provided, including:

Fill the autoclave of the high-pressure in-situ stretching machine with pure hydrogen at different pressures or hydrogen-doped natural gas with different pressures and different hydrogen-doping ratios;

Conduct a tensile test on a sample of pipeline steel L in pure hydrogen at different pressures or in a hydrogen-doped natural gas environment with different pressures and hydrogen doping ratios, measure the section shrinkage of the sample, calculate the hydrogen embrittlement index, and determine the quality of the pipeline steel. L hydrogen embrittlement index is exactly 35% of the critical pure hydrogen pressure or critical hydrogen-doped natural gas pressure and hydrogen doping ratio;

In the hydrogen permeation electrolytic cell with a high-pressure gas phase reactor, the critical pure hydrogen pressure or critical hydrogen-doped natural gas pressure and hydrogen doping ratio of the pipeline steel L are charged. Calculate the surface adsorbed hydrogen concentration of the pipeline steel L sample at this time. This adsorbed hydrogen concentration is the critical adsorbed hydrogen concentration S that does not cause hydrogen embrittlement for the pipeline steel L in a pure hydrogen/hydrogen-doped natural gas environment.

In some embodiments, an experimental method for measuring the effective hydrogen embrittlement protection time of prefilled protective gas for pipeline steel in a pure hydrogen/hydrogen-doped natural gas environment is provided, including:

The hydrogen permeation electrolytic cell with a high-pressure gas phase reactor is filled with a protective gas G of a certain pressure P, such as carbon monoxide, oxygen, etc., so that the pipeline steel L sample is allowed to stand in the protective gas G of a pressure P Precharge time T; precharge time T can be the preset first duration;

Evacuate the protective gas G with a pressure of P, and fill the hydrogen permeation electrolytic cell with a high-pressure gas phase reactor with pure hydrogen at a certain pressure or hydrogen-doped natural gas at a certain pressure and a certain hydrogen-doping ratio. The environment is recorded as W. Measure the change of the adsorbed hydrogen concentration of the pipeline steel L sample in the environment W with time. The time for the adsorbed hydrogen concentration of the pipeline steel L sample in the environment W to increase to the critical adsorbed hydrogen concentration S is the pressure of the precharge time T. The protective gas G of P has an effective hydrogen embrittlement protection time V for the pipeline steel L sample in the environment W, and the effective hydrogen embrittlement protection time V can be a preset second duration.

In some embodiments, a method for calculating the effective protection time of pure hydrogen/hydrogen-doped natural gas pipelines with protective gas based on the above experimental method is provided, including:

In a pure hydrogen/hydrogen-doped natural gas pipeline made of pipeline steel L, after pre-charging the protective gas G with a pressure of P for a period of time T, the safe operation time of pipeline steel L without hydrogen embrittlement in the working environment W is V.

The above descriptions are only preferred embodiments of this embodiment and are not intended to limit this embodiment. For those skilled in the art, this embodiment may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this embodiment shall be included in the protection scope of this embodiment.

Claims (9)

1. A gas transportation method with pipeline hydrogen embrittlement protection, which is characterized by including: Determine the pressure and hydrogen doping ratio of the gas to be transported; Based on the pressure and hydrogen doping ratio of the gas to be transported, the protective gas is precharged under a preset pressure, and the prefilling stops after continuing for a first preset time; After the pre-charging stops, the pipeline transports the gas to be transported, and the transportation stops after continuing for a second preset time; during the gas transportation process, the time for the pipeline's adsorbed hydrogen concentration to increase to the critical adsorbed hydrogen concentration is used as the second preset time; According to the first preset time length and the second preset time length, the pipeline alternately performs pre-charging of the protective gas and transportation of the gas to be transported. 2. A gas transportation method with a pipeline hydrogen embrittlement protection function as claimed in claim 1, characterized in that when the gas to be transported is pure hydrogen, the pressure of the pure hydrogen is determined. 3. A gas transportation method with pipeline hydrogen embrittlement protection as claimed in claim 1, characterized in that when the gas to be transported is hydrogen-doped natural gas, the pressure and hydrogen-doping ratio of the hydrogen-doped natural gas are determined. 4. A gas transportation method with pipeline hydrogen embrittlement protection as claimed in claim 1, characterized in that the pipeline is filled with gas at a critical pressure and a critical hydrogen doping ratio, and the surface adsorbed hydrogen concentration of the pipeline at this time is calculated as Critical adsorbed hydrogen concentration. 5. A gas transportation method with pipeline hydrogen embrittlement protection as claimed in claim 4, characterized in that in gas environments with different pressures and different hydrogen doping ratios, the section shrinkage of the pipeline is measured and the hydrogen embrittlement index is calculated. , determine the critical pressure and critical hydrogen doping ratio that make the hydrogen embrittlement index of the pipeline sample reach the preset value. 6. A gas transportation method with pipeline hydrogen embrittlement protection as claimed in claim 5, characterized in that pipeline samples are made and pure hydrogen or pure hydrogen at different pressures is filled into the autoclave of the high-pressure in-situ stretching machine. Hydrogen-doped natural gas at different pressures and different hydrogen-doping ratios; In the environment of pure hydrogen at different pressures or hydrogen-doped natural gas environments with different pressures and different hydrogen doping ratios, tensile experiments are conducted on pipeline specimens, the section shrinkage of the pipeline specimens is measured, the hydrogen embrittlement index is calculated, and the hydrogen embrittlement of the pipeline specimens is determined. The index is the critical pure hydrogen pressure or critical hydrogen-doped natural gas pressure and hydrogen doping ratio of 35%. 7. A gas transportation method with pipeline hydrogen embrittlement protection as claimed in claim 6, characterized in that a protective gas with a preset pressure is filled into a hydrogen permeation electrolytic cell with a high-pressure gas phase reactor, and the pipeline The sample is left standing in the protective gas for a pre-charge time of the first preset time period. 8. A gas transportation method with a pipeline hydrogen embrittlement protection function as claimed in claim 1, characterized in that the protective gas is carbon monoxide. 9. A gas transportation method with pipeline hydrogen embrittlement protection as claimed in claim 1, characterized in that the protective gas is oxygen.