Method for predicting corrosion degree of natural gas pipeline under gas-liquid two-phase flow

A technology for natural gas pipelines and prediction methods, which is applied in the field of prediction of corrosion degree of natural gas pipelines under gas-liquid two-phase flow, and can solve problems such as corrosion, reduction of medium flow rate, and increased consumption of power and energy for pipeline transportation

Active Publication Date: 2018-06-05
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The internal corrosion of natural gas pipelines is not only difficult to predict and detect, but also seriously affects the transmission efficiency, equipment safety and pipeline reliability
The internal corrosion of the pipeline will not only shorten the maintenance and replacement period of the pipeline, but also the corrosion product layer will reduce the heat transfer efficiency of the pipe string, reduce the flow rate of the medium, and increase the power and energy consumption of the pipeline.

Method used

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  • Method for predicting corrosion degree of natural gas pipeline under gas-liquid two-phase flow
  • Method for predicting corrosion degree of natural gas pipeline under gas-liquid two-phase flow
  • Method for predicting corrosion degree of natural gas pipeline under gas-liquid two-phase flow

Examples

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Embodiment 1

[0023] This embodiment provides a method for predicting the corrosion degree of a natural gas pipeline under gas-liquid two-phase flow, including the following steps:

[0024] Step 1) Collect natural gas pipeline operating condition information, including temperature, pressure, medium composition, gas-liquid ratio, carbon dioxide content, and flow rate of each phase;

[0025] Step 2) establish the momentum equation, energy equation, and mass equation of each component, and establish the gas-liquid two-phase fluid model of the natural gas pipeline;

[0026] Step 3) Based on the gas-liquid two-phase fluid model of the natural gas pipeline, on the basis of the collection and analysis of the working condition information of the natural gas pipeline, through modeling, the numerical simulation of the two-phase flow flow pattern and flow state change of the fluid in the pipeline is carried out to obtain the pipeline section Temperature, pressure, carbon dioxide partial pressure, flow...

Embodiment 2

[0029] On the basis of Example 1, this example provides a method for predicting the corrosion degree of a gas-liquid two-phase flow natural gas pipeline, and the specific steps are as follows:

[0030] Step 1) Collect natural gas pipeline operating condition information, including temperature, pressure, medium composition, gas-liquid ratio, carbon dioxide content, and flow rate of each phase;

[0031] Step 2) According to the theory of fluid mechanics and the state of motion involved in the two-phase flow of natural gas pipelines, the gas-liquid two-phase fluid model of natural gas pipelines is established by theoretical analysis. The models include momentum, energy, and mass models, and the momentum conservation equations, energy conservation equations, and Mass conservation equations and mass transfer models;

[0032] (1) Establish mass conservation equation (continuity equation):

[0033]

[0034] In the formula, ρ is the fluid density, V is the fluid velocity, Tensor...

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Abstract

The invention provides a method for predicting the corrosion degree of a natural gas pipeline under a gas-liquid two-phase flow. The method comprises firstly collecting and analyzing information on the working conditions of the natural gas pipeline; establishing a gas-liquid two-phase fluid model of the natural gas pipeline; performing numerical simulation of two-phase flow pattern and flow stateevolution based on the two-phase fluid model of the natural gas pipeline; finally establishing a carbon dioxide corrosion model, obtaining the carbon dioxide corrosion rate, calculating the pipeline corrosion rate by combination with the obtained pipeline corrosion damage probability Ptot, and predicting the pipeline service life. In the method, based on actual data collection on site, two-phase flow fluid calculation and carbon dioxide corrosion model are proposed, the effect of two-phase flow on carbon dioxide corrosion in the natural gas pipeline undergoes concentrated discussion, and computer numerical simulation is used to simulate the full set of carbon dioxide corrosion prediction of the natural gas pipeline under two-phase flow. Technical support is provided for the safety of the natural gas pipeline under gas-liquid two-phase flow.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field equipment, and in particular relates to a method for predicting the corrosion degree of a gas-liquid two-phase flow natural gas pipeline. Background technique [0002] With the growth of my country's demand for clean energy, the extraction of natural gas continues to increase. However, during the extraction of natural gas, most of the blocks contain CO 2 、H 2 O and other corrosive media. Natural gas is also accompanied by these corrosive media during transportation, which not only affects the service life of natural gas pipelines and equipment, but also pollutes the environment. As the amount of natural gas continues to increase, the requirements for the transportation capacity of natural gas continue to increase, the temperature, pressure, and flow rate during the transportation process continue to increase, and the corrosion of pipes under the action of the flow field is also becomi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F17D5/02G06F17/50
CPCF17D5/02G06F30/20
Inventor 朱方辉周志平李琼玮刘伟李明星董晓焕张振云赵晓伟谭军张迪李曙华徐广军
Owner PETROCHINA CO LTD
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