Apparatus and method for the non-destructive measurement of hydrogen diffusivity

Patent metadata

Field	Value
Publication number	US-2019265220-A1
Application number	US-201916408668-A
Country	US
Kind code	A1
Filing date	May 10, 2019
Priority date	Apr 28, 2017
Publication date	Aug 29, 2019
Grant date	—

Abstract

Apparatuses and methods of measuring a hydrogen diffusivity of a metal structure including during operation of the metal structure, are provided. A hydrogen charging surface is provided at a first location on an external surface of the structure. In addition, a hydrogen oxidation surface is provided at a second location adjacent to the first location on the external surface of the structure. Hydrogen flux is generated and directed into the metal surface at the charging surface. At least a portion of the hydrogen flux generated by the charging surface is diverted back toward the surface. A transient of the diverted hydrogen fluxes measured, and this measurement is used to determine the hydrogen diffusivity of the metal structure in service.

First claim

1 . A method of measuring a hydrogen diffusivity of a metal structure comprising:
providing a hydrogen charging surface at a first location on an external surface of the structure; providing a hydrogen oxidation surface at a second location adjacent to the first location on the external surface of the structure; generating a hydrogen flux directed into the metal surface at the charging surface; detecting a current representative of a transient of the hydrogen flux diverted back toward the oxidation surface form the metal structure; and determining the hydrogen diffusivity of the metal structure based on the detected hydrogen flux.

2 . The method of claim 1 , wherein the hydrogen charging surface is produced by a first electrochemical cell and the hydrogen oxidation surface is produced by a second electrochemical cell.

3 . The method of claim 2 , further comprising adding a coating at the oxidation surface to promote oxidation of hydrogen.

4 . The method of claim 3 , wherein the coating includes palladium.

5 . The method of claim 2 , further comprising measuring an oxidation current in the oxidation cell in order to measure the transient.

6 . The method of claim 1 , wherein the hydrogen diffusivity is determined from the transient of hydrogen flux using a direct simulation technique based on a Fickian diffusion model that uses initial conditions based on an experimental apparatus.

7 . The method of claim 6 , further comprising:
setting a value for the hydrogen diffusivity; executing the diffusion model using the set value of hydrogen diffusivity; comparing results of the Fickian diffusion model to results using the experimental apparatus; and repeating the previous steps with different values of hydrogen diffusivity until a closest match between the results of the diffusion model and the results using the experimental apparatus is reached.

8 . The method of claim 1 , wherein the hydrogen diffusivity is determined from the transient of hydrogen flux using a simulated master graph for a particular experimental apparatus design, the simulated master graph being independent of geometric dimensions, and experimental parameters.

9 . The method of claim 8 , further comprising:
performing sensitivity analysis on each geometrical parameter to determine an influence of the parameter on a normalized transient curve; and identifying the curve as a master curve, with respect to a parameter, if the curve is invariant to changes in the parameter.

10 . The method of claim 9 , wherein the parameters include at least two of the following: metal structure thickness, a size of the charging surface, a width of the oxidation surface and a wall thickness of the charging cell.

11 . The method of claim 1 , wherein the measurement of hydrogen diffusivity is performed while the metal structure is in service and operational

12 - 21 . (canceled)

Assignees

• Saudi Arabian Oil Co

Inventors

• Traidia Abderrazak
• Shahrani Mohammed
• Duval Sebastien A

Classifications

• G01N2013/003

  Diffusion; diffusivity between liquids · CPC title

• G01N13/00 Primary

  Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects (scanning-probe techniques or apparatus G01Q) · CPC title

• C25B1/02

  Hydrogen or oxygen · CPC title

• H01M4/92

  Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) · CPC title

• G01N33/20

  Metals · CPC title