Laboratory Hydrogen Permeation Testing Under H2S, Heat, and Tensile Stress
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Solution Overview
Problem
Existing systems lack flexibility to measure hydrogen permeation and corrosion of different strength steels under high partial pressures of hydrogen sulfide, relatively high temperatures, and varying levels of tensile stress, failing to distinguish the independent effects of these parameters over time.
Innovation Solution
A system comprising a first cell housing with a process fluid reservoir and a second cell housing with a basic solution reservoir, a test specimen between them, potentiostats for voltage application, and a loading device for tensile strain, allowing independent monitoring of hydrogen permeation and corrosion rates under controlled conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing measurement systems are used, then hydrogen permeation and corrosion can be measured, but the systems lack flexibility to measure different strength steels under high partial pressures of hydrogen sulfide, relatively high temperatures, and varying levels of tensile stress
Solution Approach 1:
The apparatus is designed as a universal testing system that can measure hydrogen permeation, corrosion rates, and mechanical properties of different steel strengths under multiple conditions (high H2S pressure, elevated temperatures, varying tensile stresses) using a single integrated platform with interchangeable test cells and loading mechanisms
Solution Approach 2:
The system incorporates dynamic control capabilities allowing real-time adjustment of test parameters including temperature, pressure, stress magnitude and type (constant, cyclic, slow strain rate), enabling flexible adaptation to different material and environmental conditions during measurement
2Measurement precision
If existing systems are used, then measurements can be performed, but they fail to distinguish the independent effects of test parameters over time
Solution Approach 1:
The apparatus divides the measurement function into separate test cells (charging cell, permeation cell, electrochemical cell) that can be independently controlled and measured, allowing the independent effects of each parameter (pressure, temperature, stress) to be distinguished through systematic variation of one parameter while holding others constant
Solution Approach 2:
The system incorporates real-time monitoring and feedback control of multiple parameters simultaneously, with data acquisition systems that track temporal evolution of hydrogen permeation, corrosion rates, and mechanical properties, enabling precise distinction of parameter effects through controlled experimentation and data analysis
3Reliability
If atomic hydrogen permeates through steel structures, then hydrogen molecules form and disperse harmlessly, but under tensile stress atomic hydrogen migrates into microvoids causing trapped molecular hydrogen that exerts internal pressure leading to blistering or cracks
Solution Approach 1:
The apparatus applies controlled tensile stresses to test specimens before hydrogen charging to create and maintain microvoids and defects that can trap hydrogen atoms, preventing their harmful migration through the steel matrix and reducing the formation of hydrogen-induced cracks and blistering
Solution Approach 2:
The system converts the harmful effect of tensile stress (which normally promotes hydrogen penetration) into a beneficial testing parameter by using controlled stress application to create predictable microvoid structures that trap hydrogen, thereby enabling measurement and evaluation of hydrogen-induced damage mechanisms
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables simultaneous measurement of hydrogen permeation and corrosion rates under high pressures and temperatures, with independent control of tensile stress, providing comprehensive data on material performance in sour environments.
Implementation Method 1
Due to a concentration gradient, hydrogen atoms diffuse from the entry side of the steel specimen to the exit side
Implementation Method 2
an electrochemical potential is applied to the exit side of the specimen forcing hydrogen atoms to instantaneously oxidize
Implementation Method 3
Dissolved H2S dissociates fully in two steps into protons and sulfides
Implementation Method 4
Atomic hydrogen is very soluble in the mild steel materials typically used to fabricate natural gas conduits and tends to diffuse into and permeate solid steel structures
Data Source
AI summary
A system for performing electrochemical and hydrogen permeation measurements using a test specimen subject to tensile stress comprises a first housing filled with a process fluid supplied via an inlet with hydrogen sulfide, a second housing filled with a basic solution, a test specimen positioned between the first and second housings exposed to the process fluid on one side and to the basic solution on the other, first and second potentiostats coupled to the first and second housings to measure corrosion and induce hydrogen permeation, a loading device adapted to apply a longitudinal strain on the specimen, and a computing device configured to control operation of the potentiostat and loading device. The hydrogen sulfide in the process fluid impedes formation of diatomic hydrogen from atomic hydrogen, allowing adsorbed atomic hydrogen to enter into the steel test specimen from one side and permeate into the other side of the test specimen.