Investigation of hydrogen diffusion and accumulation in X70 pipeline steel

View/ Open
Date
2019-12-06Author
Thomas, Alen 1990-
ORCID
0000-0002-7155-2051Type
ThesisDegree Level
MastersMetadata
Show full item recordAbstract
Pipelines quickly, safely and economically transport large volumes of oil and gas compared to trains, trucks and ships. However, they occasionally fail leading to environmental pollution, fatalities and financial losses. Pipeline cracking by hydrogen embrittlement is the main cause of pipeline failure. The main focus of this research was on the effect of grain size and misorientation on hydrogen diffusion and accumulation in X70 pipeline steel.
In this investigation, the hydrogen permeation experiment was used to determine the parameters for hydrogen diffusion, and the hydrogen microprint technique was used to visualize the diffusion path in X70 steel. Hydrogen atoms were oxidized in the hydrogen permeation experiment, whereas they were reacted with an emulsion coating in the hydrogen microprint experiment. The samples for studying the effect of grain size on hydrogen diffusion and accumulation were taken from the mid-layer at the segregation zone and the top-layer of the first batch of X70-1 steel. The top-layer of another batch of steel, X70-2, was used to study the effect of misorientation on hydrogen diffusion and accumulation.
Hydrogen permeation experiment, in X70-1 steel, allowed in concluding that the permeability increased for larger grain sizes in both layers of steel. Also, the density of total, reversible, and irreversible hydrogen trapping sites of top-layer decreased for larger grains. However, the irreversible and total trapping sites of mid-layer showed an initial growth and subsequent decay with an increase in grain size. The hydrogen permeation experiment, in X70-2 steel, allowed in concluding that the permeability and effective diffusion coefficient decreased with an increase in grain misorientation. Also, the density of total and irreversible trapping sites increased with an increase in grain misorientation. The conclusions from hydrogen permeation experiments were validated with hydrogen microprint technique results. Grain boundaries, triple junctions and deformed grains in the steel microstructure are considered as reversible trapping sites due to their superior hydrogen diffusion in hydrogen microprint experiments. Also, preferential hydrogen diffusion through steel microstructure increased in the order of non-deformed grains, grain boundaries, inclusion interfaces, triple junctions, cementites and matrix-inclusion interfaces with matrix-inclusion interfaces being the easy path for diffusion. The analysis of hydrogen microprint technique results also allowed in concluding that the presence and absence of a circular pattern of superimposed white silver particles around inclusions and precipitates is a method to distinguish the type of hydrogen traps in materials.
Degree
Master of Science (M.Sc.)Department
Mechanical EngineeringProgram
Mechanical EngineeringCommittee
Odeshi, Akindele; Oguocha, Ikechukwuka N.; Bradley, Michael P.Copyright Date
November 2019Subject
Pipeline steel
Hydrogen Diffusion
Hydrogen Accumulation
Hydrogen Permeation
Hydrogen Microprint Technique
Grain Size, Grain Misorientation
Hydrogen Traps
Cold Rolling
Annealing
Collections
Related items
Showing items related by title, author, creator and subject.
-
THE EXPERIMENTAL AND THEORETICAL INVESTIGATION OF THE HYDROGEN SULFIDE SPLITTING CYCLE FOR HYDROGEN PRODUCTION
Moniri, Armin 1981- (2015-05-28)In Dr. Hui Wang’s research group at the University of Saskatchewan, an H2S splitting cycle was earlier developed as a novel method to convert H2S, a significant waste product in the oil and gas industry, to hydrogen, which ... -
Optimization of transition metal nanoparticle- phosphonium IL composite catalytic systems for deep hydrogenation and hydrodeoxygenation reactions
Banerjee, Abhinandan; Scott, Robert WJ (Royal Society of Chemistry, 2015)A variety of metal nanoparticle (NP)/tetraalkylphosphonium ionic liquid (IL) composite systems were evaluated as potential catalysts for the deep hydrogenation of aromatic molecules. Particles were synthesized by reducing ... -
Supercritical water gasification of lignocellulosic biomass materials for hydrogen production
Okolie, Jude Awele; 0000-0001-9769-7307 (2021-07-15)The primary aim of this research is to optimize supercritical water gasification process operating conditions and develop a cost effective heterogeneous catalyst to reduce reaction temperature and improve H2 yield. ...