Erosion-corrosion and its mitigation on the internal surface of the expansion segment of N80 steel tube

Erosion-corrosion is an ineluctable flow assurance problem confronted in hydrocarbon transportation and production systems. In this work, the effect of sand fines velocity on the erosion-corrosion behavior of AISI 1018 carbon steel long radius 90° elbows was experimentally and numerically investigated for liquid-solid flow conditions. Experiments were effectuated for sand fines of mean diameter 50 µm circulated in a flow loop with three different velocities (0.5, 1 and 2 m/s). To elucidate the erosion-corrosion mechanism and degradation rate, the material loss analysis, multilayer paint modeling (MPM) and microscopic imaging technique were employed, with computational fluid dynamics (CFD) and discrete phase modeling (DPM) also capacitating to evaluate the erosion distribution. It was perceived that increasing slurry velocity significantly changes the particle-wall impaction mechanism, leading to an increase in material degradation in the elbow bottom section up to 2 times in comparison to the low transport velocity. The erosion scars and pits development at the elbows internal surface was found to govern the wear mechanism in the carbon steel and made downstream section susceptible to erosion and corrosion. The material removal mechanisms were ascertained to change from cutting to pitting and plastic deformation with an increase of sand fines transportation velocity from 0.5 m/s to 2 m/s.

Download Full-text

Microstructure, mechanical properties and corrosion of ceramic-lined composite steel pipe prepared by centrifugal-SHS process

Science of Sintering ◽

10.2298/sos1704359a ◽

2017 ◽

Vol 49 (4) ◽

pp. 359-372 ◽

Cited By ~ 1

Author(s):

Jian An ◽

Xiaohan Yan ◽

Xiaoxia Lv ◽

Zi Wen

Keyword(s):

Mechanical Properties ◽

Centrifugal Casting ◽

Steel Tube ◽

Ceramic Layer ◽

Steel Pipe ◽

Casting Technique ◽

N80 Steel ◽

High Temperature Synthesis ◽

Wear And Corrosion ◽

Composite Steel

A ceramic-lined composite steel pipe (CLCSP) was fabricated with N80 steel tube as substrate by self-propagating high-temperature synthesis and centrifugal casting technique. The constituent phases and microstructure of the ceramic layer were analyzed, and the mechanical properties of CLCSP were measured, including hardness, crashing strength, compression-shear strength and tensile performance. The wear and corrosion behaviors between CLCSP and N80 steel tube were also compared. The results show that ceramic layer consists of columnar dendrites of Al2O3 and spinel-like structure FeAl2O4, CLCSP has a much higher hardness, squeezing deformation resistance, wear and corrosion resistance as compared with N80 steel tube.

Download Full-text

What catalysis needs from the electron microscopist

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105539 ◽

1988 ◽

Vol 46 ◽

pp. 694-695

Author(s):

Alexis T. Bell

Keyword(s):

Active Sites ◽

Heterogeneous Catalysts ◽

Catalyst Deactivation ◽

Surface Composition ◽

Internal Surface ◽

Active Phase ◽

Atomic Scale ◽

Metal Catalyst ◽

Internal Surface Area ◽

Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

Download Full-text

The distribution and density of ciliary tufts on the siphons of Anodonta cygnea (Mollusca: Bivalvia)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160145 ◽

1990 ◽

Vol 48 (3) ◽

pp. 518-519

Author(s):

Wen-lung Wu

Keyword(s):

Osmium Tetroxide ◽

Internal Surface ◽

Mechanical Stimuli ◽

Type Ii ◽

Sensory Receptors ◽

Anodonta Cygnea ◽

Type Iv ◽

Sem Study ◽

Inhalant Siphon ◽

Type V

The mantle of bivalves has come entirely to enclose the laterally compressed body and the mantle margin has assumed a variety of functions, one of the pricipal ones being sensory. Ciliary tufts, which are probably sensory, have been reported from the mantle and siphons of several bivalves1∽4. Certain regions of the mantle margin are likely to be more or less, sensitive to certain stimuli than others. The inhalant siphon is likely to be particularly sensitive to both chemical and mechanical stimuli, whereas the exhalant siphon will be less sensitive to both. The distribution and density of putative sensory receptors on the in-and ex-halant siphon is compared in this paper.The excised siphons were fixed in glutaraldehyde and osmium tetroxide, the whole procedure of SEM study is recorded in Wu's thesis.Type II cilia cover the tips of tentacles, 6.13um. Type IV and type V cilia are found on the surface of tentacles. Type IV cilia are occasionally present at the tips of tentacles, 8 um long. They are the commonest type on the surface of tentacles. Type VI cilia occor in the internal surface of the inhalant siphon, but are not found on the surface of tentacles, 6.7-10um long.

Download Full-text