Assessment of Weld Overlay Defects in a Hydrocracking Unit Reactor

2013 ◽  
Author(s):  
Mohammed S. Robai ◽  
Jarallah A. Al-Sudairy ◽  
Abdullah M. Al-Harbi ◽  
Joy Joseph
Keyword(s):  
Stainless Steel ◽  
Performance Management ◽  
Base Material ◽  
Material Degradation ◽  
Safe Operation ◽  
Weld Overlay ◽  
Temperature And Pressure ◽  
Operational Excellence ◽  
Very High

Asset Performance Management is a key element of operational excellence. It refers to the management systems, strategies and activities aimed at maintaining the integrity of plant assets for their desired life. The safe operation of the assets is to be ensured at any cost. The objective of this paper is to offer one of the most critical assets in a refinery, namely the Hydrocracking Unit (HCU) reactor, as a case study addressing assessment of defects found in the weld overlay. The reactor was built in 1978 according to ASME Sec. VIII Div. 2 and has been in operation since then. The reactor is constructed of Chromium-Molybdenum (Cr-Mo) base material (SA 336 F21) with thickness of 266 mm and corrosion resistant stainless steel (TP-347 with thickness of 3.2 mm) weld overlay. The very high operating temperature and pressure of the reactor in hydrogen rich hydrocarbon service and the resulting thermal stress and material degradation caused disbonding and cracks in the stainless steel weld overlay. This paper will address the approach that was used to alleviate such type of defects. Also, various considerations that go into the assessment are discussed and recommendations are suggested.

Guidelines for Repair Welding of Pressure Equipment in Refineries and Chemical Plants: Part 4—Weld Repair for Specific Materials - Stainless Steel, Clad Steel and Dissimilar Joints

2011 ◽  
Author(s):  
Tsukasa Okazaki ◽  
Rinzo Kayano ◽  
Takahisa Hoshika ◽  
Shinta Niimoto
Keyword(s):  
Stainless Steel ◽  
Chemical Plants ◽  
Safe Operation ◽  
Weld Repair ◽  
Dissimilar Joints ◽  
Weld Overlay ◽  
Repair Welding ◽  
Engineering Society ◽  
Clad Steel

It has been recognized that repair welding plays an important role in the long term, safe operation of pressure equipment. In 2009, the Japan Welding Engineering Society (JWES) published guidelines for repair welding of pressure equipment to meet the great need for the safe operation and proper maintenance of aging plants. This paper describes Part 4 of the guideline, which covers repair welding of stainless steel, clad steel, weld overlay and dissimilar joints.

Case Study of the Surface Cracking of Austenite Stainless Steel Weld Overlay Cladding in Hydrogen Environment

2016 ◽  
Author(s):  
Xufeng Li ◽  
Kesheng Ou ◽  
Lei Wang ◽  
Jiong Zheng ◽  
Weijian Luo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Difficult Problem ◽  
Steel Weld ◽  
Weld Overlay ◽  
Surface Cracking ◽  
Austenite Stainless Steel ◽  
Hydrogen Environment ◽  
Stainless Steel Weld ◽  
Defect Elimination

Austenite stainless steel weld overlay cladding is widely used for the equipments working in pressurized hydrogen environment such as hydrogenation reactors. Surface cracking is a basic failure mode of the weld overlay cladding, and also a quite difficult problem for safety assessment and defect elimination. In this paper, two cases of surface cracking of austenite stainless steel weld overlay cladding are introduced. Firstly, the inspection results and cracking causes are analyzed in detail. Secondly, two kinds of treatment methods for the defects are introduced. Finally, some suggestions for inspection and assessment of surface cracking of weld overlay cladding are proposed.

Some aspects of the defect structure in an austenitic stainless steel

1978 ◽  
Vol 36 (1) ◽  
pp. 314-315
Author(s):  
R. Gonzalez ◽  
L. Bru
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cellular Structures ◽  
Total Strain Amplitude ◽  
Total Deformation ◽  
Density Of Dislocations ◽  
Planar Arrays ◽  
Stacking Fault Tetrahedra ◽  
Distribution Of Dislocations ◽  
Very High

The analysis of stacking fault tetrahedra (SFT) in fatigued metals (1,2) is somewhat complicated, due partly to their relatively low density, but principally to the presence of a very high density of dislocations which hides them. In order to overcome this second difficulty, we have used in this work an austenitic stainless steel that deforms in a planar mode and, as expected, examination of the substructure revealed planar arrays of dislocation dipoles rather than the cellular structures which appear both in single and polycrystals of cyclically deformed copper and silver. This more uniform distribution of dislocations allows a better identification of the SFT.The samples were fatigue deformed at the constant total strain amplitude Δε = 0.025 for 5 cycles at three temperatures: 85, 293 and 773 K. One of the samples was tensile strained with a total deformation of 3.5%.

Pyrolysis of brown algae (Bifurcaria Bifurcata) in a stainless steel tubular reactor: From a review to a case study

2018 ◽  
Vol 14 (1) ◽  
pp. 31-60 ◽  
Author(s):  
M. Y. Guida ◽  
F. E. Laghchioua ◽  
A. Hannioui
Keyword(s):  
Particle Size ◽  
Stainless Steel ◽  
Flow Rate ◽  
Brown Algae ◽  
Tubular Reactor ◽  
Nitrogen Flow ◽  
Nitrogen Flow Rate ◽  
Bifurcaria Bifurcata ◽  
Bio Oil

This article deals with fast pyrolysis of brown algae, such as Bifurcaria Bifurcata at the range of temperature 300–800 °C in a stainless steel tubular reactor. After a literature review on algae and its importance in renewable sector, a case study was done on pyrolysis of brown algae especially, Bifurcaria Bifurcata. The aim was to experimentally investigate how the temperature, the particle size, the nitrogen flow rate (N2) and the heating rate affect bio-oil, bio-char and gaseous products. These parameters were varied in the ranges of 5–50 °C/min, below 0.2–1 mm and 20–200 mL. min–1, respectively. The maximum bio-oil yield of 41.3wt% was obtained at a pyrolysis temperature of 600 °C, particle size between 0.2–0.5 mm, nitrogen flow rate (N2) of 100 mL. min–1 and heating rate of 5 °C/min. Liquid product obtained under the most suitable and optimal condition was characterized by elemental analysis, 1H-NMR, FT-IR and GC-MS. The analysis of bio-oil showed that bio-oil from Bifurcaria Bifurcata could be a potential source of renewable fuel production and value added chemicals.

ALLVAC 13-8

Alloy Digest ◽  
2002 ◽  
Vol 51 (11) ◽  
Keyword(s):  
Stainless Steel ◽  
Precipitation Hardening ◽  
Cold Working ◽  
High Strength ◽  
Heat Treating ◽  
General Corrosion ◽  
Single Treatment ◽  
Good Resistance ◽  
Temperature Performance ◽  
Very High

Abstract Allvac 13-8 has good fabricability and can be age hardened by a single treatment in the range 510-620 deg C (950-1150 deg F). Cold working prior to aging enhances the aging. This martensitic precipitation-hardening stainless steel has very good resistance to general corrosion and stress-corrosion cracking. It develops very high strength and exhibits good transverse ductility and toughness in heavy sections. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-866. Producer or source: Allvac Metals Company.

NAS 74N

Alloy Digest ◽  
2010 ◽  
Vol 59 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Crevice Corrosion ◽  
Heat Treating ◽  
Super Duplex Stainless Steel ◽  
Duplex Microstructure ◽  
Temperature Performance ◽  
Resistance To Stress ◽  
Very High

Abstract NAS 74N is a super duplex stainless steel with very high molybdenum for pitting and crevice corrosion resistance and a duplex microstructure for resistance to stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1070. Producer or source: Nippon Yakin Kogyo Company Ltd.

CSS-42L VIM-VAR

Alloy Digest ◽  
2014 ◽  
Vol 63 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Physical Properties ◽  
Heat Treating ◽  
Steel Company ◽  
Specialty Steel ◽  
Very High

Abstract CSS-42L is a stainless steel containing good contents of cobalt and molybdenum. It can be case hardened to very high levels while maintaining good interior toughness and ductility. This datasheet provides information on composition and physical properties as well as fracture toughness. It also includes information on forming and heat treating. Filing Code: SS-1171. Producer or source: Latrobe Specialty Steel Company.

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

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