Heat-Traced Pipelines: A Double-Containment Solution for a High-Temperature Pipeline

2014 ◽  
Author(s):  
Christian Geertsen
Keyword(s):  
High Temperature ◽  
High Risk ◽  
Mass Balance ◽  
Heat Loss ◽  
Surveillance System ◽  
Thermal Stresses ◽  
Insulation System ◽  
External Anchor ◽  
Northern Alberta ◽  
Multiple Obstacles

A pipe-in-pipe (PiP) technology was selected to transport hot fluids through muskeg and multiple obstacles dealt with Horizontal Directional Drillings (HDDs) in Northern Alberta. The system offers both integrity and construction advantages. • The outer pipe provides an obvious secondary barrier to any leak. It also provides the basis for a surveillance system with a sensitivity more than 1000 times the sensitivity provided by the standard mass-balance. • The system is pre-constrained: the inner pipe is pre-heated using electrical heat tracing at a temperature such that the system, once installed, has thermal stresses reduced by half and thus permits the installation of the high-temperature pipeline in non-competent soils with no expansion loop and no external anchor. • The insulation system between the two pipes reduces the heat loss to only 0.3 W/(m2.K), leading to a very long cool down time. Finally, the pipe-in-pipe can be a simple solution to high-risk and/or high scrutiny areas such as HDDs, sensitive wetlands, unstable soils, etc.

A Multiscale NDT System for Damage Detection in Thermal Barrier Coatings

2009 ◽  
Author(s):  
A. M. G. Luz ◽  
D. Balint ◽  
K. Nikbin
Keyword(s):  
High Temperature ◽  
Damage Detection ◽  
Luminescence Spectrum ◽  
Bond Coat ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Assessment Tool ◽  
Diagnostic Tools ◽  
Spectral Parameters ◽  
Temperature Oxidation

Progress in aero-engines and land-based gas turbines is continuously linked with a rise of the operating temperature. TBCs are multilayered structures which function together to effectively lower the temperature of its load-bearing superalloy substrate while simultaneously providing oxidation protection against high temperature combustion environments during operation. They typically comprise of a ceramic top coat for thermal insulation and a metallic bond coat that provides oxidation/corrosion resistance and enhances the adhesion of the YSZ to the superalloy substrate. Due to high-temperature oxidation of the bond coat, a thermally grown oxide (TGO) scale of continuous Al2O3 is formed between the ceramic top coat and the bond coat. The formation and growth of the TGO increases the mismatch of thermal expansion coefficients among the multilayered TBC and induce high thermal stresses leading to spallation of the YSZ coat from the underlying metal. Hence, nondestructive diagnostic tools that could reliably probe the subsurface damage state of TBCs are essential to take full advantage of these systems. In this contribution, a new concept of multiscale NDT system is presented. The instrument uses a combination of imaging-based methods with photoluminescence piezospectroscopy, a laser-based method. Imaging-based methods like mid-infrared reflectance, laser optical backscatter and infrared tomography were used to predict the overall lifetime of the coated component. When TBCs approach the end of life, micro-crack nucleation and propagation at the top coat/bond coat interface increases the amount of reflected light. This rise in reflectance was correlated with the lifetime of the component using a neural network that merges the mean and standard deviation value of the gray level. Photoluminescence piezospectroscopy was subsequently used to give information about the structural integrity of the hot spots identified in the image analysis. This laser-based technique measures in-situ the residual stress in the TGO at room temperature. Damage leads to a relaxation of the local stress which is in turn reflected in the luminescence spectrum shape. However, presently there is no agreement on the best spectral parameters that should be used as a measure of the damage accumulation in the coatings. Therefore, the evolution of luminescence spectrum from as-manufactured to critically damaged TBCs was determined using the finite element method. This approach helped to identify the most suitable spectral parameters for damage detection, improving the reliability of photoluminescence piezospectroscopy as a failure assessment tool for TBCs.

Healthcare-associated infections in high-risk neonates: Temporal trends in a national surveillance system

2021 ◽  
pp. 105394
Author(s):  
Ralciane P. Menezes ◽  
Sávia G.O. Melo ◽  
Murilo B. Oliveira ◽  
Felipe F. Silva ◽  
Priscila G.V. Alves ◽  
...  
Keyword(s):  
High Risk ◽  
Surveillance System ◽  
Temporal Trends ◽  
Healthcare Associated Infections ◽  
National Surveillance ◽  
Healthcare Associated ◽  
National Surveillance System

Transient Analysis of a Ceramic High Temperature Heat Exchanger and Chemical Decomposer

2007 ◽  
Author(s):  
Valery Ponyavin ◽  
Taha Mohamed ◽  
Mohamed Trabia ◽  
Yitung Chen ◽  
Anthony E. Hechanova
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Heat Exchanger ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Failure Criteria ◽  
Operating Conditions ◽  
Finite Element Software ◽  
Micro Channels ◽  
Temperature Heat

Ceramics are suitable for use in high temperature applications as well as corrosive environment. These characteristics were the reason behind selection silicone carbide for a high temperature heat exchanger and chemical decomposer, which is a part of the Sulphur-Iodine (SI) thermo-chemical cycle. The heat exchanger is expected to operate in the range of 950°C. The proposed design is manufactured using fused ceramic layers that allow creation of micro-channels with dimensions below one millimeter. A proper design of the heat exchanges requires considering possibilities of failure due to stresses under both steady state and transient conditions. Temperature gradients within the heat exchanger ceramic components induce thermal stresses that dominate other stresses. A three-dimensional computational model is developed to investigate the fluid flow, heat transfer and stresses in the decomposer. Temperature distribution in the solid is imported to finite element software and used with pressure loads for stress analysis. The stress results are used to calculate probability of failure based on Weibull failure criteria. Earlier analysis showed that stress results at steady state operating conditions are satisfactory. The focus of this paper is to consider stresses that are induced during transient scenarios. In particular, the cases of startup and shutdown of the heat exchanger are considered. The paper presents an evaluation of the stresses in these two cases.

scholarly journals Probability Study on the Thermal Stress Distribution in Thick HK40 Stainless Steel Pipe Using Finite Element Method

Designs ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 9
Author(s):  
Sujith Bobba ◽  
Shaik Abrar ◽  
Shaik Mujeebur Rehman
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
High Temperature ◽  
Material Properties ◽  
Thermal Stresses ◽  
Steel Pipe ◽  
Stress Distributions ◽  
Stainless Steel Pipe ◽  
Deterministic Solution ◽  
Analytical Expressions

The present work deals with the development of a finite element methodology for obtaining the stress distributions in thick cylindrical HK40 stainless steel pipe that carries high-temperature fluids. The material properties and loading were assumed to be random variables. Thermal stresses that are generated along radial, axial, and tangential directions are generally computed using very complex analytical expressions. To circumvent such an issue, probability theory and mathematical statistics have been applied to many engineering problems, which allows determination of the safety both quantitatively and objectively based on the concepts of reliability. Monte Carlo simulation methodology is used to study the probabilistic characteristics of thermal stresses, and was implemented to estimate the probabilistic distributions of stresses against the variations arising due to material properties and load. A 2-D probabilistic finite element code was developed in MATLAB, and the deterministic solution was compared with ABAQUS solutions. The values of stresses obtained from the variation of elastic modulus were found to be low compared to the case where the load alone was varying. The probability of failure of the pipe structure was predicted against the variations in internal pressure and thermal gradient. These finite element framework developments are useful for the life estimation of piping structures in high-temperature applications and for the subsequent quantification of the uncertainties in loading and material properties.

scholarly journals Using an Open GIS Framework and Epidemiological Intelligence for Dengue Surveillance

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Ta-Chien Chan ◽  
Bo-Cheng Lin ◽  
Chiao-Ling Kuo ◽  
Li-hsiang Chiang
Keyword(s):  
Public Health ◽  
High Risk ◽  
Dengue Fever ◽  
Surveillance System ◽  
Health Workers ◽  
Open Data ◽  
Outbreak Investigation ◽  
First Line ◽  
Public Health Workers ◽  
Risk Areas

Objective: In this paper we designed one cross-platform surveillance system to assist dengue fever surveillance, outbreak investigation and risk management of dengue fever.Introduction:In the 2015 dengue outbreak in Taiwan, 43,784 people were infected and 228 died, making it the nation’s largest outbreak ever. Facing the increasing threat of dengue, the integration of health information for prevention and control of outbreaks becomes very important. Based on past epidemics, the areas with higher incidence of dengue fever are located in southern Taiwan. Without a smart and integrated surveillance system, the information on case distribution, high risk areas, mosquito surveillance, flooding areas and so on is fragmented. The first-line public health workers need to check all this information through different systems manually. When outbreaks occurred, paper-based outbreak investigation forms had to be prepared and filled in by public health workers. Then, they needed to enter part of this information into Taiwan CDC’s system. Duplicated work occurred and cost lots of labor time during the epidemic period. Therefore, we choose one rural county, Pingtung County, with scarce financial resources, to set up a new dengue surveillance system.Methods: We designed a web-based cross-platform system based on an open geographical information system (GIS) framework including Openlayers, Javascript, PHP, MySQL and open data from government open data in Taiwan. There were seven epidemiological intelligence functions within the system including risk management, outbreak investigation, planning controlled areas, intelligent detection of high-risk areas, useful tools for decision making, historical epidemics, and system management. The website was developed by responsive web design which can let public health workers check information and fill in the investigation form by any devices.Results: The system was promptly set up in June 2016. With first-line public health workers’ efforts and the help of the surveillance system, there were no indigenous dengue fever cases after the system was implemented. There were sporadic imported cases from south-east Asia. The dengue surveillance system achieved three major improvements: integration of all decision support information; digitalization and automation of outbreak investigation; and planning the control areas. The results on outbreak investigation and mosquito surveillance can directly transfer to Taiwan CDC’s database by Web Application Programming Interface (API). It can avoid duplicated work for disease surveillance.Conclusions: Through introducing the new dengue surveillance system into local health departments, first-line public health workers can update all epidemic information at the same time. During epidemic periods, it can provide demographic, epidemiological, environmental, and entomological information for decision making. During non-epidemic periods, it can highlight the high risk areas for enhanced surveillance to reduce the risk of outbreaks.

Assembly of Bolted Flanged and Support Joints for Use in Elevated Temperature Exhaust Systems

2018 ◽  
Author(s):  
Jason E. Dorgan ◽  
Agron E. Gjinolli
Keyword(s):  
High Temperature ◽  
Best Practice ◽  
Thermal Stresses ◽  
Exhaust System ◽  
Metal Plate ◽  
Industry Standard ◽  
Metal On Metal ◽  
Industry Practice ◽  
Gasket Material

Ancillary exhaust system structural design for turbines typically employs a separation of responsibilities between the design and installation functions. The design expectations must be implemented correctly during the installation phase to allow long-term serviceability and success of the turbine exhaust system. This paper will explore a case study reviewing bolt tightening of duct structural angle and plate flange joints using compressible high temperature fiberglass gasket material, as well as design suggestions for metal-on-metal duct sliding support joints to structural steel. Improper design and operation can lead to failure, downtime, warranty cost and reduced design life of the exhaust system. It is not uncommon for field installation personnel to modify key system design requirements during the installation phase; typically out of habit, perceived best practice, missed installation instructions and/or misunderstanding the system behavior. In addition, maintenance recommendations are often overlooked. Literature provides extensive background for bolting of stationary metal-to-metal plate joints, rigid gaskets and pressure vessel joints. There is a gap with respect to structural angle and plate flange joint bolt tensioning using compressible fiberglass gaskets at low pressures and high temperatures. Much of the industry standard tightening philosophy is useful, but has not been extensively studied and written about with respect to flanges under high exhaust temperatures or for sliding joints exposed to thermal expansion. This paper summarizes current industry practice, presents relevant test data and a case study, analyzes the effects of high thermal stresses, and recommends a tightening procedure for typical field applications of flange joints using high temperature gaskets, and the design of metal-to-metal sliding support joints.

Fabrication of Grade 91 Materials Experience in Oil and Gas Applications

2020 ◽  
Author(s):  
Bhadresh A. Prajapati ◽  
Jorge A. Penso
Keyword(s):  
High Temperature ◽  
Success Factors ◽  
Thermal Stresses ◽  
National Laboratory ◽  
Welding Parameters ◽  
Steam Generation ◽  
Creep Ductility ◽  
Ethane Conversion ◽  
Oak Ridge ◽  
Grade 91

Abstract A modified 9-Cr alloy was developed by Oak Ridge National Laboratory, in early 1980s, to increase high temperature capabilities of ferritic steels for superheater tubing. The material improved high temperature creep properties by controlling alloying elements and microstructure. The material was added to ASME BPVC in 1983 (thru Code Case 1943) as Grade 91. Higher yield and tensile strength, in comparison to other low-Cr alloy steels (like Grade 22), allowed for fabrication of thinner component wall thickness. This in-turn reduced susceptibility to through-wall thermal stresses during transient events. Directionally this also reduced material costs. Consequently, petrochemical industries have utilized Grade 91 in applications at Heat Recovery Steam Generation units (HRSG), Steam Methane Reformers (SMR), CO2 Boilers and as convection coils in Ethane conversion units. Grade 91 material has complex microstructure and requires careful control of welding parameters to assure crack free welds that provide adequate creep ductility and retain creep strength at high temperatures. The current guidelines documented in API 582 and Technical Report 938 provide limited insights on success factors for weldability. Grade 91 material use has been growing in the recent past Petrochemicals Complex and in offshore applications, at once-throw steam generators (OTSG). The aim of this paper is to share experience on welding parameters. Guidance needs be adjusted to specific projects and repair activities.

Computational Models for High-Temperature Multilayered Composite Plates and Shells

1992 ◽  
Vol 45 (10) ◽  
pp. 419-446 ◽  
Author(s):  
Ahmed K. Noor ◽  
W. Scott Burton
Keyword(s):  
High Temperature ◽  
Computational Models ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Composite Plates ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Composite Models ◽  
Sandwich Plates And Shells ◽  
Plates And Shells

The focus of this review is on the hierarchy of composite models, predictor-corrector procedures, the effect of temperature-dependence of material properties on the response, and the sensitivity of the thermomechanical response to variations in material parameters. The literature reviewed is devoted to the following eight application areas: Heat transfer; thermal stresses; curing, processing and residual stresses; bifurcation buckling; vibrations of heated plates and shells; large deflection and postbuckling problems; and sandwich plates and shells. Extensive numerical results are presented showing the effects of variation in the lamination and geometric parameters of temperature-sensitive angle-ply composite plates on the accuracy of thermal buckling response, and the sensitivity derivatives predicted by nine different modeling approaches (based on two-dimensional theories). The standard of comparison is taken to be the exact three-dimensional thermoelasticity solutions. Some future directions for research on the modeling of high-temperature multilayered composites are outlined.

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