Investigation of Bulging Behavior of Coke Drum—A Practical Analysis of Bulging Under Complex Quench Conditions

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Toshiya Yamamoto ◽  
Kazuaki Arii ◽  
Shinta Niimoto ◽  
Mitsuru Ohata ◽  
Tetsuya Tagawa ◽  
...  
Keyword(s):  
Temperature Profile ◽  
Cooling Water ◽  
Fe Analysis ◽  
Temperature Fields ◽  
Large Strains ◽  
Analysis Model ◽  
Actual Operation ◽  
Feasible Study ◽  
Temperature Strain ◽  
Rapid Drop

Coke drums undergo cyclic operations typically in the temperature range from room temperature to about 500 °C (930 °F). During quenching, the coke drum is inevitably subjected to a rapid drop in temperature because cooling water is injected directly into the coke drum through the bottom inlet nozzle. The temperature profile on the shell surface is uneven during quenching, and can vary in each cycle of the quenching operation. Such a complicated thermal profile induces large strains in the shell portion of the coke drum, and eventually causes damage like bulging and/or cracking. The authors have investigated the bulging behavior of the coke drum by the thermal elastic-plastic finite element (FE)-analysis, considering the existence of the overmatch welds and uneven temperature field during quenching (Ohata et al., 2011, “Investigation of Bulging Behavior of Coke Drum—Feasible Study on Causes of Bulging,” ASME PVP2011-57276, Baltimore). In this paper, a practical FE-analysis is developed to estimate the complex strain that leads to bulging under uneven temperature fields during quenching. The actual temperature and strain data during operation are collected by thermocouples and high temperature strain gauges. A thermal analysis model, including an evaluation of boiling heat transfer on the shell's inner surface, is established to simulate the measured shell behavior of the coke drum. By utilizing this FE-analysis model, several parameters thought of as causal factors in bulging can be examined under the uneven temperature profile that is likely to occur during actual operation. This analytical approach can also provide effective technique for improvements in shell durability.

Investigation of Bulging Behavior of Coke Drum: A Practical Analysis of Bulging Under Complex Quench Conditions

2011 ◽  
Author(s):  
Toshiya Yamamoto ◽  
Kazuaki Arii ◽  
Huhetaoli ◽  
Shinta Niimoto ◽  
Mitsuru Ohata ◽  
...  
Keyword(s):  
Temperature Profile ◽  
Cooling Water ◽  
Fe Analysis ◽  
Temperature Fields ◽  
Large Strains ◽  
Analysis Model ◽  
Strain Data ◽  
Actual Operation ◽  
Temperature Strain ◽  
Rapid Drop

Coke drums undergo cyclic operations typically in the temperature range from room temperature to about 500°C (930°F). During quenching, the coke drum is inevitably subjected to a rapid drop in temperature because cooling water is injected directly into the coke drum through the bottom inlet nozzle. The temperature profile on the shell surface is uneven during quenching, and can vary in each cycle of the quenching operation. Such a complicated thermal profile induces large strains in the shell portion of the coke drum, and eventually causes damage like bulging and/or cracking. The authors have investigated the bulging behavior of the coke drum by the thermal elastic-plastic FE-analysis, considering the existence of the overmatch welds and uneven temperature field during quenching [1]. In this paper, a practical FE-analysis is developed to estimate the complex strain that leads to bulging under uneven temperature fields during quenching. The actual temperature and strain data during operation are collected by thermocouples and high temperature strain gauges. A thermal analysis model, including an evaluation of boiling heat transfer on the shell’s inner surface, is established to simulate the measured shell behavior of the coke drum. By utilizing this FE-analysis model, several parameters thought of as causal factors in bulging can be examined under the uneven temperature profile that is likely to occur during actual operation. This analytical approach can also provide effective technique for improvements in shell durability.

Investigation of Bulging Behavior of Coke Drum: Feasible Study on Causes of Bulging

2011 ◽  
Author(s):  
Mitsuru Ohata ◽  
Nana Kawai ◽  
Tetsuya Tagawa ◽  
Fumiyoshi Minami ◽  
Toshiya Yamamoto ◽  
...  
Keyword(s):  
Temperature Field ◽  
Ambient Temperature ◽  
Temperature Profile ◽  
Shell Structure ◽  
Cooling Water ◽  
Fe Analysis ◽  
Large Strains ◽  
Shell Surface ◽  
Feasible Study ◽  
Rapid Drop

Coke drums undergo cyclic operations typically in the temperature range from ambient temperature to about 500°C (930°F). During quenching, the coke drum is inevitably subjected to a rapid drop in temperature because cooling water is injected directly into the coke drum through the bottom inlet nozzle. The temperature profile on the shell surface is no more uneven in quenching, and can vary in each cycle of quenching operation. Such complicate thermal profile induces large strains in the shell portion of the coke drum, and eventually causes damage like bulging or cracking. This study makes investigations into the bulging behavior of the coke drum by the thermal elastic-plastic FE-analysis. In this work, a feasible study is conducted on potential causes of bulging. As factors inducing a heterogeneous plasticity in the shell structure of the coke drum, the strength overmatch of welds and the uneven temperature field in quenching as well as quenching conditions are focused.

Investigation of Bulging Behavior of Coke Drum: Feasible Study on Causes of Bulging

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Mitsuru Ohata ◽  
Nana Kawai ◽  
Tetsuya Tagawa ◽  
Fumiyoshi Minami ◽  
Toshiya Yamamoto ◽  
...  
Keyword(s):  
Cooling Water ◽  
Large Strains ◽  
Shell Wall ◽  
Shell Surface ◽  
Operating Cycle ◽  
Plastic Distortion ◽  
Rate Of Cooling ◽  
Analytical Result ◽  
Feasible Study ◽  
Rapid Drop

Coke drums undergo cyclic operations typically in the temperature range from ambient temperature to about 500 °C (930 °F). During quenching, the coke drum is inevitably subjected to a rapid drop in temperature because cooling water is injected directly into the coke drum through the bottom inlet nozzle. The temperature profile on the shell surface is no more uneven in quenching, and can vary in each cycle of quenching operation. Such complicate thermal profile induces large strains in the shell portion of the coke drum, and eventually causes damage like bulging or cracking. This study makes investigations into the bulging behavior of the coke drum by the thermal elastic-plastic FE-analysis. In this work, a feasible study is conducted on potential causes of bulging. As factors inducing a heterogeneous plasticity in the shell structure of the coke drum, the strength overmatch of welds and the uneven temperature field in quenching as well as quenching conditions are focused. The analytical result shows that strength overmatch in girth seam welds can be one of the causes of plastic distortion under one operating cycle. The lower rising rate of cooling source can induce plastic straining over the whole shell wall, which tends to induce more remarkable plastic distortion.

scholarly journals Insights into Machining of a β Titanium Biomedical Alloy from Chip Microstructures

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 710 ◽  
Author(s):  
Damon Kent ◽  
Rizwan Rahman Rashid ◽  
Michael Bermingham ◽  
Hooyar Attar ◽  
Shoujin Sun ◽  
...  
Keyword(s):  
Shear Band ◽  
Shear Zone ◽  
Biomechanical Properties ◽  
Temperature Fields ◽  
Large Strains ◽  
Shear Direction ◽  
Grain Sizes ◽  
Β Phase ◽  
Secondary Shear Zone ◽  
Cutting Speeds

New metastable β titanium alloys are receiving increasing attention due to their excellent biomechanical properties and machinability is critical to their uptake. In this study, machining chip microstructure has been investigated to gain an understanding of strain and temperature fields during cutting. For higher cutting speeds, ≥60 m/min, the chips have segmented morphologies characterised by a serrated appearance. High levels of strain in the primary shear zone promote formation of expanded shear band regions between segments which exhibit intensive refinement of the β phase down to grain sizes below 100 nm. The presence of both α and β phases across the expanded shear band suggests that temperatures during cutting are in the range of 400–600 °C. For the secondary shear zone, very large strains at the cutting interface result in heavily refined and approximately equiaxed nanocrystalline β grains with sizes around 20–50 nm, while further from the interface the β grains become highly elongated in the shear direction. An absence of the α phase in the region immediately adjacent to the cutting interface indicates recrystallization during cutting and temperatures in excess of the 720 °C β transus temperature.

Analytical Formulation for the Temperature Profile by Duhamel’s Theorem in Bodies Subjected to an Oscillatory Heat Source

2005 ◽  
Vol 129 (2) ◽  
pp. 236-240 ◽  
Author(s):  
Jun Wen ◽  
M. M. Khonsari
Keyword(s):  
Finite Element Method ◽  
Heat Flux ◽  
Heat Source ◽  
Temperature Profile ◽  
Rectangular Domain ◽  
Temperature Fields ◽  
Heat Sources ◽  
Point Heat Source ◽  
Analytical Formulation ◽  
Analytical Technique

An analytical technique is presented for treating heat conduction problems involving a body experiencing oscillating heat flux on its boundary. The boundary heat flux is treated as a combination of many point heat sources, each of which emits heat intermittently based on the motion of the flux. The working function of the intermittent heat source with respect to time is evaluated by using the Fourier series and temperature profile of each point heat source is derived by using the Duhamel’s theorem. Finally, by superposition of the temperature fields over all the point heat sources, the temperature profile due to the original moving heat flux is determined. Prediction results and verification using finite element method are presented for an oscillatory heat flux in a rectangular domain.

A Study on Development of Optimum FE Analysis Model on Welding Stress Analysis for CEDM Penetration Nozzle

2014 ◽  
Author(s):  
Tae-young Ryu ◽  
J. B. Choi ◽  
Kyoung S. Lee
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Experimental Methods ◽  
Fe Analysis ◽  
Welding Residual Stress ◽  
Hole Drilling ◽  
Fe Model ◽  
Analysis Model ◽  
Welding Stress ◽  
Mesh Density

For decades, the PWSCC on the penetration nozzles like BMI and CEDM nozzles are widely occurred all around the world. The PWSCC is dependent on the tensile stress condition, specific materials and chemical environment. Therefore, to evaluate the severity of the PWSCC, prediction of the welding residual stress on the J-groove welding part in the penetration nozzles is essential. Residual stress can be measured by using experimental methods like deep-hole drilling and X-ray diffraction, etc. However, the results of experimental methods are quite doubtable and these methods are hard to apply on the actual equipment. Therefore, computational approach like the FE analysis has been considered. The FE analysis results are very sensitive to the FE model density and analysis conditions. In this paper the optimized FE model for the residual stress analysis will be developed in the case of CEDM penetration nozzle. The optimized parameters contains bead number and mesh density. The bead numbers along the longitudinal and circumferential directions are considered and the mesh density in each the bead is also considered. The model will be verified by numerical error control.

Space Optical Remote Sensor of the CAE Thermal Control Index Calculation Method

2011 ◽  
Vol 308-310 ◽  
pp. 2328-2333
Author(s):  
Li Fu Li
Keyword(s):  
Optical System ◽  
Thermal Loading ◽  
Surface Deformation ◽  
Thermal Control ◽  
Temperature Fields ◽  
Deformation Analysis ◽  
Analysis Model ◽  
Zernike Polynomial ◽  
Remote Sensors ◽  
Remote Sensor

The thermal control indicators CAE methods of Space optical remote sensor are analyzed in the presented work. We sat up a thermal optical analysis model for space optical remote sensor. By assuming fully covered by in-orbit temperature load, and using the finite element method for thermal deformation analysis, we obtained the optical remote sensor surface deformation and displacement under various thermal loading. Using ZERNIKE polynomial, wave was fitted to obtain ZERNIKE polynomial coefficients which were incorporated into the optical system design. Using CODE V optical calculation software, heat-ray machines under elastic deformation of the system point spread function, transfer function (MTF), wave front differential (WFE) etc. were calculated. Image quality changes of remote sensors are discussed in variety assumed cases such as temperature loads of quality change. By repeated iteration, critical value of temperature fields meeting the design requirements are obtained for the optical system. Optical indicators were converged to the temperature field indicator, then reasonable indicators of thermal control for remote sensors were obtained. For the thermal control design, this method provided a reliable basis for design.

scholarly journals Investigation on the effect of electrode tip on formation of metal droplets and temperature profile in a vibrating electrode electroslag remelting process

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 743-751 ◽  
Author(s):  
Fang Wang ◽  
Jakov Baleta ◽  
Qiang Wang ◽  
Baokuan Li
Keyword(s):  
Temperature Profile ◽  
Electroslag Remelting ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Periodic Pattern ◽  
Coupled Modelling ◽  
Frequency Changes ◽  
Volume Method ◽  
Peak Value ◽  
Metal Droplets

Abstract In the present work, a transient full-coupled modelling approach has been put forward to study the effect of electrode tip on formation of metal droplets and temperature profile in the electromagnetically-controlled electroslag-remelting furnace with vibrating electrode. The electromagnetic field, momentum and energy conservation equations are solved simultaneously based on the finite volume method. The interface of slag and metal is traced using the volume of fluid approach. The results show that in the case of cone tip electrode the average dimension of metal droplets is smaller compared to the flat tip electrode. In addition, the bigger and stretched metal droplets are not observed with the cone tip electrode. The temperature fields with the cone tip electrode are distributed in a prominent periodic pattern compared to the case with flat tip electrode. The maximum temperature zone with the cone tip electrode is located along the z axial in the upper part of slag, not in the lower part. When the frequency changes from 0.17 Hz to 1 Hz, the maximum temperature reduces from 2050 K to 1985 K and the peak value of velocity decreases from 0.20 m/s to 0.125 m/s. When the vibration amplitude varies from 3mm to 6mm, the maximum temperature in the slag cover drops by 3.9% and the peak value of velocity rises by 16.7%.

Biological Monitoring of Thermal Effects of Cooling Water Discharges from Danish Power Plants

1983 ◽  
Vol 15 (10) ◽  
pp. 89-99
Author(s):  
Bo Møller ◽  
K I Dahl-Madsen
Keyword(s):  
Water Quality ◽  
Biological Monitoring ◽  
Benthic Community ◽  
Power Plants ◽  
Water Discharge ◽  
Cooling Water ◽  
Temperature Fields ◽  
Planning System ◽  
Excess Temperature ◽  
Water Entrainment

In the years from 1970-1982 52 site studies and monitoring studies have been carried out at major existing and planned power plants. The results from the studies have been used in a planning system for water quality. This planning system, which is water quality related, is described in this paper. An important part of the planning system is the description of size and distribution of excess temperature fields and the related biological conditions. In the biological monitoring, emphasis is placed on the benthic community as more vulnerable to the cooling water discharge. The studies have shown that the excess temperature field within the 1-2° isotherm can produce measurable changes in the benthic community. The temperature effect in the pelagic zone is marginal, however, some effects are seen at sites with a deep water intake of nutrient rich water. Entrainment of fish and Zooplankton can be important in bays and estuaries.

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