Academic literature on the topic 'Zone Refining Process'
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Journal articles on the topic "Zone Refining Process"
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Yoon, Young Ok, Hyung Ho Jo, Hoon Cho, Shae K. Kim, and Young Jig Kim. "Effect of Distribution Coefficient on Copper Purification by Zone Refining Process." Materials Science Forum 449-452 (March 2004): 173–76. http://dx.doi.org/10.4028/www.scientific.net/msf.449-452.173.
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It has been generally known that the refining efficiency in zone refining process depends on travel rate, number of pass and distribution coefficient of impurity. In the present study, the effect of distribution coefficient on copper purification was investigated by zone refining process. A numerical model capable of predicting the solute redistribution at any stage of zone refining was proposed. The composition profiles of each segment at the given condition were compared with the results of micro hardness profiles. After zone refining, metallic elements were analyzed by GDOS (Glow Discharge Optical Spectroscopy) and GDMS (Glow Discharge Mass Spectrometry). The impurities Ag, Pb, S and Ti, whose distribution coefficients are below 0.5, were concentrated at the finishing position. Cr, Mn, Si and Zn, whose distribution coefficients are between 0.5 and 1, were distributed irregularly. Fe and Ni, whose distribution coefficients are greater than 1, moved to the starting position. It was found that zone refining process was actually effective to remove impurities whose distribution coefficients are below 0.5. The experimental results agreed well with the simulation result.
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Karlström, Anders, and Jan Hill. "Control strategies for refiners Part I: Soft sensors for CD-refiner control." Nordic Pulp & Paper Research Journal 33, no. 1 (May 23, 2018): 28–43. http://dx.doi.org/10.1515/npprj-2018-3007.
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Abstract Internal variables in (C)TMP-refining processes (e. g. temperature, consistency, fiber residence time, backward flowing steam and forces acting upon the chips and pulp) are defined as physical states obtained in different parts of the refining zones. In short, they differ from the traditional external variables (e. g. dilution water feed rate and specific energy) which are not obtained from measurements or physical models of the process in the refining zone. The internal variables are the backbone of physical models and are used in this paper as soft sensors for advanced process control. Besides the shape of the temperature profile, the position of the maximum temperature and the shape of the consistency profiles inside the refining zones are important to control as they are directly linked to the development of different pulp and handsheet properties. To illustrate the capability when using combined modeling and control strategies, the concept is applied on a full scale CD82 refiner. This means both temperature and consistency control in the flat zone and the conical zone, together with an overall estimator for fiber development. Finally, in this paper it is shown that the production can be increased significantly without changing the refiner motor load nor violating the pulp property specification.
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Karlström, Anders, and Karin Eriksson. "Fiber energy efficiency Part I: Extended entropy model." Nordic Pulp & Paper Research Journal 29, no. 2 (May 1, 2014): 322–31. http://dx.doi.org/10.3183/npprj-2014-29-02-p322-331.
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Abstract This is the first in a series of papers presenting the development of a comprehensive multiscale model with focus on fiber energy efficiency in thermo mechanical pulp processes. The fiber energy efficiency is related to the defibration and fibrillation work obtained when fibers and fiber bundles interact with the refining bars. The fiber energy efficiency differs from the total refining energy efficiency which includes the thermodynamical work as well. Extracting defibration and fibrillation work along the radius in the refining zone gives information valuable for fiber development studies.Models for this process must handle physical variables as well as machine specific parameters at different scales. To span the material and energy balances, spatial measurements from the refining zone must be available. In this paper, measurements of temperature profile and plate gaps from a full-scale CD-refiner are considered as model inputs together with a number of process variables. This enables the distributed consistency in the refining zone as well as the split of the total work between the flat zone and the CD-zone to be derived. As the temperature profile and the plate gap are available in the flat zone and the CD-zone at different process conditions it is also shown that the distributed pulp dynamic viscosity can be obtained. This is normally unknown in refining processes but certainly useful for all fluid dynamic models describing the bar-to-fiber interactions. Finally, it is shown that the inclusion of the machine parameters will be vital to get good estimates of the refining conditions and especially the split between the thermodynamical work and the defibration/fibrillation work.
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Ferritsius, Rita, Olof Ferritsius, Jan Hill, Anders Karlström, and Karin Eriksson. "TMP properties and refining conditions in a CD82 chip refiner. Part I: Step changes of process variables, description of the tests." Nordic Pulp & Paper Research Journal 33, no. 1 (May 23, 2018): 69–81. http://dx.doi.org/10.1515/npprj-2018-3002.
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Abstract The study explores how changes in process variables, residence time and pulp consistency in refining influence the pulp properties. The equipment utilized in this study was a conical disc chip refiner (RGP82CD) producing thermomechanical pulp (TMP). The focus was on the ratio between tensile index and specific energy consumption. Pulp properties were measured for composite pulp samples taken from the refiner blow line. Residence times and pulp consistencies were estimated by use of the extended entropy model. This showed that the CD-refiner, with the flat and conical refining zone, has a process performance similar to that of a two-stage refiner set-up, and that the consistency in both refining zones is of high importance. Comparing different periods revealed that even if the values of measured blow line consistency are similar, significant differences in the estimated consistency in the flat zone can prevail. Therefore, only monitoring blow line consistency is not enough. Specifically, it was found that the pulp consistency after the flat zone could be very high, considerably higher than in the blow line, and this could have negative effects on tensile index and fibre length.
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Zhang, Xiaoxin, Semiramis Friedrich, and Bernd Friedrich. "Characterization and Interpretation of the Aluminum Zone Refining through Infrared Thermographic Analysis." Materials 11, no. 10 (October 19, 2018): 2039. http://dx.doi.org/10.3390/ma11102039.
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High purity metals are nowadays increasingly in demand to serve in electronic, photovoltaic, and target materials industries. The zone refining process is the most common way to achieve high purity in the final step of metal purification. Zone length and crystal growth rate are the main parameters that control the zone refining process. To determine these values, information about temperature profiles in the molten zone is necessary due to its direct correlation with these values. As the determination of this profile is not practically achievable in the present, the novel approach of applying an infrared (IR) camera during the zone refining of 2N8 aluminum is the focus of the investigation in this work. The whole temperature profile of the region near the molten zone was recorded by IR camera during the entire running process. The zone length and the crystal growth rate at each thermographic image shooting moment were successfully extracted by thermographic analysis. Results showed that both factors varied significantly, which is in contrast to the assumption in literature about their stability while running under constant input power and heater movement velocity, though noticeable purification took place in all of these experiments. However, the impurity concentration during refinement fluctuated remarkably. This was well-demonstrated by the tendency of variation in crystal growth rate attained in this work. These results provide a better understanding of the mechanisms of zone refining with an inductive heater and contributes to the optimization of the process.
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Park, Hyeong-Hun, Chul-Hwan Kim, Ji-Su Lee, and Cheong-Ha Lee. "Effects of Refiner Plates with Different Fillings on TMP Properties." Applied Sciences 13, no. 8 (April 19, 2023): 5091. http://dx.doi.org/10.3390/app13085091.
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This study conducted a comparative analysis of two refiner plates that had different bar patterns. The plates were designed with three distinct zones, including the high-intensity zone, the transition zone, and the low-intensity zone, and had a draft angle of 4–5 degrees. The two refiner plates had a significant difference in cutting edge length (CEL) of approximately four times. Specifically, TMP plate A (TP A) had a CEL of 5.1 km/s, while plate B (TP B) had a CEL of 22.7 km/s, indicating that TP A applied greater force to the wood chips during refining. TP A exhibited greater stock throughput at the same refining energy compared to TP B due to its smaller CEL. The low-intensity refining of TP B promoted the fibrillation of TMP fibers, leading to a large decrease in fiber width without significantly changing the mean fiber length before and after refining. The bulk of TMP and CTMP increased slightly more in TP B than in TP A. However, TP A showed a greater decrease in tensile strength due to a larger decrease in fiber length, whereas there was no significant change in tear strength between the two plates.
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Li, Yang, Zhou Hua Jiang, Shi You Yin, Ying Zhuang, and Ming Li. "Effect of Refining Slag on the Inclusions of Hard Wire Steel during Melting Process." Advanced Materials Research 217-218 (March 2011): 1174–79. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.1174.
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The effect of the refining slag composition on the total oxygen content and inclusions in steel was investigated in 100 t UHP Electric Furnace – LF – Billet CC process. The test steel was 77B hard wire steel and Si-Mn alloy was used as the deoxidizer. Three types slag were used in the industrial tests, which including CaO-CaF2, CaO-CaF2 adding CaC and CaO-Al2O3 refining slag. The results shown that the lowest total oxygen contents of rolled bar can be gained using the CaO-CaF2 refining slag adding CaC, which is 0.0036%, while the total oxygen contents of rolled bar using CaO-Al2O3 refining slag is higher a little than the heats using CaO-CaF2 refining slag. The CaO-SiO2 and CaO-Al2O3-SiO2 compound inclusions with the size of about 5 μm are the main inclusions in the heats refining by the CaO-CaF2 refining slag in the rolled bar, but the pure, indeformable Al2O3 inclusion can also be found with the size of about 10 μm. The CaO-Al2O3-SiO2 and Al2O3-SiO2-MnO compound inclusions are the main inclusions in the heats refining by the CaO-CaF2-CaC refining slag, but most of the inclusion shape is irregular with bigger size of about 10 μm. Similar with the heat using CaO-CaF2 refining slag, the pure Al2O3 inclusion with edge angle can be found in the rolled bar. The inclusions in the rolled bar treated by CaO-Al2O3 refining slag are CaO-Al2O3-SiO2 compound inclusions, most of which are nearly globular shape with the relative small size of about 5 μm. All of the inclusions in rolled bar lie on the low melting zone in the CaO-Al2O3-SiO2 ternary phase diagram in the heats using CaO-Al2O3 refining slag. The similar condition appeared on the most of the inclusions in the heats using CaO-CaF2 and CaO-CaF2 refining slag adding CaC, while part of which are lied on the high melting zone. Therefore, considering of the plastic deformation ability, the CaO-Al2O3 refining slag is the best slag for the melting process of hard wire steel.
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Wen, Jiajun, Meizhen Wu, Jubo Peng, and Hongxing Zheng. "Purification of High-Purity Tin via Vertical Zone Refining." Separations 10, no. 7 (June 28, 2023): 380. http://dx.doi.org/10.3390/separations10070380.
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The present investigation delves into the potential of vertical zone refining as an effective purification technique for achieving high-purity tin (Sn) metal. The utilization of vertical zone refining offers distinct advantages over traditional horizontal zone refining, as it allows for enhanced control over the molten zone and solid–liquid interface, ultimately leading to superior impurity separation efficiency. The present study reveals that the solute partition coefficients (k0) of various impurity elements, such as Zn, Ag, Al, Mg, Ca, Ni, In, Co, Cu, As, Pb, Fe, and Bi, during the vertical zone refining process consistently demonstrate values below one. Notably, the partition coefficient of Sb deviates slightly from the others, being greater than one but approaching one. The authors achieve exceptional levels of purity in both the bottom and middle regions of the rod by subjecting the Sn melt to nine passes of vertical zone refining at a heating temperature of 405 °C and a downward pulling rate of 10 µm/s, resulting in purities exceeding 6N4. Furthermore, by evaluating the effective partition coefficients (keff), it was determined that impurity elements, such as Cu and Bi, closely approach their equilibrium partition coefficients, reaching values of approximately 0.492 and 0.327, respectively. To further enhance the purity of Sn metal and maximize product yield, we propose the utilization of electrolytic refining and vacuum distillation, with particular emphasis on the efficient separation of five specific elements, including Cu, Fe, As, Pb, and Sb. By elucidating these findings, this study not only contributes valuable insights into the efficacy of vertical zone refining as a purification technique for high-purity tin metal, but also offers important recommendations for refining strategies and impurity element separation.
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Karlström, Anders, and Karin Eriksson. "Fiber energy efficiency Part II: Forces acting on the refiner bars." Nordic Pulp & Paper Research Journal 29, no. 2 (May 1, 2014): 332–43. http://dx.doi.org/10.3183/npprj-2014-29-02-p332-343.
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Abstract In this paper it is shown that the defibration and fibrillation work in thermo mechanical pulp refiners can differ significantly dependent on the process conditions. This has a direct impact on the distributed force in the refining zones obtained when the bars hit the fibers or fiber bundles. The distributed force, which is defined as a vector along the surface of the refining segments, is estimated using a model where the total work can be split into reversible and irreversible work. Besides traditional refiner variables such as motor load, dilution water added and inlet- and casing pressures, measurements of temperature profiles in the refining zone and plate gaps from a fullscale CD-refiner are available as inputs. Three data sets are analyzed and it is shown that the shape of the temperature profile and the force distribution vary significantly. This means that the fiber distribution in the refining zone varies as well which affects the final development of the pulp properties. The refining segment pattern and taper play an important role when estimating the force distribution and it is stated that the force distribution close to the contraction part of the flat zone as well as the outer part of the conical section are larger than in other positions. Therefore, specific energy which can be seen as the integral of the total energy distribution along the refining segments cannot be used when describing the variations in the distributed forces.
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Alashkevich, Yuriy Davydovich, Anna Aleksandrovna Fomkina, and Aleksandra Aleksandrovna Karelina. "INTERRELATION OF INDIVIDUAL PAPER-FORMING PROPERTIES AND THE DYNAMIC VISCOSITY COEFFICIENT DURING THE GRINDING OF THE FIBROUS MASS." chemistry of plant raw material, no. 4 (December 15, 2022): 371–76. http://dx.doi.org/10.14258/jcprm.20220411374.
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The refining process is associated with the movement of large masses of fibrous suspensions in the working bodies of refining machines, which affects both the refining process itself and energy consumption when moving the fibrous suspension. In this regard, the efficiency of refining equipment can be ensured on the basis of knowledge of the hydrodynamic processes that occur during the interaction of the working bodies of refining equipment with a fibrous suspension.
During the flow of fibrous suspensions, the basic rheological feature is their viscosity, which makes it possible to judge the internal forces acting in the flow. This is especially important for the bladeless refining method using the “jet-barrier” installation.
In order to most fully judge the direction of the refining process (in the direction of the transverse shortening of the fibers or in the direction of their longitudinal fibrillation), it is necessary to control the paper-forming properties of the fibrous mass and the physical and mechanical properties of the castings.
The publication presents an analysis of the influence of the paper-forming properties of the fibrous mass on the quality of its refining, it is advisable to find the dependence of these indicators on the rheological features of the fibrous suspension flow in the refining zone, that is, to determine the relationship of the paper-forming properties of the fibrous mass with the dynamic viscosity coefficient during the flow of the fibrous suspension in the refining zone.
Dissertations / Theses on the topic "Zone Refining Process"
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Zhang, Xiaoxin [Verfasser]. "Behaviour Comparison and Process Optimization of Al and Sb Zone Refining / Xiaoxin Zhang." Düren : Shaker, 2020. http://d-nb.info/1208599208/34.
Full textBooks on the topic "Zone Refining Process"
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Encyclopedia of Chemical Processing and Design: Volume 68 - Z-Factor (Gas Compressibility) Errors to Zone Refining (Encyclopedia of Chemical Processing and Design). CRC, 1999.
Find full textBook chapters on the topic "Zone Refining Process"
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Kim, Wan Gou, Hong Youl Ryu, Man Sik Kong, Soon Jik Hong, Hwa Young Lee, Joon Chul Choi, and Jong Hyeon Lee. "Preparation of High Purity Tellurium by Zone Refining Process." In PRICM, 2679–85. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118792148.ch332.
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Kim, Wan Gou, Hong Youl Ryu, Man Sik Kong, Soon Jik Hong, Hwa Young Lee, Joon Chul Choi, and Jong Hyeon Lee. "Preparation of High Purity Tellurium by Zone Refining Process." In Proceedings of the 8th Pacific Rim International Congress on Advanced Materials and Processing, 2679–85. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-48764-9_332.
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Wan, Heli, Baoqiang Xu, Jinyang Zhao, Bin Yang, and Yongnian Dai. "Analysis of the High-Purity Aluminum Purification Process Using Zone-Refining Technique." In TMS 2019 148th Annual Meeting & Exhibition Supplemental Proceedings, 1697–706. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05861-6_157.
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Finney, Mark A., Jason M. Forthofer, Xinle Liu, John Burge, Matthias Ihme, Fei Sha, Yi-Fan Chen, Jason Hickey, and John Anderson. "Deep Learning for High-Resolution Wildfire Modeling." In Advances in Forest Fire Research 2022, 136–41. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_21.
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We demonstrate the use of a deep learning (DL) approach for representing the behavior of a high-resolution physics-based wildland fire spread model. The ultimate objective is being able to efficiently use the DL model for intensive simulations of large fires while retaining fidelity to the fine-scale physical processes. We begin with a fire model that reduces the spatial domain of the fire spread problem to one dimension (1D). The 1D model explicitly resolves cm-scale fuel variations, heat transfer and heating/drying dynamics of individual fuel particles and burning behavior of the bed. We then ran the fire model for 78,125 factorial combinations of fuel, weather, and topographic conditions as training data for the DL algorithm. The results of the DL analysis show overall agreement of 96% of the variation in fire behavior as represented by steady state rate of spread, flame length and flame zone depth. Exceptions to the DL regression indicate areas where more work is required in refining the resolution in training cases and use of advanced methods of embedding the fire model inside the DL algorithm loop.
Conference papers on the topic "Zone Refining Process"
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Kotland, A., S. Chollet, JM Autret, G. Calmels, C. Diard, J. Hubert, L. Marchal, and JH Renault. "Purification of alkaloids from Catharanthus roseus by pH-Zone Refining Centrifugal Partition Chromatography: process intensification and scale up." In GA 2017 – Book of Abstracts. Georg Thieme Verlag KG, 2017. http://dx.doi.org/10.1055/s-0037-1608276.
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Haferkamp, H., M. Goede, and O. Thürk. "Short Time Process Observation During Laser Remelting of Aluminium Diecast Alloys." In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/cleo_europe.1998.cthh93.
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Rapid solidification of aluminium alloys during the remelting process using high power laser radiation results in refining effects of the solidified grain texture and improved wear resistance and material hardness. High temperature gradients can be achieved as well as energy coupling into the aluminium alloy is locally restricted, and can be precisely controlled. For the adjustment of defined grain textures, the dynamic behaviour of the melted material on the irradiated material surface is of high interest. Most of the optical set-ups currently used for process visualisation only image the plasma formation within the laser beam interaction zone. Available systems for frequency-selective irradiation and visualisation provide insufficient time resolutions with respect to rapid melting and solidifying processes.
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Pussegoda, L. N., A. Fredj, A. Fonzo, G. Demofonti, G. Mannucci, and B. Rothwell. "Ductile Fracture Resistance Measurements in High Grade Steels." In 2006 International Pipeline Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ipc2006-10231.
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Recent developments in ductile fracture resistance measures in high grade steels in the pipeline industry include the crack tip opening angle (CTOA) and “steady state” fracture propagation energy, using 3-point bend specimens. The CTOA has been found to be a function of specimen ligament size. With the availability of instrumented hammers, it became possible to resolve propagation energy using the load-displacement curve using a single specimen. This paper focuses on refining the steady state fracture propagation energy, using back-slotted Drop Weight Tear Test (DWTT) specimens. The study included numerical simulation of the dynamic response of back-slotted specimens. The significance of the back-slot in altering the stress/strain field ahead of the propagation crack is discussed. The numerical simulation was also used to determine the strain rate in the “process zone” of the crack tip during steady state fracture propagation.
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Chen, Xuedong, Zhibin Ai, Zhichao Fan, Rongrong Li, Peng Xu, and Huifeng Jiang. "Integrity Assessment of Pressure Vessels and Pipelines Under Fire Accident Environment." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78222.
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In recent years, fire accidents take place frequently in Chinese oil refining plants. More and more attentions have been paid to the safety assessments of pressure vessels and pipelines exposed to high temperature of the fire scene. In this paper, combining with several integrity assessment cases of pressure vessels and pipelines after fire accidents in China, the effects of thermal exposure temperature, duration time and cooling rate on the microstructure, mechanical properties, corrosion resistance and fatigue fracture behavior were studied by simulation test research and field inspection. Based on analysis and study of API 579 standard, a method of integrity assessment is proposed under the condition that the information on fire accident is not clear, the thermal exposure zone cannot be classified and the field sampling is limited. This assessment method is based on the similarity of hardness and metallographic structure of the material during the fire accident, by which the like material was treated by thermal simulation tests to obtain the similar damage material with similar hardness and metallographic structure to one obtained in the field examination, and the similar damage material is used to obtain various properties of the materials, and then the integrity assessment of the equipment experiencing the fire accident can be completed. The thermal simulation process to obtain similar damage materials is in fact the reproduction process of thermal exposure temperature, duration time, and cooling rate of the metal in the fire accident. This integrity assessment method is faster and simpler compared to API 579 standard and is suitable for the equipment subject to severe fire accident and in high-class thermal exposure zone.
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Stone, J., and C. A. Burrus. "Single-crystal fiber devices." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.wb1.
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Single-crystal fibers of Nd:YAG, Nd:Y2O3, ruby, sapphire, LiNbO3, and LiTaO3 were pulled (in diameters from 15 to 100 µm) from a tiny melt obtained by heating the tip of a thin rod of the parent crystal in air with the focused beam of a CO2 laser. Short Nd:YAG fibers, some with a fused-glass cladding, were made into lasers by attaching suitable dielectric mirrors to the ends and end pumping with a single 0.8-µm wavelength AIGaAs LED. Laser output was obtained at 1.06-µm and 1.318-1.338-µm wavelength. Up to 1 mW of single-mode output power, limited primarily by imperfect coupling between the LED pump and the fiber laser, was measured. Similar laser structures made with Nd:Y2O3 and ruby were pumped with a krypton gas laser. The thermal efficiency of the fiber geometry both promoted homogeneous crystal growth and permitted cw laser operation, and all devices could be operated cw at room temperature. LiNbO3 and LiTaO3 fibers were grown for possible use as modulators. The crystalline orientation of any of the fibers could be predetermined by selecting the seed orientation, and some resultant growth habits are shown. In general, since the growth process inherently involves zone refining, single-crystal fibers are of very high purity and optical quality.
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Tanaka, Tomohiro, Masamitsu Abe, Mitsuyoshi Nakatani, and Hidenori Terasaki. "Effect of Postweld Heat Treatment Conditions on Mechanical Properties of 9Cr-1Mo-V Steel Welds for Pressure Vessel." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65320.
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2¼Cr-1Mo steel and 2¼Cr-1Mo-V steel which have high performance in high-temperature and high-hydrogen service are widely used in fabricating process equipment for the oil refining industry. With the demand for plants using low-grade crude oil expected to increase in the future, equipment will after to operate at higher temperatures and higher pressures to meet such demand. In addition, the demand for gasification process equipment for coal using high-temperature strength material, which is to be used as an alternative of oil, is expected to grow also. Although 2¼Cr-1Mo steel and 2¼Cr-1Mo-V steel are adopted for high-temperature and high-pressure equipment used at temperatures up to 450°C, 9Cr-1Mo-V steel is suited for operation at even higher temperatures and pressures. It is used as structural material for boilers of power plants and elsewhere. The application of 9Cr-1Mo-V steel is anticipated for oil refineries. However, it is necessary for the welds to consider the hardness and the low-temperature toughness in addition to the high-temperature strength. In this paper, the effect of postweld heat treatment (PWHT) conditions on mechanical properties of 9Cr-1Mo-V steel welds was investigated. The PWHT conditions are organized with reference to the tempering parameter (Larson-Miller Parameter), with the heat treatment conducted in an LMP range of 20.46 to 22.42 × 103. As LMP increased, the hardness and high-temperature strength decreased. In the hardness distribution of the welds subjected to PWHT, the hardness tended to maximize near the bond of the heat affected zone (HAZ); however, applying heat treatment to materials with an LMP equal to or higher than 21.15 × 103 allowed a hardness of 260HV or less to be obtained. In terms of the high-temperature strength, the welds met the specified value as the 0.2 proof stress of ASME SA387-91-2, the base metal, under the PWHT conditions of an LMP equal to 22.42 × 103; the tensile strength was 0.9 times or more of the specified value. The Charpy absorbed energy increased with the LMP, and, when an LMP of 21.99 × 103 or more was used as the PWHT conditions, an absorbed energy of 60 J or more could be obtained at 0°C, as well. From the above results, the effect of PWHT conditions on mechanical properties of the welds is clarified, and it is suggested that 9Cr-1Mo-V steel can be used for the equipment in oil refining plants.
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Nagai, Yoshihide, Hidenori Fukami, Hajime Inoue, Takao Nakashima, Akihiko Kojima, Toshiyuki Kajitani, Toshihiko Adachi, and Yuzuru Yoshida. "Production of High-Strength and High-Toughness Steel for Offshore Structures." In ASME 2003 22nd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2003. http://dx.doi.org/10.1115/omae2003-37436.
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By the utilization of new fine particles, steels refining the heat affected zone (HAZ) structure have been developed. This has made possible the mass-production of offshore structural steels which have high-strength of 460–500N/mm2 in yield strength (YS) and excellent crack-tip opening displacement (CTOD) properties. These newly developed steels for offshore structures have been mass-production to over 45,000 tons. The new particles are dispersed finely in the developed steels and show a strong pinning effect. The newly developed steels also use the intragranular ferrite (IGF) like titanium oxide bearing steel (TiO steel). In mass-production heats, γ grain size is restricted below 200 μm under conditions of 1400°C for 60 seconds. The improvement of HAZ toughness and the utilization of the thermo-mechanical control process (TMCP) has restrained the increase in carbon equivalent (Ceq,PCM) far as possible. By application of these technologies, it has been possible to mass-produce steels with high-strength, excellent CTOD properties and good weldability. As for steel plates of YS500N/mm2, the production of steel plates up to 70mm in thickness was carried out. The properties of welded joints for the 70mm-thick plates of YS500N/mm2 steel have been evaluated under heat input in 0.7kJ/mm of flux-cored are welding (FCAW) and 3.5kJ/mm of sub-merged arc welding (SAW). They have shown excellent CTOD and Charpy impact properties at welded joints; and have moreover indicated good weldability when PCM has been restricted to 0.22% or lower.
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Hamilton, Ian S., Donald A. Halter, Donald F. Haumann, Erich H. Fruchtnicht, and Matthew G. Arno. "Characterization of NORM Sources in Petroleum Coke Calcining Processes." In ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16314.
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Petroleum coke, or “petcoke,” is a waste by-product of the oil refining industry. The majority of petcoke consumption is in energy applications; catalyst coke is used as refinery fuel, anode coke for electricity conduction, and marketable coke for heating cement kilns. Roskill has predicted that long-term growth in petroleum coke production will be maintained, and may continue to increase slightly through 2012. Petcoke must first be calcined to drive off any undesirable petroleum by-products that would shorten the coke product-life cycle. As an example, the calcining process can take place in large, rotary kilns heated to maximum temperatures as high as approximately 1400–1540°C. The kilns and combustion/settling chambers, as well as some cooler units, are insulated with refractory bricks and other, interstitial materials, e.g., castable refractory materials, to improve the efficiency of the calcining process. The bricks are typically made of 70–85-percent bauxite, and are slowly worn away by the calcining process; bricks used to line the combustion chambers wear away, as well, but at a slower rate. It has been recognized that the refractory materials contain slight amounts of naturally occurring radioactive materials (NORM) from the uranium- and thorium-decay series. Similarly, low levels of NORM could be present in the petcoke feed stock given the nature of its origin. Neither the petcoke nor the refractory bricks represent appreciable sources of radiation or radioactive waste. However, some of the demolished bricks that have been removed from service because of the aforementioned wearing process have caused portal alarms to activate at municipal disposal facilities. This has lead to the current investigation into whether there is a NORM concentrating mechanism facilitated by the presence of the slightly radioactive feed stock in the presence of the slightly radioactive refractory materials, at calcining-zone temperatures. Research conducted to date has been used to determine the speciation and concentration of nuclides in both the feed stock and the various refractory materials, as well as the slag that forms at the interface of the two materials, as a function of temperature. Further investigation into any potential for generation of a NORM hazard as a result of refractory demolition has been conducted. Aerosol generation (mass loading), particle size distribution, and pulmonary solubility class have been investigated as a function of demolition-task description. In addition, external radiation levels in the kilns, chambers and waste piles, as a function of temperature profile and brick/operating history have been investigated.
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Rollins, Brandon C., Oliver J. Tarbard, Kenneth E. Bagnoli, and Ramgopal Thodla. "Fracture Toughness Behavior of Carbon Steels in Mildly Sour Waters." In ASME 2021 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/pvp2021-63030.
Full textAbstract:
Abstract Corrosion and cracking of typical materials used in refinery equipment exposed to sour water has long been a concern for the industry [1]. The failure of an amine absorber tower in 1984 heightened the need to understand the performance of these materials in sour water encountered by the industry [2]. This phenomenon is often generically referred to as “wet H2S cracking”, though it includes various forms of damage. In the years following the absorber tower failure numerous studies were undertaken to understand the performance of typical pressure vessel steels exposed to sour water including fracture toughness testing in NACE A or NACE B solutions [3]. NACE A and B solutions are significantly more aggressive solutions (lower pH and higher Hydrogen Sulfide [H2S] concentration) than most common refinery sour waters. Due to the severity of the testing solution, the results are likely overly conservative and may lead to unrealistic integrity assessments of refinery vessels by applying API 579 Fitness for Service (FFS) assessments. Following the 1984 incident, most of the research carried out into sour water environments was targeted to material susceptibility and effects of sour water on new steel. Limited baseline data are available that quantify the effects of sour water on the mechanical properties on service aged or vintage materials. In fact, most data generated on the fracture toughness of steels in sour water has been undertaken for upstream projects, where the conditions are often more aggressive than in downstream applications. An ASME-API 579 Part 9 flaw analysis is required to be performed on wet H2S crack-like defects that fail an ASME-API 579 Part 7 Level 2 analysis [4]. To account for the loss in toughness associated with the presence of hydrogen embrittlement, lower bound crack arrest fracture toughness (KIR) is normally used as a lower bound estimate. Some wet H2S defects, such as Hydrogen Induced Cracking (HIC), require an API 579 Part 9 crack like flaw assessments even though they typically pass the Level 2 analysis. However, the FFS assessment is limited by the small tolerable crack lengths from API 579 Part 9 analysis due to the application of the lower bound KIR values. The use of lower bound KIR values is potentially overly conservative because it is a key input parameter into a crack like flaw assessment. Furthermore, the presence of H2S typically will cause subcritical crack growth due to the presence of hydrogen in the fracture process zone ahead of the crack tip. This can take place under constant load, or under fatigue. The latter issue is often evaluated for oil production facilities, particularly for offshore applications. In the downstream sector of the refining industry, the application of crack growth modelling is not normally applied due to the scarcity of applicable experimental data. As a result, either weld repair or protective coatings are typically used to prevent known tolerable flaw sizes from growing during future operation. To address such issues, a comprehensive test program was conducted to evaluate both the fracture toughness and subcritical crack growth properties of ex-service steels in mildly sour waters, which are more applicable to the downstream refining industry. The environmental severity was also explored by varying combinations of pH and H2S partial pressure. The main objective was to characterize the steel specimen performance in near neutral pH with high as well as low H2S concentrations.
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You Wen, Ma Haitao, and Cao Zhiqiang. "Control Method of preventing splashing in the refining process of AOD furnace based on equal temperature zones." In 2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering (CMCE 2010). IEEE, 2010. http://dx.doi.org/10.1109/cmce.2010.5610319.
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