Papers by Keyword: Process Simulation

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Authors: Xin Tong Xia, Jia Wu, Long Yong Lin
Abstract: The energy saving, waste water reduction and economic performance of a novel process for purifying methanol, which employs dividing wall column and double effect distillation, was investigated by steady state simulation in comparison with two-column conventional distillation process and three-column double effect distillation process. Results showed that the novel process could reduce steam consumption by 34% comparing to the two-column process and had comparative ability in energy saving with three-column double effect process. Meanwhile it can reduce waste water by 20% and 20%, period for recovery of investment by 8.6% and by 5.1%, comparing to the two processes above respectively.
Authors: Seung Chae Yoon, Do Minh Nghiep, Sun Ig Hong, Z. Horita, Hyoung Seop Kim
Abstract: Manufacturing bulk nanostructured materials with least grain growth from initial powders is challenging because of the bottle neck of bottom-up methods using the conventional powder metallurgy of compaction and sintering. In this study, bottom-up type powder metallurgy processing and top-down type SPD (Severe Plastic Deformation) approaches were combined in order to achieve both full density and grain refinement of metallic powders. ECAP (Equal-Channel Angular Pressing), one of the most promising processes in SPD, was used for the powder consolidation method. For understanding the ECAP process, investigating the powder density as well as internal stress, strain and strain rate distribution is crucial. We investigated the consolidation and plastic deformation of the metallic powders during ECAP using the finite element simulations. Almost independent behavior of powder densification in the entry channel and shear deformation in the main deformation zone was found by the finite element method in conjunction with a pressure dependent material yield model. Effects of processing parameters on densification and density distributions were investigated.
Authors: Can Can Zhao, Xiao Dong Zhang, Shao Juan Lei, Jun Jiang Qiu
Abstract: Supply chain simulation is a fundamental approach for supply chain prediction, management, evaluation, and improvement. In order to simulate member behavior, organizational strategy, and management strategy of the supply chain, an agent-based modeling and simulation approach on multi-stage supply chain operation was proposed in this paper. First, the model structure of multi-stage supply chain operation was introduced. Then, the individual agent behavior model was emphatically studied, and hierarchical colored Petri-nets were used to describe the agent behavior process and cooperative behavior process. Finally, the model was validated using a series of simulation which focused on the agent inventory strategy.
Authors: Jéssica dos Santos Cruz de Almeida, José Luiz de Medeiros, Ofélia Queiroz Fernandes de Araújo
Abstract: The exploration of pre-salt introduces challenges beyond those posed by ultra-deep waters and the thick of carbonaceous reservoirs. Among the main difficulties are the high gas-oil ratio and the high content of carbon dioxide (CO2) present in the gas. This paper proposes an alternative to the technology currently used in the exploration of pre-salt, in which the gas is treated on the platform. The proposed alternative is applicable to reservoirs which CO2 concentration in gas is greater than 50%, like Jupiter that contains 79% of CO2. For this scenario is suggested that exploration occurs in three production areas: subsea, offshore and onshore. The proposed technology includes the construction of three subsea pipelines: one for the transportation of untreated gas (that is treated onshore); a second for the return of the recovered hydrate inhibitor (in order to be re-injected into the gas pipe) and the last for the return of the carbon dioxide stream separated from the gas.
Authors: Yan Cao, Hua Chen, Hai Xia Zhao
Abstract: Based on the study on metal cutting theories and rigid-plastic finite element method, taking Sweden SECO lathe tool MDT as the researching object, the cutting force in cutting process is analyzed after a cutting process simulation model is constructed using finite element method. Different simulation parameters and cutting parameters are used to carry out analyses time after time. The dynamic changing curves of the cutting force in cutting process are obtained. Through the comparison of the cutting force in different cutting conditions, the influence of cutting parameters on the cutting force is summarized. The research can provide useful data for improvement of metal cutting technology and tool cutting performance.
Authors: Antonino La Magna, Ioannis Deretzis, Filippo Giannazzo, Giuseppe Nicotra, Fabrizio Roccaforte, Corrado Spinella, Rositza Yakimova
Abstract: A Kinetic Monte Carlo scheme is applied to simulate with atomic resolution the synthesis of mono (few) layer(s) graphene (Gr) from a silicon carbide (SiC) substrate by selective evaporation of silicon (Si) atoms. The simulation computes the individual dynamics of the residual carbon (C) atoms which diffuse and reconfigure starting from the positions occupied in the SiC hexagonal lattice to the final Gr honeycomb structure. During the transition they gradually modify hybridization (from sp3 to sp2) and bond partners (from Si-C to C-C). We demonstrate that our method is able to recover the complex evolution steps of the epitaxial Gr on SiC in large systems for large time intervals. Moreover, the simulation results can be validated directly by means of comparison with experimental data when varying the material (e.g. initial surface configuration or polarity) or process (e.g. temperature and pressure) conditions.
Authors: Shuichi Ono, S. Katakami, Manabu Arai
Abstract: The avalanche breakdown characteristics of a graded p+-n junction formed with aluminum ion-implantation for 4H-SiC were investigated. The breakdown voltage of the graded p+-n junction was calculated using a commercial process/device simulator and considering the ion-implanted distribution of aluminum. To compare the calculated results to the experimental results, a p+/n/n+ diode with an aluminum ion-implanted p+-layer was fabricated on a 2.8-μm-thick 1.1 × 1017-cm-3 n-type epitaxial layer. The breakdown voltage of the fabricated diode showed a higher breakdown voltage than that of the calculation. The cause of the difference in the breakdown voltages between the fabricated diode and the calculation is discussed.
Authors: Vladimir Kandinskiy, Ivan Korolev, Vladimir I. Udovitskiy
Abstract: Gravity separation is considered as the most used processing technique for thermal coal cleaning. A broad variety of methods and machines was developed for that purpose. However, the performance of those apparatus under different conditions is not the same. In this article, the results of coarse thermal coal cleaning in various equipment were simulated by means of mathematical modelling. The comparison of obtained quantitative and qualitative indicators of gravity separation showed that for processing of difficult-to-wash thermal coal the heavy medium-based processes are more favorable, whereas for more easily washable coal jigging can be efficiently used as well.
Authors: Tatsuhiko Aizawa, Fujio Tsumori
Authors: Li Li Liu, Jin Sheng Sun, Lan Mei, Yan Hong Wang
Abstract: In this preparation, FCCU main fractionator and corresponding absorption-stabilization system are systemically simulated on the basis of industrial data. Through analysis, a heat exchanging column is added to improve the flowsheet before rich gas cooler to make good use of heat of the compressed rich gas. To decrease LPG lost along with dry gas, a dry gas compression-expansion refrigeration circle is proposed to offer refrigeration capacity in place of the cooling water for the absorber pumparounds. Compared with the regular scheme, energy consumption and C3+ components in dry gas is reduced respectively by 17.18% and 7.16% and LPG yield is increased by 0.41% simultaneously.
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