The Experts below are selected from a list of 46893 Experts worldwide ranked by ideXlab platform
K Li - One of the best experts on this subject based on the ideXlab platform.
-
mixed conducting ceramic hollow fiber membranes for Air Separation
Aiche Journal, 2005Co-Authors: K LiAbstract:Mixed conducting ceramic hollow-fiber membranes, which possess an asymmetric structure, were prepared by a combined phase inversion and sintering technique where precursors of the hollow fibers were first spun using a polymer solution containing suspended LSCF powders and were then sintered at elevated temperature. By controlling the weight ratio of the LSCF powder to the polymer binder, sintering temperature, and time, the LSCF hollow fibers with gastight properties have been prepared and evaluated using an apparatus developed during the course of this study. Using the gastight LSCF hollow fibers, a membrane module was assembled for Air Separation. The performances of the module for Air Separation have been studied under various operating modes and at different temperatures and feed flow rates both experimentally and theoretically. The results reveal that the surface exchange reaction at the downstream side is much more important than that at the upstream side, especially for lower operating temperatures. The porous inner surface of the prepared LSCF hollow-fiber membranes substantially favors the oxygen permeation when Air is fed in the shell side of the membrane module. At high operating temperatures, oxygen permeation can be enhanced by the countercurrent flow operation. Vacuum operation favors the oxygen permeation kinetically in the LSCF hollow-fiber membrane modules. © 2005 American Institute of Chemical Engineers AIChE J, 2005
-
mixed conducting ceramic hollow fiber membranes for Air Separation
Aiche Journal, 2005Co-Authors: K LiAbstract:Mixed conducting ceramic hollow-fiber membranes, which possess an asymmetric structure, were prepared by a combined phase inversion and sintering technique where precursors of the hollow fibers were first spun using a polymer solution containing suspended LSCF powders and were then sintered at elevated temperature. By controlling the weight ratio of the LSCF powder to the polymer binder, sintering temperature, and time, the LSCF hollow fibers with gastight properties have been prepared and evaluated using an apparatus developed during the course of this study. Using the gastight LSCF hollow fibers, a membrane module was assembled for Air Separation. The performances of the module for Air Separation have been studied under various operating modes and at different temperatures and feed flow rates both experimentally and theoretically. The results reveal that the surface exchange reaction at the downstream side is much more important than that at the upstream side, especially for lower operating temperatures. The porous inner surface of the prepared LSCF hollow-fiber membranes substantially favors the oxygen permeation when Air is fed in the shell side of the membrane module. At high operating temperatures, oxygen permeation can be enhanced by the countercurrent flow operation. Vacuum operation favors the oxygen permeation kinetically in the LSCF hollow-fiber membrane modules. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Atsushi Tsutsumi - One of the best experts on this subject based on the ideXlab platform.
-
an elevated pressure cryogenic Air Separation unit based on self heat recuperation technology for integrated gasification combined cycle systems
Energy, 2016Co-Authors: Qian Fu, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:An advanced elevated-pressure cryogenic ASU (Air Separation unit) for IGCC (Integrated gasification combined cycle) system was proposed based on self-heat recuperation technology. In the proposed ASU, only one distillation column was used against the double columns in a conventional ASU. The N2 gas drawn from the top of the distillation column is first compressed to elevate the boiling temperature, and then undergo heat exchange with the liquid O2 stream from the bottom of the distillation column. Both the latent and the sensible heat of the process steams are recuperated in the proposed process, resulting in a large reduction of the energy requirement in ASU. We compared four different cryogenic Air Separation processes for IGCC systems: conventional low-pressure ASU, conventional elevated-pressure ASU, proposed low-pressure and elevated-pressure ASU based on self-heat recuperation technology. The simulation results show that the energy requirement of the proposed elevated-pressure ASU is the most suitable choice for IGCC systems, which was reduced by approximately 11.1% comparing with the conventional low-pressure ASU when only nitrogen injection is integrated with IGCC systems.
-
an advanced cryogenic Air Separation process for integrated gasification combined cycle igcc systems
Chemical engineering transactions, 2014Co-Authors: Qian Fu, Yasuki Kansha, Masanori Ishizuka, Chufeng Song, Atsushi TsutsumiAbstract:An advanced cryogenic Air Separation unit (ASU) process for integrated gasification combined cycle (IGCC) system is proposed based on self-heat recuperation technology. In the proposed ASU process, only one distillation column was used in contrast to double columns in the conventional ASU process. The N2 product gas from the top of the distillation column is first compressed, and then exchange heat with the Air liquid from the bottom using the self-heat recuperation technology. Thus, both the latent heat and the sensible heat of the N2 product steam are circulated, resulting in a significant reduction of energy consumption in cryogenic ASU process. In addition, the exergy destruction of the compressors, which contributes to the largest part in previous study, is significantly reduced as no high-pressure column is used in the proposed process. The simulation results show that the total energy consumption of the proposed cryogenic Air Separation process is reduced by around 30 % compared with the conventional cryogenic Air Separation process for IGCC systems.
-
an advanced cryogenic Air Separation process based on self heat recuperation for co2 Separation
Energy Procedia, 2014Co-Authors: Qian Fu, Yasuki Kansha, Masanori Ishizuka, Chunfeng Song, Atsushi TsutsumiAbstract:Abstract An advanced cryogenic Air Separation process for oxy-combustion is proposed based on self-heat recuperation technology. Compared with the conventional double-column cryogenic Air Separation process, only one distillation column is used in the proposed process. The heat of N2 product gas from the top of the distillation column is recirculated by exchanging latent heat with the liquid O2 in the bottom and feed streams, largely reducing the energy consumption. The simulation results showed that the energy consumption of the proposed cryogenic Air Separation process was decreased by 30% comparing with the conventional process, when producing O2 with low purity (95 mol%) and low pressure (120 kPa).
-
a novel cryogenic Air Separation process based on self heat recuperation
Separation and Purification Technology, 2011Co-Authors: Yasuki Kansha, Akira Kishimoto, Tsuguhiko Nakagawa, Atsushi TsutsumiAbstract:In this paper, a novel cryogenic Air Separation process that reduces energy consumption by self-heat recuperation is proposed. In the proposed cryogenic Air Separation process, heat from the top vapor stream of the column is recuperated and exchanged with heat in the bottom liquid and feed streams, using self-heat recuperation technology. As a result, not only the latent heat but also the sensible heat of the process stream is circulated in the process. Furthermore, the pressure in the column can be decreased compared with the high pressure part of a conventional cryogenic Air Separation system, in which high and low pressure columns are combined to exchange nitrogen latent heat with oxygen latent heat. Thus, the energy input to the main compressor located before the column can be dramatically reduced. A simulation demonstrated that the energy consumption of the proposed cryogenic Air Separation process with self-heat recuperation decreased by more than 36% compared with the conventional cryogenic Air Separation process, when producing 99.99 mol% oxygen from Air.
Yasuki Kansha - One of the best experts on this subject based on the ideXlab platform.
-
an elevated pressure cryogenic Air Separation unit based on self heat recuperation technology for integrated gasification combined cycle systems
Energy, 2016Co-Authors: Qian Fu, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:An advanced elevated-pressure cryogenic ASU (Air Separation unit) for IGCC (Integrated gasification combined cycle) system was proposed based on self-heat recuperation technology. In the proposed ASU, only one distillation column was used against the double columns in a conventional ASU. The N2 gas drawn from the top of the distillation column is first compressed to elevate the boiling temperature, and then undergo heat exchange with the liquid O2 stream from the bottom of the distillation column. Both the latent and the sensible heat of the process steams are recuperated in the proposed process, resulting in a large reduction of the energy requirement in ASU. We compared four different cryogenic Air Separation processes for IGCC systems: conventional low-pressure ASU, conventional elevated-pressure ASU, proposed low-pressure and elevated-pressure ASU based on self-heat recuperation technology. The simulation results show that the energy requirement of the proposed elevated-pressure ASU is the most suitable choice for IGCC systems, which was reduced by approximately 11.1% comparing with the conventional low-pressure ASU when only nitrogen injection is integrated with IGCC systems.
-
an advanced cryogenic Air Separation process for integrated gasification combined cycle igcc systems
Chemical engineering transactions, 2014Co-Authors: Qian Fu, Yasuki Kansha, Masanori Ishizuka, Chufeng Song, Atsushi TsutsumiAbstract:An advanced cryogenic Air Separation unit (ASU) process for integrated gasification combined cycle (IGCC) system is proposed based on self-heat recuperation technology. In the proposed ASU process, only one distillation column was used in contrast to double columns in the conventional ASU process. The N2 product gas from the top of the distillation column is first compressed, and then exchange heat with the Air liquid from the bottom using the self-heat recuperation technology. Thus, both the latent heat and the sensible heat of the N2 product steam are circulated, resulting in a significant reduction of energy consumption in cryogenic ASU process. In addition, the exergy destruction of the compressors, which contributes to the largest part in previous study, is significantly reduced as no high-pressure column is used in the proposed process. The simulation results show that the total energy consumption of the proposed cryogenic Air Separation process is reduced by around 30 % compared with the conventional cryogenic Air Separation process for IGCC systems.
-
an advanced cryogenic Air Separation process based on self heat recuperation for co2 Separation
Energy Procedia, 2014Co-Authors: Qian Fu, Yasuki Kansha, Masanori Ishizuka, Chunfeng Song, Atsushi TsutsumiAbstract:Abstract An advanced cryogenic Air Separation process for oxy-combustion is proposed based on self-heat recuperation technology. Compared with the conventional double-column cryogenic Air Separation process, only one distillation column is used in the proposed process. The heat of N2 product gas from the top of the distillation column is recirculated by exchanging latent heat with the liquid O2 in the bottom and feed streams, largely reducing the energy consumption. The simulation results showed that the energy consumption of the proposed cryogenic Air Separation process was decreased by 30% comparing with the conventional process, when producing O2 with low purity (95 mol%) and low pressure (120 kPa).
-
a novel cryogenic Air Separation process based on self heat recuperation
Separation and Purification Technology, 2011Co-Authors: Yasuki Kansha, Akira Kishimoto, Tsuguhiko Nakagawa, Atsushi TsutsumiAbstract:In this paper, a novel cryogenic Air Separation process that reduces energy consumption by self-heat recuperation is proposed. In the proposed cryogenic Air Separation process, heat from the top vapor stream of the column is recuperated and exchanged with heat in the bottom liquid and feed streams, using self-heat recuperation technology. As a result, not only the latent heat but also the sensible heat of the process stream is circulated in the process. Furthermore, the pressure in the column can be decreased compared with the high pressure part of a conventional cryogenic Air Separation system, in which high and low pressure columns are combined to exchange nitrogen latent heat with oxygen latent heat. Thus, the energy input to the main compressor located before the column can be dramatically reduced. A simulation demonstrated that the energy consumption of the proposed cryogenic Air Separation process with self-heat recuperation decreased by more than 36% compared with the conventional cryogenic Air Separation process, when producing 99.99 mol% oxygen from Air.
Lawrence Megan - One of the best experts on this subject based on the ideXlab platform.
-
a non gaussian pattern matching based dynamic process monitoring approach and its application to cryogenic Air Separation process
Computers & Chemical Engineering, 2013Co-Authors: Jingyan Chen, Mudassir Rashid, Jie Yu, Junichi Mori, Gangshi Hu, Honglu Yu, Jesus Florescerrillo, Lawrence MeganAbstract:Abstract Principal component analysis (PCA) based pattern matching methods have been applied to process monitoring and fault detection. However, the conventional pattern matching approaches do not specifically take into account the non-Gaussian dynamic features in chemical processes. Furthermore, those techniques are more focused on fault detection instead of fault diagnosis. In this study, a non-Gaussian pattern matching based fault detection and diagnosis method is developed and applied to monitor cryogenic Air Separation process. First, independent component analysis (ICA) models are built on the normal benchmark and monitored data sets along sliding windows. The IC subspaces from the benchmark and monitored data are then extracted to evaluate the non-Gaussian patterns and detect process faults through a mutual information based dissimilarity index. Further, a difference subspace between the two IC subspaces is computed to characterize the divergence of the dynamic and non-Gaussian patterns between the benchmark and monitored data. Subsequently, the mutual information between the IC difference subspace and each process variable direction is defined as a new non-Gaussian contribution index for fault identification and diagnosis. The presented approach is applied to a simulated cryogenic Air Separation plant and the monitoring results are compared against those of PCA based pattern matching techniques and ICA based monitoring method. The application study demonstrates that the developed non-Gaussian pattern matching approach can effectively monitor the complex Air Separation process with superior fault detection and diagnosis capability.
-
nonlinear model predictive control of high purity distillation columns for cryogenic Air Separation
IEEE Transactions on Control Systems and Technology, 2010Co-Authors: Zhongzhou Chen, Paul W Belanger, Michael A Henson, Lawrence MeganAbstract:High purity distillation columns are critical unit operations in cryogenic Air Separation plants that supply purified gases to a number of industries. We have developed a nonlinear model predictive control (NMPC) strategy based on the assumption of full-state feedback for a prototypical cryogenic distillation column to allow effective operation over a wide range of plant production rates. The controller design was based on a reduced-order compartmental model derived from detailed mass and energy balances by exploiting time-scale Separations. Temporal discretization of the compartmental model produced a very large set of nonlinear differential and algebraic equations with advantageous sparsity properties, enabling online solution of the NMPC problem. The synergistic combination of several real-time implementation techniques were found to be essential for further reducing computation time and allowing reliable solution within the 2-min controller sampling interval. Closed-loop simulation studies demonstrated the performance advantages of NMPC compared to linear model predictive control technology currently used in the Air Separation industry.
-
compartmental modeling of high purity Air Separation columns
Computers & Chemical Engineering, 2005Co-Authors: Shoujun Bian, Paul W Belanger, Michael A Henson, Suabtragool Khowinij, Lawrence MeganAbstract:High purity distillation columns are critical unit operations in cryogenic Air Separation plants. The development of nonlinear control technology is motivated by the need to frequently change production rates in response to time varying utility costs. Detailed column models based on stage-by-stage balance equations are too complex to be incorporated directly into optimization-based strategies such as nonlinear model predictive control. In this paper, we develop reduced order dynamic models for the upper column of a cryogenic Air Separation plant by applying time scale arguments to a detailed stage-by-stage model that includes mass and energy balances and accounts for non-ideal vapor–liquid equilibrium. The column is divided into compartments according to the locations of liquid distributors and feed and withdrawal streams. The differential equations describing each compartment are placed in singularly perturbed form through the application of a physically based coordinate transformation. Application of singular perturbation theory yields a differential–algebraic equation model with significantly fewer differential variables than the original stage-by-stage model. A rigorous column simulator constructed using Aspen Dynamics (Aspen Technology) is used to access the tradeoff between reduced order model complexity and accuracy as the number of compartments is varied. © 2005 Elsevier Ltd. All rights reserved.
Mehdi Mehrpooya - One of the best experts on this subject based on the ideXlab platform.
-
novel cryogenic argon recovery from the Air Separation unit integrated with lng regasification and co2 transcritical power cycle
Sustainable Energy Technologies and Assessments, 2020Co-Authors: Mehdi Mehrpooya, Behrooz Golestani, S Ali M MousavianAbstract:Abstract Two novel Air Separation units at cryogenic temperature were proposed to reach high purity nitrogen, oxygen, and argon. The first process refers to a three-column cryogenic Air Separation plant without using an external refrigeration system. An integrated process including cryogenic Air Separation, combined-cycle power plants (e.g., transcritical CO2 cycle and gas turbine), and LNG regasification was presented and analyzed as the second process to produce liquid oxygen and vaporize LNG without using external refrigeration source. Results of the first proposed process demonstrate that the specific energy consumption of high purity nitrogen, oxygen, and argon reduces to 18.7%, 13%, and 12% respectively when compared with the conventional processes. Specific energy consumptions and exergy efficiency for the second plant improved by nearly 33% and 16% in comparison with the first process. Also, the gas turbine and CO2 power cycle efficiencies were almost 35% and 45% in the second process. Exergy analysis on both systems demonstrated that expansion valve V-2 (99.42%), high-pressure distillation columns (99.41%), and argon recovery section (98.34%) have the lowest irreversibility and highest exergy efficiency. Meanwhile, the highest exergy destructions in the first and second proposed plants belong to the low-pressure distillation tower of the first process and the combustion chamber of the second process with around 3400 kW and 24,000 kW respectively.
-
investigation of novel integrated Air Separation processes cold energy recovery of liquefied natural gas and carbon dioxide power cycle
Journal of Cleaner Production, 2016Co-Authors: Mehdi Mehrpooya, Masoud Kalhorzadeh, Mahmood ChahartaghiAbstract:Abstract Cryogenic Air Separation unit (ASU) consume high amount of energy to produce oxygen and nitrogen with high purity. Liquefied natural gas (LNG) regasification process provides low temperature cryogenic refrigeration source which can be used in ASU with high efficiency. In this study two cryogenic Air Separation processes for production of high purity nitrogen and oxygen with low energy consumption are proposed and analyzed. The first proposed process is a two-column configuration which power consumption per oxygen production is 16.6% lower, compared to a convectional cryogenic Air Separation process. In the second one, liquefied natural gas cold energy is used for pre-cooling the feed Air. This greatly reduces the energy consumption of the compressors located before the columns by more than 55.6% compared to the first proposed process, without much change in purity of the products. In the second process, energy saving in the Air Separation unit and power generation cycle is 2715 kW and 17,810 kW respectively. Both processes use an integrated heat exchanger which is both condenser of the high pressure column and reboiler of the low pressure column. With this integration latent heat of the pure nitrogen and pure oxygen can be exchanged in a two-column process configuration. The second proposed process is a hybrid with a carbon dioxide trans-critical power cycle. The liquefied natural gas cold energy is used for cooling the power cycle condenser. Energy and exergy analysis are carried out on the Air Separation unit and power generation cycle.
-
optimum design and exergy analysis of a novel cryogenic Air Separation process with lng liquefied natural gas cold energy utilization
Energy, 2015Co-Authors: Mehdi Mehrpooya, Mohammad Mehdi Moftakhari Sharifzadeh, Marc A RosenAbstract:A novel cryogenic Air Separation process with LNG (liquefied natural gas) cold energy utilization that produces liquid nitrogen and oxygen is proposed and analyzed. Air Separation process problems such as process configuration complexity, extreme operating conditions and high operating costs are covered. In this process heat from the top vapor stream of the column is recovered and exchanged with heat in the bottom liquid and feed streams. It is noted that column operating pressure can be decreased compared with the high pressure portion of the Air Separation systems. In fact, the high and low pressure columns are combined here to exchange nitrogen latent heat with oxygen latent heat. This significantly reduces the energy input to the main compressor located before the column. Also, to completely utilize the cold energy of the LNG and to offset some of the consumed power, a power generation cycle is integrated with the process. This cycle utilizes pure oxygen from the Air Separation unit. The cryogenic Air Separation process is simulated and the main parameters are analyzed. It is shown that the energy consumption for the proposed Air Separation process with LNG cold recovery is about 38.5% lower compared for a convectional cryogenic Air Separation process. The energy and exergy efficiencies increase by 59.4% and 67.1%, respectively.