The Experts below are selected from a list of 41571 Experts worldwide ranked by ideXlab platform
Jixin Qian - One of the best experts on this subject based on the ideXlab platform.
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Adding rectifying/stripping section type Heat Integration to a pressure-swing distillation (PSD) process
Applied Thermal Engineering, 2008Co-Authors: Kejin Huang, Lan Shan, Qunxiong Zhu, Jixin QianAbstract:This paper studies the economical effect of considering rectifying/stripping section type Heat Integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging Heat Integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the Heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and Heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type Heat Integration with the rectifying/stripping section type Heat Integration in process synthesis and design.
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adding rectifying stripping section type Heat Integration to a pressure swing distillation psd process
Applied Thermal Engineering, 2008Co-Authors: Kejin Huang, Lan Shan, Qunxiong Zhu, Jixin QianAbstract:This paper studies the economical effect of considering rectifying/stripping section type Heat Integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging Heat Integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the Heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and Heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type Heat Integration with the rectifying/stripping section type Heat Integration in process synthesis and design.
Kejin Huang - One of the best experts on this subject based on the ideXlab platform.
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Interpreting the dynamic effect of internal Heat Integration on reactive distillation columns
Chinese Journal of Chemical Engineering, 2016Co-Authors: Yang Yuan, Liang Zhang, Haisheng Chen, Shaofeng Wang, Kejin Huang, Huan ShaoAbstract:Abstract In this work, the impact of internal Heat Integration upon process dynamics and controllability by superposing reactive section onto stripping section, relocating feed locations, and redistributing catalyst within the reactive section is explored based on a hypothetical ideal reactive distillation system containing an exothermic reaction: A + B ↔ C + D. Steady state operation analysis and closed-loop controllability evaluation are carried out by comparing the process designs with and without the consideration of internal Heat Integration. For superposing reactive section onto stripping section, favorable effect is aroused due to its low sensitivities to the changes in operating condition. For ascending the lower feed stage, somewhat detrimental effect occurs because of the accompanied adverse internal Heat Integration and strong sensitivity to the changes in operating condition. For descending the upper feed stage, serious detrimental effect happens because of the introduced adverse internal Heat Integration and strong sensitivity to the changes in operating condition. For redistributing catalyst in the reactive section, fairly small negative influence is aroused by the sensitivity to the changes in operating condition. When reinforcing internal Heat Integration with a combinatorial use of these three strategies, the decent of the upper feed stage should be avoided in process development. Although the conclusions are derived based on the hypothetical ideal reactive distillation column studied, they are considered to be of general significance to the design and operation of other reactive distillation columns.
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Adding rectifying/stripping section type Heat Integration to a pressure-swing distillation (PSD) process
Applied Thermal Engineering, 2008Co-Authors: Kejin Huang, Lan Shan, Qunxiong Zhu, Jixin QianAbstract:This paper studies the economical effect of considering rectifying/stripping section type Heat Integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging Heat Integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the Heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and Heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type Heat Integration with the rectifying/stripping section type Heat Integration in process synthesis and design.
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adding rectifying stripping section type Heat Integration to a pressure swing distillation psd process
Applied Thermal Engineering, 2008Co-Authors: Kejin Huang, Lan Shan, Qunxiong Zhu, Jixin QianAbstract:This paper studies the economical effect of considering rectifying/stripping section type Heat Integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging Heat Integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the Heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and Heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type Heat Integration with the rectifying/stripping section type Heat Integration in process synthesis and design.
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Towards further internal Heat Integration in design of reactive distillation columns—Part II. The process dynamics and operation
Chemical Engineering Science, 2006Co-Authors: Kejin Huang, Masaru Nakaiwa, Atsushi TsutsumiAbstract:Abstract In the first paper of this series, it has been demonstrated that the capital investment and operating cost can frequently be reduced substantially through seeking further internal Heat Integration between the reaction operation and separation operation for a reactive distillation column involving reactions with highly thermal effect. In this paper, the dynamics and operation of the resultant reactive distillation system is to be examined, with special emphasis focused on the dynamic effect of the supplementary internal Heat Integration. It has been found that seeking further internal Heat Integration can sometimes improve process dynamics and lessen difficulties in process operation. This outcome stems from the refined relationship between the reaction operation and separation operation involved and is of great significance in tightening process design for a reactive distillation column containing reactions with highly thermal effect. It should, however, be pointed out that seeking further internal Heat Integration might also confine severely the flexibility of the resultant reactive distillation column due to the reduction of mass transfer driving forces. When encountering a sharp increase in the product specification that is more relevant to the supplementary internal Heat Integration, the process might show deteriorated dynamic performance and can even converge to an undesirable steady state where the economical advantages of the supplementary internal Heat Integration are lost totally. Therefore, some effective measures to increase the redundancy of the resultant process design have to be taken to deal with the side-effect during process development.
Lan Shan - One of the best experts on this subject based on the ideXlab platform.
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Adding rectifying/stripping section type Heat Integration to a pressure-swing distillation (PSD) process
Applied Thermal Engineering, 2008Co-Authors: Kejin Huang, Lan Shan, Qunxiong Zhu, Jixin QianAbstract:This paper studies the economical effect of considering rectifying/stripping section type Heat Integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging Heat Integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the Heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and Heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type Heat Integration with the rectifying/stripping section type Heat Integration in process synthesis and design.
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adding rectifying stripping section type Heat Integration to a pressure swing distillation psd process
Applied Thermal Engineering, 2008Co-Authors: Kejin Huang, Lan Shan, Qunxiong Zhu, Jixin QianAbstract:This paper studies the economical effect of considering rectifying/stripping section type Heat Integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging Heat Integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the Heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and Heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type Heat Integration with the rectifying/stripping section type Heat Integration in process synthesis and design.
Qunxiong Zhu - One of the best experts on this subject based on the ideXlab platform.
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Adding rectifying/stripping section type Heat Integration to a pressure-swing distillation (PSD) process
Applied Thermal Engineering, 2008Co-Authors: Kejin Huang, Lan Shan, Qunxiong Zhu, Jixin QianAbstract:This paper studies the economical effect of considering rectifying/stripping section type Heat Integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging Heat Integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the Heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and Heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type Heat Integration with the rectifying/stripping section type Heat Integration in process synthesis and design.
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adding rectifying stripping section type Heat Integration to a pressure swing distillation psd process
Applied Thermal Engineering, 2008Co-Authors: Kejin Huang, Lan Shan, Qunxiong Zhu, Jixin QianAbstract:This paper studies the economical effect of considering rectifying/stripping section type Heat Integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging Heat Integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the Heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and Heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type Heat Integration with the rectifying/stripping section type Heat Integration in process synthesis and design.
Thokozani Majozi - One of the best experts on this subject based on the ideXlab platform.
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Long-term Heat Integration in multipurpose batch plants using Heat storage
Journal of Cleaner Production, 2017Co-Authors: Jane D. Stamp, Thokozani MajoziAbstract:Abstract Most scheduling methods are limited to the short-term scheduling case and solution of problems over long time horizons may prove challenging or impossible with these methods. Including additional considerations such as Heat Integration further complicates the problem. A model for the simultaneous optimisation of the schedule and energy usage in Heat integrated multipurpose batch plants operated over long time horizons has been presented. The method uses a cyclic scheduling solution procedure. The proposed model includes indirect Heat Integration via Heat storage, rather than just direct Heat Integration. This has not been considered in long-term Heat Integration models in current literature. Both the Heat storage size and initial Heat storage temperature are also optimised. The solution obtained over 24 h using the proposed cyclic scheduling model with direct Heat Integration for a multipurpose example was compared to the result obtained from the direct solution and an error of less than 6% was achieved.
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Heat Integration in multipurpose batch plants using a robust scheduling framework
Energy, 2014Co-Authors: Esmael R. Seid, Thokozani MajoziAbstract:Energy saving is becoming increasingly important in batch processing facilities. Multipurpose batch plants have become more popular than ever in the processing environment due to their inherent flexibility and adaptability to market conditions, even though the same flexibility may lead to complexities such as the need to schedule process tasks. These are important features to producing high value added products such as agrochemicals, pharmaceuticals, polymers, food and specialty chemicals where the demand has grown in recent decades. Many current Heat Integration methods for multipurpose batch plants use a sequential methodology where the schedule is solved first followed by Heat Integration. This can lead to suboptimal results. In this paper, the Heat Integration model is built upon a robust scheduling framework. This scheduling formulation has proven to lead to better results in terms of better objective values, fewer required time points and reduced computational time. This is important as inclusion of Heat Integration into a scheduling model invariably complicates the solution process. The improved scheduling model allows the consideration of industrial sized problems to simultaneously optimize both the process schedule and energy usage. Both direct and indirect Heat Integration are considered as well as fixed and variable batch sizes.
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Heat Integration in Batch Processes
Handbook of Process Integration (PI), 2014Co-Authors: Thokozani MajoziAbstract:Abstract: This chapter addresses Heat Integration in multipurpose batch plants in situations where the schedule is known a priori, as well as cases that are characterised by unknown prior production schedules. In most published literature, Heat Integration of batch facilities is treated as a secondary objective to production scheduling, which implies that the starting and ending times of tasks are fixed a priori. However, suppression of time as a variable in the overall optimisation framework has proven to result in suboptimal results. True optimum is achieved when time is treated as a variable. The chapter presents a promising graphical technique that could be used in setting targets for Heat recovery and design of the corresponding utility system. As in all graphical techniques, time is treated as a parameter rather than as a variable. This is followed by a mathematical model that allows time to be treated as a variable in setting energy targets and storage design. The performance of this model is demonstrated through a case study.
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Heat Integration in Multipurpose Batch Plants: II. Indirect Heat Integration
Batch Chemical Process Integration, 2009Co-Authors: Thokozani MajoziAbstract:This chapter is, in essence, an extention of Chapter 10 which focused on direct Heat Integration as encountered in the absence of Heat storage (Majozi, J. Cleaner Prod., 17: 945–950, 2006). The inclusion of Heat storage in the exploration of energy saving opportunities through Heat Integration adds more degrees of freedom in the analysis, which is likely to improve the optimum point. The necessity of Heat storage arises from the time dimension that is inherent in batch plants as mentioned severally in the foregoing chapters. Storage of Heat allows the time dimension to be bypassed by allowing the task that serves as the Heat source to take place before the task that is appropriate to serve as the corresponding Heat sink without losing the opportunity for Heat Integration. Heat transfer fluids, e.g. water, are normally used for this purpose. The presented mathematical formulation exhibits an MILP structure for the fixed capacity of storage. Application of the proposed method to an agrochemical facility demonstrates savings of more than 75% in external utility steam consumption.
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Heat Integration of multipurpose batch plants using a continuous time framework
Applied Thermal Engineering, 2006Co-Authors: Thokozani MajoziAbstract:Presented in this paper is a continuous-time mathematical formulation for optimization of Heat integrated batch chemical plants. This formulation is applicable to both multipurpose and multiproduct facilities in which opportunities for direct Heat Integration exist. It is assumed that thermal driving forces and Heat duties between operations identified as potential Heat Integration candidates are sufficient. These operations can either belong to the same batch plant or distinct batch facilities within the same site. Two scenarios are explored in this paper. The first scenario entails a situation where energy requirement is dependent on batch size, which is allowed to vary with distinct task occurrences within the time horizon of interest. The second scenario is based on fixed batch sizes in which the duty requirement is specified as a parameter. In the first scenario, the resulting formulation is initially cast as a nonconvex mixed integer nonlinear program (MINLP), which is linearized exactly to yield a convex MILP problem. This linearization is not necessary in the second scenario, as the resulting model is readily an MILP problem. A literature example and a case study are used to demonstrate the effectiveness of the formulation.
