• Journal of Institute of Control, Robotics and Systems
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• v.12 no.12
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• pp.1163-1168
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• 2006

Manufacturing technology for the production of high value-added fine chemical products is emphasized and getting more attention as the diversified interests of customers and the demand of high quality products are getting bigger and bigger everyday. Thus, the development of advanced batch processes, which is the preferred and most appropriate way of producing these types of products, and the related technologies are becoming more important. Therefore, high-precision batch distillation is one of the important elements in the successful manufacturing of fine chemicals, and the importance of the process operation strategy with quality assurance cannot be overemphasized. Accordingly, proposing a process structure explanation and operation strategy of such processes including batch processes and batch distillation would be of great value. We investigate optimal operation strategy and production planning of multi-purpose plants consisting of batch processes and batch distillation for the manufacturing of fine chemical products. For the short-term scheduling of a sequential multi-purpose batch plant consisting of batch distillation under MPC and UIS policy, we proposed a MILP model based on a priori time slot allocation. Also, we consider that the waste product of being produced on batch distillation is recycled to the batch distillation unit for the saving of raw materials. The developed methodology will be especially useful for the design and optimal operations of multi-purpose and multiproduct plants that is suitable for fine chemical production.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.12
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• pp.1197-1201
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• 2006

In order to improve the operability in a fully thermally coupled distillation column the main column is separated into an upper and a lower column, and its design method is explained. With a distillation experiment using a two-inch column the operability of the proposed column is examined. Readily available methanol, ethanol and propanol are used as the feed, and the experimental result is compared with that of the HYSYS simulation. It is found from the experiment that the recovery ranges between 58.8% and 68% and the distillation efficiency is lower than that of the simulation. consumes less energy than an original column, it is not widely implemented in practice due to its operational difficulty. However, it is proved that the proposed distillation column can be operated without compressors and it can be practically utilized.

• Membrane and Water Treatment
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• v.7 no.4
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• pp.367-375
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• 2016

Although the bucky paper (BP) made from carbon nanotubes (CNTs) possesses beneficial characteristics of hydrophobic nature and high porosity for membrane distillation (MD) application, weak mechanical strength of BP has often prevented the stable operation. This study aims to fabricate the BP with high mechanical strength to improve its MD performance. The strategy was to increase the purity level of CNTs with an assumption that purer CNTs would increase the Van der Waals attraction, leading to the improvement of mechanical strength of BP. According to this study results, the purification of CNT does not necessarily enhance the mechanical strength of BP. The BP made from purer CNTs demonstrated a high flux ($142kg/m^2{\cdot}h$) even at low ${\Delta}T$ ($50^{\circ}C$ and $20^{\circ}C$) during the experiments of direct contact membrane distillation (DCMD). However, the operation was not stable because a crack quickly formed. Then, a support layer of AAO (anodic aluminum oxide) filter paper was introduced to reinforce the mechanical strength of BP. The support reinforcement was able to increase the mechanical strength, but wetting occurred. Therefore, the mixed matrix membrane (PSf-CNT) using CNTs as filler to polysulphone was fabricated. The DCMD operation with the PSf-CNT membrane was stable, although the flux was low ($6.1kg/m^2{\cdot}h$). This result suggests that the mixed matrix membrane could be more beneficial for the stable DCMD operation than the BP.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.815-824
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• 2012

Extractive distillation system can be used when the components to be separated have close boiling points or form azeotropes. Extractive distillation is one of the most important and widely used separation methods in chemical process industry. The main disadvantage of the distillation is its high-energy requirements. Thermally coupled distillation system (TCDS) can provide significant savings in energy consumption and capital cost over the operation of sequences based on conventional distillation column. Despite such advantages of the thermally coupled distillation system, the process is not widely used in industry because control and operation of the column are difficult. In this study, we propose several control schemes for thermally coupled distillation system to overcome the difficulties and make the column stable when the process is confronted with feed disturbances. Profile position control scheme shows best control performance among the proposed control schemes.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.89-92
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• 2009

Because many research using concentrated hydrogen peroxide as propellant is studied, research for distillation method for domestic production of rocket grade hydrogen peroxide is needed. To distill hydrogen peroxide, vacuum distillation will be used because of heat decomposition of hydrogen peroxide. Distillation pressure is 30 torr which is determined by Raoult's law to distill under $40^{\circ}C$. Variable of distillation experiment is distillation temperature. And the comparison of distillation results was done by yield and operation time. In the result, generally, yield was lower and the water in receiver had higher concentration with shorter distillation time. And with similar time, when distillation temperature was higher, yield was lower and hydrogen peroxide became higher concentration.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1826-1829
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• 2003

Fine chemical production must assure high-standard product quality as well as characterized as multi-product production in small volumes. Installing high-precision batch distillation is one of the common elements in the successful manufacturing of fine chemicals, and the importance of the process operation strategy with quality assurance cannot be overemphasized. In this study, we investigate the optimal operation strategy and production planning of a sequential multi-purpose plants consisting of batch processes and batch distillation with unlimited intermediate storage. We formulated this problem as an MILP model. A mixed-integer linear programming model is developed based on the time slot, which is used to determine the production sequence and the production path of each batch. Illustrative examples show the effectiveness of the approach.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.9
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• pp.945-953
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• 2006

Though a fully thermally coupled distillation column consumes less energy than an original column, it is not widely implemented in practice due to its operational difficulty. A new fully thermally coupled distillation column is proposed for the operability improvement, and its performance is investigated. The main improvement is the separation of a main column to give an upper and lower columns and the installation of an intermediate heat exchanger between them to regulate the fluctuation of product compositions. A proper manipulation of column pressure in the separated main columns made easy vapor flow without a compressor. The operability improvement is examined in a hexane process from the dynamic simulation using a commercial design software HYSYS. The simulation results indicate that the coupling among inputs and outputs is loosened to make easy manipulation of product compositions in the proposed distillation system.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.83-83
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• 2017

Electrorefining is a key step in pyroprocessing. The electrorefining process is generally composed of two recovery steps - the deposit of uranium onto a solid cathode and the recovery of the remaining uranium and TRU elements simultaneously by a liquid cadmium cathode. The solid cathode processing is necessary to separate the salt from the cathode since the uranium deposit in a solid cathode contains electrolyte salt. Distillation process was employed for the cathode processing. It is very important to increase the throughput of the salt separation system due to the high uranium content of spent nuclear fuel and high salt fraction of uranium dendrites. In this study, a mesh-covered crucible was investigated for the sat distillation of electrorefiner uranium deposits. A liquid salt separation step and a vacuum distillation step were combined for salt separation. The adhered salt in uranium deposits was efficiently removed in the mesh-covered crucible. The salt distiller was operated simply since repeated cooling - heating step was not necessary for the change of the crucible. The operation time could be reduced by the use of the mesh-covered crucible and the combined operation of the two steps. A method to preserve a vacuum level was proposed by double O-rings during the operation of the distiller with the mesh-covered crucible. After the salt distillation, the salt content was measured and was below 0.1wt% after the salt distillation. The residual salt after the salt distillation can be removed further during melting of uranium metal.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.327-331
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• 2009

A thermally coupled distillation system is constructed using two columns used in a conventional two column system, and its operability is examined by investigating the dynamic behavior. For the control of three product specifications, the step response test is performed and a $3{\times}3$ control structure using flow rates of overhead and side products and vapor boilup is suggested. The performance of the proposed control system indicates that the specification control of bottom product is the most difficult but the operation of the proposed system is available.

• Applied Biological Chemistry
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• v.37 no.1
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• pp.9-13
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• 1994

Baikhaju, the traditional Korean rice wine was brewed and distilled at various conditions-at different pressure (760, 460, 260 mmHg), different reflux ratio (3.1 : 1, 1 : 1) and different column conditions (packed and unpacked), and distillation operation was investigated. The sample wine, Baikhaju showed alcohol content of 14.2%, acidity 8.3 (g/100 ml), ethyl acetate 49 ppm, fusel oil 657 ppm. As the distillation was proceeded, alcohol concentration of distillate was decreased and that was higher in atmospheric pressure rather than reduced pressure. When the pressure was increased, the slope showed the relation of alcohol concentration between still liquid and vapour was increased, and also as the reflux ratio was increased, alcohol concentration of distillate was increased, and that was 0.56 mole at the reflux ratio 3.1 : 1 at atmospheric pressure, where 0.54 mole at 1 : 1 reflux ratio. As the distillation was proceeded, the rate of distillation was decreased, and that was higher values in the reduced pressure than atmospheric pressure. The maximum value (0.14 ml/s) of rate of distillation was observed in the packed column at 260 mmHg. As the reflux ratio was increased, the rate of distillation was decreased, and that was 0.05 ml/sec at reflux ratio 3.1 : 1 at atmospheric pressure, where 0.06 ml/sec at 1 : 1 reflux ratio.