• Journal of Institute of Control, Robotics and Systems
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• v.8 no.10
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• pp.833-841
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• 2002

We develope a model that can manipulate the reflux ratio of a batch distillation process in real time for optimal operations. Firstly, reflux ratio decision model for batch distillation unit was developed using the simple short-cut method. Secondly, more detailed rigorous method was applied to improve the accuracy of the model. Based on these models, operational strategies for the optimal reflux ratio was proposed. The results are illustrated with suitable examples and compared with the results using commercial simulator.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.145-150
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• 2002

The distillation column is one of large energy consumable units in the cryogenic air separation process and the accurate energy analysis of this unit is necessary for choice of energy saving process. In this work, the energy method was adopted for energy analysis of a cryogenic nitrogen distillation column. In order to designing the energy saving distillation column, the exergy distribution of feed air, exergy efficiency and exergy loss for process condition was investigated and the optimal process condition to minimize the exergy loss was found. The result from this work can be used as a guideline for the choice of the process design conditions and efficiency improvement of cryogenic distillation column.

• 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.

• Proceedings of the Korean Professional Engineer Association Conference
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• 1984.12a
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• pp.84-91
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• 1984

Heavy Residual Fuel oils is a mixture of reduced crude from crude unit, bottom products from vacuum and/or catalytic cracking unit with distillate to meet the specification and generally used as Heavy Fuel Oil for large combustion engines, boilers, etc…. But this study was made to investigate Heavy Residual Fuel oils for using as industrial raw material and resulted the following possibilties as valuable raw material as well as Heavy Fuel Oil. 1) Production of straight asphalt through vacuum distillation unit. 2) Using straight asphalt from vacuum distillation unit for manufacturing of Blown Asphalts, Cut Back Asphalts, Emulsified Asphalts and Asphalt Compound, etc…. 3) Using waxy oil side streams for manufacturing of raw oil to be Lube Oil base stocks through solvent dewaxing. 4) Production of lube base oils from dewaxed raw oil through chemical treatments. 5) Manufacturing of paraffine wax from slack wax to be produced as by product of dewaxing process.

• Membrane and Water Treatment
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• v.10 no.5
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• pp.321-330
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• 2019

The objective of this study was to examine the recovery of the power plant cooling tower blowdown water (CTBD) by membrane distillation. The experiments were carried out using a flat plate poly vinylidene fluoride (PVDF) membrane with a pore diameter of $0.22{\mu}m$ by a direct contact membrane distillation unit (DCMD). The effects of operating parameters such as transmembrane temperature difference (${\Delta}T$), circulation rate and operating time on permeate flux and membrane fouling have been investigated. The results indicated that permeate flux increased with increasing ${\Delta}T$ and circulation rate. Whereas maximum permeate flux was determined as $47.4L/m^2{\cdot}h$ at ${\Delta}T$ of $50^{\circ}C$ for all short term experiments, minimum permeate flux was determined as $7.7L/m^2{\cdot}h$ at ${\Delta}T$ of $20^{\circ}C$. While $40^{\circ}C$ was determined as the optimum ${\Delta}T$ in long term experiments. Inorganic and non-volatile substances caused fouling in the membranes.

• Korean Journal of Metals and Materials
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• v.46 no.1
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• pp.13-19
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• 2008

To develop a recycling process of magnesium alloy scrap, a fundamental study on the distillation of magnesium alloy melt was carried out. Melt temperature, vacuum degree and reaction time were considered as experimental variables. The amount of vaporized magnesium melt per unit surface area of melt increases with the increase of melt temperature, reaction time and vacuum degree. The vapor condensed at the tip of water cooling Cu-condenser as a form of pine cone. Magnesium and zinc were vaporized easily from the melt. However, It's difficult to separate magnesium and zinc by vacuum distillation because vapor pressure of zinc is similar to one of magnesium. The contents of aluminum, manganese and iron, etc. in residual melt increase due to the decrease of magnesium and zinc content after the distillation of magnesium alloy.

• Elastomers and Composites
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• v.20 no.2
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• pp.115-131
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• 1985

Heavy residual fuel oils is a mixture of reduced crude from crude unit, bottom products from vacuum and/or catalytic cracking unit with distillate to meet the specification and generally used as heavy fuel oil for large combustion engines, boilers, etc$\cdots$. But this study was made to investigate heavy residual fuel oils for using as industrial raw material and resulted the following possiblities as valuable raw material as well as heavy fuel oil. 1) Production of straight asphalt through vacuum distillation unit. 2) Using straight asphalt from vacuum distillation unit for manufacturing of blown asphalts, cut back asphalts, emulsified asphalts and asphalt compound, rubber/asphalt sheet, etc$\cdots$. 3) Using waxy oil side streams for manufacturing of raw oil to be lube oil base stocks through solvent dewaxing. 4) Production of lube base oils and rubber process oils from dewaxed raw oil through chemical treatments. 5) Manufacturing of paraffine wax from slack wax to be produced as by product of dewaxing process.

• Progress in Superconductivity and Cryogenics
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• v.3 no.1
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• pp.69-73
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• 2001

For developing the cryogenic air separation unit, it requires some technology such as basic process design. equipment design and manufacturing based on the cryogenic physical properties and separation theory. In this study, we developed a process and equipment for producing high purity nitrogen which has the production capacity of 1600N㎥/h under 1 ppm $O_2$ and $H_2O$. Also we found that the number of theoretical plate(NTP) of distillation column was 44 and maximum nitrogen recovery ration of this process was 42% from the process simulation. The performance test was also carried out for the nitrogen recovery ratio and equipment efficiency. The results showed that the optimum nitrogen recovery was 41% and the maximum equipment efficiency was attained.

• Journal of Hydrogen and New Energy
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• v.31 no.3
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• pp.322-327
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• 2020

In this work, a study for the reduction of the electric power consumption has been estimated in main air compressors in the air separation unit through cryogenic distillation columns with PRO/II with PROVISION V10.2 at AVEVA company. Both required LNG mass flow rate and cold heat contained in 1 ton of LNG were also predicted using Peng-Robinson equation of state with Twu's new alpha function. Through this work, we concluded that 32.33-48.69% of electric power could be saved by using LNG cold heat.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.131-134
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• 2003

There has been a renewed interest in the use of hydrogen peroxide as an oxidizer in bipropellant liquid rocket engines as well as in hybrid rocket engines. This is because hydrogen peroxide is a propellant of low toxicity and enhanced versatility. The present paper details the features of the designed engine of l00N thrust and its facility. Also explained is the arrangement of the distillation unit to be used to prepare rocket-grade hydrogen-peroxide propellant. Results of the simulated "cold" tests are presented.