• 펄프종이기술
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• 제47권2호
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• pp.34-41
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• 2015

Recovered paper has been widely used as a main raw material of papermaking in Korea. Recycling of recovered paper helps to reduce production cost and preserve an environment. To recycle recovered paper efficiently, de-inking is a key process in recycling mills. De-inking process would be affected by various influencing factors such as the type of de-inking agent, mixed ratio of recovered paper, season, and process conditions. In this study, fatty acid and nonionic surfactant were used as the de-inking agent in froth-flotation process of mixed recovered paper. De-inking properties of mixed recovered paper were investigated according to the addition level of each chemical. Nonionic surfactant had a small effect on de-inking efficiency of mixed recovered paper due to decreased reject. As the additional level of fatty acid increases, fragmented ink particles increased and then optical properties of recycled paper decreased because fragmented ink particles adsorbed onto the fiber surface.

• 산업경영시스템학회지
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• 제28권2호
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• pp.36-45
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• 2005

This paper aims to investigate and analyze the process solving problems with activities of Quality Control Circle, carried out on a small scale, among various activities of industrial fields. Then this paper intends to provide and integrated model through integrating each process into one. In addition, this paper also aims to enhance the efficiency of the suggested model by realizing the model through support system.

• 기술혁신학회지
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• 제4권1호
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• pp.32-48
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• 2001

Many Korean companies have grown up through technology import, learning, development, innovation and export. This process is called as "the dynamic development process of technology". Among many companies which have grown up by way of this process, the Hyundai Motor Company has shown a very remarkable achievement in technological growth. In short, this paper deals with the growth of Korean companies in the view of the dynamic development process of technology. As a case study, the paper analyzes the Hyundai Motor Company.r Company.

• 산업공학
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• 제10권3호
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• pp.167-177
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• 1997

This paper deals with an application of process value analysis method for a manufacturing process in order to redesign facility layout in a paper company. We have used the value analysis method which permits an overall and rigorous study of process by a functional approach. Firstly, customer's expectations for the future process are clearly and precisely expressed with specifications of the Functional Extern Analysis. The existing process is analyzed using various tool of the Functional Internal Analysis in the second part. From the results of these analysis, we find out that the main problems of current facility are due to scheduling and facility layout. This paper is devoted to resolve the second problem. We suggest an ideal solution in order to have a reference solution. Nextly, We give realistic choices and the final solution for the facility layout.

• 펄프종이기술
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• 제37권3호
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• pp.59-65
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• 2005

There are accumulations of remained chemical additives and contaminants in the process water of semi-closed linerboard mill. High temperature of the process water aggravates the anaerobic digestion of contaminated process water and causes the generation of hazardous gases, which are from the biological reaction of varied additives and contaminants. The hydrogen sulfide in the gases easily combine with moisture in the air, and become sulfuric acid, which causes corrosion of paper machinery. This hydrogen sulfide is from the reduction of sulfate ions in the process water, and the sulfate ions are mostly from the alum. We changed the alum to PAC (Poly Aluminum Chloride). The results were preventing generation of hydrogen sulfide, and equivalent sizing effect by the use of PAC.

• 펄프종이기술
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• 제36권3호
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• pp.15-34
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• 2004

Diverse benefits such as reduction of fresh water consumption and effluent discharge, efficient use of raw materials and energy savings can be obtained by papermaking system closure. Closure of papermaking processes, however, causes many problems including reduction of the efficiency of additives, decrease of retention and dewatering, felt plugging, poor Paper quality, generation of slime and odor, poor vacuum efficiency, etc, and it has been recognized that accumulation of Inorganic and organic substances in the process white water is the prime cause of these problems. Therefore, technological developments for preventing accumulation of these detrimental substances are urgently required for Implementing papermaking system closure. Understanding of the accumulation phenomena of the inorganic and organic substances in the papermaking process white water is prerequisite for papermaking system closure. In this study a process simulation method was used to analyze the accumulation phenomena of anionic starch In the process white water as the closure level of a fine paper making process is increased. A pilot paper machine was used as a model process. Starch adsorption and desorption models were developed based on the concept of starch adsorption ratio, which was not considered in previous studies. Steady state simulation studies were carried out based on this model using a commercial simulator. In steady state simulation, the variation of dissolved starch concentration in each process unit was monitored as a function of white water usage for wire shower. The result of the steady state simulation showed that dissolved starch concentration and its increase ratio in Process units increased as white water usage ratio for wire shower increased.

• 펄프종이기술
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• 제36권1호
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• pp.16-23
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• 2004

Recently the increased concerns about the cost reduction and environmental protection make the paper industry increase the closure level of papermaking system, which results in the buildup of organic and inorganic materials in the papermaking process water. Increase of the system closure causes deterioration of additive performance and provokes diverse problems in papermaking process and product quality. To investigate the effects of process water quality on the physical properties of fine papers handsheets were prepared with process water containing various amounts of inorganic and organic contaminants including calcium or sodium ions and oxidized or cationic starches. Inorgainc and organic materials did not show any significant effect on the physical properties of handsheets. Recycled GCC showed the same trends as inorganic and organic materials. The performance of cationic starch was deteriorated, however, in the recycled white water, which resulted in the reduction of tensile index of handsheets.

• 펄프종이기술
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• 제36권2호
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• pp.33-38
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• 2004

Toner particles used in laser and xerographic printing process is fused on paper surface so strongly that they tend not to detach easily from the recylced paper surface during pulping. Furthermore, the removal efficiency of detached toner particles by conventional screening and flotation process has limitation due to the platy shape and large size of detached toner particles. It has been shown that the removal efficiency of toners in the screening process can be increased by agglomerating the toner particles with fatty alcohol. It is not possible, however, to remove small and platy toner particles by screening process. These small and platy toner particles should be removed by flotation process. In this study the effect of fatty alcohol that used for toner agglomeration on flotation efficiency has been examined. It was shown that flotation efficiency decreased when fatty alcohol was used most probably due to its effect of reducing hydrophobicity of toner particles.

• 상하수도학회지
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• 제14권2호
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• pp.157-163
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• 2000

An experimental study was conducted to evaluate the treatment efficiency of paper-mill wastewater using pure oxygen activated sludge process. Effects of hydraulic retention time (HRT) and organic loading on process performance and kinetics were investigated. The raw paper-mill wastewater(BOD concentration ${\leq}500mg/L$) and the effluent from dissolved air flotation(DAF) treatment(BOD concentration ${\geq}500mg/L$) were used as influent for pure oxygen activated sludge process. Average BOD removal efficiencies were above 89.3% under 6hours or longer of HRT, while under 3hours of HRT they decreased to about 82%. With the effluent from DAF process, the half saturation constants($K_S$) and the maximum specific substrate removal rate($K_{max}$) were 85 mg/L and 2.25 L/day, respectively. However, with the raw paper-mill wastewater, both $K_S$ and $K_{max}$ increased to 156 mg/L and 3.84 L/day, respectively. The microbial yield coefficient(Y) and the decay coefficient($K_d$) were 0.46 gVSS/gBOD and 0.03 L/day, respectively, with effluent from DAF process. While, Y and $K_d$ were 0.24 gVSS/gBOD and 0.035 L/day, respectively, with the raw paper-mill wastewater.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.2021-2034
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• 2008

This paper shows the result of study on the process improvement/innovation based on CMMI(Capability Maturity Model Integration) for Development V1.2 staged representation in the view of engineering area of software, hardware and system. This paper intend to help rolling stock industry to define & innovate process and finally obtain certificate for achievement of CMMI V1.2 from SEI authorized SCAMPI Lead Appraiser through the introduction experienced by Hyundai Rotem Company(car-builder and supplier of electronic & electrical equipment) such as why CMMI-based process definition & improvement are planned and how each processes of CMMI V1.2 Level 3 have been implementing and how obtaining the certificate of CMMI Maturity Level 3 of CMMI for Development V1.2 staged representation etc. This paper shows the introduction to CMMI V1.2 model, process improvement methodology and CMMI appraisal on the basis of Standard $CMMI^{SM}$ Appraisal Method for Process Improvement($SCAMPI^{SM}$), V1.2. And, this paper shows about what kinds of activities/practices of 18 processes(CMMI Maturity Level 3) is essentially implemented to satisfy their's specific goal and general geal through Hyundai Rotem Company's experiences. This paper shows the advantage and problem by adopting CMMI V1.2 model. Especially, it present the corrective/preventive actions against the identified problem in order to improve processes.