• Clean Technology
• /
• v.3 no.1
• /
• pp.106-113
• /
• 1997

The objectives of this study were to investigate the characteristics of limestone calcination and sulfation in a fluidized bed reactor with bed temperature and air velocity. The experimental results were presented as follows ; First, the bed temperature had a great influence on the calcination and the sulphur retention of limestone and paper sludge. In paper sludge, the optimum conditions in calcination and desulfurization temperature was at $800^{\circ}C$ and in natural limestone, that was at $850^{\circ}C$ or $900^{\circ}C$. Second, as air velocity increased, the specific surface area of particles decreased. But the difference of surface area according to air velocity was not too large. The specific surface area of paper sludge was larger than that of natural limestone. Third, as air velocity increased, the absorbed amount of sulfur dioxide decreased. And the absorbed amount of sulfur dioxide by paper sludge was larger than that of by natural limestone. Therefore, we knew that paper sludge was excellent absorbent and bed temperature had a great important variable on the calcination and sulphur retention in a fluidized bed.

• Proceedings of KOSOMES biannual meeting
• /
• 2007.11a
• /
• pp.43-49
• /
• 2007

The metals we are familiar with(Al, Ag, Au, Cu, Cd, Co, Fe, Ni, Pb, Zn, etc) are common elements and conservative pollutants. Although metals are often vital constituents of the metabolism of living organisms(trace elements}, a number of them are toxic if their concentration exceeds a certain threshold. It has long been recognized that measurements of trace metals in natural waters are often subject to large errors in terms of precision and accuracy. Since 1975 in US and European countries, seawater concentration of many trace metals have been shown to be factors of 10-1,000 lower than those previously accepted. Vertical profiles have been found to be consistent with known biological, physical and/or geochemical processes. These are resulted from major advances in analytical instrumentation and methodology for trace elements, and greater attention has been given to assuring the elimination of contamination during sampling, storage, and analysis.

• Clean Technology
• /
• v.2 no.1
• /
• pp.60-68
• /
• 1996

The oxidation of carbon monoxide of low concentration on the natural manganese dioxide (NMD) has been investigated in a fixed bed reactor. The experimental variables were concentration of oxygen (500ppm~99.8%) and carbon monoxide (500ppm~10000ppm) and catalyst temperature ($50{\sim}750^{\circ}C$). The NMD(Natural Manganese Dioxide) has been characterized by temperature - program reduction(TPR) using 2.4% $CO/H_2$ as a reducing agent, thermogravimetric analysis (TGA), and reduction of NMD by 2.4% $CO/H_2$. It was found that the NMD catalyst activity on the unit area was greater than the $MnO_2$ catalyst for oxidation of CO at the same temperature. The thermal stability of oxidation activity was considered to be maintained when the NMD was heated to $750^{\circ}C$. The TGA, reduction by CO, and TPR of the NMD showed that the NMD had active lattice oxygen which was easily liberated on heating in the absence and low concentration of oxygen. The reaction order in CO is 0.701 between 500~3500ppm and almost zero between 3500~10000ppm of CO.

• Clean Technology
• /
• v.7 no.4
• /
• pp.281-290
• /
• 2001

A microwave-assisted process to prepare chitosan from natural crabshells has been investigated. This study was primarily to examine the effectiveness of microwave as clean energy for chitosan preparation. Several human-edible organic acids were used as clean catalyst, possibly to improve the current HCl-based hydrolysis process of polymeric chitosan. The microwave was found to be effective substantially in reducing the reaction time. Nonetheless, no beneficial effect of microwave other than time, such as the chemical selectivity, was hardly observed. The organic acids were very effective in the hydrolysis reaction of polymeric chitosan. Their catalytic behavior was greatly improved especially when reactions were performed under pressure. In the case of autoclave reaction for 60 minutes at $120^{\circ}C$, viscous solution of polymeric chitosan (mol. wt. > 300,000) turned into thin solutions of water-like viscosity, which means chitosan molecules were decomposed to very small-sized oligomers.

• Korean Journal of Environment and Ecology
• /
• v.12 no.4
• /
• pp.389-397
• /
• 1999

The purpose of this study was to analyze visitors' behavior in Hallyo-Haesang National Park, Korea. To accomplish the purpose, questionnaire survey, using self-developed questions, was employed from August 21 to 23 in 1998. 303 samples for the survey were selected in 4 different zones(Koje, Tongyong, Namhae, and Odongdo) within park boundary. As the results, socioeconomic characteristics, such as gender, education and income level, age, and others, were showed similar trends with results from visitor surveys in other national parks. Most respondents were pointed out unintentional violation due to habit as a major reason of littering. And, majority of respondents didn't know the Clean-up-Time Movement Program in this park. In addition, ecosystem condition, natural landscape, trash problem, safety, and kindness of park rangers were recognized as the major influencing factors that can affect to visitors' recreation experience in this park but existing conditions for each influencing factor were evaluated lower than level of their expectation. Overall level of recreation satisfaction in Hanryohaesang national park were, however, perceived in the affirmative.

• Resources Recycling
• /
• v.14 no.5 s.67
• /
• pp.54-61
• /
• 2005

In 2006, the coal usage that is used as energy source of power plant will meet 16,000 MW which is 30% of the whole energy usage. A Coal deposits among the fossil fuels is very plentiful in natural resources and has high economical efficiency but application technique is very inconvenient. Also when burned for utilization, it generate various toxic and untoxic air pollution materials; fly ash, bottom ash, sulfurous acid gas etc. In this study, we could establish a preparation of clean coal by triboelectrostatic separation. In this study, we made a bench-scale's triboelectrostatic separation equipment using electrostatic technology, and got an optimum conditions of various factors for increasing recovery rate and purification in separation. A test result, we got a clean coal that recovery rate is 68.10%, rejection rate of ash and sulfur content is 31.23% and 28.33%.

• Journal of the Korean Wood Science and Technology
• /
• v.35 no.1
• /
• pp.1-10
• /
• 2007

This study was reviewed on the bioethanol production from biomass resources and feedstock supply in America. U.S. Department of Energy (USDE) and the u.s. Department of Agriculture USDA) are both strongly committed to expand the role of biomass as an energy source. They support biomass fuels and products as a way to reduce the need for oil and gas imports, to strengthen the nation's energy security and environmental quality. And it was envisioned a 20 percent replacement of the current U.S.transportation fuel consumption in 2030. Also it was reviewed policies to encourage the expanding of Bio-based fuel use to replace gasoline, such as Clean Air Act, Federal Clean Fuel Program and American Jobs Creation Act. In feedstock supply it was assumed forest biomass will be supplied in 368 million dry tons yearly and the agriculture derived biomass adopted by new technologies and land use change will be supplied in 998 million dry tons, including highly 818 million dry tons of lignocellulosic biomass such as perenial crops (hybrid trees, grasses) corn stover, other crop residues. This amount is 5 times to the amount from based current agricultural technology and crop land.

• Clean Technology
• /
• v.16 no.3
• /
• pp.182-190
• /
• 2010

The feasibility of clean technology to minimize the $CO_2$ emission by recycling and reuse the waste materials and energy have been studied for the cement industry. A life cycle assessment (LCA) was performed for an alternative raw material-supply method to use the molted slag as the major raw material in the cement clinker manufacturing. Using this new method, a 60% of $CO_2$ could be reduced that comes out during the decarboxylation from the cement rotary kiln. The energy-efficiency improvement and the alternative energy methods that had been determined in our previous study through the environmental assessment of cement industry were applied to the study for the reduction of $CO_2$ emission. The natural gas, one of the fossil fuels, was also used as the first choice to get the result at the earliest time by the most economic and the most efficient green technology and to switch into the carbon neutral energy consumption pattern.

• Fashion & Textile Research Journal
• /
• v.10 no.6
• /
• pp.1045-1050
• /
• 2008

Developing of high technology, productivity of the fiber product has being rapidly increased and also various kinds of advanced treatment process lead consumer's needs to more high functional, clean and healthy goods. Moreover, increasing in the concern of eco-friendly material and processing, it has been getting popular that the dyeing method like as using natural dyes is more eco-friendly and natural-friendly treatment process. The method, used in this study, adhesion by binding with micro-capsulized natural material to fabric has low change in quality by external influence and high ability in spray effect by broken capsule which comes to pressure and friction when it dressed. Also it has wide application from natural fiber to synthetic fiber. The purpose of this study is development of multi-functional synthetic material with micro-capsulized Scutellaria baicalensis on PET. Moreover, it was driven by comparison of colormetric properties and fastness between regular dip-dyeing method and binding with micro-capsulized material method. Dye ability was arranged mostly low exhaustion but the PET treated by micro-capsule was more or less better than the dip-dyeing PET. Through the SEM(Scanning Electron Microscope) of PET treated by micro-capsule, it has good residence of capsules even after 5 or 10 times washing. Wash and light fastness was arranged some different grade by each condition but mostly high achievement and the micro-capsulized PET was more improved than regular dip-dyed PET.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.3288-3293
• /
• 2007

Compressed natural gas has good potential for alternative vehicle fuel due to its economical and clean characteristics. However, the composition of natural gas based on production location is known to affect performance and emissions of CNG engine. Thus, the objective of this paper is to clarify the effect of fuel composition on combustion and emissions of CNG engine. This paper presents combustion characteristics obtained from running a 2.5L, 4-cylinder CNG engine retrofitted IDI diesel engine with engine dynamometer. BSFC, emissions, fuel consumption and combustion pressure were measured under steady state operating conditions especially at partial load for CNG engine. Based on the experimental results, we found that CNG composition affects engine performance, fuel conversion efficiency and burning rate.