• Clean Technology
• /
• v.19 no.2
• /
• pp.173-183
• /
• 2013

A various methodologies like eco product design, recycling, remanufacturing have been proposed for the increase of resource recirculation and energy saving worldwide. Uni-materialization in this paper, one of measures is presented. Uni-materialization is defined as the unification or simplification of material that is easy resource recycling and reduce waste generation at source during product design, manufacturing, delivery, use and disposal. This study developed calculates the qualitative and quantitative of assessment index for evaluating target products applicable uni-materialization. There are 9 assessment articles considered economic performance, technological property and environmental property and a study on target product applied assessment indexes. As a result it is possible for 3 target products to apply uni-materialization product except for a window blind, and the concrete concept of uni-materialization for improving objectivity of assessment index and the consideration of industrial distinct character are needed.

• Clean Technology
• /
• v.29 no.1
• /
• pp.1-9
• /
• 2023

Waste explosives such as useless ammunition discharged from the military and coproduced useless explosives during the manufacturers production process have been continuously produced. These are difficult to dispose with normal waste treatment facilities due to the dangers of fire and explosion. An open burning or an open detonation at military designated disposal facilities is a classical treatment method for the dangerous explosives. The classical method raises various environmental problems by the emission of hazardous materials. An air pollution by the emission of hazardous gases such as SO_x and NO_x, soil and water contaminations by the accumulation of non-biodegradable heavy metals, are representative pollution examples. To overcome these problems, various processes for eco-friendly waste treatment methods have been developed, and some processes have already been operated in some countries. In the current report, various eco-friendly disposal processes for waste explosives or harmful materials, and their advantages and disadvantages are documented to suggest future development directions for reducing the hazardous substances by the treatment processes.

• Proceedings of the KWS Conference
• /
• 2010.05a
• /
• pp.41-41
• /
• 2010

에어컨용 냉매 압축기, 냉장고용 냉매압축기 및 자동차 샷시 부품들은 주로 겹치기 필릿용접을 GMAW 으로 실시하고 있다. 그러나 용접 시 스패터 발생으로 인한 추가공수가 요구되며 작업환경 또한 열악한 실정이다. 따라서 저가의 고생산이면서 용접비드의 외관이 미려하고 스패터, 소음 그리고 Fume 이 발생되지 않는 청정한 TIG 용접이 있지만, 용접속도가 수십 cpm 이하로 제한되어 생산성이 낮다는 기술적 모순을 가지고 있다. TIG 용접에서 생산성을 증가시키기 위해 모재와 와이어를 고속 용융 시키려면 전류를 높여 입열량을 증가시켜야 하지만, 증가된 전류로 인하여 상승된 아크력이 험핑비드와 언더컷이 발생되는 물리적 모순을 가진다. 또한 필러와이어를 사용한 기존의 TIG 용접에서 필러 와이어는 주로 원형 단면 와이어를 사용하게 되는데 와이어의 직경이 증가함에 따라 비표면적은 감소하여 용융효율이 낮아지므로 $\Phi$1.2 이하의 필러와이어를 송급하여 용접하였다. 그러나 요구되는 용착량이 큰 경우 필러 와이어를 고속으로 송급하게 되는데 이 경우 필러 와이어 용융이 곤란하거나 송급상의 문제가 자주 생겨 용접속도를 고속으로 하기 곤란하였다. 따라서 필러와이어를 사용한 TIG 용접에서 용착금속의 용융효율을 높게 함으로서 전류를 크게 증가시키지 않으면서도 용접속도를 높일 수 있는 용접 공정개발이 필요한 실정이다. 본 연구에서는 비표면적을 증가시켜 용착금속의 높은 용융효율을 얻을 수 있도록 개발된 와이어와 기존의 $\Phi$3.2 일반와이어 및 를 이용하여 BOP TIG 용접에 비교 실험하였으며, 개발된 와이어와 기존의 $\Phi$1.2 필러와이어를 이용하여 필릿용접부에 적용 실험하여 비교하였다. 그 결과 개발된 와이어의 경우 적절한 비드를 형성하였으나 3.2 일반와이어의 경우 과도한 볼록비드와 불용착부의 문제가 발생하였고, 필릿용접 비교실험에서는 각각 200cpm과 50cpm에서 적절한 비드가 형성되어 더 높은 용착금속 용융효율을 얻을 수 있었다.

• 한국석유지질학회:학술대회논문집
• /
• autumn
• /
• pp.28-46
• /
• 2001

Natural gas is a mixture of hydrocarbon gases and impurities such as nitrogen, hydrogen sulfide, and carbon dioxide and a clean energy producing no pollution materials for combustion. Currently, the demand of the natural gas is rapidly increasing due to worldwide environmental problems. According to Hubbert's study in the past, the natural gas was predicted as rapidly depleted resources, and then the results led to high gas price and limitation of usage during 1980s. Afterward, the study of natural gas resources based on geology identified the additional natural gas resources that were not considered in Hubbert's study. They are unconventional gas, additional resources in the existed reservoirs, and natural gas in deep subsurface areas. Such additional resouces made the future of natural gas bright and pormised low and stable gas price in the future. Deep natural gas is defined as the gas existing at or below 15,000ft$(4,752{\cal}m)$ in depth from the surface. According to the study from the U.S. Geological Survey(USGS) in 1995, 1,412 TCF of technically recoverable natural gas was remained to be discovered or developed in the onshore of United States. A significant part of that resource base, 114 TCF, exists at deep sedimentary basins, and it shows wide distribution with various geological environments. In 1995, the deep gas contributed to $6.7\% of total supply amount of natural gas in the United States and is expected to be $18.7\% by 201.5. However, the development of the deep gas is a high risky business due to expensive investment and high portion of dry holes, although it is developed. Thus, for developing the deep gas economically, it is necessary to overcome many technical challenges. In this paper, for increasing success rate of the deep gas, 1) geologic and compositional characteristics, and production cost have been analyzed according to depth, 2) technical problems related to deep gas production have been summarized, and 3) finally future study areas for increasing application of the deep gas have been suggested. For reference, this paper was written based on the study results from USGS and Gas Research Institute(GRI), for the United States is doing the most active R&D in the deep gas area, and thus, has many reliable data.

• The Korean Journal of Petroleum Geology
• /
• v.14 no.1
• /
• pp.45-52
• /
• 2008

The GTL(Gas to Liquids) technology, manufacturing synthesized oil from natural gas, had been developed about 1920 for the military purpose by Fischer and Tropsch, German scientists. And 1960, Sasol company had started commercializing the FT(Fischer-Tropsch) synthesis technology, for the transport fuel in South Africa. Until a recent date, the commercialization of GTL technology had been delayed by low oil price. But concern about depletion of petroleum resources, and development in synthesizing technology lead to spotlight on the GTL businesses. Especially, Qatar, which has rich natural gas fields, aims at utilizing natural gas like conventional oil resources. Therefore, around this nation, GTL plants construction has been promoted. There are mainly 3 processes to make GTL products(Diesel, Naphtha, lube oil, etc) from natural gas. The first is synthesis gas generation unit reforming hydrogen and carbomonoxide from natural gas. The second is FT synthesis unit converting synthesized gas to polymeric chain-hydrocarbon. The third is product upgrading unit making oil products from the FT synthesized oil. There are quite a little sulfur, nitrogen, and aromatic compounds in GTL products. GTL product has environmental premium in discharging less harmful particles than refinery oil products from crude to the human body. In short, the GTL is a clean technology, easier transportation mean, and has higher stability comparing to LNG works.

• Design & Manufacturing
• /
• v.17 no.2
• /
• pp.1-8
• /
• 2023

This study aims to enhance the price and quality competitiveness of imported tiles by developing a robotic tile production automation line. The development process involved several steps, such as requirement analysis, derivation of technical specifications, conceptual design, engineering feasibility review, detailed design, and production. Emphasis was placed on the transfer process of the tiles' molds, and technological advancements were achieved through engineering interpretation, feasibility review, and performance evaluation. The developed automation system incorporates key specifications to ensure a transfer success rate of over 90%, thereby ensuring stable transportation of the tiles and minimizing defect rates during production. The maximum weight capacity for tile pick-up was set above 6 kg, allowing effective handling of tiles weighing 6 kg or less in automated tasks. Furthermore, the system enables safe and precise movement of the tiles to the desired location, with a transfer distance of at least 1.3 m and a transfer speed exceeding 0.2 m/sec, thereby increasing production efficiency.

• Clean Technology
• /
• v.20 no.2
• /
• pp.103-107
• /
• 2014

Acrylic acid is a commodity chemical which is applicable for various industries such as polymer and textile industry. Currently, it has been produced by chemical synthesis from petroleum. However, due to the high price of petroleum and global $CO_2$ emission, renewable materials such as sugar are interesting alternative carbon sources for the biological production of acrylic acid. For an economic production of acrylic acid from renewable carbon sources, a cost effective separation process for acrylic acid should be needed. In this study, reactive extraction by TOA (tri-n-octylamine) was used for the recovery of acrylic acid from its aqueous solutions. The effects of polarity of diluents and concentration of TOA on extraction equilibrium were investigated. The extraction efficiency was proportional to concentration of TOA and polarity of diluents and its value was more than 95% in the case of sufficient concentration of TOA. From IR spectroscopy, it was concluded that the ratio of (1,1) acid-amine complex was increased and the ratio of acid dimer was decreased with concentration of TOA. Equilibrium model based on IR spectroscopy was well fitted with experimental data.

• Clean Technology
• /
• v.26 no.1
• /
• pp.55-64
• /
• 2020

According to the Korean Renewable Energy 3020 Implementation Plan, the installation capacity of renewable energy is expected to increase whereas technology for storing excess electricity and stabilizing the power supply of renewable energy sources is extremely required. Power-to-Gas is one of energy storage technologies where electricity is converted into gas fuel such as hydrogen and methane. Basically, Power-to-Gas system could be effectively utilized to store excess electricity generated by an imbalance between supply and demand. In this study, the economic feasibility analysis of Power-to-Gas reflecting the domestic situation was carried out. Total revenue requirement method was utilized to estimate the levelized cost of hydrogen. Validation on the economic analysis method in this study was conducted by comparison of the result, which is published by the International Energy Agency. The levelized cost of hydrogen of a 100-MW Power-to-Gas system reflecting the current economic status in Korea is 8,344 won kg^-1. The sensitivity analysis was carried out, applying the main analysis economic factors such as electricity cost, electrolyser cost, and operating year. Based on the sensitivity analysis, the conditions for economic feasibility were suggested by comparing the cost of producing hydrogen using renewable energy with the cost of producing natural gas reformed hydrogen with carbon capture and storage.

• Clean Technology
• /
• v.17 no.4
• /
• pp.395-405
• /
• 2011

To develop the technology for cultivation of high-density seaweed, sea tangle was cultured from varying depths(0.5 m, 3 m) of seawater at Gijang and Wando area. Proximate composition, component sugar, total amino acid, fatty acid composition, and element composition of different parts of sea tangle (Saccharina japonica) have been examined. Significant differences were found in the amount of crude protein and ash content in lower, middle, and upper parts of algal blades. The upper parts of the sea tangle was rich in crude protein, while lower parts was rich in crude ash. Crude lipid content was higher in the middle parts than those of the other parts. The component sugars were not significantly different from all parts of algal blades. The highest content of most of the amino acids were found in the upper parts of the blades. The amount of saturated fatty acids concentrated mostly in lower parts of blades, while the content of polyunsaturated fatty acids concentrated in the upper parts. The highest N element contents were found in upper part of algal blades. However, the contents of those chemical component were not affected by the depths of seawater.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.196.2-196.2
• /
• 2011

지구온난화와 화석연료 고갈에 대한 우려로 전세계적으로 신재생에너지의 개발 및 활용이 본격화되고 있다. 특히, 다양한 신재생에너지원 중에서 날씨 및 계절에 의한 영향, 기저부하 담당, 지상 점유 면적, 소음 등 생활환경 영향, 경제성 등을 고려할 때 지열에너지는 미래 청정에너지원로서 기대와 관심이 집중되고 있다. 화산이 존재하지 않는 우리나라에서의 지열발전은 거의 불가능한 것으로 인식되어 지금까지의 심부 지열에너지 개발 프로젝트는 대부분 지역난방, 시설영농 등 직접이용을 목표로 추진되어 왔다. 그러나, 2003년부터 한국지질자원연구원에서 수행한 포항 심부지열에너지 개발사업의 결과로 얻어진 다양한 지질학적/지열학적 증거들을 토대로 분석한 결과, 국내 일부 지역에서는 지하 5 km 심도에서 최대 약 $180^{\circ}C$의 지온이 예상되어 국내에서도 심부 지열에너지를 이용한 지열발전에 대한 가능성이 제기되어 왔다. 여기에, 유럽과 미국 그리고 호주 등 선진국을 중심으로 비화산 지역에서 지하 심부에 인공적으로 지열저류층(파쇄대)을 생성하고 이를 통해 열매체(물)를 순환시킴으로써 생산된 증기를 발전에 활용하는 EGS (Enhanced Geothermal System) 기술이 개발되고 몇몇 성공사례가 발표되었다. 또한, 이러한 기술개발에 힘입어 EGS 지열발전에 대한 선진국의 과감한 연구비 투자가 이어졌다. 이러한 기술적 배경에 발맞추어 우리나라에서도 2010년 12월에 EGS 지열발전 과제가 착수되었다. 이 프로젝트는 아시아에서는 최초로 수행되는 EGS 기술 개발과제로서 2015년까지 약 480억원의 R&D 예산을 투입하여 MW급의 지열발전 pilot plant의 구축을 목표로 하고 있다. 프로젝트가 성공적으로 추진될 경우 국내외적인 파급효과는 매우 클것이다. 특히 2015년까지 1.5 MW의 pilot plant의 구축이 성공적으로 추진될 경우 국내에서는 2017년까지 3 MW 이상, 2020년까지 20 MW이상, 2030년까지 200 MW 이상의 지열발전이 가능할 것으로 기대된다. 또한 축적된 기술개발 경험을 바탕으로 인도네시아, 필리핀 등의 해외의 지열발전 사업에도 진출할 수 있는 계기가 될 것이다. 프로젝트는 넥스지오를 주관기관으로 하고 한국지질자원연구원, 한국건설기술연구원 및 서울대학교 등의 지질자원 관련 연구 및 교육기관과 포스코, 이노지오테크놀로지 등의 산업체가 참여하여 컨소시엄 형태로 추진하고 있으며, 향후 관심있는 여러 기관 및 산업체의 지원과 참여를 기대한다.