• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2940-2945
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• 2008

The scale of 2.4 MW MCFC was taken to construct a high-efficiency and economical power generation system without CO2 emission into the atmosphere for utilizing its exhaust gas. The conventional steam turbine power generation system (STGS) was evaluated and the net generated power (NGP) was estimated to be only 133 kW and the STGS is not economically feasible. A CO2-caputuring repowering system was proposed, where low temperature steam (LTS) produced at HRSG by using exhaust gas from MCFC is utilized as a main working fluid of a gas turbine, and the temperature of LTS was raised by combusting fuel in a combustor by using pure oxygen, not the air. It has been shown that NGP of the proposed system is 264 kW, and CO2 reduction amount is 608 t-CO2/y, compared to 306 t-CO2/y of STGS. The CO2 reduction cost was estimated to be negligible small, even when the costs of oxygen production and CO2 liquefaction facilities etc. were taken into account.

• Journal of Korean Society of Steel Construction
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• v.24 no.3
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• pp.313-323
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• 2012

The purpose of this study is to evaluate $CO_2$ reduction and the flexural performance of steel wire-integrated void deck plate slabs that were inserted in omega-shaped steel plates to reduce concrete and welded H-section beams. The void deck plate slab can secure the structure, not only reducing the weight of the building but it is also eco-friendly. Therefore, this study evaluated the flexural performance of the composite beam by conducting a monotonic loading test with the use of actuators. It quantitatively evaluated the $CO_2$ emission based on earlier studies. The main test parameters are the concrete thickness of upper slabs, and the interrupted width of the omega-shaped steel plate. The result of the test showed that the welded H-section beam applied steel wire-integrated void deck plate slabs that were inserted into the omega-shaped steel plate declined in flexural performance on the composite beam after reducing concrete volume. Likewise, it is effective in reducing $CO_2$.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.4
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• pp.42-50
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• 2001

In this paper, the reduction of CO₂ gas emission and exhaust gas emission by using the shift of coastal transport from land transport for import-export container cargo was proposed. At first, the domestic CO₂ gas emission, exhaust gas emission and the transportation of import-export container cargo are investigated. And also, we investigated the reduction of CO₂ gas emission and exhaust gas emission by the shift of coastal transport from land transport for the transportation of import-export container cargo between Kyongin area and Pusan Port. Finally, the change of NOx gas emission due to the change of the share of coastal transportation and using the 320TEU container ship are investigated. The research results show that the shift of coastal transport from land transport was effective to reduce the CO₂ gas emission and exhaust gas emission.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.250-251
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• 2014

With the recent movement toward sustainable development, many efforts have been made to reduce environmental loads in various domains of industry. In particular, a great deal of research and technology development has been underway on approaches to reducing industrial waste and the emission of greenhouse gases. For this reason, a quantitative analysis of the reduction in CO₂ emission that could be achieved by replacing limestone material with cementitious waste powder was performed in this study. Through the analysis, it was found that CO₂ emissions were reduced by up to 50 percent compared with the scenario in which OPC was used, which suggests that it is possible to reduce global CO₂ emissions by approximately 5percent, or by 446.4 Tg of the 965 Tg of CO₂ emissions generated by the cement industry, in the total global CO₂ emissions of 19300Tg.

• Journal of Electrochemical Science and Technology
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• v.10 no.3
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• pp.313-320
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• 2019

In this study, cobalt diselenide ($CoSe_2$) and the composites ($CoSe_2@RGO$) of $CoSe_2$ and reduced graphene oxide (RGO) were synthesized by a facile hydrothermal reaction using cobalt ions and selenide source with or without graphene oxide (GO). The formation of $CoSe_2@RGO$ composites was identified by analysis with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and scanning electron microscopy (SEM). Electrochemical analyses demonstrated that the $CoSe_2@RGO$ composites have excellent catalytic activity for the reduction of $I_3{^-}$, possibly indicating a synergetic effect of $CoSe_2$ and RGO. As a consequence, the $CoSe_2@RGO$ composites were applied as a counter electrode in DSSC for the reduction of redox couple electrolyte, and exhibiting the comparable power conversion efficiency (7.01%) to the rare metal platinum (Pt) based photovoltaic device (6.77%).

• New & Renewable Energy
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• v.16 no.4
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• pp.9-22
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• 2020

This study analyzed the short- and long-term effects of nuclear and renewable energy generation on CO2 emissions in Korea, Japan, and Germany from 1987 to 2016 by using the unit root test, Johansen cointegration test, and ARDL model. The unit root test was performed, and the Johansen cointegration test showed cointegration relationships among variables. In the long run, in Germany, the generation of both nuclear and renewable energy was found to affect CO2 emission reduction, while South Korea's renewable energy generation, including hydropower, increased the emissions. Japan only showed significance in fossil fuels. In the short run, in the three countries, the generation of nuclear and renewable energy, excluding hydropower, affected CO2 emission. However, in Korea and Germany, nuclear and renewable energy generation, respectively, affected CO2 emission reduction. Although the rest are significant, the results showed that they increased CO2 emissions.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.120-121
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• 2006

Magnetic properties of nanostructured materials are affected by the microstructures such as grain size (or particle size), internal strain and crystal structure. Thus, it is necessary to study the synthesis of nanostructured materials to make significant improvements in their magnetic properties. In this study, nanostructured Fe-20at.%Co and Fe-50at.%Co alloy powders were prepared by hydrogen reduction from the two oxide powder mixtures, $Fe_2O_3$ and $Co_3O_4$. Furthermore, the effect of microstructure on the magnetic properties of hydrogen reduced Fe-Co alloy powders was examined using XRD, SEM, TEM, and VSM.

• Journal of Korean Society of Forest Science
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• v.97 no.5
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• pp.530-539
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• 2008

The study evaluates the greenhouse gas (GHG) reduction potential of paper recycling by paper industry in South Korea and determines the positive impact on global warming by conserving the world's forests through decreasing pulp wood use. South Korea is one of the leading countries in the world thai recycle papers with a collection rate of 71.8 percent and a recycling rate of 74.4 percent in 2005. Greenhouse gas emission reduction potential in terms of carbon dioxide ($CO_2$) equivalent from paper recycling was assessed scientifically by the use of Life Cycle Assessment (LCA). Three types of papers including newsprint, container-board, and white-board were used for assessment in this study. Results of this study indicate that $CO_2$ emission reduction potential of recycling paper varies according to its types and recycling rates. Greenhouse gas emission reduction factor of 0.74869 $tCO_2$ per ton of recycled paper was derived from this study. In applying this factor. it was found out that the South Korean paper industry reduced GHG emission of around 6,364,550 $tCO_2$ by recycling paper in 2005. With this. the country's paper industry could claim that by recycling in thai particular year. approximately $23.8million\;m^3$ of woods were not harvested and thus 212,500 ha of world's forests were estimated to be saved in that particular year. Overall. it could be concluded that the Korean paper industry was able to reduce $CO_2$ emission and was able to conserve world's forests by its high rates of paper recycling.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.231-240
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• 2002

Microbial metal reduction influences the biogeochemical cycles of carbon and metals as well as plays an important role in the bioremediation of metals, radionuclides, and organic contaminants. The use of bacteria to facilitate the production of magnetite nanoparticles and the formation of carbonate minerals may provide new biotechnological processes for material synthesis and carbon sequestration. Metal-reducing bacteria were isolated from a variety of extreme environments, such as deep terrestrial subsurface, deep marine sediments, water near Hydrothemal vents, and alkaline ponds. Metal-reducing bacteria isolated from diverse extreme environments were able to reduce Fe(III), Mn(IV), Cr(VI), Co(III), and U(VI) using short chain fatty acids and/or hydrogen as the electron donors. These bacteria exhibited diverse mineral precipitation capabilities including the formation of magnetite ($Fe_3$$O_4$), siderite ($FeCO_3$), calcite ($CaCO_3$), rhodochrosite ($MnCO_3$), vivianite [$Fe_3$($PO_4$)$_2$ .$8H_2$O], and uraninite ($UO_2$). Geochemical and environmental factors such as atmospheres, chemical milieu, and species of bacteria affected the extent of Fe(III)-reduction as well as the mineralogy and morphology of the crystalline iron mineral phases. Thermophilic bacteria use amorphous Fe(III)-oxyhydroxide plus metals (Co, Cr, Ni) as an electron acceptor and organic carbon as an electron donor to synthesize metal-substituted magnetite. Metal reducing bacteria were capable of $CO_2$conversion Into sparingly soluble carbonate minerals, such as siderite and calcite using amorphous Fe(III)-oxyhydroxide or metal-rich fly ash. These results indicate that microbial Fe(III)-reduction may not only play important roles in iron and carbon biogeochemistry in natural environments, but also be potentially useful f3r the synthesis of submicron-sized ferromagnetic materials.

• Journal of Mechanical Science and Technology
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• v.18 no.12
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• pp.2303-2309
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• 2004

Flue gas recirculation (FGR) is a method widely adopted to control NOx in combustion system. The recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel induced recirculation (FIR), could enhance a much improved reduction in NOx per unit mass of recirculated gas, as compared to the conventional FGR in air. In the present study, the effect of FGR/FIR methods on NOx reduction in turbulent swirl flames by using N$_2$ and CO$_2$ as diluent gases to simulate flue gases. Results show that CO$_2$ dilution is more effective in NO reduction because of large temperature drop due to the larger specific heat of CO$_2$ compared to N$_2$ and FIR is more effective to reduce NO emission than FGR when the same recirculation ratio of dilution gas is used.