• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.408-414
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• 2008

Importance of climate change and its impact on agriculture and environment has increased with the rise Green House Gases (GHGs) concentration in the atmosphere. To slow down the speed of climate change many efforts have been applied in industrial sectors to reduce GHGs emission and to enhance carbon storage. In agricultural sector, many researches have been performed on GHGs emission reduction, but few on the role of carbon sink. In this study, we investigated carbon balance and soil carbon storage in agricultural field in the barley-red pepper and barley-soybean cropping system. With the system for automatic measuring of carbon dioxide, net ecosystem production(NEP) was estimated to be $6.3ton\;CO_2\;ha-1$ for N-P-K chemical fertilizer treatment plot and $10.6ton\;CO_2\;ha^{-1}$ for N-P-K chemical fertilizer with swine manure treatment plot in the barley-soybean rotation cropping. In the barley-red pepper rotation cropping, it was $12.0ton\;CO_2\;ha^{-1}$ for N-P-K chemical fertilizer treatment plot and $13.2ton\;CO_2\;ha^{-1}$ for N-P-K chemical fertilizer with swine manure treatment plot. Soil carbon storage rate was estimated to be $0.7ton\;C\;ha^{-1}$ for the barley-soybean cropping system and $0.5ton\;C\;ha^{-1}$ for barley-pepper cropping system. In appeared that agricultural lands may contribute to the greenhouse effect as a potential carbon sink preserving carbon into soil.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.185-189
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• 2011

In this work, nano-sized M-ferrites (M=Co, Ni, Cu, Zn) for the decomposition of carbon dioxide were synthesized by the chemical co-precipitation. From the thermogravimetric analysis, it was clear that the maximum weight loss of each sample took place below $350^{\circ}C$. High temperature calcination resulted in more systematic crystallines, smaller specific surface area and larger particle size. An analysis by FTIR in the range of $375{\sim}406cm^{-1}$ revealed the presence of chelates at the octahedral site, which implies the formation of spinel structure in the ferrites. The current work showed that a $500^{\circ}C$ is the optimum heat treatment temperature of metal ferrites for $CO_2$ decomposition reaction.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.574-580
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• 2014

Storage tanks of Carbon dioxide ($CO_2$) carriers utilized for the purpose of carbon capture and storage (CCS) into subsea strata have to undergo a pre-cooling session before beginning to load cryogenic liquid cargos in order to prevent physical and thermal deterioration of tanks which may result from cryogenic $CO_2$ contacting tank walls directly. In this study we propose dynamic model to calculate the tank inflow of $CO_2$ gas injected for precooling process and its dynamic simulation results under proportional-integral control algorithm. We selected two cases in which each of them had one controlled variable (CV) as either the tank pressure or the tank temperature and discussed the results of that decision-making on the pre-cooling process. As a result we demonstrated that the controlling instability arising from nonlinearity and singularity of the mathematical model could be avoided by choosing tank pressure as CV instead of tank temperature.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.217-222
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• 2012

The synthesis of dimethyl carbonate(DMC) is a promising reaction for the use of naturally abundant carbon dioxide. DMC has gained considerable interest owing to its versatile chemical reactivity and unique properties such as high oxygen content, low toxicity, and excellent biodegradability. In this study, the synthesis of DMC through the transesterification of ethylene carbonate(EC) with methanol was investigated by using ionic liquid and metal oxide catalysts. The screening test of different catalysts revealed that choline hydroxide ([Choline][OH]) and 1-n-butyl-3-methyl imidazolium hydroxide([BMIm][OH]) had better catalytic performance than metal salts catalysts such as MgO, ZnO and CaO. The effects of reaction parameters such as reaction temperature, MeOH/EC mole ratio, and carbon dioxide pressure on the reactivity of [Choline][OH] catalyst were discussed. High temperature and high MeOH/EC mole ratio were favorable for high conversion of EC. However, the yield of DMC showed a maximum when carbon dioxide pressure was 1.34 MPa, and then it decreased for higher carbon dioxide pressure. Zinc chloride($ZnCl_2$) was used as co-catalyst with the ionic liquid catalyst. The mixed catalyst showed a synergy effect on the EC conversion and DMC yield probably due to the acid-base properties of the catalysts.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.313-317
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• 2023

In this study, the physicochemical characterization and adsorption performance of air pollutants (VOCs, SO₂, and CO₂) were evaluated for the recycling of zeolite used in the ion exchange process. The surface characteristics of the zeolite used were confirmed through Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) analysis, and the composition and specific surface area were measured through X-Ray Fluorescence (XRF) and Brunauer-Emmett-Teller (BET). There was no change in the surface properties of the used zeolite, but the content of potassium and calcium increased and the specific surface area decreased. The toluene, sulfur oxides, and carbon dioxide adsorption performance of the used zeolite was evaluated, and it was confirmed that the performance was improved compared to the fresh zeolite. In particular, for toluene and sulfur oxides, the adsorption amount increased by 2.6 times and 2.3 times, respectively, which might be due to the enhancement of the polymerization reaction and the increase of the base point, according to the composition of the used zeolite.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.1
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• pp.73-79
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• 2011

A portion of oil for lubrication of compressor flows together with refrigerant in the refrigeration system. If the oil discharge from a compressor is increased in the refrigeration system, not only pressure drop is increased in other components, such as evaporator and gas cooler, but also heat transfer coefficient in the heat exchangers is decreased. Oil discharge rate from a compressor may strongly depend on operating conditions of a compressor. In this study, one stage single rotary compressor is employed for measuring oil circulation ratio(OCR). Carbon dioxide and PAG oil are used as refrigerant and lubricant. Using a U-tube densimeter, mixture density is measured. Oil circulation ratio(OCR) can be estimated by measured mixture density. The results obtained indicate that the oil circulation ratio(OCR) is increased as the suction temperature or compressor operating frequency is increased. Oil circulation ratio(OCR) correlation of the compressor is also suggested.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.493-501
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• 2004

The principle of vortex tube and cyclone was introduced to enhance the treatment efficiency of waste air streams containing particulate matters, toluene, and others developed by Hangreen Tech, Ltd. and Hoseo Chemical and Industrial Technology R＆D Center. Adsorption, condensation, and/or coagulation could be induced at low temperature zone formed by vortex tube and Joule-Thomson expansion. The pressurized air was introduced at the tangential direction into the cyclone system applied with the coaxial funnel tube. Easily condensible vapors such as toluene. carbon dioxide, and water vapor were adsorbed enforcedly on coagulated or condensed materials which were formed as cores for coagulation or condensation by themselves. These types of coagulation or condensation rates were rapidly promoted as the diameter being growing up. The maximum removal efficiency for carbon dioxide and toluene was achieved to about 87 and 90 percent, respectively. The Joule-Thomson coefficients were increased with the pressure of air injected in the range of the relative humidities between 10% and 30%. An optimum value was observed within the range of the tested temperatures at a fixed pressure. In conclusion. it could be identified that the treatment efficiency would be depended on the pressure of the process air introduced and physical and chemical characteristics of waste air streams containing target materials for a designed system. The final design parameters should be decided depending upon the given system and target materials.

• KIEAE Journal
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• v.11 no.3
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• pp.31-36
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• 2011

People spend most of their time inside buildings recently, so the indoor air quality is one of the most important factors to human health. Furthermore, minimum energy use with proper ventilation systems for pleasant indoor environment is necessary because of energy shortage over the world. The concern to maintain proper indoor air quality at home has been increased, and a proper indoor air quality is continuously requested by the residents. By measuring and analyzing the density fluctuation of $CO_2$ through indoor humidity and testing personal reactions regarding comfort condition, we can obtain a way to effective ventilation. Heat and carbon dioxide emissions from resident's metabolism and construction materials could be the causes of indoor air pollution. If these materials stay indoors for a long time, it could directly influence the resident's health condition with diseases. It also leads massive energy use. Therefore, the way to save energy and to have effective control of indoor ventilation is needed. This study presented the control method of bedroom ventilation by $CO_2$ concentration change and subjective evaluation.

• Asian Journal of Business Environment
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• v.11 no.1
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• pp.39-50
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• 2021

Purpose: This study seeks to establish the environmental damage theory applicable to Kenya. The analysis is based on annual data drawn from World Bank on carbon dioxide emissions (CO2e) and gross domestic product per capita (GDPPC) for Kenya spanning 1963 to 2017. Research Methodology: The study adopts explanatory research design and autoregressive distributed lag model for analysis. Results: The results revealed a coefficient of -0.017 for GDPPC and 0.004 for GDPPC squared indicating that economic growth has negative effect on CO2e in the initial stages of growth but positive effect in the high growth regime with the marginal effect being higher in the initial growth regime. The findings suggest a U-shaped relationship consistent with Brundtland Curve Hypothesis (BCH). Conclusions: The findings emphasize the need for sustainable development path that enables present generations to meet own needs without compromising the capacity of future generations to meet their own. Sustainable development may include, investment in renewable energies like wind, solar and adoption of energy efficient technologies in production and manufacturing. The study concludes that BCH is applicable to Kenya and that developing affordable and effective mechanisms to boost sustainable development implementation is necessary to decrease the anthropogenic impact in the environment without any attendant reduction in the economic growth.

• Journal of Climate Change Research
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• v.2 no.4
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• pp.317-331
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• 2011

The CERES-Barley crop simulation model of DSSAT package was used to assess the impacts of climate change on potential yield of winter covered barley in Korea. 56 sites over the southern part of Korean peninsula were selected to compare the climate change impacts in various climatic conditions. The climatological normals (1971~2000) and the three future climatological normals (2011~2040, 2041~2070, and 2071~2100), based on A1B climate change scenarios of Korea, were used in this study, and the three future climatological normals were simulated under three environmental conditions, where only temperature change, only carbon dioxide change, and both of temperature and carbon dioxide change with future A1B climate change scenarios, respectively. Results: The CERES-Barley model was suitable for predicting climate change impacts on the potential yield of winter covered barley, because of the agreement between observed and simulated outcomes (e.g., the coefficient of determination of grain yield equals 0.84). (1) The only increased temperature effect with the climate change scenarios was mostly negative to the potential yield of winter covered barley and its magnitude ranges from -21% to +1% for the three future normals. (2) The effect of the only elevated carbon dioxide on the potential yield of winter covered barley was positive and its magnitude ranged from 12% to 43% for the three future normals. (3) For increased temperature and elevated carbon dioxide change cases, potential yields increased by 13%, 21%, 19% increase for the 2011~2040, 2041~2070, 2071~2100 normals, respectively.