• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.1-10
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• 2024

In this study, we constructed a process simulation model for an agricultural by-products based Solid Oxide Fuel Cell (SOFC) combined heat and power generation system as part of the introduction of technology for energy self-sufficiency in the agricultural sector. The aim was to reduce the burden of increasing fuel and electricity consumption due to rapid fluctuations in international oil prices and the expansion of smart farming in domestic farms, while contributing to the national greenhouse gas reduction goals. Based on the experimental results of 0.3 ton/day torrefied agricultural by-product gasification experiment, a model for an agricultural by-product-based SOFC cogeneration system was constructed, and optimization of the heat exchange network was conducted for SOFC capacities ranging from 4 to 20 kW. The results indicated that an 8 kW agricultural by-product-based SOFC cogeneration system was optimal under the current system conditions. It is anticipated that these research findings can serve as foundational data for future commercial facility design.

• Environmental and Resource Economics Review
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• v.12 no.2
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• pp.347-382
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• 2003

The paper presents available options that Korea can adopt in an effort to promote eco-industrial development in a near future. What is missing and the reasons why Korea is behind the other countries in the area are: 1) Lack of holistic view and the integrated approach toward economy and environment in policy implementation, 2) Lack of understanding, among entrepreneurs, of the concept of productivity per input resource, and the fact that not only labor and capital productivity but also the total productivity enhancement is vital for industry's competitive edge; There has been no driving force in the market to develop economies of system integration to turn industrial wastes to valuable input resources, 3) Unsupportive regulatory system regarding the trade of by products, and 4) Lack of financing and incentive mechanism. 5) Lack of information forum. Regulatory reform should be taken for the direction that in effect increase the price of disposal and motivate firms to seek symbiotic relationship with other firms, and facilitate trade by-product between firms. Financing and incentive mechanism should be introduced in order for the industry to find easy access to the opportunities for organizing the network to transform wastes in negative value to the value added resources. Also information network should be established to provide a market for by-product exchange and public education to improve industry's environmental performance.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.1
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• pp.63-69
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• 2015

This work aimed to analyze current status of by-products generation and industrial symbiosis network in Pohang steel industrial complex, South Korea. Pohang is the largest generating city of both total and the non-recycled industrial waste in Gyeongsangbuk-do, and most of the waste is generated from Pohang steel industrial park. Symbiosis map in Pohang steel industrial park shows that most of the current material symbiosis in the industrial park is for waste refractories and slag.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.169-176
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• 2023

This study aims to develop a thermally conductive backfill by applying the prepacked concrete concept, in which a coarse aggregate with relatively high thermal conductivity was first filled and then the voild filled with grout. Backfill with improved thermal conductivity can increase the heat exchange efficiency of underground heat exchangers or underground transmission facilities. The backfills was prepared by using crushed concrete as the coarse aggregate, fly ash-based grout, and a small amount of cement for solidification. The results of this study showed that the fly ash-cement-sand-based grout with a flow of at least 450 mm accor ding to ASTM D 6103 could fill the void of pr epactked coar se aggr egates with a maximum size of 25 mm. The thermal conductivity of the backfil with coarse aggregate was over 1.7 W/m·K, which was higher than that of grout-type backfills.

• Nuclear Engineering and Technology
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• v.13 no.3
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• pp.145-152
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• 1981

Even though a lately reported method of high temperature exchange labelling of o-iodo-hippuric acid (Hippuran) in the absence of oxidizing agent was considered to be an attractive one, the exchange mechanism was somewhat unclear. In this study iodine isotope exchanges between o-iodohippuric acid (OIH) and radioiodide ($^{125}$ $I^{ }$) or between OIH and molecular radioiodine ($^{125}$ $I_2$) were carried out at two different temperatures. Rate constants and activation parameters were measured by applying a radio-paper chromatography technique. Since o-iodobenzoic acid is known as a by-product in the exchange labelling of OIH, data were also obtained for the OIB-iodide systems for comparison. The rate constant was increased in the order of OIB...$^{125}$ $I^{[-10]}$ >OIB...$^{125}$ $I_2$>OIH..$^{125}$ $I^{[-10]}$ >OIH...$^{125}$ $I_2$ and the activation parameters for OIH were generally larger than those for OIB :$\Delta$H$\neq$$_{OIH}$>$\Delta$H$\neq$$_{OIB}$, $\Delta$S$\neq$$_{OIH}$>$\Delta$S$\neq$$_{OIB}$. These results suggest that the mechanism of the high temperature exchange is predominantly nucleophilic even though some electrophilic character can also be involved depending upon reaction conditions. Such a fact may well be caused by a feasible formation of hydrogen bonding type transition state due probably to the ortho substituent effect of-CONHC $H_2$COOH. Thus, the high temperature exchange method is estimated to be quite effective for labelling Hippuran especially at a small research center where reducing agent-free $^{131}$ I is unavailable.ailable..

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.234-241
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• 2007

Biological amendments consisting of suspensions of selected microorganisms are often used in conjunction with various organic materials for amending soils to improve soil quality and plant growth. The effects of the biological amendment on chemical and biological properties of soil were investigated for a biological amendmentalone and when combined with different organic materials includingmunicipal compost (MC), poultry litter (PL), and cover crops (red clover (RC) and spring oats). A liquid preparation of a biological amendment called Effective Microorganisms was sprayed on the tested plots three times over a two-year period. Effective Microorganisms alone did not influence pH, K, or organic matter content in soil. However, increases in P in PL-treated soils in fall of both years andCa in MC-treated soil in fall 2001, and decreases in Ca, Mg, and cation exchange capacity (CEC) in RC-planted soil were associated with EM. Increased dehydrogenase(DH) activitiesassociated with Effective Microorganismswere only detected in July (P=0.0222) and October (P=0.0834) for RC-planted soils in the first year. Fluorescein diacetate (FDA) hydrolysisappeared to be enhanced by Effective Microorganisms in soils untreated or treated with MC and oatsbut only sporadically during the sampling period. FDA hydrolysis in both PL- and RC-treated soils as well as DH activity in PL-treated soils decreased with Effective Microorganisms treatment. Effective Microorganisms did not influence substrate utilization patterns expressed by the BIOLOG assay. We conclude that Effective Microorganisms effects on soil chemical and biological properties varied depending on the added organic materials. Effective Microorganisms periodically increased soil DH activity and FDA hydrolysis with RC and with MC plus oats, respectively.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.377-380
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• 2015

In this paper, we have investigated the optimization of $I_2$ recovery process from $NH_4I$ solution, which is generated as by-product during the amination reaction of p-diiodobenzene (PDIB) for p-phenylenediamine (PPD) synthesis. The recovered $I_2$ is then recycled as a raw material for PDIB synthesis. We have employed a cation exchange resin to recover $I_2$ from $NH_4I$ sample solution, and determined the breakthrough point and exchange capacity from the breakthrough curve. Furthermore, we have suggested optimum conditions of our $I_2$ recovery process by measuring the purity and yield of recovered $I_2$ with respect to the concentrations of $NH_4I$ and oxidant ($H_2O_2$) solutions, the oxidation time, and the temperature of drying process. Finally, the yield and purity as high as 94.96% and 96.65%, respectively were obtained by reusing the residual solution still containing unrecovered iodide ions.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.272-275
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• 2017

최근 국내 대부분의 원자력 발전소 2차 계통 중 복수 탈염설비의 운전 시 pH를 제어하기 위해 에탄올아민(Ethanolamine, ETA)를 사용하고 있으나 ETA를 적용한 후 발생하는 폐수에 의한 방류수의 화학적 산소요구량(COD) 및 총 질소(TN)의 증가는 심각한 환경적인 문제를 발생 시킨다. ETA가 강이나 하천과 같은 수계로 유입되면 자연적으로 생분해되기 힘들고, 분해부산물이 증가되어 수질을 악화시킬 수도 있다. 이러한 문제점을 해결하기 위해 본 연구에서는 폐경석, 제강슬래그, 저회를 혼합하여 제올라이트화(zeolitization)과정을 통해 새로운 형태의 저비용, 고효율의 ETA 처리용 복합흡착제를 제조하였다. 최적의 흡착 및 이온교환능력을 갖는 복합흡착제는 폐경석, 제강슬래그 및 저회의 혼합조성비를 Mixture Analysis 통계법을 통해 도출하였다.

• Membrane Journal
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• v.29 no.3
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• pp.173-182
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• 2019

Much research has been made for finding new and eco-friendly alternative sources of energy to solve the problems related with the pollution caused by emissions of greenhouse gases such as carbon dioxide as the use of fossil fuels increases worldwide. Among them, fuel cells draws particular interests as an eco-friendly energy generator because only water is obtained as a by-product. Anion exchange membrane-based alkaline fuel cell (AEMFC) that uses anion exchange membrane as an electrolyte is of increased interest recently because of its advantages in using low-cost metal catalyst unlike the PEMFC (potton exchange membrane fuel cell) due to the high-catalyst activity in alkaline conditions. The main properties required as an anion exchange membrane are high hydroxide conductivity and chemical stability at high pH. Recently we reported a chemically crosslinked poly(2-dimethyl-1,4-phenylene oxide) (PPO) by reacting PPO with N,N,N',N'-tetramethyl-1,6-hexanediamine as novel anion exchange membranes. In the current work, we further developed the same crosslinked polymer but having enhanced physicochemical properties, including higher conductivity, increased mechanical and dimensional stabilities by using the PPO with a higher molecular weight and also by increasing the crosslinking density. The obtained polymer membrane also showed a good cell performance.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.318-323
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• 1993

Pentachloroethane($CHCl_2CCl_3$) was synthesized and reacted with hydrogen fluoride using antimony pentahalide catalyst($SbCl_xF_y$) in order to manufacture HCFC-123$(CF_3CHCl_2)$, a potential CFC-11$(CFCl_3$) substitute candidate. Products analyses showed the fluorination proceeds through fluorine-chlorine exchanges between $HF/SbCl_xF_y$ and $SbCl_xF_y/CCl_3CHCl_2$ respectively. The degree of fluorination of $CCl_3$ group in pentachloroethane was greatly affected on the reaction temperature, but the effect of catalyst concentration was relatively small. Mechanistic study was also performed to elucidate the pathway to the formation of side-products such as $CCl_3CFCl_2$, $CFCl_2CFCl_2$ and $CF_2ClCFCl_2$.