• 한국수소및신에너지학회논문집
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• 제30권2호
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• pp.178-187
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• 2019

Due to the increasing demand of high rank coal, the use of low rank coal, which has economically advantage, is rising in various industries using carbonaceous solid fuels. In addition, the severe disaster of global warming caused by greenhouse gas emissions is becoming more serious. The Republic of Korea set a goal to reduce greenhouse gas emissions by supporting the use of biomass from the Paris International Climate Change Conference and the 8th Basic Plan for Electricity Supply and Demand. In line with these worldwide trends, this paper focuses on investigating the combustibility of high rank coal Carboone, low rank coal Adaro from Indonesia, Baganuur from Mongolia and, In biomass, wood pellet and herbaceous type Kenaf were simulated as kinetic reactivity model. The accuracy of the pore development model were compared with experimental result and analyzed using carbon conversion and tau with grain model, random pore model, and flexibility-enhanced random pore model. In row lank coal and biomass, FERPM is well-matched kinetic model than GM and RPM to using numerical simulations.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.159-159
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• 2022

Soil represents a substantial component within the global carbon cycle and small changes in the SOC stock may result in large changes of atmospheric CO₂ particularly over tens to hundreds of years. In this study, we aim to (i) evaluate the SOC stock in the topsoil 0 - 15 cm from soil physical and chemical characteristics and (ii) find the correlation of SOC and soil organic matter (SOM) for national-scale in South Korea. First of all, based on the characteristics of the soil to calculate the soil hydraulic properties, SOC stock is the SOC mass per unit area for a given depth. It depends on bulk density (BD-g/cm³), SOC content (%), the depth of topsoil (cm), and gravel content (%). Due to insufficient data on BD observation, we establish a correlation between BD and SOC content, sand content, clay content parameter. Next, we present linear and non-linear regression models of BD and the interrelationship between SOC and SOM using a linear regression model and determine the conversion factor for them, comparing with Van Bemmelen 1890's factor value for the country scale. The results obtained, helps managers come up with suitable solutions to conserve land resources.

• Carbon letters
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• 제12권3호
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• pp.131-137
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• 2011

Kenaf fibers, cellulose-based natural fibers, were used as precursor for preparing kenafbased carbon fibers. The effects of carbonization temperature ($700^{\circ}C$ to $1100^{\circ}C$) and chemical pre-treatment (NaOH and $NH_4Cl$) at various concentrations on the thermal change, chemical composition and fiber morphology of kenaf-based carbon fibers were investigated. Remarkable weight loss and longitudinal shrinkage were found to occur during the thermal conversion from kenaf precursor to kenaf-based carbon fiber, depending on the carbonization temperature. It was noted that the alkali pre-treatment of kenaf with NaOH played a role in reducing the weight loss and the longitudinal shrinkage and also in increasing the carbon content of kenaf-based carbon fibers. The number and size of the cells and the fiber diameter were reduced with increasing carbonization temperature. Morphological observations implied that the micrometer-sized cells were combined or fused and then re-organized with the neighboring cells during the carbonization process. By the pre-treatment of kenaf with 10 and 15 wt% NaOH solutions and the subsequent carbonization process, the inner cells completely disappeared through the transverse direction of the kenaf fiber, resulting in the fiber densification. It was noticeable that the alkali pre-treatment of the kenaf fibers prior to carbonization contributed to the forming of kenaf-based carbon fibers.

• 한국수소및신에너지학회논문집
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• 제34권2호
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• pp.100-112
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• 2023

This study evaluated the contribution of carbon neutrality by calculating the carbon reduction amount and reduction intensity targeting the hydrogen pilot city and applying it to the carbon neutral reduction target. In the building sector, the reduction amount for 2030 was 10.8% on average. In addition, by 2050, the contribution to carbon neutrality of plan A was 14.1% on average, and the contribution to carbon neutrality of plan B was 15.1% on average. In the 2030 reduction amount of the transportation sector, the contribution to carbon neutrality was 138.4% on average. In addition, by 2050, the contribution to carbon neutrality in plan A was 82.5% on average, and the contribution to carbon neutrality in plan B was 74.9%. From the above research results, additional carbon reduction is possible when creating a hydrogen city, so it will be used as a basis of city-level carbon neutral model. It will also be used as a basis for technology development and investment promotion for various hydrogen supply methods in the future.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.238.2-238.2
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• 2015

Surface modification of vertically-aligned carbon nanotube (VACNT) is essential in order to meet specific demands for particular applications such as field emission displays, heat dissipation device and potential sun energy conversion due to their superior electrical and thermal conductivity and strong light absorption. In this study, we observe the effect of exposure to water vapor on a different lengths of the surfaces of VACNT. The study was conducted on three different lengths of the VACNT: short length around $200{\mu}m$, medium-length around $500{\mu}m$, and high length around 1 mm. Water exposure time ranges between 2-10 min and temperature of the water ranges from 60 to 120 oC. The result of water vapor exposure mainly show that increasing the exposure time and water temperature give rise to increase of the speed of change on the surface of the VACNT. Especially, the shorter VACNT change their surface morphology most rapidly.

• Environmental Engineering Research
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• 제13권4호
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• pp.192-196
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• 2008

The generation of high purity hydrogen from reformed hydrocarbon fuels, or syngas, is essential for efficient operation of the fuel cell (PEMFC, Polymer Electrolyte Membrane Fuel Cell). Usually, major components of reformed gas are $H_2$, CO, $CO_2$ and $H_2O$. Especially a major component, CO poisons the electrode of fuel cells. The water gas shifter (WGS) that shifts CO to $CO_2$ and simultaneously produces $H_2$, was developed to a two stage catalytic conversion process involving a high temperature shifter (HTS) and a low temperature shifter (LTS). Also, experiments were carried out to reduce the carbon monoxide up to $3{\sim}4%$ in the HTS and lower than 5,000 ppm via the LTS.

• 한국응용과학기술학회지
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• 제20권4호
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• pp.309-315
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• 2003

Extraction of Natural Artemisia by using super critical carbon dioxide is operated under $40-50^{\circ}C$ and 200-250 atm, thus, conversion rate is very low as 7wt% while high energy is being wasted. When Natural Artemisia Extract is applied in the control of microbe, concentration and reaction time greatly affected to the growth of microbe. Especially, when refined oil concentration from Natural Artemisia added more than 1,000ppm, staphylococcus aureus and fungi are terminated completely. Thus, it is proven that Natural Artemisia Extract has antimicrobial effect.

• 제어로봇시스템학회논문지
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• 제8권5호
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• pp.407-412
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• 2002

A measurement device for gas concentration and flow rate using hot wire is developed for the utilization in industrial applications. The device has two cells of measuring and reference, and a bridge circuit is installed to detect electric current through the hot wire in the cells. An amplification of the signal and conversion to digital output are conducted for the on-line measurement with a personal computer. The flow rate of air and carbon dioxide gas is separately measured for the performance examination of the device. Also, the concentration of air-carbon dioxide and carbon dioxide-argon mixtures is determined for the same evaluation. The outcome of the performance test indicates that the accuracy and stability of the device is satisfactory for the purpose of industrial applications.

• 한국응용과학기술학회지
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• 제34권4호
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• pp.1046-1057
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• 2017

국가 온실가스 인벤토리를 Tier 2 이상의 수준으로 향상시키기 위해서는 IPCC 기본값 대신 국가 고유의 배출계수가 개발 및 이용되어야 한다. 국가 고유 배출계수는 에너지원 종류, 에너지 공정, 시간 추세에 따라 달라지기 때문에, 각 에너지원별 특성값을 파악하는 것은 정확한 인벤토리 구축에 중요한 부분을 차지한다. 국내 석유계 에너지원의 물성은 시간의 경과에 따라 큰 변화는 없었으며, 국내에서 고시되고 있는 에너지원별 열량환산기준 상의 석유계 에너지원에 대한 열량 및 탄소배출계수를 2013년과 2016년에 실제 시료를 수집하여 발열량, 탄소함량 및 탄소배출계수를 산정한 결과값과의 비교분석에서는 대체적으로 일정한 값을 유지하고 있는 것으로 나타났다. 또한, 석유계 에너지원별로 산출된 순발열량과 탄소배출계수는 2006 IPCC Guideline에 나타낸 값들과 비교하였으며, 대부분의 에너지원이 2006 IPCC G/L의 기본값 및 상한, 하한 범위내의 값을 나타내었다.

• 대한화학회지
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• 제30권1호
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• pp.105-108
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• 1986

초음파(50KHz)가 상온 상압하에서 히드라진 철 활성탄을 이용한 방향족 니트로기를 방향족 아미노기로의 환원반응을 크게 가속시켜 3시간만에 100% 전환율을 얻을 수 있었다. 활성탄은 탈색이나 반응성이 큰 물질의 분말을 섞는데 사용되어 왔으나 히드라진 철을 이용한 방향족 니트로기의 환원반응에서는 활성탄 없이는 반응이 전혀 일어나지 않으며 활성탄의 증가에 따라 환원율이 높아지는 결과를 얻었다.