• 대한토목학회논문집
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• 제42권3호
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• pp.351-357
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• 2022

본 연구에서는 하수재이용과 해수담수화를 동시에 진행할 수 있는 규모 1,000 m³/d의 FO-RO 융합공정과 동일한 규모의 기존 SWRO 공정의 탄소배출량을 계산하여 비교 분석하였다. FO-RO 융합공정은 FO 공정을 도입하여 RO 공정 원수를 희석시킬 수 있기 때문에 RO 공정의 요구 압력이 감소되고 이는 곧 에너지소비량 감소로 이어진다. 에너지소비량에 따른 탄소배출량은 FO-RO 융합공정이 SWRO 공정보다 -0.73 kgCO₂(coal로 전력생산 시) 낮으며, FO 공정 추가 건설로 인해 발생되는 탄소배출량은 +0.16 kgCO₂로 계산되어 FO-RO 융합공정의 총 탄소 배출량이 더 낮은 것으로 나타났다. 하지만, Coal나 oil과 같은 화석연료로 전력을 생산하지 않고, 전력생산 시 탄소배출량이 적은 nuclear나 solar 등으로 사용하면 FO-RO 융합공정의 총 탄소배출량이 SWRO 공정보다 더 높은 것으로 나타났다. 즉, 탄소배출량 관점에서는 전력생산 시 필요 재료(예: coal, oil, nuclear, solar 등)에 따라 친환경적인 공정 판단 여부가 결정되므로 FO-RO 융합공정 도입 필요성을 좌우하는 핵심 요소라고 할 수 있다.

• 한국토양비료학회지
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• 제47권5호
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• pp.374-380
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• 2014

To estimate greenhouse gas (GHG) emission, the inventory of rice cultivation at the farming without agricultural chemicals was established from farmers in Gunsan, Jeonbuk province in 2011~2012. The objectives of this study were to calculate carbon footprint and analyse the major factor of GHGs. To do this, we carried out a sensitivity analysis using the analyzed main factors of GHGs and estimated the mitigation potential of GHGs. Also we suggested agricultural methods to reduce GHGs that can be appled by farmers at this region. At the farming system without agricultural chemicals, carbon footprint of rice production unit of 1 kg was 2.15 kg $CO_2.-eq.kg^{-1}$. Although the amount of carbon dioxide ($CO_2$) emission was the largest among GHGs, methane ($CH_4$) emission had the highest contribution to carbon footprint on rice production system when it was converted to carbon dioxide equivalent ($CO_2-eq.$) multiplied by the global warming potential (GWP). Main source of $CO_2$ emission in the rice farming system without agricultural chemicals was combustion of fossil fuels used by agricultural machinery. Most of the $CH_4$ was emitted during rice cultivation practice and its major emission factor was flooded paddy field in anaerobic condition. Also, most of the $N_2O$ was emitted from rice cultivation process. Major sources of the $N_2O$ emission was application of fertilizer such as compound fertilizer. As a result of sensitivity analysis in energy consumption, diesel had the highest sensitivity among the energy inputs. With the reduction of diesel consumption by 10%, it was estimated that $CO_2$ potential reduction was about 2.0%. With reducing application rate of compound fertilizer by 10%, the potential reduction was calculated that $CO_2$ and $N_2O$ could be reduced by 0.5% and 0.9%, respectively. At the condition of 10% reduction of silicate and compost, $CO_2$ and $CH_4$ could be reduced by 1.5% and 1.6%, respectively. With 8 days more drainage than the ordinary practice, $CH_4$ emission could be reduced by about 4.5%. Drainage and diesel consumption were the main sources having the largest effect on the GHG reduction at the farming system without agricultural chemicals. Based on the above results, we suggest that no-tillage and midsummer drainage could be a method to decrease GHG emissions from rice production system.

• 반도체디스플레이기술학회지
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• 제12권3호
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• pp.19-22
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• 2013

The purpose of this study is to develop a system that can monitor the amounts of energy consumption during CVD and etching process for semiconductor manufacturing. Specifically, this system is designed to measure the $CO_2$ emission amounts quantitatively by measuring the flow rate of gas used and amount of power consumed during the processes. The processes of CVD equipment can be classified generally into processing step and cleaning step and all the two steps were monitored. In CVD and etcher equipments, various gases including Ar and $O_2$ are used, but Ar, $O_2$ and He were monitored with the use of the LCI data of Korea Environmental Industry & Technology Institute and carbon emission coefficients of EcoInvent. As a result, it was found that the carbon emission amounts of CVD equipment for Ar, $O_2$ and He were $0.030kgCO_2/min$, $4.580{\times}10^{-3}kgCO_2/min$ and $6.817{\times}10^{-4}kgCO_2/min$, respectively and those of etcher equipment for Ar and $O_2$ are $5.111{\times}10^{-3}kgCO_2/min$ and $7.172kgCO_2/min$, respectively.

• 한국대기환경학회지
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• 제20권5호
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• pp.615-623
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• 2004

This study was conducted for developing the emission factors of nitrogen oxide(NOx) and carbon monoxide (CO) from the combustion boilers burning liquefied natural gas (LNG). These emission factors were compared with those of U.S. EPA and European Environment Agency (EEA). NOx and CO concentration in the flow gas were measured using Kane-May, KM9106 and Thermo Environmental Instruments Inc., 42C-HL. Measurement were conducted at thirty industrial and commercial LNG boilers. Emission factors were calculated on the basis of fuel consumption (kg-pollutant/㎥-fuel burned). NOx concentration at industrial boiler was 14~125 ppm and it was measured as 35~125 ppm at commercial boiler. NOx emission factors of industrial boiler and commercial boiler were 1.84kg/$m^3$ and 2.09kg/$m^3$, respectively. NOx emission factor of commercial boiler was higher than that of industrial boiler. The NOx emission factors estimated in this study were lower than those of U.S. EPA and higher than those of EEA. Average CO emission factor of industrial boiler was 0.65 kg/$m^3$ and at commercial boiler it was 0.70kg/$m^3$, CO emission factor at industrial boiler was lower than that at commercial boiler.

• 한국대기환경학회지
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• 제26권6호
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• pp.657-665
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• 2010

Carbon dioxide ($CO_2$) is known to be a major greenhouse gas partially emitted from waste combustion facilities. According to the greenhouse gas emission inventory in Korea, the quantity of the gas emitted from waste sector in 2005 represents approximately 2.5 percent of all domestic greenhouse gas emission. Currently, the emission rate of greenhouse gas from the waste sector is relatively constant partly because of both the reduced waste disposal in landfills and the increased amounts of waste materials for recycling. However, the greenhouse gas emission rate in waste sectors is anticipated to continually increase, mainly due to increased incineration of solid waste. The objective of this study was to analyze the property of Municipal Solid Waste (MSW) and estimate $CO_2$ emissions from domestic MSW incineration facilities. The $CO_2$ emission rates obtained from the facilities were surveyed, along with other two methods, including Tier 2a based on 2006 IPCC Guideline default emission factor and Tier 3 based on facility specific value. The $CO_2$ emission rates were calculated by using $CO_2$ concentrations and gas flows measured from the stacks. Other parameters such as waste composition, dry matter content, carbon content, oxidation coefficient of waste were included for the calculation. The $CO_2$ average emission rate by the Tier 2a was 34,545 ton/y, while Tier 3 was 31,066 ton/y. Based on this study, we conclude that Tier 2a was overestimated by 11.2 percent for the $CO_2$ emission observed by Tier 3. Further study is still needed to determine accurate $CO_2$ emission rates from municipal solid waste incineration facilities and other various combustion facilities by obtaining country-specific emission factor, rather than relying on IPCC default emission factor.

• 한국대기환경학회지
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• 제32권6호
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• pp.613-623
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• 2016

In this study, pilot experiments were conducted by setting operation conditions to analyze characteristics of emission for air pollutant from small two-stroke engines. Emission factors of the measured concentration of pollutant were compared with EEA. Emission factor of CO analyzed by experiments - concentration, flow rate, fuel consumption, etc.- was estimated at 816,011 g-CO/ton-fuel in average. It was confirmed that more than 80% of the fuel consumption is discharged to the Carbon Monoxide, and that as the engine load becomes higher, emission factor of CO increases in the form of log function. The average emission factor of $NO_x$ and $PM_{10}$ was $3,801g-NO_x/ton-fuel$ and $3,730g-PM_{10}/ton-fue$l each. The deviation was not large by comparing the fuel-based emission factor of EEA and the result of this study. Since considerable pollutants are expected to be discharged from the small two-stroke engines, continuous research and support of the policy is required.

• 한국가구학회지
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• 제22권2호
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• pp.118-125
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• 2011

These days global warming is the most important problem and the most important factor is high emission of carbon dioxide. The 23% of carbon dioxide emission for building construction must be reduced. Thermal conductivity is the most basic factor that can decrease the energy consumption especially insulation. Therefore, an accurate and continuous thermal conductivity measurement can be a way to save energy. In this paper, there are methods about how to investigate thermal conductivity measurements and comparing two methods which are the Heat Flow Meter 436 and TCi.

• 한국재료학회지
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• 제15권11호
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• pp.711-716
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• 2005

The effects of change in the component of bonding materials in carbon nanotube cathode (CNT-cathode) on field enhancement and field emission characteristics were investigated. The field enhancement factor$\beta$ was dependent on the electrical conductivity of the bonding materials. The use of frit glass as a bonding material showed a higher field enhancement factor and better field emission characteristics than an Ag paste. The reason for why the frit glass showed better field emission characteristics can be summarized as follows. First, a frit glass improves the real aspect ratio of CNTs compared to an Ag paste. Second, the number of CNTs in CNT-cathodes is considerably reduced because the CNTs were extensively oxidized during $390^{\circ}C$ heat treatment in air atmosphere in the case of Ag paste.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.62-62
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• 1999

Carbon based materials have many attractive properties such as a wide band gap, a low electron affinity, and a high chemical and mechanical stability. Therefore, researches on the carbon-based materials as field emitters have been drawn extensively to enhance the field emission properties. Especially, diamond gives high current density, high current stability high thermal conductivity durable for high temperature operation, and low field emission behaviors, Among these properties understanding the origin of low field emission is a key factor for the application of diamond to a filed emitter and the verification of the emission site and its distribution of diamond is helpful to clarify the origin of low field emission from diamond There have been many investigations on the origin of low field emission behavior of diamond crystal or chemical vapor deposition (CVD) diamond films that is intentionally doped or not. However, the origin of the low field emission behavior and the consequent field emission mechanism is still not converged and those may be different between diamond crystal and CVD diamond films as well as the diamond that is doped or not. In addition, there have been no systematic studies on the dependence of nondiamond carbon on the spatial distribution of emission sites and its uniformity. Thus, clarifying a possible mechanism for the low field emission covering the diamond with various properties might be indeed a difficult work. On the other hand, it is believed that electron emission mechanisms of diamond are closely related to the emission sites and its distributions. In this context, it will be helpful to compare the spatial distribution of emission sites and field emission properties of the diamond films prepared by systematic variations of structural property. In this study, we have focused on an understanding of the field emission variations of structural property. In this study, we have focused on an understanding of the field emission mechanism for the CVD grown undoped polycrystalline diamond films with significantly different structural properties. The structural properties of the films were systematically modified by varying the CH4/H2 ratio and/or applying positive substrate bias examined. It was confirmed from the present study that the field emission characteristics are strongly dependent on the nondiamond carbon contents of the undoped polycrystalline diamond films, and a possible field emission mechanism for the undoped polycrystalline diamond films is suggested.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4282-4286
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• 2023

Nuclear energy is estimated by the machine learning method as the mathematical quantifications where neural networking is the major algorithm of the data propagations from input to output. As the aspect of nuclear energy, the other energy sources of the traditional carbon emission-characterized oil and coal are compared. The artificial intelligence (AI) oriented algorithm like the intelligence of a robot is applied to the modeling in which the mimicking of biological neurons is utilized in the mathematical calculations. There are graphs for nuclear priority weighted by climate factor and for carbon dioxide mitigation weighted by climate factor in which the carbon dioxide quantities are divided by the weighting that produces some results. Nuclear Priority and CO2 Mitigation values give the dimensionless values that are the comparative quantities with the normalization in 2010. The values are 1.0 in 2010 of the graphs which are changed to 24.318 and 0.0657 in 2040, respectively. So, the carbon dioxide emissions could be reduced in this study.