• Nuclear Engineering and Technology
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• 제51권4호
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• pp.1154-1162
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• 2019

China is undertaking an energy reform from fossil fuels to clean energy to accomplish $CO_2$ intensity (CI) reduction commitments. After hydropower, nuclear energy is potential based on breadthwise comparison with the world and analysis of government energy consumption (EC) plan. This paper establishes a CI energy policy response forecasting model based on national and provincial EC plans. This model is then applied in Fujian Province to predict its CI from 2016 to 2020. The result shows that CI declines at a range of 43%-53% compared to that in 2005 considering five conditions of economic growth in 2020. Furthermore, Fujian will achieve the national goals in advance because EC is controlled and nuclear energy ratio increased to 16.4% (the proportion of non-fossil in primary energy is 26.7%). Finally, the development of nuclear energy in China and the world are analyzed, and several policies for energy optimization and CI reduction are proposed.

• Journal of Electrochemical Science and Technology
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• 제10권2호
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• pp.104-114
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• 2019

Energy is an essential driving force for modern society. In particular, electricity has become the standard source of power for almost every aspect of life. Electric power runs lights, televisions, cell phones, laptops, etc. However, it has become apparent that the current methods of producing this most valuable commodity combustion of fossil fuels are of limited supply and has become detrimental for the Earth's environment. It is also self-evident, given the fact that these resources are non-renewable, that these sources of energy will eventually run out. One of the most promising alternatives to the burning of fossil fuel in the production of electric power is the proton exchange membrane (PEM) fuel cell. The PEM fuel cell is environmentally friendly and achieves much higher efficiencies than a combustion engine. Water management is an important issue of PEM fuel cell operation. Water is the product of the electrochemical reactions inside fuel cell. If liquid water accumulation becomes excessive in a fuel cell, water columns will clog the gas flow channel. This condition is referred to as flooding. A number of researchers have examined the water removal methods in order to improve the performance. In this paper, a new water removal method that investigates the use of vibro-acoustic methods is presented. Piezo-actuators are devices to generate the flexural wave and are attached at end of a cathode bipolar plate. The "flexural wave" is used to impart energy to resting droplets and thus cause movement of the droplets in the direction of the traveling wave.

• 신재생에너지
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• 제16권4호
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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.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1288-1294
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• 2022

Hydrogen as an environmentally friendly energy carrier has received special attention to solving uncertainty about the presence of renewable energy and its dependence on time and weather conditions. This material can be prepared from different sources and in various ways. In previous studies, fossil fuels have been used in hydrogen production, but due to several limitations, especially the limitation of the access to this material in the not-too-distant future and the great problem of greenhouse gas emissions during hydrogen production methods. New methods based on renewable and green energy sources as energy drivers of hydrogen production have been considered. In these methods, water or biomass materials are used as the raw material for hydrogen production. In this article, after a brief review of different hydrogen production methods concerning the required raw material, these methods are examined and ranked from different aspects of economic, social, environmental, and energy and exergy analysis sustainability. In the following, the current position of hydrogen production is discussed. Finally, according to the introduced methods, their advantages, and disadvantages, solar electrolysis as a method of hydrogen production on a small scale and hydrogen production by thermochemical method on a large scale are introduced as the preferred methods.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.580-586
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• 2023

Diversified fuel types such as methanol, hydrogen, liquefied natural gas, ammonia, biofuels, have been come to fore in consideration of the limitations, regulations, environmental perception and efficient use of resources on maritime sector. NE is described as a substantial alternative energy source on the marine vessels in the sense of de-carbonization and fuel efficiency activities carried out by IMO. Although NPVs have been constructed for the merchant, navy and supply fields over the years, their numbers are few and working ranges are quite limited. NE generation techniques, reactor types, safety and security issues in case of any leakage or radiation pollution are analyzed and comparisons are performed between fossil-based fueled and NP based on icebreakers. The comparison are conducted on the basis of dimensions, resistances and operational competences by the VIKOR. NP icebreakers operated in recent years occupy a notable position in the ranking, although fossil fueled ones are most prevalent. Consequently, refueling period and emissions are the principal benefits of NPVs. Nevertheless, the use of such systems on marine vessels especially for merchant ships may come to the fore when all concerns in terms of safety, security and society are resolved since the slightest mistake can have irreversible consequences.

• 대한조선학회논문집
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• 제61권2호
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• pp.88-97
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• 2024

This study performed the analysis on an economic feasibility of each marine fuel, potential fuel pathways and the relevance of compliance measures to ensure compliance with the FuelEU Maritime regulation. Additionally, it identified certain regulatory gaps to encourage the use of alternative marine fuels. Regarding GHG emissions calculations, the existing GHG regulations for ships applies the Tank-to-Wake (TtW) method, whereas FuelEU Maritime applies the Well-to-Wake (WtW) method. The main results present that important information to establish response strategy for FuelEU Maritime including the costs and benefits of each marine fuel, the minimum blending ratio of alternative fules, and compliance impacts of measures. For the regulatory costs and benefits of marine fuels following the implementation of the FuelEU Maritime from 2025, our findings indicate that while most fossil fuels incur regulatory costs from 2025, most of biofuels and RFNBO fuels do not incur costs until 2050. This will play a role to narrow the price gap between fossil fuels and alternative fuels.

• 펄프종이기술
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• 제48권2호
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• pp.34-45
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• 2016

Global warming and climate change have been caused by combustion of fossil fuels. The greenhouse gases contributed to the rise of temperature between $0.6^{\circ}C$ and $0.9^{\circ}C$ over the past century. Presently, fossil fuels account for about 88% of the commercial energy sources used. In developing countries, fossil fuels are a very attractive energy source because they are available and relatively inexpensive. The environmental problems with fossil fuels have been aggravating stress from already existing factors including acid deposition, urban air pollution, and climate change. In order to control greenhouse gas emissions, particularly CO2, fossil fuels must be replaced by eco-friendly fuels such as biomass. The use of renewable energy sources is becoming increasingly necessary. The biomass resources are the most common form of renewable energy. The conversion of biomass into energy can be achieved in a number of ways. The most common form of converted biomass is pellet fuels as biofuels made from compressed organic matter or biomass. Pellets from lignocellulosic biomass has compared to conventional fuels with a relatively low bulk and energy density and a low degree of homogeneity. Thermal pretreatment technology like torrefaction is applied to improve fuel efficiency of lignocellulosic biomass, i.e., less moisture and oxygen in the product, preferrable grinding properties, storage properties, etc.. During torrefacton, lignocelluosic biomass such as palm kernell shell (PKS) and empty fruit bunch (EFB) was roasted under an oxygen-depleted enviroment at temperature between 200 and $300^{\circ}C$. Low degree of thermal treatment led to the removal of moisture and low molecular volatile matters with low O/C and H/C elemental ratios. The mechanical characteristics of torrefied biomass have also been altered to a brittle and partly hydrophobic materials. Unfortunately, it was much harder to form pellets from torrefied PKS and EFB due to thermal degradation of lignin as a natural binder during torrefaction compared to non-torrefied ones. For easy pelletization of biomass with torrefaction, pellets from PKS and EFB were manufactured before torrefaction, and thereafter they were torrefied at different temperature. Even after torrefaction of pellets from PKS and EFB, their appearance was well preserved with better fuel efficiency than non-torrefied ones. The physical properties of the torrefied pellets largely depended on the torrefaction condition such as reaction time and reaction temperature. Temperature over $250^{\circ}C$ during torrefaction gave a significant impact on the fuel properties of the pellets. In particular, torrefied EFB pellets displayed much faster development of the fuel properties than did torrefied PKS pellets. During torrefaction, extensive carbonization with the increase of fixed carbons, the behavior of thermal degradation of torrefied biomass became significantly different according to the increase of torrefaction temperature. In conclusion, pelletization of PKS and EFB before torrefaction made it much easier to proceed with torrefaction of pellets from PKS and EFB, leading to excellent eco-friendly fuels.

• 자원환경지질
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• 제45권4호
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• pp.407-429
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• 2012

도미분지에 위치한 도미-1공과 소라-1공을 대상으로 와편모조류 미화석, 유기물상 분석 및 탄성파자료 해석을 통한 지층대비의 방법으로 연구지역의 층서와 고환경을 해석하고, 그 결과를 일본 북서 큐슈지역의 기존 연구결과와 비교하였다. 생물상변화를 토대로 상부에서부터 Ecozone A, Ecozone B(Barren zone), Ecozone C, Ecozone D(Barren zone)로 각각 4개의 생태층서대로 나누었다. 표준화석에 의한 지질시대는 2개 시추공 모두 하부로부터 에오세 - 올리고세, 마이오세, 플라이오세 - 플라이스토세 시기로 나타났다. 유기물상에 의한 고환경은 상부에서 시작하여 다음과 같이 5개로 나누었다; Association I(Inner neritic), Association II(Freshwater), Association III(Inner neritic), Association IV(Freshwater), Association V(Swamp). 두 개의 시추공 자료를 토대로 일본 측 생층서 자료와 비교 한 결과, Heteraluacacysta campanula, Tubiosphaera galatea 등의 에오세 - 올리고세 표준화석이 양측 연구 모두 동일하게 나타나고, 두 지역의 군집조성이 유사함을 확인하였다. 이는 도미분지와 일본의 북서 큐슈 지역의 고제3기층 발달사에 서로 연관성이 있음을 시사한다.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2005년도 추계정기총회 및 제26회 학술발표대회 고분자리싸이클링기술 특별심포지엄
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• pp.34-46
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• 2005

대량 발생되어 환경 문제를 유발하는 폐플라스틱의 처리방법으로 열분해에 의한 대체 연료유 생산 기술이 부각되고 있다. 본 연구에서는 폐플라스틱의 발생 현황, 국내 외 유화 기술 현황, 유화의 기본적인 공정 기술과 문제점, 그리고 한국에너지기술연구원에서 개발된 유화의 신기술을 소개하였다. 이 공정의 특징은 열가소성 폐플라스틱이 혼합된 원료에 대해 공정 운전이 자동화에 의한 연속 운전이 가능하고, 반응 공정이 무촉매이지만 왁스 생성을 최소화한 순환식 분해 반응 공정이며, 또한 생성 가스의 재 사용과 슬러지의 오일 회수에 의한 배출 잔사물의 양을 줄이는 등의 특징을 가진 경제적, 환경적으로 많은 장점을 가지고 있다. 파이롯트 플랜트 실험 결과는 정상 운전이 3일 이상의 연속 운전에 의해 오일 수율이 81% 정도 얻었다. 증류탑 상단과 하단에서 얻은 생성유는 각각 가솔린과 디젤인 경유보다 조금 높은 끊는점 분포를 보였다.

• 한국산학기술학회논문지
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• 제17권8호
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• pp.502-507
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• 2016

화석연료에 기반을 둔 경제구조에서 수소경제로의 이행은 에너지 안보와 기후변화의 대응이라는 측면에서 중요한 과제이다. 이러한 경제구조의 변환과정에서 발생할 수 있는 파급효과를 사전적으로 분석하는 연구가 필요하다. 따라서 이 논문은 동태 연산일반균형모형을 이용하여 수소에너지 도입이 경제와 환경에 미치는 영향을 분석하였다. 첫째, 수소 에너지 도입은 투자증대와 생산비용의 감소를 통해 GDP 증대에 기여한다. 둘째, 수소에너지와 같은 신재생에너지 도입을 위한 정부보조의 경우 재원마련을 위한 세수증대로 인해 총수요가 감소하는 효과가 있다. 마지막으로 화석연료에서 수소경제로 전환시키는 수소에너지 도입은 이산화탄소 배출을 감소시키는 환경적 효과가 있다 온실가스 감소를 통한 기후변화에 보다 효과적으로 대응하기 위해서는 신재생에너지에 기반을 둔 수소에너지로의 전환이 필요하다. 즉 정부는 지속가능성에 기반을 둔 수소에너지 정책을 추진해야 하며, 향후 신재생에너지에 기반을 둔 수소에너지 도입의 경제적, 환경적 효과를 분석할 필요성이 있다.