• 신재생에너지
• /
• 제4권2호
• /
• pp.21-30
• /
• 2008

Anaerobic digestion (AD) is the most promising method of treating and recycling of different organic wastes, such as OFMSW, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. degradation in the absence of oxygen, organic material is decomposed by anaerobes forming degestates such as an excellent fertilizer and biogas, a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to producing renewable energy and to reducing $CO_2$ and other GHG emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. A classification of the basic AD technologies for the production of biogas can be made according to the dry matter of biowaste and digestion temperature, which divide the AD process in wet and dry, mesophilic and thermophilic. The biogas produced from AD plant can be utilized as an alternative energy source, for lighting and cooking in case of small-scale, for CHP and vehicle fuel or fuel in industrials in case of large-scale. This paper provides an overview of the status of biogas production and utilization technologies.

• 한국수소및신에너지학회논문집
• /
• 제30권1호
• /
• pp.21-28
• /
• 2019

Reversible solid oxide fuel cell (ReSOC) system was integrated with waste steam for electrical energy storage in distributed energy storage application. Waste steam was utilized as external heat in SOEC mode for higher hydrogen production efficiency. Three system configurations were analyzed to evaluate techno-economic performance. The first system is a simple configuration to minimize the cost of balance of plant. The second system is the more complicated configuration with heat recovery steam generator (HRSG). The third system is featured with HRSG and fuel recirculation by blower. Lumped models were used for system performance analyses. The ReSOC stack was characterized by applying area specific resistance value at fixed operating pressure and temperature. In economical assessment, the levelized costs of energy storage (LCOS) were calculated for three system configurations based on capital investment. The system lifetime was assumed 20 years with ReSOC stack replaced every 5 years, inflation rate of 2%, and capacity factor of 80%. The results showed that the exergy round-trip efficiency of system 1, 2, 3 were 47.9%, 48.8%, and 52.8% respectively. The high round-trip efficiency of third system compared to others is attributed to the remarkable reduction in steam requirement and hydrogen compression power owning to fuel recirculation. The result from economic calculation showed that the LCOS values of system 1, 2, 3 were 3.46 ¢/kWh, 3.43 ¢/kWh, and 3.14 ¢/kWh, respectively. Even though the systems 2 and 3 have expensive HRSG, they showed higher round-trip efficiencies and significant reduction in boiler and hydrogen compressor cost.

• 유기물자원화
• /
• 제20권1호
• /
• pp.23-30
• /
• 2012

본 연구는 향후 최적 소각용량의 산정에 관해 재평가가 요구되고 있는 실정에서 반입되는 폐기물 발생량, 발열량 증가 및 B시 구역별 유동인구 변화 등을 고려하여 소각 사업소의 최적 가용용량을 예측하고, 예측된 가용용량을 기초로 하여 각 소각 사업소 별 처리량 대안에 대해 연구하는 게 목적이다. B시의 과거 인구추이를 바탕으로 인구변화량을 예측한 결과 전체 인구는 감소추세에 있으나, 일부 지역에 따라서는 아파트 단지 증가 등으로 인구 집중 현상이 나타나 현재와 비슷할 것으로 판단된다. 또한 인구예측을 통한 폐기물 발생량 예측 시 인구의 감소에 의한 폐기물 발생량은 감소할 것으로 판단되지만, 총 폐기물 발생량 중 가연성분 발생량은 증가할 것으로 예측되어 가연성 성분 및 소각 처리량은 D 소각 사업소를 제외하고는 적정할 것으로 예측된다. 따라서 현재 D소각 사업소의 소각율은 72.7%로 전국 소각비율 59.1%보다는 높지만 향후 소각량 확보를 위하여 B시의 MBT시설의 잔재폐기물 및 RDF 회수 잔재물 등과의 혼재 소각과 하수슬러지 및 음식물 쓰레기의 혼재소각이 필요하다고 판단되어지며 2015년 이후 D 소각 사업소를 폐쇄한다고 가정하였을 때는 각 소각장과의 거리와 가용할 수 있는 소각장 규모를 파악하여 경제성에서 가장 적합한 연동구역에 운반(연동제)하여 운영하는 방법이 경제적일 것으로 예측된다. 이에 D 소각 사업소의 경우는 새로운 소각시설 설치에 따른 주민불편 및 사회적 피해를 고려하여 폐수처리장 통합연계 시스템 구축에 따라 폐기물과 혼재 처리할 수 있는 장래의 여유 소각을 할 수 있는 시설 확보 측면에서 2020년까지 운영이 필요하고, H나 M 소각 사업소는 적정 소각량이 감소하는 경우 3개 소각시설이 운휴 기간이 없이 운영되기 위해서 2기를 확보하고 단위사업별 1기 단위로 6개월씩 단위 운영 병행제로 하는 관리방안의 구상도 해결방안이라고 판단되어 진다.

• KIEAE Journal
• /
• 제14권4호
• /
• pp.119-125
• /
• 2014

This study investigated the effects of pipe network materials and distance on system performance utilizing unused energy sources in large-scale horticulture facility. For this, the modeling was performed with a 100 m long and 100 m wide rectangular shaped glass house having an area of 1ha ($10,000m^2$) using EnergyPlus software. The heat sources considered were air source, geothermal heat, power plant waste heat, sea water heat, and river water. The temperature variation of the fluid with regard to pipe material and distance from the heat source and the resultant heat pump electricity consumptions were calculated. It turned out that the fluid temperature reaching the heat pump increased as the distance from the heat source increased in case of sea water and river water, which have higher temperatures than the surrounding soil, improving the heat pump efficiency. It was vice versa in case of the power plant waste heat. In addition, pipe material of PVC showed the smallest effect on the system performance variation due to the lowest thermal conductivity, compared to PB and HDPE.

• Corrosion Science and Technology
• /
• 제15권3호
• /
• pp.113-119
• /
• 2016

Corrosion science faces new challenges in various nuclear environments. Three main areas may be identified where increases of knowledge and understanding have been done and are still needed to face the technical needs: (i) the extension of the service time of nuclear power plants from 40 years, as initially planned, to 60 years and probably more as expected now, (ii) the prediction of long term behaviour of metallic materials in nuclear waste disposal where the corrosion processes have to be predicted over large periods of time, some thousands years and more, (iii) the choice of materials for use at very high temperatures as expected in Generation IV power plants in environments like gas (helium), supercritical water, liquid metals or salts. Service time extension, deep geological waste repositories and high temperature reactors sustain researches and developments to model corrosion phenomena at various scales, from atoms to components.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2022년도 추계학술대회
• /
• pp.162-163
• /
• 2022

Maritime transportation is going to transfer to alternative fuels as a result of the worldwide demands toward decarbonization and tougher maritime emissions regulations. Methanol is considered as a potential marine fuel, which has the ability to reduce SOx and CO₂ emissions, reduce climate change effects, and achieve the objective of green shipping. This work proposes and combines the innovative combination system of direct methanol solid oxide fuel cells (SOFC), proton exchange membrane fuel cells (PEMFC), gas turbines (GT), and organic Rankine cycles (ORC) for maritime vessels. The system's primary power source is the SOFC, while the GT and PEMFC use the waste heat from the SOFC to generate useful power and improve the system's ability to use waste heat. Each component's thermodynamics model and the combined system's model are established and examined. The multigeneration system's energy and exergy efficiency are 76.2% and 30.3%, respectively. When compared to a SOFC stand-alone system, the energy efficiency of the GT and PEMFC system is increased by 19.2%. The use of PEMFC linked SOFC has significant efficiency when a ship is being started or maneuvered and a quick response from the power and propulsion plant is required.

• 방사성폐기물학회지
• /
• 제4권2호
• /
• pp.153-159
• /
• 2006

우라늄 변환시설 가동 중 발생하여 라군(lagoon)에 저장중인 방사성 슬러지 폐기물에 대한 처리는 시설 해체과정에서 매우 중요한 업무 중 하나이다. 슬러지 구성성분 중 다량을 차지하는 질산암모늄의 폭발 위험성 등으로 인해 미생물을 이용한 질산염의 분해는 질산염을 안정적으로 처리할 수 있는 효과적인 방법이라 할 수 있다. 본 연구에서는 라군 슬러지의 약 60 wt%를 차지하는 질산염을 혐기성 균주의 하나인 Pseudomonas halodenidificans를 이용하여 탈질하기위한 공정 변수에 대한 영향을 평가하였다. 온도, 질산염 농도, 전자공여체의 영향, C/N 비율, 초기 접종하는 균주의 비율, pH등의 공정변수에 대하여 실험한 이번 결과는 향후 연속식 공정 설계를 위한 기초 자료로 사용될 것이다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
• /
• pp.202-205
• /
• 2008

Anaerobic digestion(AD) is the most promising method of treating and recycling of different organic wastes, such as OFMSW, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. degradation in the absence of oxygen, organic material is decomposed by anaerobes forming degestates such as an excellent fertilizer and biogas, a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to producing renewable energy and to reducing $CO_2$ and other GHG emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. A classification of the basic AD technologies for the production of biogas can be made according to the dry matter of biowaste and digestion temperature, which divide the AD process in wet and dry, mesophilic and thermophilic. The biogas produced from AD plant can be utilized as an alternative energy source, for lighting and cooking in case of small-scale, for CHP and vehicle fuel or fuel in industrials in case of large-scale. This paper provides an overview of the status of biogas production and utilization technologies.

• Nuclear Engineering and Technology
• /
• 제41권4호
• /
• pp.427-446
• /
• 2009

In order to meet the increasing demand for electricity, Korea has to rely on nuclear energy due to its poor natural resources. In order for nuclear energy to be expanded in its utilization, issues with uranium supply and waste management issues have to be addressed. Fast reactor system is one of the most promising options for electricity generation with its efficient utilization of uranium resources and reduction of radioactive waste, thus contributing to sustainable development. The Korea Atomic Energy Research Institute (KAERI) has been performing R&Ds on Sodium-cooled Fast Reactors (SFRs) under the national nuclear R&D program. Based on the experiences gained from the development of KALIMER conceptual designs of a pool-type U-TRU-10%Zr metal fuel loaded reactor, KAERI is currently developing Advanced SFR design concepts that can better meet the Generation IV technology goals. This also includes developing, Advanced SFR technologies necessary for its commercialization and basic key technologies, aiming at the conceptual design of an Advanced SFR by 2011. KAERI is making R&D efforts to develop advanced design concepts including a passive decay heat removal system and a supercritical $CO_2$ Brayton cycle energy conversion system, as well as developing design methodologies, computational tools, and sodium technology. The long-term Advanced SFR development plan will be carried out toward the construction of an Advanced SFR demonstration plant by 2028.

• 한국해양환경ㆍ에너지학회지
• /
• 제5권1호
• /
• pp.30-37
• /
• 2002

최근 연안의 해양오염 증가로 인하여 매년 발생되는 적조현상 등이 연안 생태계에 영향을 많이 끼치는 문제점으로 되고 있다. 해양오염 요인 중에 어선에서 발생되는 선저폐수나 폐윤활유의 무단 배출은 큰 비중을 차지하고 있으므로 효율적인 관리방법을 찾아야 한다. 이런 문제점을 해결하기 위한 방안으로 선저폐수처리장치를 어항별로 설치하여 소형 어선에서 발생되는 선저폐수와 폐윤활유를 육상으로 이송ㆍ처리하여 해양으로의 무단 배출을 막아야 한다. 그에 대한 선결연구과제로 어선에서 발생되는 선저폐수와 폐윤활유 발생량 추정에 관한 연구의 필요성이 대두된다. 본 연구의 주요내용은 톤급별 어선에서 발생되는 선저폐수와 폐윤활유 현황 조사 및 고찰과 선저폐수와 폐윤활유 발생량에 영향을 주는 파라미터 도출을 통한 발생량 모델링과 이를 이용한 샘플어장에 대한 선저폐수와 폐윤활유 발생량 추정을 포함하고 있다.