The brief review on Coal origin and distribution of rare earth elements in various Coal Ash Samples

Ramakrishna, Chilakala,Thenepalli, Thriveni,Nam, Seong Young,Kim, Chunsik,Ahn, Ji Whan The Korean Society for Energy 2018 에너지공학 Vol.27 No.2

Rare earth elements together with Y and Sc (REEs) are essential in the development of technology for clean and efficient use of energy. In recent years coal deposits have much attention and attracted as a promising alternative raw sources for rare earth elements, not only because the REEs concentrations in many coals or coal ashes are equal to or higher than those found in conventional types of REEs ores but also because of the world wide demand for REEs in recent years has been greater than supply. In the coal ashes, REEs are mainly associated with carbonates, silicates and aluminosilicates in ashes at 800 and $1100^{\circ}C$. These elements are known to be powerful environmental tracers in natural biogeochemical compartments. In this study, to reviewed the REEs originating and distribution patterns in coal ash samples from the bedrock and/or soil weathering that were entrapped by lichens and mosses was investigated. The REEs patterns of different organisms species allowed minor influence of the species to be highlighted compared to the regional lithology.

Cost effective and low energy consuming hydrothermal synthesis of Ni based MOF

Israr, Farrukh,Kim, Duk Kyung,Kim, Yeongmin,Oh, Seung Jin,Ng, Kim Choon,Chun, Wongee The Korean Society for Energy 2015 에너지공학 Vol.24 No.2

The mesoporous metal organic framework structure of Ni-BTC was successfully synthesized in a low temperature and short operation time via hydrothermal synthesis process. Such operational route virtuously consumed less electrical and thermal energy. It proved time saving along with acceptable product yield (38%). The product was characterized through FESEM, FT-IR, XRD and $N_2$ gas adsorption measurement. Hightemperature stability of synthesized MOF was gauged by diffraction indexing of XRD patterns of as synthesized and heat treated samples of MOFs. The mathematically calculated particle size of Ni-BTC was found to be 42nm.

The Concept of a Gravity Engine and Energy Performance for Tidal and Hydro-Power

Lee, Jae-Young The Korean Society for Energy 2000 에너지공학 Vol.9 No.1

This paper is to propose the concept and performance of a gravity engine which could extract energy from sea or river as a clean. renewable and sustainable power. the vertical motion of the buoyancy cylinder of the present gravity engine is converted to the mechanical work directly without any hydraulic loss. The positive net energy between the imposed and harnessed one is achieved by the specific operating procedure. The detailed derivation of the energy balance is made based on the first principle of thermodynamics. The calculation demonstrates that the present gravity engine could harness more energy than the conventional turbine system in the same basin area because of the relatively high efficiency in the energy conversion system and added mass from the buoyancy cylinder.

Energy Auditing Using a Building Energy Simulation Program BLDSYM

Lee, E.J.,Yoon, J.H.,Kang, Y.H.,Jeon, H.S. The Korean Solar Energy Society 1995 한국태양에너지학회 논문집 Vol.15 No.3

The objectives of this study are to introduce the energy simulation program BLDSYM, to verify the approach, and to demonstrate the energy saving opportunities. A case study model for Hoover Middle School, OK, USA has been introduced as a base case simulation. Air-side variable air volume(VAV) and water-side variable flow hydronic(VFH) system have been recommended, modeled and simulated to quantify the energy savings compared with the base system, which is typically constant air and water flow system. More than 30% of energy savings could be obtained with the optimum variable flow system.

The Cement Industry in Ethiopia

Mulatu, Dure,Habte, Lulit,Ahn, Ji Whan The Korean Society for Energy 2018 에너지공학 Vol.27 No.3

The cement industry is one of the rapidly growing industry in Ethiopia. The average per capita cement consumption of the country has increased from 39kg to 62kg. However, this is still way below than the global average per capita consumption of 500kg. The Ethiopian government is planning to expand its cement industry by upgrading the current cement plants and also opening of new cement plants in order to meet the future demand of the country. Currently, the number of cement plants in Ethiopia has reached to 20. By the year 2025, per capita cement consumption is expected to increase to 179kg. Recently, Ethiopia has become one of Africa's largest market for the cement industry. In addition, Ethiopia has become the major exporter of cement in the Sub-Saharan African region. The Ethiopian cement industry is highly dependent on the use of imported energy sources for its production. This situation has a significant amount of impact on the high production costs of the industry. This paper will try to review the history, production, available resources, the technologies and energy use of the Ethiopian cement industry.

Technologies for Sustainable Energy Sources and Systems

Chung, Kun-Mo The Korean Society for Energy 1999 에너지공학 Vol.8 No.1

지속 가능한 개발을 위해서는 환경영향을 최소화하고 능률이 높은 에너지의 활용을 위한 기존 기술의 개선과 신기술의 창출이 필요로 하다. 이 논문에서는 현재 진행중인 화력발전기술 및 원자력발전기술의 연구개발 현황과 앞으로의 전마을 평가예측하고 기술개발에 있어서 중요한 과제를 어떻게 해결해야 하는가를 제시한다. 또한 대체에너지기술개발의 현황을 평가하고 앞으로의 개발 가능성을 분석한다. 에너지의 운송과 배분 및 저장 기술 중 주목을 끌고 있는 연구개발 사업을 평가하고 최종수요자가 사용하는 에너지소비기술개발에 있어서 주어진 과제들을 분석평가하고 앞으로의 성취 가능한 기술개발 목표를 제시하였다.

Non-energy Use and $CO_2$ Emissions: NEAT Results for Korea

Park, Hi-chun The Korean Society for Energy 2002 에너지공학 Vol.11 No.1

Carbon accounting is a key issue in the discussions on global warming/CO$_2$mitigation. This paper applies both the IPCC Approach and the NEAT (Non-Energy use Emission Accounting Tables) model, a bottom-up approach, to estimate the potential CO$_2$ emissions (carbon storage) originating from the non-energy use as to assess the actual CO$_2$ emissions (carbon release) from the use of fossil fuels in Korea. The current Korean carbon accounting seems to overestimate the potential CO$_2$ emissions and with it to underestimate the actual CO$_2$ emissions. The estimation shows that the potential CO$_2$ emissions calculated according to the IPCC Approach are lower than those calculated using the NEAT model. This is because the IPCC default storage fraction for naphtha seems to be low for the Korean petrochemical production structure, on the one hand and because the IPCC Approach does not consider the trade with short life petrochemical products, on the other hand. This paper shows that a bottom-up approach like the NEAT model can contribute to overcome some of limitations of the IPCC guidelines, especially by considering the international trade with short life petrochemical products and by estimating the storage fractions of fossil fuels used as feedstocks for the country in consideration. This paper emphasizes the importance of accurate energy statistics for carbon accounting.

Global technologies for the removal of water scaling & water recovery - Department of Energy (DOE) USA

Ramakrishna, Chilakala,Thriveni, Thenepalli,Whan, Ahn Ji The Korean Society for Energy 2018 에너지공학 Vol.27 No.1

In this paper, we reported the current technologies of water scaling removal and also water recovery from the flue gases, which are funded by Department of Energy (DOE), USA. Globally, water resources are limited due to the climate change. The potential impacts of climate change is food and water shortages. In the $21^{st}$ century, water shortages and pollution are expected to become more acute as populations grow and concentrate in cities. At present, the water stress increases over 62.0 ~ 75.8% of total water basin area and decreases over 19.7 ~ 29.0%. Many renewable energy sources demand secure water resources. Water is critical for successful climate change mitigation, as many efforts to reduce greenhouse gas emissions depend on reliable access to water resources. Water hardness is one of the major challenge to coal power plants. Department of energy (DOE) funded and encouraged for the development of advanced technologies for the removal of hardness of water (scaling) and also water recovery from the flue gases from coal power plants.

A STUDY ON THE ENGINE PERFORMANCE OF A SPARK IGNITION ENGINE ACCORDING TO THE IGNITION ENERGY

Han, Sung Bin The Korean Society for Energy 2014 에너지공학 Vol.23 No.3

The more or less homogeneous fuel-air mixture that exists at the end of the compression process is ignited by an electric ignition spark from a spark plug shortly before top dead center. The actual moment of ignition is an optimization parameter; it is adapted to the engine operation so that an optimum combustion process is obtained. Brake mean effective pressure (BMEP) of the spark ignition energy control device (IECD) than conventional spark system at the stoichiometric mixture is increased about 9%. For lean burn engine, the lean limit is extended about 25% by using the IECD. It was considered the stability of combustion by the increase of flame kernel according to the high ignition energy supplies in initial period and discharge energy period lengthen by using the IECD.

CO₂ sequestration and heavy metal stabilization by carbonation process in bottom ash samples from coal power plant

Ramakrishna., CH,Thriveni., T,Nam, Seong Young,kim, Chunsik,Ahn, Ji Whan The Korean Society for Energy 2017 에너지공학 Vol.26 No.4

Coal-fired power plants supply roughly 50 percent of the nation's electricity but produce a disproportionate share of electric utility-related air pollution. Coal combustion technology can facilitate volume reduction of up to 90%, with the inorganic contaminants being captured in furnace bottom ash and fly ash residues. These disposal coal ash residues are however governed by the potential release of constituent contaminants into the environment. Accelerated carbonation process has been shown to have a potential for improving the chemical stability and leaching behavior of bottom ash residues. The aim of this work was to quantify the volume of $CO_2$ that could be sequestrated with a view to reducing greenhouse gas emissions and stabilize the contaminated heavy metals from bottom ash samples. In this study, we used PC boiler bottom ash, Kanvera reactor (KR) slag and calcined waste lime for measuring chemical analysis and heavy metals leaching tests were performed and also the formation of calcite resulting from accelerated carbonation process was investigated by thermo gravimetric and differential thermal analysis (TG/DTA).