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        검색결과 18

        2.
        2019.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Indirect oxidation using chlorine species oxidizing agents is often effective in wastewater treatment using an electrochemical oxidation process. When chlorine ions are contained in the wastewater, oxidizing agents of various chlorine species are produced during electrolysis. In a ballast water management system, it is also used to treat ballast water by electrolyzing seawater to produce a chlorine species oxidizer. However, ballast water in the brackish zone and some wastewater has a low chlorine ion concentration. Therefore, it is necessary to study the chlorine generation current efficiency at various chlorine concentration conditions. In this study, the chlorine generating current efficiency of a boron-doped diamond(BDD) electrode and insoluble electrodes are compared with various chloride ion concentrations. The results of this study show that the current efficiency of the BDD electrode is better than that of the insoluble electrodes. The chlorine generation current efficiency is better in the order of BDD, MMO(mixed metal oxide), Ti/RuO2, and Ti/IrO2 electrodes. In particular, when the concentration of sodium chloride is 10 g/L or less, the current efficiency of the BDD electrode is excellent.
        4,000원
        4.
        2015.06 구독 인증기관·개인회원 무료
        Korean society is aging at a fast rate and the ratio of elderly population is expected to increase by 38.2% in 2050 (Statistics Korea, 2011). The extension of average life expectancy of the elderly generation leads to various problems and the most important issue is the mental health of the elderly. The suicide rate of the elderly is increasing every year and is the highest rate among OECD nations (OECD, 2014). The primary reason for the rapidly increasing suicide rate is psychological hardship caused by personal, social, and environmental factors such as a generation gap from nuclearization, decreased social position, retirement, economic hardship, spousal bereavement, and separation. The importance of education to improve quality of life through the mental stability of the elderly generation is emphasized. Continued education has a positive effect on the physical, social, and psychological health of the elderly generation (Kim, 2011), successful aging (Jee, 2010), and quality of life (Kim &An, 2008). Arts and crafts education can achieve development in visual perception, sense of touch, and continued elderly education (Mo, 2011). Arts and crafts education improves accomplishments and creative thinking ability through analogue behavior of making by hand. This study conducted 12 hours of education for 3 days from 1pm to 5 pm at 1 week intervals on 5 elderly women between 55 and 70 years of age to investigate physical and psychological effects on elderly women through natural wool craft activity. Before the education, the anxiety degree of subjects of the past week was measured with the Beck Anxiety Inventory (BAI) to verify the effect of sensibility education by conducting electroencephalogram(EEG) and PortaLite before after conducting education on subjects. As a result of analyzing the before and after numerical mean value through brainwave test, the increasing phenomenon of an alpha waves appeared and showed that the psychology of subjects is stable and secure. The result of this study showed that wool craft education decreased anxiety, increased alpha waves and improved the psychological stability of elderly women.
        5.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        본 연구는 우리나라의 1990-2014년 시계열 자료를 활용하여 물 효율성, 경제성장, 전력생산 및 이산화탄소 배출 간의 장·단기 인과관계를 실증적 으로 분석하였다. 기존 연구들이 경제성장, 이산화탄소 배출 및 전력 및 에너지에 국한되어 분석을 한 반면 본 연구는 기존 변수들과 더불어 물 효율성과의 관계를 설명하였다는 기여를 가지고 있다. 실증분석결과를 살펴보면, 네 변수들은 단기조정관계를 통해 장기적으로 균형상태에 도달한다는 것과 변수들 간의 인과관계에서 이산화탄소 배출과 경제성장은 물 효율성의 원인이 되고 이산화탄소 배출과 경제성장 및 물 효율성은 전력생산의 원인이 된다는 사실을 발견하였다. 또한 물 효율성에 대한 장기 영향계수 추정결과를 통해 전력생산의 증가와 경제성장 및 이산화탄소 배출의 감소는 물 효율성을 증가시키며, 일정 수준 이상의 경제성장은 물 효율성의 증가속도를 감소시킨다는 경제성장과 물 효율성의 역U자형 관계를 확인하였다.
        6.
        2018.05 서비스 종료(열람 제한)
        To achieve energy efficiency improvement is used to lower temperature for emission gas at catalyst inlet, or to reduce/stop using steam to reheat emission gas. Saved energy from this process can be used as power source in order to increase generation efficiency. Dry emission gas treatment, on the other hand, is the technology to increase generation efficiency by using highly efficient desalination materials including highly-responsive slaked lime and sodium type chemicals in order to comply with air pollution standards and reduce used steam volume for reheating emission gas. If dry emission gas is available, reheating is possible only with the temperature of 45℃ in order to expect generation efficiency by reducing steam volume for reheating. Retention energy of emission gas from combustion is calculated by emission gas multiplied by specific heat and temperature. In order to obtain more heat recovery from combustion emission gas, it is necessary to reduce not only exothermic loss from boiler facilities but emission calorie of emission gas coming out of boiler facilities. In order to reduce emission calorie of emission gas, it is efficient to realize temperature lowering for the emission gas temperature from the exit of heat recovery facility and reduce emission gas volume. When applying low temperature catalysts, the energy saving features from 0.03% to 2.52% (average 1.28%). When increasing the excess air ratio to 2.0, generation efficiency decreases by 0.41%. When the inlet temperature of the catalyst bed was changed from 210℃ to 180℃, greenhouse gas reduction results were 47.4, 94.8, 118.5, 142.2 thousand tons-CO2/y, CH4 was calculated to be 550.0, 1100.1, 1375.1, 1650.1 kg-CH4/y, and N2O was 275.0, 550.0, 687.6, 825.1 kg-N2O/y. In the case of high efficiency dry flue gas treatment, reduction of greenhouse gases by the change of temperature 120~160℃ and exhaust gas 5,000 ~ 6,500 ㎥/ton is possible with a minimum of 355,461 ton/y of CO2 and minimum 4,125 tons of CH4/y to a maximum of 6,325 ton/y and N2O to a minimum of 2,045 kg/y to a maximum of 3,135 kg/y.
        7.
        2018.05 서비스 종료(열람 제한)
        국가별 환경, 정채 흐름에 따라 상이하게 적용되어온 폐기물 에너지화 기술은 도시고형폐기물을 비롯한 폐자원을 증기, 열, 전력 등으로 전환하는 기술을 의미한다. 국내 「신재생에너지 개발・이용・보급촉진법」에 의거하여 사업장에서 폐기물을 변환시켜 생산된 연료 및 소각 열에너지를 신재생에너지로 정의하고 있으며, 「자원순환기본법」의 소각처분부담금 감면을 위한 에너지 회수율 증진을 목적으로 폐기물 에너지화 기술이 주목을 받고 있다. 폐기물 에너지화 기술 중 열적처리의 시장 규모는 연간 190만 달러, 연평균 4.3%의 성장세를 보이고 있으나, 선진국 대비 국내 폐기물 에너지화 기술력은 50% 이하의 낮은 수준을 보유하고 있는 실정이다. 또한 국내 생활폐기물 소각시설의 평균 증기발전 효율이 10% 정도로 매우 낮으며, 사업장폐기물 소각시설은 주로 발전 보다 증기의 직접적 이용에 편향된 경향을 보이고 있다. 따라서 본 연구에서는 국내 사업장폐기물 소각시설 공정에 요소기술 적용 시 에너지 절감량을 열정산법에 따라 산정하여 에너지 고효율화 및 온실가스 감축 효과를 분석하고자 하였다. 소각시설에 적용한 요소기술은 증기 회수 및 활용을 중점으로 ①열 회수 능력강화(저온이코노마이저, 낮은 공기비 연소), ②증기의 효율적 이용(저온촉매탈질, 고효율 건식 배기가스 처리, 백연저감 미적용 또는 가동 중지, 배수폐쇄 시스템 미적용), ③증기터빈 시스템의 효율 향상(고온고압 보일러)으로 구분하여 결과를 정리하였다. 에너지 절감 및 온실가스 감축량 산정은 요소기술 적용 시 추가적으로 회수할 수 있는 증기량을 기준으로 보일러 배기가스량, 폐기물 저위발열량, 각 요소기술 변화 요인(과잉공기비, 출구온도 등), 국가고유 전력배출계수를 바탕으로 산정하였다.
        8.
        2017.11 서비스 종료(열람 제한)
        Depending on the steam pressure and temperature balance, it is possible to increase the power generation efficiency of the steam turbine by increasing the heat loss of the turbine by increasing the temperature and pressure. As the high temperature and high pressure increase, the boiler main steam amount is reduced by about 10%, but the increase rate of the heat drop is larger than the decrease rate of the steam flow rate, leading to improvement of power generation efficiency. Utilizing the US Department of Energy Steam Turbine Calculator, we calculated the electricity produced by steam temperature and pressure changes. In this study, the steam temperature was increased from 50℃ to 500℃ at the steam temperature of 20 kg/cm²×300℃, and increased by 10 kg/cm² at the pressure of 20 kg/cm² at the pressure of 60 kg/cm² to investigate the changes in electricity production. Electricity production increased with increasing temperature and pressure. The electricity production was increased by 40.11% at 40 kg/cm²×400℃ and 75.56% at 60 kg/cm²×500℃ compared to the standard condition of 20 kg/cm²×300℃ for comparison.
        9.
        2017.11 서비스 종료(열람 제한)
        Energy can be reduced by reducing the exhaust gas temperature at the catalyst inlet and reducing or not using the amount of steam to reheat the exhaust gas. At this time, it is a method to improve the power generation efficiency by using the saved energy for power generation. When the exhaust gas temperature at the inlet of the catalytic reaction tower is operated at about 210℃, it is necessary to increase the temperature of the flue gas downstream of the bag filter at 165℃ to 45℃ to 210℃ required for the catalytic reaction. In the case of low temperature catalyst application, the temperature required for the catalytic reaction tower may be 185℃ and the temperature may be raised only 20℃. Therefore, the amount of steam for heating can be reduced. If the exhaust gas temperature of the bag filter inlet can be increased to 190℃, it can be combined with the low-temperature catalyst to reduce the energy consumed by removing exhaust gas ash. On the other hand, since the high-pressure steam is used as the heat source for reheating the exhaust gas, the reheating temperature is limited. According to such conditions, the exhaust gas temperature at the inlet of the catalytic reaction tower is often designed at about 200 to 220℃.
        10.
        2017.11 서비스 종료(열람 제한)
        Even if the amount of exhaust gas is the same, it is possible to reduce the exhaust gas exit heat at the outlet of the boiler facility by lowering the outlet temperature of the economizer, so that it is possible to increase the heat quantity recovered from the boiler facility. There are many cases where the existing facility adopts 220~250℃ as the design value of the exhaust gas temperature at the exit of the economizer. However, in recent years, there has been a case of cooling and recovering heat to 200℃ or less from the viewpoint of active heat recovery. The amount of combustion exhaust gas is reduced by reducing the amount of combustion air supplied to the incinerator, and the amount of heat exhausted from the boiler facility is reduced, thereby improving the boiler efficiency. The holding energy of the combustion exhaust gas is the product of the exhaust gas amount and the specific heat and the temperature. In order to recover more heat from the combustion exhaust gas, not only the heat loss in the boiler facility is reduced, but also the heat radiated from the boiler facility is reduced. It is effective to reduce the exhaust gas temperature at the outlet of the heat recovery equipment and reduce the amount of exhaust gas in order to reduce the amount of exhaust heat of the exhaust gas. Even if the exhaust gas temperature at the outlet of the economizer is the same, the amount of exhaust gas discharged at the boiler facility outlet is reduced by reducing the amount of exhaust gas, and an increase in the recovered heat quantity at the boiler is expected.
        11.
        2017.05 서비스 종료(열람 제한)
        As of 2013, approximately 253 domestic incineration facilities including incineration facilities for municipal waste and industrial wastes were collected. The distribution of domestic incineration heat through these incineration facilities is estimated to reach about 1,756 thousands toe by 2013. In this study, a high temperature and pressure boiler was applied to evaluate the improvement effect of power generation efficiency of waste incineration facilities. It is possible to increase the power generation efficiency of the steam turbine by increasing the heat loss of the turbine through the high temperature and pressure depending on the steam pressure and the temperature. The boiler main steam amount is reduced by about 10% due to the high temperature and pressure, but the increase rate of the heat fall rate is larger than the decrease rate of the steam flow rate, so that the power generation efficiency is improved. In case of steam temperature, the steam temperature is increased by 50 ℃ at 500 ℃ and 20 kg/㎠ at the pressure of 20 kg/㎠×300 ℃, and it is increased by 10 kg/㎠ to 60 kg/㎠, electricity production changes were investigated. Electricity production increased with increasing temperature and pressure. The electricity production increased by 51.03 % at 40 kg/㎠×400 ℃ and by 89.07 % at 60 kg/㎠×500 ℃, compared to the standard condition of 20 kg/㎠×300 ℃ for comparison. The boiler main steam amount is reduced by about 10 % due to the high temperature and pressure, but the increase rate of the heat fall rate is larger than the decrease rate of the steam flow rate, so that the power generation efficiency is improved. In case of steam temperature, the steam temperature is increased by 50 ℃ at 500 ℃ and 20 kg/㎠ at the pressure of 20 kg/㎠×300 ℃, and it is increased by 10 kg/㎠ to 60 kg/㎠. Electricity production changes were investigated. Electricity production increased with increasing temperature and pressure. The electricity production increased by 51.03 % at 40 kg/㎠×400 ℃ and by 89.07 % at 60 kg/㎠×500 ℃, compared to the standard condition of 20 kg/㎠×300 ℃ for comparison.
        12.
        2017.05 서비스 종료(열람 제한)
        WtE of MSW plays a crucial role in renewable energy production in Korea. Municipal solid waste (MSW) is an important energy resource for combined heat and power (CHP) production. This study investigated an increasing method to the power generation efficiency by MSW to energy (WtE) plants in South Korea and discussed the issues related to energy efficiency improvement. To achieve energy efficiency improvement is used to lower temperature for emission gas at catalyst inlet, or to reduce/stop using steam to reheat emission gas. Saved energy from this process can be used as power source in order to increase generation efficiency. It is possible to increase denitrification efficiency by maintaining the temperature of emission gas for catalyst denitrification. The temperature of emission gas of which moisture is increased to saturation point (relative humidity of 100%) at the exit of wet scrubber is between 50 and 60℃. This means there should be reheating of emission gas with the approximate temperature of 150℃. Dry emission gas treatment, on the other hand, is the technology to increase generation efficiency by using highly efficient desalination materials including highly-responsive slaked lime and sodium type chemicals in order to comply with air pollution standards and reduce used steam volume for reheating emission gas. If dry emission gas is available, reheating is possible only with the temperature of 45℃ in order to expect generation efficiency by reducing steam volume for reheating.
        13.
        2017.05 서비스 종료(열람 제한)
        When adopting drain close system, the temperature of emission gas at the boiler exit is set high by spraying and evaporating drained water on quencher tower. According to applying drain close system boiler and power generation efficiency were decreased. In case of the water close system is not applied to treat the wastewater from incineration facility, the economizer outlet temperature can be reduced to 190∼220℃. And this leads to the increased ability of boiler's heat recovery. However, the temperature of emission gas at economizer exit should be set at 250℃ or higher if applying drain close system (minor conditions can affect as well). Boiler efficiency and generation efficiency can be improved by comparing the temperature of emission gas at economizer exit at 190℃ without the introduction of drain close system and 250℃ with drain close system. There are three types of white plume reduction equipment: one is offline type to blow air into chimney through heat source and exchange points after heating the air by using steam from equipment like boiler; another is in-line type to blow air into chimney through heat exchanger of combustion emission gas (mainly boiler exit); and the other is to blow air into chimney through hot wind burner by using fuels including kerosene. At a facility with white plume reduction equipment equipped with 5℃ of outdoor temperature and 60% of humidity, power generation volume and generation efficiency can be improved by using leftover steam for steam turbine from suspension of using white plume reduction equipment.
        14.
        2015.05 서비스 종료(열람 제한)
        Incineration allows for the recovery of energy from combustible waste. It would be highly beneficial to society if this heat could be used efficiently. However, due to the difficulties involved with storing and transporting heat energy, consumers would need to live near incineration facilities in order to make efficient use of this heat energy. Moreover, it is usually difficult to achieve a balance between heat demand and supply. For instance, although there is a significant demand for heat in Northern Europe, the demand for electricity in that region is larger than the demand for heat in Central/Southern Europe. Hence, the preferred form of energy recovery differs depending on the nation or regional conditions. However, there are no limitations with regard to electricity because it can be used in a variety of ways. As a result, leading countries such as those in the European Union and the United States have been developing technologies and building facilities to recover electricity. In Korea, stable operation (steam condition 200-300℃, 20-25bar) was given priority over energy recovery because the country’s background with regard to the measure for dioxin is different from that of Europe or the United States. In addition, the produced energy has been mostly self-consumed rather than sold. While Korea is implementing incineration energy recovery, the country’s incineration power generation is considerably lower than that of leading nations. According to the 6thbasic plan for power supply(2013–2027), which was announced in 2013, the government of Korea is planning to secure a power generation capacity of 688 MW (as of 2012, a level of 74 MW was attained) from waste. Accordingly, this paper examined trends and efficiency improvements for incineration power generation in leading countries.
        16.
        1999.06 KCI 등재 서비스 종료(열람 제한)
        This study aims to observe the inhibition of methane generation, the decomposition of organic matter, and the trend of outflowing leachate, using the simulated column of the anaerobic sanitary landfill structure of sulfate addition type which is made by adding sulfate to a current anaerobic landfill structure, and the simulated column of semi-aerobic landfill structure in the laboratory which is used in the country like Japan in order to inhibit methane from a landfill site among the gases caused by a global warming these days, and at the same time to promote the decomposition of organic matter, the index of stabilization of landfill site. As a result of this study, it is thought that the ORP(Oxidation Reduction Potential) of the column of semi-aerobic landfill structure gradually represents a weak aerobic condition as time goes by, and that the inside of landfill site is likely to by in progress into anaerobic condition, unless air effectively comes into a semi-aerobic landfill structure in reality as time goes by. In addition, it can be seen that the decomposition of organic matter is promoted according to sulfate reduction in case of R1, a sulfate-added anaerobic sanitary landfill structure, and that the stable decomposition of organic matter in R1 makes a faster progress than R2. Moreover it can be estimated that R1, a sulfate-added anaerobic sanitary landfill structure has an inhibition efficiency of 55% or so, compared with R2, a semi-aerobic landfill structure, in the efficiency of inhibiting methane.
        17.
        1975.12 KCI 등재 서비스 종료(열람 제한)
        유채성분육종을 효율적으로 수행하기 위한 수단으로써 세대단축기수를 개발코자 전 I, II 보를 통하여 Green Plant Vernalization과 고온처리에서 채종후 46~49일째 개화하는데까지 가능하였으나 개화수분후 등숙기간의 발아능력은 2개월이상의 숙도와 일정기간을 경과치 않고는 발아력을 갖추지 않는다는 것도 인정되었다. 여기서는 등숙기간의 발아능력을 촉진코자 시험을 실시하였든바 기결과를 요약하면 다음과 같다. 1. 유채의 발아촉진제 Hydroperoxide(H2O 2 )를 사용하여도 개화후 40일 이전에는 발아치 않으며 40일이후에도 50%이하의 발아력을 가질뿐이며(생체종자)종자를 Heating했을 때만이 55일에서 90% 이상이 발아능력을 가지고 있을 뿐이다. 2. 개화후 Ethrel처리시기는 개화후 15일에 Ethrel 처리후의 유효발아율에 도달하는 것은 10~15일째였었다. 3. Ethrel농도로는 일정한 경향은 없으나 개화후 15일 Ethrel 2,000ppm처리한 다음 처리후 10일째 (총등숙소요일수 25일)에 76% 발아되였으며 Ethrel 500ppm처리한 것은 처리후 15일째 (총등숙소요일수 30일)에 96% 발아능력을 가지고 있어서 가장 효과적이였다. 4. 유채에서 Ethrel과 Hydroperoxide처리로 개화후 25~30일에 76~96%의 발아율로 무려 1개월이상 등숙기간을 단축할수 있었든 것은 각 약제의 상가적인 효과라기보다 두 약제의 상승효과로 인정된다. 5. 유채세대단축은 1세대에 66일~71일을 소요하며 년간 4세대 내지 5세대를 단축할 수 있을 것으로 인정되었다.
        18.
        1975.12 KCI 등재 서비스 종료(열람 제한)
        유체의 성분육종효율을 증진키 위한 세대단축기술개발에 있어서 개화수분후의 등숙차이가 종자발아능력 및 휴면에 미치는 영향을 조사하였든 바 기 결과를 요약하면 다음과 같다. 1. 유채종자는 생체에서 개화수분후 40일이전에는 거의 발아력이 없으며, 건조시켰을때는 50일이전에 발아력이 없었다. 2. 세대단축에 이용할 수 있는 유효발아력에 있어서는 (발아율 70%이상) 생체종자로는 D.A.F. 75~80일이라야하며 건조종자에서는 55일이면 거의 100% 가까운 발아력을 갖추게되는데 건조처리는 휴면타파효과가 인정되였다. 3. 유채의 휴면주기는 2회의 싸이클이 있으며 생태형별로 주기가 다른데 만숙군과 조생군은 경향이 비슷하며 중생군은 품종에 따라 주기가 각각 달라서 매우 휴면기작이 복잡하다. 4. 춘파성 정도별발아력은 D.A.F. 50일이후에서는 파종성정도가 낮을수록(만생일수록) 발아력이 높은 경향이었으며 D.A.F. 45일이전의 미숙종자에서는 만생인 I, II가 특히 높았다. 5. 종자, 치상후의 발아세는 치상 2일에 가장높았고 그 이후는 점차 낮으며 생체종자일 때 발아기간이 건조종자일 때보다 길었다. 6. 휴면타파제 H2O2 의 효과에 있어서 완숙종자에서는 발아촉진효과가 없으며 미숙종자에서는 촉진효과가 있었는데 생체종자에서 더욱 컸다