• Journal of Environmental Health Sciences
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• v.31 no.1
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• pp.15-22
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• 2005

This study was conducted to evaluate air injection mode on stabilization of solid waste in lysimeter. For three lysimeters, one was maintained under anaerobic condition as control, and air was injected into two lysimeters in continuous mode (atmospheric pressure) and intermittent mode (high pressure of 2 bar). Distilled water was sprayed over solid waste in 1.4 l/$m^3$(solid waste)/day, supposing rainfall intensity of 1,200 mm/yr and 30% infiltration. Oxygen in landfill gas was not detected in control lysimeter during operational days. After 30 day-aeration, oxygen concentrations of continuous and intermittent modes were maintained in 14% and 6%, respectively. $COD_{Cr}$ removal efficiencies of continuous and intermittent modes were about 70% and 50%, and BOD5 removal efficiencies were about 80% and 20%, respectively. In view of oxygen supply, and $COD_{Cr}$ and $BOD_5$ removal, continuous air injection mode of atmospheric pressure was more effective than intermittent mode of 2 bar. Settling degree of solid waste in case of two air injection modes was 3 times higher than that of anaerobic condition as control. Considering the above results, it was thought that air injection (especially continuous atmospheric pressure) could improve degradation of solid waste and induce preliminary stabilization in landfill site.

• Journal of environmental and Sanitary engineering
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• v.23 no.3
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• pp.59-71
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• 2008

In this study, we intend to present the uncontrolled landfill maintenance plans by diversely reviewing the operating conditions of landfill and environmental effects and economical issues resulted from the operation of landfill for the purpose of suggesting the optimal maintenance plans applicable to the uncontrolled landfill and unused landfill located in Korea. We perform the basic and precise surveys against three landfill sites showing the biggest problem out of 8 unsanitary landfills sites located in Y County. We compare and review the treatment plans prepared and operated by the N Landfill. The compared and reviewed results show that the local stabilization plan is more effective than the excavation and transfer treatment plan when considering the economic efficiency only. However, the excavation and transfer treatment plan is valid when considering the diverse elements. The G Landfill is operated with separated into living waste landfill section and construction waste landfill section. However, some landfill gas collection bores or holes are installed in its living waste landfill section, which has not been used for about 20 years, as a part of follow-up control. The element causing the environmental damage is considerably reduced in its living waste landfill section. However, the effort to keep the follow-up control through the local stabilization work is required. The landfill is under processing in the construction waste landfill section. However, most of buried wastes are the inorganic wastes such as waste materials and concrete, so the maintenance plan focused on the use of top land by installing the local stabilization facilities is considered as an effective plan. The landfill is under processing in the K Landfill. It seems to be difficult to maintain this landfill through the local stabilization. The excavation and transfer treatment plan to completely remove the potential environmental pollution source is considered as the valid plan.

• New & Renewable Energy
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• v.16 no.2
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• pp.47-53
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• 2020

The amount of food waste and its water content depends on both the season and region. In particular, the water content typically varies between 73.8 wt.% and 83.3 wt.%, depending on the proportion of vegetables. Current food waste drying technologies are capable of reducing the water content to less than 10 wt.%, while increasing the heating value. Ongoing studies aim to utilize dried food waste as fuel. Food waste can be used to produce solid refuse fuel (SRF) by mixing it with various solid fuels or other types of waste. The analysis of specimens is very important when considering the direct combustion of food waste or its co-firing with solid fuels. In this study, the weight reduction of specimens after burning them in a small combustor, and compared with the results of thermogravimetric analysis (TGA). The concentration of various chemicals was also measured to define the characteristics of waste generation. Performed proximate analysis, elemental analysis, TGA, combustion experiment, the heating value, and derivative thermogravimetry (DTG).

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.483-486
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• 2008

본 연구에서는 디스크 이동식 열분해 실증 설비를 이용하여 폐타이어 열분해 반응을 수행하였고, 생성된 열분해 생성물들의 특성을 분석하였다. 폐타이어 열분해 반응은 약 $550^{\circ}C$에서 90분간 진행되었고, 반응 결과 Recovered Oil, Carbon Black, Non Condensing Gas(NC Gas)가 생성되었다. 폐타이어 열분해 생성물의 수율은 Recovered Oil $40{\sim}50%$, Carbon Black 30$\sim$35%, NC Gas 10$\sim$15%, Steel 10$\sim$15%로 나타났다. 폐타이어 열분해 반응 후 생성된 Recovered Oil은 비점 및 특성 분석 결과 상업용 중유와 비슷한 성질을 나타냈고, 폐타이어 열분해 반응의 또 다른 생성물인 Carbon Black은 특성 분석 결과 고정 탄소 비율이 낮은 반면 회분과 휘발분의 비율이 높아 상업용으로 사용하기 위해서는 적절한 정제 과정이 필요함을 알 수 있었다.열분해 과정 중에 생성된NC Gas는 GC/MS를 이용하여 성분 분석을 수행한 결과, $CO_2$, $CH_4$를 비롯하여 주로 탄화수소류로 이루어졌으며, 대부분이 연료 가스로 구성되어 있어 열분해 반응의 열원으로서 사용이 가능하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.172.2-172.2
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• 2011

다양한 저급연료나 폐기물로부터 가스엔진이나 연료전지의 연료로 사용하기위한 연료가스를 얻기 위한 방법으로 가스화 기술을 적용할 수 있다. 폐기물의 가스화를 통해 발생된 합성가스에는 CO, $H_2$, $CO_2$와 같은 주요성분 이외에 황화합물($H_2S$, COS), 염소화합물(HCl), 고형 물질(분진)등의 오염물질이 포함되어 있으므로, 이용목적에 따라 적절한 정제 기술이 필요하게 된다. 현재 가장 널리 알려진 저온 습식 정제공정은 장치운전이 쉽고 오염물질 제거효율이 높은 장점이 있으나, 합성가스 온도를 상온까지 낮추기 때문에 현열 손실이 발생하는 단점을 가지고 있다. 고온 건식 정제공정에 의해 $300^{\circ}C$ 이상의 고온에서 오염물질의 제거가 가능하다면 에너지 이용효율을 높일 수 있고, 습식공정에 의해 발생되는 폐수처리에 따른 비용 절감효과도 얻을 수 있다. 폐기물 합성가스를 최종 적용처에 이용하기위한 고온 정제 공정의 적용을 위해 흡착제를 이용하여 탈황, 탈염 실험을 실시하였고, 실험결과로부터 장치 설계의 기초인자를 도출하였다.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.209-211
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• 2002

A simple-structured thermal plasma generator for waste gas treatment has been studied. The thermal plasma technology applied to waste treatment has undoubtedly gained high importance owing to its outstanding properties such as flexibility, compact reactor, and clean treatment. Moreover, the thermal plasma generated by ac power has some additional advantages such as simple electrode system and easy maintenance. A prototype 200kW class plasma generator with specifications of 10-30m/sec gas velocity and 3000-5000K temperature on the center just outside of the nozzle has been designed and tested. Case studies on heat transfer, heat flow, velocity distribution, and temperature distribution using a commercial simulation package show lots of flexibility in design. The experimental results from theprototype generator show that the ac thermal plasma is easily controlled by working gas flow once it is ignited. A stabilization condition is discussed with the data from monitoring arc voltage drops with respect to gas flow rate during the test.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.85-88
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• 2000

• Journal of the Korean Professional Engineers Association
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• v.31 no.5
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• pp.26-31
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• 1998

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1703-1705
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• 2014

Bubble column reactors are considered the reactor of choice for numerous applications including oxidation, hydrogenation, waste water treatment, and Fischer-Tropsch (FT) synthesis. They are widely used in a variety of industrial applications for carrying out gas-liquid and gas-liquid-solid reactions. In this paper, the computational fluid dynamics (CFD) model is used for predicting the gas holdup and its distribution along radial and axial direction are presented. Gas holdup increases linearly with increase in gas velocity. Gas bubbles tends to concentrate more towards the center of the column and follows a wavy path.

• Advances in Energy Research
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• v.3 no.3
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• pp.181-194
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• 2015

In this work, an experimental study of the gasification on wood was carried out in downdraft type fixed bed Gasifier attached with 10 kW duel fuel diesel engine. The main objective of the study was to use wood as the biomass fuel for downdraft Gasifier and to evaluate the operating parameter of gasifier unit to predict its performance in terms of gas yield and cold gas efficiency. The influence of different biomass on fuel consumption rate, gas yield and cold gas efficiency was studied. Composition of producer gas was also detected for measuring the lower heating value of producer gas to select the feed stock so that optimum performance in the existing gasifier unit can be achieved. Under the experimental conditions, Lower heating value, of producer gas, cold gas efficiency and gas yields, using wood as a feed stock, are $4.85MJ/m^3$, 46.57% and $0.519m^3/kg$.