• Journal of Climate Change Research
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• v.4 no.1
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• pp.51-61
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• 2013

To address the problems associated with climate change and energy shortage, Korea has been making efforts to turn waste materials into usable energy. Due to the ongoing efforts to convert waste materials into energy, waste incineration is expanding to utilize the heat generated, and the subsequent greenhouse gas emissions from these waste material incineration are expected to increase. In this study, a municipal waste incineration plant that generates heat and electricity through heat recovery was selected as a subject facility. Methods for estimating the greenhouse gas emissions in the municipal waste incineration plant that was selected as a subject plant were sought, and the greenhouse gas emissions and emission factor were estimated. The $CO_2$ concentrations in discharge gas from the subject facility were on average 6.99%, and the result from calculating this into greenhouse gas emissions showed that the total amount of emissions was $254.60ton\;CO_2/day$. The net emissions, excluding the amount of greenhouse gas emitted from biomass incineration, was shown to be $110.59ton\;CO_2/day$. In addition, after estimating the emissions by separating the heat and electricity generated in the incineration facility, greenhouse gas emission factors were calculated using the greenhouse gas emissions produced per each unit of output. The estimated emission factor for heat was found to be $0.047ton\;CO_2/GJ$ and the emission factor for electricity was found to be $0.652ton\;CO_2/MWh$. The estimated emission factor was shown to be about 17% lower than the $0.783ton\;CO_2/MWh$ emission factor for thermal power plants that use fossil fuels. Waste material types and fossil carbon contents were evaluated as being the factors that have major effects on the greenhouse gas emissions and emission factor.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.13-21
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• 2022

Mushroom waste medium refers to the waste biomass generated after mushroom cultivating. And, the burden of treatment on mushroom farmhouse is increasing due to the absence of appropriate treatment method and increase of treatment costs of the mushroom waste medium. In this study, in order to assess the energy value of mushroom waste medium by an anaerobic digestion, methane potential and anaerobic organic matter decomposition characteristics were investigated. The theoretical methane potential(B_th) of mushroom medium(MM) was 0.481 Nm³-CH₄/kg-VS_added, and the B_th of mushroom waste medium(MWM) was 0.451 Nm³-CH₄/kg-VS_added. The biochemical methane potential(B_u-exp) of MWM was increased by 18% from 0.155 for MM to 0.183 Nm³-CH₄/kg-VS_added for MWM. In the reaction kinetics analysis by the Modified Gompertz model, the maximum methane production rate(R_m) was increased from 4.59 for MM to 7.21 mL/day for MWM and the lag growth phase time(λ) was decreased from 2.78 for MM to 1.96 days for MWM. In the reaction kinetics analysis by the parallel first order kinetics model, the easily degradable organic matter(VS_e) content was increased by 5.89% and the persistently degradable organic matter(VS_p) content was 2.03% in MWM, and the non-degradable organic matter(VS_NB) content was decreased by 7.85%. Therefore, it was evaluated that the anaerobic digestion efficiency of MWM was increased. The anaerobic digestion efficiency of MWM was assessed to be more improved than that of MM.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.3
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• pp.402-408
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• 2011

Organic Rankine cycles (ORC) can be used to produce power from heat at different temperature levels available as geothermal heat, as biogenic heat from biomass, as solar or as waste heat. In ORC working fluids with relatively low critical temperatures and pressures can be compressed directly to their supercritical pressures and heated before expansion so as to obtain a better thermal match with their heat sources. In this work thermal performance of ORC with and without an internal heat exchanger is comparatively investigated in the range of subcritical and transcritical cycles. R134a is considered as working fluid and special attention is paid to the effect of turbine inlet pressure on the characteristics of the system. Results show that operation with supercritical cycles can provide better performance than subcritical cycles and the internal heat exchanger can improve the thermal efficiency when the temperature of heat source becomes higher.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.153-153
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• 2010

The world is moving towards a post-carbon society and needs clean and renewable energy for sustainable development. There are many methodological approaches which are helping this shift based on analyzed data about energy resources and which focus on limited types of energy including liquid fossil, solid fossil, gaseous fossil, and biomass (e.g. IPCC Guidelines, ISO 14064-1, WRI Protocol, etc.). We should also consider environmental impact (e.g. greenhouse gas emissions, water use, etc.) and the economic cost of the renewable energy to make a better decision. Recently, researchers have addressed the environmental impact of new technologies which include photovoltaics, wind turbines, hydroelectric power, and biofuel. In this work, we analyze the environmental impact with a carbon emission factor to present a correlation between $CO_2$ emission and the cost of energy resources standardized by the energy output. In addition, we reviewed Life Cycle Assessment (LCA) as another methodology. Researchers who are studying energy systems have ignored the impacts of entire energy systems, e.g. the extraction and processing of fossil fuels. In power sector, the assessment should include extraction, processing, and transportation of fuels, building of power plants, production of electricity, and waste disposal. Therefore LCA could be more suitable tool for energy cost and environmental impact estimation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.46-55
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• 2016

The microcrystalline cellulose (MCC) was prepared from oil palm biomass, empty fruit bunch (EFB) for increasing the usability of EFB. The morphological, physical and chemical properties of MCC made from EFB were evaluated by comparing with those of the commercial MCC obtained from AVICEL. The EFB-MCC had the wider distribution in particle size and there were many small particles around $10{\mu}m$. There were no significant differences in the cellulose crytallinity and the chemical composition between EFB-MCC and AVICEL-MCC. The properties of tablet samples made by the common direct compression process were evaluated depending on the types of MCC and the compression pressure during tablet making process. The tablet made of EFB MCC showed the higher compressed structure, which resulted in the less disintegration by the water soaking treatment than those made of Avicel-MCC. The results of this study showed that the EFB-MCC could be utilized as one of the commercial MCC.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1947-1953
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• 2006

There have been a number of studies of methods for recycling animal wastewater to provide new bioresources. In the present work, a marine algal culture medium, designated KEP II, was prepared by adding swine waste (3% v/v) fermented by soil bacteria to a dilution of f/2 culture medium (CT). When Phaeodactylum tricornutum was grown in batch culture in KEP II, the cells lasted long at the exponential phase producing the specific growth rate and biomass; the production of total amino acids and secondary metabolites rose up to 5-fold. It also substantially enhanced the maximum quantum yield of photo system (PS) II of P. tricornutum, greatly increased the level of thylakoid membranes containing PS, and stimulated the production of pyrenoids, including enzymes for $CO_2$ fixation in chloroplasts. KEP II should improve the cost efficiency of industrial mass batch cultures and the value of microalgae for long-term preservation of fresh aquaculture feed as well as production of anticancer and antioxidant agents. Specifically, a low-cost medium for growing the diatoms of aquaculture feed will be economically advantageous.

• Journal of Biosystems Engineering
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• v.43 no.1
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• pp.14-20
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• 2018

Purpose: The purpose of this study was to investigate the performance of a vacuum pyrolysis system, to analyze bio-oil characteristics, and to examine the applicability for farm-scale capacity. Methods: The biomass was pyrolyzed at 450, 480, and $490^{\circ}C$ on an electric heat plate in a vacuum reactor. The waste heat from the heat exchanger of the reactor was recycled to evaporate water from the bio-oil. The chemical composition of the bio-oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Results: According to the analysis, the moisture content (MC) in the bio-oil was approximately 9%, the high heating value (HHV) was approximately 26 MJ/kg, and 29 compounds were identified. These 29 compounds consisted of six series of carbohydrates, 17 series of lignins, and six series of resins. Conclusions: Owing to low water content and the oxygen content, the HHV of the bio-oil produced from the vacuum reactor was higher by about 6 MJ/kg than that of the bio-oil produced from a fluidized bed reactor.

• Journal of the Korean Society of Combustion
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• v.15 no.1
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• pp.43-49
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• 2010

Co-combustion of syngas in an existing boiler can be one of the options for replacing conventional fossil fuel with alternative fuels such as waste and biomass. This study is aimed to investigate effects of syngas cocombustion on combustion characteristics and boiler efficiency. An experimental study was performed for a pilot-scale furnace with 4 oil burners. Tests were conducted with mixture-gas as a co-combustion fuel and heavy oil as a main fuel. The mixture-gas was composed of 15% CO, 7% $H_2$, 3% $CH_4$ and 75% $N_2$ for simulating syngas from air-blown gasification. And LHV of the mixture-gas was 890 kcal/$Nm^3$. Temperature distribution in the furnace and flue gas composition were measured for various heat replacement ratio by the mixture gas. Heat loss through the wall was also carried out through heat & mass balance calculation, in order to obtain informations related to boiler efficiency. Experimental results show that similar temperature distribution and flue gas composition can be obtained for the range of 0~20% heat replacement by syngas. NOx concentration is slightly decreased for higher heat replacement by the syngas because fuel NOx is decreased in the case. Meanwhile, heat loss is a bit decreased for higher heat replacement by the syngas, which implies that boiler efficiency can be a bit decreased when syngas co-combustion is applied to a boiler.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.112-118
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• 2004

Laying hens' excrement from eating food wastes was mixed with paper mill sludge, aged for 21 days and then provided to the juvenile earthworms(Eisenia fetida) for 10 weeks. Biomass of earthworm population decreased by 5.7% of initially introduced population. Very few juvenile earthworms developed into the clitellates and clitellated earthworms could not produce cocoons at all, which was supposed to be caused by inhibition effects of salts in laying hens' excrement upon the sexual development of Eisenia fetida. But there was no significant effect on the survivorship of earthworm population.

• The Korean Journal of Ecology
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• v.21 no.3
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• pp.313-320
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• 1998

Ameliorating effects of dolomite and sludge on the polluted soil sampled from Ulsan and yeocheon Industrial Complexes were investigated. Ameliorating effects were analysed by changes of soil properties and plant growth after treatment of dolomite and sludge. Soil properties were investigated by analysing organic matter, N, P, K, Ca and Mg contents and pH. Growth of sample plants was investigated by leaf area calculated from length and breadth of leaves and by biomass from diameter and height of sample plants. Quercus serrata and Celtis sinensis selected as tolerant plants in field survey were used as experimental plants. Treatment with dolomite showed ameliorating effects by increassing n, Ca, and Mg com\ntents, and pH of soil and by decreasing Al content. Treatment of sludge showed similar effects by increasing N, Ca, Mg and organic matter contents, and by decreasing A1 content. But treatment of sludge did not show any effect on pH. Both soil ameliorators showed accelerating effects on the growth of experimental plants in Ulsan soil. But those effects in Yeocheon soil were somewhat different. Treatment of sludge showed accelerating effects of the growth of both sample plants but dolomitic liming did not so. From those results, we confirmed availability of sludge, a kind of industrial waste, as one of ameliorators of the polluted soil. In addition, we recognized that soil properties had to be considered to select soil ameliorators suitable for restoration of degraded ecosystems.