• Fire Science and Engineering
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• v.30 no.1
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• pp.37-42
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• 2016

The dimensionless extinction constants of smoke particles produced from burning of soy methyl ester (B100) biodiesel and ultra low sulfur diesel (ULSD) fuels were measured. To this end, optical measurements of smoke volume fraction with the aid of a He-Ne laser at 633 nm were compared to the simultaneous gravimetric measurements. The average value of measured dimensionless extinction constants at 633 nm was 11.8 for biodiesel smoke particles and 11.1 for diesel smoke particles, respectively whose values are very comparable withing the range of measurement uncertainty (${\pm}10.1%$). The analysis of Raman spectroscopy revealed that overall characteristics of light extinction between particles produced from each fuel may differ from each other.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.508-513
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• 2011

Hemp is known as one of the most productive and useful plants, which grows quickly in a moderate climate with only moderate water and fertilizer. Traditionally in Korea, hemp bast is used to natural fibres, and remaining such as stem and root is treated as waste. Those of hemp by-products can be transformed to bio fuel such as bio-oil and activated carbon. To understand pyrolysis characteristics, thermogravimetric analysis were carried out in TGA, in which hemp by-products were mostly decomposed at the temperature range of $270{\sim}370^{\circ}C$. The corresponding kinetic parameters including activation energy and pre-exponential factor were determined by differential method over the degree of conversions. The values of activation energies for pyrolysis were increased as the conversion increased from 10 to 90%.

• New & Renewable Energy
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• v.18 no.3
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• pp.1-9
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• 2022

This study analyzed the anticipated supply-and-demand of forest biomass energy (through wood pellets) until 2050, in South Korea. Comparing the utilization rates of forest resources of five countries (United Kingdom, Germany, Finland, Japan, and S. Korea), it was found that S. Korea does not nearly utilize its forest resources for energy purposes. The total demand for wood pellets in S. Korea (based on a power generation efficiency of 38%) was predicted to be 3,629 and 4,371 thousand tons in 2034 and 2050, respectively. The anticipated total wood pellet power generation ratio to target power consumption is 1.13% (5,745 GWh), 1.17% (6,336 GWh), and 1.25% (7,631 GWh) in 2020, 2030, and 2050, respectively. Low value-added forest residues left unattended in forests are called "Unused Forest Biomass" in S. Korea. From the analysis, the total annual potential amount of raw material, sustainably collectible amount, and available amount of wood pellet in 2050 were estimated to be 6,877, 4,814, and 3,370 thousand tons, respectively. The rate of contribution to Nationally Determined Contributions was up to 0.64%. Through this study, the authors found that forest biomass energy will contribute to a carbon neutral society in the near future at the national level.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.247-247
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• 2010

본 연구는 주류 제조과정에서 발생하는 생전분발효 부산물을 펠릿(pellet)연료로 전환하는 과정에서 효율적인 방법에 대해 기술한다. 술을 정제하는 과정에서 발생하는 주박을 펠릿화하고 재생청정에너지인 폐자원의 효율성을 높이기 위한 방법을 제안한다. 술을 정제하고 남은 지게미를 주박(酒粕, 술지게미)이라 하고 흔히 부드러운 것을 단단하게 뭉친 알갱이를 펠릿이라 한다. 현재 펠릿화는 폐목재를 분쇄후 성형, 가공하여 목재펠릿을 만들어 상용화하고 있다. 목재펠릿은 성형, 가공하는데 비용이 주박보다 많이 들고 열량도 더 낮음을 확인하였다. 목재소에서 나온 나무(톱밥)와 주박을 열량측정기를 이용하여 측정한 결과로 나무는 약 1850 Kcal이고 주박은 약 1989 Kcal가 측정되었다. 나무는 일반 목재소 세 곳에서 채취한 것이고 주박은 막걸리, 약주 및 청주의 술지게미를 실험에 사용한다. 주류업체에서도 술을 정제하고 남은 주박을 처리하는데 많은 곤란과 비용이 든다. 또한 주박을 해양에 투척하여 처리해 왔으나 2012년부터 해양투기가 금지되어 더욱 처리에 곤란을 겪게 된다. 최근 주박을 토양개량제(비료)로 개발하여 사용하기도 하나 본 연구에서 제안하는 장점은 농산물을 재배해서 주류제조시 발생되는 주박을 펠릿화하여 연료로 사용하고 남은 재를 토양개량제로 사용하는 장점이 있다. 제품의 전체 라이프 사이클을 통해 환경으로 방출되는 모든 것을 가능한 한 0(zero)으로 하는 활동인 제로-이미션(zero-emision)이 된다. 이는 단순히 배출량만을 줄이는 것이 아니라 폐기물을 유용한 자원으로 활용한다는 측면이 가장 큰 이점이 된다. 주박의 효율성을 높이기 위해 주박을 종류별로 주박과 목재를 섞는 방법으로 열량을 측정하였다. 먼저 열량이 높은 순서로 막걸리 주박과 약주 주박의 비율을 1:1, 1:0.5, 1:0.2, 두 번째 막걸리 주박과 청주 주박의 비율을 1:1, 1:0.5, 1:0.2, 세 번째 막걸리 주박과 나무 톱밥의 비율을 1:1, 1:0.5, 1:0.2로 섞어서 열량을 측정하였다. 열량이 높은 순서는 세 번째(2015Kcal), 두 번째(1995Kcal), 첫 번째(1868Kcal)의 순이었다. 가장 열량이 높은 막걸리 주박과 나무 톱밥을 섞은 것이 가장 효율성이 높다. 주박 펠릿의 장점은 친환경적인 소재이고 지속적으로 재생이 가능한 에너지원이다. 더욱이 주박 펠릿은 발열량이 높고 다른 바이오매스 원료에 비해 청정하다는 큰 장점을 지니고 있다. 또한 사용에 소요되는 유지 관리비용을 최소화할 수 있고 자동화가 가능하여 사용에 편리하다. 가격면에서 화석연료에 비해 안정적이고 체적 또한 작아 이송의 큰 장점을 가지고 있다. 현재 펠릿의 경우는 목재펠릿이 제품화되어 있지만 주박을 이용하여 제품의 펠릿화를 통한 연료원으로 사용하는 경우는 전 세계 전무한 상태로 폐자원을 재사용하는 효율성이 제시된다. 향후 과제로 주박을 이용한 펠릿 연료원의 기술이 개발되고 기계적인 시스템을 개발하면 저탄소 녹색성장 신재생에너지 연료의 획기적인 미래형 에너지시스템이 될 것이다.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.75-84
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• 2018

In this study, the analysis of torrefaction products was carried out for fueling of sewage sludge. The mixed samples were composed as follows : 50% of sewage sludge and 50% of rice husk and CR(Coffee Residue). In this experiment, the reaction time(30min, 60min) and temperature($200^{\circ}C$, $250^{\circ}C$, $300^{\circ}C$) were expressed as a single variable using SF(Severity Factor). As a result, it was confirmed that as the SF increased, the heating value and fuel ratio increased, but the CI(Combustibility Index) decreased. The heating value was similarly increased as CR(Coffee Residue) and SF increased. The fuel ratio range of mixed samples was equal to that of lignite(0.5~1.0) in case of SF lower than 6.19 and that of bituminous coal(1.0~1.8) in case of SF higher than 7.36 or above. The CI showed a stable range(3,000~5,500kcal/kg) in low SF as the content of mixed samples contained more rice husk than CR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.401-408
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• 2021

Supplies of wood chips for fuel tend to increase owing to energy decentralization and new renewable energy policies. This study suggests a technical method that is necessary in order to supply heating energy to rural regions by using wood chips for fuel. Therefore, this study investigates the effects of natural drying methods for eight months by installing a drying facility with natural ventilation capable of loading 10 tons of wood chips, and which derive a natural drying method based on this to meet the quality standards of wood chips for fuel. The study results confirm that it is possible to produce wood chips for high-quality fuel with water content at 20% or less after around 90 days of drying, provided that a drying facility with natural ventilation is equipped with materials that can be procured easily in rural regions. It is also possible to block the proliferation and fermentation of molds that affect the quality of wood chips, provided that intake and exhaust systems adhering to standards are equipped.

• Korean Journal of Environmental Biology
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• v.32 no.1
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• pp.26-34
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• 2014

Due to the rapid energy consumption and fossil fuel abundance reduction, the world is progressively in need of alternative and renewable energy sources such as biodiesel. Biodiesel from microalgae offers high hopes to the scientific world for its potential as well as its non-competition with arable lands. Taking consideration to reduce the cost of production as well as to attain twin environmental goals of treatment and use of animal waste material the microalgal cultivation using piggery manure has been tested in this study. Unialgal strains such as Chlorella sp. JK2, Scenedesmus sp. JK10, and an indigenous mixed microalgal culture CSS were cultured for 20 days in diluted piggery manure using Small Scale Raceway Pond (SSRP). Biomass production and lipid productivity of CSS were $1.19{\pm}0.09gL^{-1}$, $12.44{\pm}0.38mgL^{-1}day^{-1}$, respectively and almost twice that of unialgal strains. Also, total nitrogen and total phosphorus removal efficiencies of CSS was 93.6% and 98.5% respectively and 30% higher removal efficiency compared to the use of unialgal strains. These results indicate that the piggery manure can provide microalgae necessary nitrogen and phosphorus for growth thereby effectively treating the manure. In addition, overall cost of microalgal cultivation and subsequently biodiesel production would be significantly reduced.

• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.74-82
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• 2015

Carbon dioxide was designated as one of greenhouse gases that cause global warming. Among various ways to solve the $CO_2$ emission issue, the 3rd-generation biomass (algae) production is considered as a viable method to reduce $CO_2$ in the atmosphere. In this research, we propose a design of an innovative sustainable production system by utilizing the 3rd generation biomass in the environment of floating production storage and offloading (FPSO). Existing biomass production systems depend on the solar energy and they cannot continue producing biomass at night. Electricity produced from offshore wind farms also need an efficient way to store the energy through energy storage system (ESS) or deliver it real-time through power grid, both requiring heavy investment of capital. Thus, we design an offshore grid structure harnessing LED lights to supply the necessary light energy, by using the electricity produced from the wind farm, resulting in the maximized production of biomass and efficient use of wind farm energy. The final design integrates the biomass production system enhanced by LED lights with a wind power generation. The suggested NLP model for the optimal design, implemented in GAMS, would be useful for designing improved offshore biomass production systems combined with the wind farm.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.2
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• pp.67-73
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• 2019

In this study, to optimize the production and utilization of biogas for organic waste resources, the precision monitoring of on-site facilities and the energy balance by facility were analyzed, and the solutions for field problems were investigated, and the design and operation guidelines for pretreatment facilities and generators were presented. Gas pre-treatment is required to solve frequent failures and efficiency degradation in operation of high quality refining facilities, and processing processes such as desulfurization, dehumidification, deoxidization, dust treatment, volatile organic compounds, etc. Since these processes are substances that are also eliminated from the high-quality process, quantitative guidelines are not presented in the gas pretreatment process, but are suggested to operate during the processing process as a qualitative guideline. In particular, dust, siloxane, and volatile organic compounds are the main cause of frequent failure of high-quality processes if they are not removed from the gas pretreatment process. Design of the biogas high-quality process. The operation guidelines provide quality standards [Methane content (including propane) of 95% or more] with 90% or more utilization of the total gas generation, two systems, and a margin of 10% or more. It also proposed installing gas equalization tank, installing thermal automatic control system for controlling equalization of auxiliary fuel, installing dehumidification device at the back of high quality for removing moisture generated in the process of gas compression, installing heat-resisting facilities to prevent freezing of facilities in winter and reducing efficiency, and installing membrane facilities in particular.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.193-201
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• 2022

5-HMF(5-Hydroxymethylfurfural) and LA(levulinic acid) derived from biomass are green platform chemicals, which have a wide of potential applications as biofules and biochemicals. In this study, the kinetics of LA formation from glucose decomposition with various concentration of sulfuric acid at different temperature was investigated. The experiments were performed in a broad temperature (140-200 ℃), using H₂SO₄ (1-3 wt%) as the catalyst. Glucose solution was made by dissolving 1 g of glucose in 10 ml of H₂SO₄ solution. The reactions rates increased with temperature and the activation energy showed a similar tendency to previous reported values. Reaction time for maximum concentration of 5-HMF decreased as the temperature increased. Furthermore, the decomposition of 5-HMF was fast as the acid concentration increased. Reaction time to reach maximum concentration of levulinic acid was reduced as the acid concentration increased. Continuing to raise the temperature decreased the maximum concentration of levulinic acid and increased the amount of humins. On the basis of results, kinetic parameters help to understand mechanism of LA and 5-HMF. In addition, this study provides useful information to achieve high concentration of LA and 5-HMF from biomass.