• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.115-116
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• 2023

In this study, it was confirmed whether kaolin can play a role as a bed materials and a role in reducing clinkers by using kaolin with a bed materials for the purpose of removing clinkers such as slagging and fouling generated in circulating fluidized bed combustion furnaces using solid fuel.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.21-26
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• 2014

Renewable gas fuels such as biogas and landfill gas have carbon-neutral nature which can reduce carbon dioxide. However, it is necessary to make stable combustion when this fuel is used in power generating SI(spark ignition) gas engines due to its low heating value and non-uniformity. In this study, it was shown that addition of hydrogen can increase combustion stability of gas engine which is running with high inert gas composition. Thermal efficiency and emission characteristics of this engine was also investigated. In addition, a new spark plug with a long electrode was tested and compared with a base spark plug as a way to improve engine efficiency and reduce exhaust emissions.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.107.2-107.2
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• 2011

억새는 척박한 토양 조건에서도 쉽게 자라며 관리가 용이하다는 장점이 있어 바이오에너지 작물로 주목을 받고 있다. 억새는 주로 Miscanthus sacchariflorus(물억새)와 Miscanthus sinensis(참억새) 그리고 두 억새의 잡종인 Miscanthus giganteus로 구분되며, 최근 기존의 억새보다 생체량을 크게 늘린 거대억새가 개발되기도 하였다. 본 실험에서는 우리나라 전역에서 가장 흔하게 볼 수 있는 물억새와 참억새를 유동층 반응기를 이용하여 급속열분해 하였다. 본 연구의 목적은 억새로부터 얻은 바이오원유와 나무로부터 얻은 바이오원유의 특성을 비교하고, 시료투입속도의 변화를 주어 억새로부터 얻은 바이오원유의 수율과 특성을 알아보고자 함이다. 시료의 투입속도는 200g/h, 300g/h, 500g/h, 1000g/h로 변화를 주었으며, 반응온도($500^{\circ}C$), 공탑속도(0.19m/s), 응축기온도($10^{\circ}C$)는 매 실험마다 동일하게 유지하였다. 수집한 바이오원유는 공업분석을 통해 연료로서의 가치를 알아보았다. 목재를 급속열분해 한 경우 바이오원유의 수율은 56.03wt.%로 동일한 조건에서 억새를 급속열분해 한 경우 보다 약 6wt.%가량 높았다. 바이오원유의 발열량은 큰 차이가 없었으나 수분과 점도에서 큰 차이를 보였다. 투입속도가 증가할수록 바이오원유의 수율은 증가하는 경향을 보였으며, 시간당 1000g을 투입하였을 때는 수율이 감소하였으나 수율의 변화는 크지 않았다. 투입속도가 증가하는 경우 바이오원유의 고위발열량과 점도는 감소하고 수분이 증가하는 경향을 보였다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.181-182
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• 2003

경유엔진은 가솔린엔진에 비해 연소특성상 연료소비효율이 우수하여 온실가스인 $CO_2$ 배출이 적은 반면 대기 및 인체위해성이 높은 NOx와 입자상물질(PM)의 배출이 많아 대기저감을 위한 연료의 고압분사, 전자제어식 EGR기술등 엔진개량기술과 매연여과장치, De-NOx등 후처리기술 그리고 대체연료사용 기술등 다양한 저감대책이 전세계적으로 강구되고 있다. 특히 경유엔진에서 배출되는 오염물질로 인한 대기오염영향은 점차 증가하고 있어 대체연료사용 및 배출허용기준강화둥 우리 실정에 적합한 효율적인 대기저감대책이 강구되어야 할 것이다. (중략)

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.340-360
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• 2010

The depletion of fossil fuels, ecological problems associated with $CO_2$ emissions climate change, growing world population, and future energy supplies are forcing the development of alternative resources for energy (heat and electricity), transport fuels and chemicals: the replacement of fossil resources with $CO_2$ neutral biomass. Several options exist to cover energy supplies of the future, including solar, wind, and water power; however, chemical carbon source can get from biomass only. When used in combination with environmental friend production and processing technology, the use of biomass can be seen as a sustainable alternative to conventional chemical feedstocks. The biorefinery concept is analogous to today's petroleum refinery, which produce multiple fuels and chemical products from petroleum. A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power, and value-added chemicals from biomass. Biorefinery is the co-production of a spectrum of bio-based products (food, feed, materials, and chemicals) and energy (fuels, power, and heat) from biomass [definition IEA Bioenergy Task 42]. By producing multiple products, a biorefinery takes advantage of the various components in biomass and their intermediates therefore maximizing the value derived from the biomass feedstocks. A biorefinery could, for example, produce one or several low-volume, but high-value, chemical or nutraceutical products and a low-value, but high-volume liquid transportation fuel such as biodiesel or bioethanol. Future biorefinery may play a major role in producing chemicals and materials as a bridge between agriculture and chemistry that are traditionally produced from petroleum. Industrial biotechnology is expected to significantly complement or replace the current petroleum-based industry and to play an important role.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.14-20
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• 2012

Biogas can be obtained from biogenic materials through an anaerobic digestion process. Since biogas has low calorific value and its composition significantly varies, appropriate combustion strategies need to be established to obtain stable combustion in engine applications. In this study, efforts have been made to investigate the effects of inert gas composition variations on engine performance and emissions. Results show that the MBT spark timing was advanced and $NO_x$ was reduced as the inert gas in the biogas rose. Moreover, $NO_x$ emission drop in $CO_2$ diluted biogas was more significant than that of $N_2$ due to higher heat capacity of $CO_2$, while THC emissions showed the opposite tendency. Thermal efficiency was increased in $N_2$ case with elevation of $N_2$ due to the decreased heat loss and PMEP. However, there is no difference in $CO_2$ case because of deteriorated flame propagation speed.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.25-30
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• 2011

Biogas obtained from the biodegradable organic wastes in an anaerobic digester consists of $CH_4$ and inert gases such as $CO_2$ and $N_2$. Since the composition of biogas varies by anaerobic digester conditions and the origin of wastes, it is necessary to respond to these variations so as to make stable combustion and accomplish high efficiency when it is used as a fuel for power generating SI engines. In this study, efforts have been made to investigate the effect of changes in the calorific values of biogas on the engine performance and exhaust characteristics. The biogas was simulated by supplying of $CH_4$ with $N_2$ dilution of various ratios, and ECM was developed to achieve accurate control of ignition and combustion. The results show that as the $CH_4$ concentration of the biogas decreases, the optimal spark timing is advanced due to the elevated thermal capacity and lowered $O_2$ concentration of the in-cylinder charge. Furthermore, since combustion temperature was reduced by increased inert gas, $NO_x$ emissions decreased, whereas THC emissions increased.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.2
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• pp.112-117
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• 2007

This study aims to develop an alternative energy like oil made from marine organic waste by marine products waste, spent fishing nets. There are already many commercial examples and case studies based on the petroleum industry-refuse plastic or refuse tire, however, it is rare that a research developing alternative energy from food waste and organic waste. Therefore, this study investigated the oil made from thermal decomposition under the high temperature and high pressure condition, and examined the possibility for commercial use by testing its own characteristics. A bio-oil from thermal decomposition at $250^{\circ}C$ and 40 atm was hard to remove impurities because of its high viscosity, showed lower caloric value than heavy oil, and generated various gases which were not appropriate for the use of fuel. It is noticeable that thermal decomposition was occurred at $250{\pm}5^{\circ}C$ using steam pressure, which much lower compared to the existing method of thermal decomposition, more than $500^{\circ}C$. Since the high viscosity of bio-oil, it is necessary a further study to use as liquid fuel.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.136-147
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• 2015

As it carry out RPS(Renewable Portfolio Standards), power producers are using the power bio-fuel oil to meet their RPS quota. In this study, we test the quality characteristics of raw materials for power bio-fuel oil and the property changes of power bio-fuel oil by the kind of feedstocks. The power bio-fuel oil and feedstocks were analyzed for item of quality standard such as acid number, viscosity and metal contents. And it was analyzed for composition distribution by FT-IT and HPLC. Such as low priced palm oil series has high acid number and ash contents due to high free-fatty acid and metal contents. And by-product of biodiesel have a tendency of high viscosity. The fuel properties of power bio-fuel oil, such as viscosity, acid number and metal contents are correlated with the constituent and the mixing ratio of the feedstocks.

• Clean Technology
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• v.27 no.3
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• pp.269-274
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• 2021

Bioenergy is generally considered to be one of the options for pursuing carbon neutrality. However, for a period of time, combustion of harvested plant biomass inevitably causes more carbon dioxide in the atmosphere than combustion of fossil fuels. This paper proposes a method that predicts and minimizes the total amount and payback period of this carbon debt. As a case study, a carbon cycle impact assessment was performed for immediate switching of the currently used fossil fuels to biomass. This work points out a fundamental vulnerability in the concept of carbon neutrality. As an action plan for the sustainability of bioenergy, formulas for afforestation proportional to the decrease in the forest area and surplus harvest proportional to the increase in the forest mass are proposed. The results of optimization indicate that the carbon debt payback period is about 70 years, and the carbon dioxide in the atmosphere increases by more than 50% at a maximum and 3% at a steady state. These are theoretically predicted best results, which are expected to be worse in reality. Therefore, biomass is not truly carbon neutral, and it is inappropriate as an energy source alternative to fossil fuels. The method proposed in this work is expected to be able to contribute to the approach to carbon neutrality by minimizing present and future carbon debt of the bioenergy that is already in use.