• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.21-24
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• 2014

In the entrained-flow coal gasifier, coal ash turns into a molten slag most of which deposits onto the wall to form liquid and solid layers. Critical viscosity refers to the viscosity at the interface of the two layers. The slag layers play an important role in protecting the wall from physical/chemical attack from the hot syngas and in continuously discharging the ash to the slag tap at the bottom of the gasifier. For coal with high ash melting point and slag viscosity, CaO-based flux is added to coal to lower the viscosity. This study evaulates the effect of critical viscosity temperature and ash/flux ratio on the slag behavior using numerical modelling in a commercial gasifier. The changes in the slag layer thickness, heat transfer rate, surface temperature and velocity profiles were analyzed to understand the underlying mechanism of slag flow and heat transfer.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.107.2-107.2
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• 2010

고온건식탈황기술은 고온고압에서 석탄가스에 함유된 황화합물을 제거하는 기술로 석탄가스화에 의해 생성된 고온의 석탄가스의 열손실을 최소화하여 열효율이 높은 기술이다. 본 연구에서는 석탄으로부터 합성원유를 생산하는 0.3 배럴/일 규모 석탄액화(CTL)공정의 연계운전을 통하여 건식탈황공정의 성능을 평가하였다. 0.3 배럴/일 규모 석탄액화공정은 석탄가스화기, 건식탈황공정, 액화공정으로 구성되어 있으며 30 atm의 고압에서 운전된다. 건식탈황공정은 석탄가스화기와 액화공정 사이에 위치하여 석탄가스화로부터 생성된 석탄가스에 함유된 황화합물을 아연계 건식탈황제에 의해 제거한 후 액화반응기로 공급하여 황화합물에 의한 촉매의 피독을 막아주는 역할을 수행한다. 본 연구에서는 기존에 개발된 두 개의 기포유동층 반응기로 구성된 탈황장치를 30 atm에서 운전이 가능하도록 수정/보완하여 실제 운전압력인 30 atm의 고압에서 연속운전을 수행하였다. 실험 결과 탈황효율은 99% 이상이며 탈황반응기 출구 황화합물의 농도는 1 ppmv 이하로 유지하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.461-461
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• 2007

석탄을 합성석유로 전환시키는 석탄액화(CTL) 공장은 2차 세계대전시 독일 및 영국에서 가동되어 대량의 연료를 공급한 바 있다. 전후 대형 유전이 발견되어 값싼 석유가 공급되면서 CTL 공장의 운전은 중단되었다. 남아프리카공화국의 Sasol사만이 유일하게 1955년에 CTL공장의 조업을 시작하여 현재 하루 15만배럴의 석탄합성석유를 생산하고 있다. 최근 고유가가 지속되고 석유공급에 대한 불안감 때문에 여러 개의 석탄액화 프로젝트가 진행되고 있다. 중국은 2030년까지 석탄합성석유를 연간 3천만톤(60만배렬/일) 생산할 계획을 수립하였고, 2만배럴/일 규모의 석탄직접액화공장이 2008년 완공될 예정이다. 미국에서도 8개의 CTL 프로젝트가 진행되고 있다. 호주, 필리핀, 인도네시아, 인도 등에서도 석탄액화 프로젝트를 추진하고 있다. 석유를 전량 수입하는 우리나라도 에너지안보 차원에서 CTL에 대한 접근이 필요하다. 본고에서는 한국에너지기술연구원에서 추진되고 있는 석탄 기준 10톤/일급 석탄 합성석유 생산 공정 설계, 설비 시공 현황 및 향후 계획에 대하여 기술하였다.

• Journal of Magnetics
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• v.18 no.3
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• pp.365-369
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• 2013

Coal ash is known to contain a noticeable amount of valuable elements, including transition metals and lanthanides. Therefore it is quite actual problem to extract them for metallurgy and other applications. This paper presents the results of high gradient magnetic and mechanical separation, microscopy, element analyses and optical spectroscopy of brown coal ash taken from the combustion camera and chimney-stalk of Angren thermal power station. The separated magnetic fraction was 3.4 wt.%, where the content of Fe in ferrospheres increased to 58 wt.%. The highest contents of Fe and rare earth elements were found in the fine fractions of $50-100{\mu}m$. Optical absorption spectroscopy of water solutions of the magnetic fractions revealed $Fe^{2+}$ and $Fe^{3+}$ ions in the ratio of ~1:1. The separated coal ash could be used for cleaning of technological liquid waste by means of the high gradient magnetic field.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.6
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• pp.581-589
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• 2015

In this study, the viscosity of a liquid carbon dioxide ($LCO_2$) that can potentially be used in a wet feed coal gasifier was evaluated. A pressurized capillary viscometer was employed to obtain the viscosity data of $LCO_2$ using two different methods. During the first method, the measurements were conducted under quasi-steady and high pressure flow conditions where two-phase flow was greatly minimized. The viscosity of $LCO_2$ was determined using turbulent friction relationship. At the second flow condition where unsteady flow is induced, the viscosity of $LCO_2$ was measured using the half-time pressure decay data and was further compared with values calculated by the first method.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1143-1148
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• 2010

We investigated the separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction comprising four kinds of NHC [indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)], three kinds of bicyclic aromatic compound (BAC) [1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN) mixture with ten structural isomers (DMNs; regarded as one component)], biphenyl (Bp) and phenyl ether (Pe) by liquid membrane permeation (LMP). A batch-stirred tank was used as the permeation unit. An aqueous solution of saponin and n-hexane were used as the liquid membrane and the outer oil phase, respectively. Yield and selectivity of individual NHC was much larger than that of BAC, Bp and Pe. Increasing the initial mass fraction of the saponin to the membrane solution ($C_{sap,0}$) and the initial volume fraction of O/W emulsion to total liquid in a stirred tank (${\phi}_{OW,0}$) resulted in deteriorating the yield of individual NHC, but increasing the stirring speed (N) resulted in improving the yield of each NHC. With increasing $C_{sap,0}$, the selectivity of each NHC based on DMNs increased. Increasing ${\phi}_{OW,0}$ and N resulted in decreasing the selectivity of individual NHC based on DMNs. At an experimental condition fixed, the sequence of the yield and selectivity in reference to DMNs for each NHC was Q > Qu = iQ > In. Furthermore, we compared LPM method with methanol extraction method in view of the separation efficiency (yield, selectivity) of NHC.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.781-787
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• 2009

This report investigates the economic proprieties of commercial 50,000 barrel per day direct/indirect coal liquefaction(DCL/ICL) plants to produce commercial-grade diesel and naphtha liquids. The scope of the study includes capital and operating cost estimates, sensitivity analyses and a comparative financial analyses. Based on plant capacity of 50,000BPD, employing Illinois #6 bituminous coal as feed coal, the total capital cost appeared $3,994,858,000(DCL) and $4,962,263,000(ICL). Also, the internal rate of return of DCL/ICL appeared 13.27% and 12.68% on the base condition respectively. In this case, coal price and sale price of products were the most influence factors. And ICL's payback period(6.8 years) was longer than DCL's(6.6 years). According to sensitivity analyses, the important factors on both DCL/ICL processes were product sale price, feed coal price and the capital cost in order.

• Resources Recycling
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• v.4 no.1
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• pp.20-24
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• 1995

When the slurry of water and coal which is produced from hydraulic coal mining was dehydrated by COM(Coal Oil Mixtue), the effects of flocculant were measured by light transmittance of supernatant liquid, The experimental results obtamed m this study are summarized as follows; The efficient flocculant is anionic flocculant(AllO), and in this case, the required concentration is about l00g/t. When diesel oil is used with flocculant, COM is formed in lower impeller speed than when only diesel oil is used. The amout of diesel oil required to form COM is 10% of that of coal.

• Advances in Energy Research
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• v.7 no.2
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• pp.101-121
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• 2020

Coal has made a wonderful contribution to the production of cheap electricity. Coal based power plants have been the backbone of world's electricity for a long time now. Coal while being cheap and easily available is also a source of various solid, liquid and gaseous effluents which are responsible for the environmental degradation. Environmental issues caused by coal need to be studied and analyzed, then a common global consensus must be formed. Efficient action must be taken against each and every type of pollutant that is produced by this particular industry. The research aims to provide a brief overlook of the environmental impact of India's coal-based power plants. The aim of this study is to introduce a novel environmentally feasible energy scenario for the future of Indian power sector which has been named as "OPES". OPES is mathematically simulated using the combination of GAMS and LEAP. OPES is simple to comprehend and can be reproduced easily for other case studies as well. Results show that OPES can help the Indian power sector to minimize its environmental impact without causing any problems in the energy supply.

• Journal of the Korean Applied Science and Technology
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• v.19 no.4
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• pp.251-257
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• 2002

Liquid-phase methanol synthesis via methyl formate using coal-derived syngas was carried out in a bench-scale(diameter 173 mm and dispersion height 1200 mm) slurry bubble column reactor(SBCR) Under the condition of $180^{\circ}$. 61 atm, 30 L/min, $H_{2}$/CO=2 and a slurry mixture of 2 kg of copper chromite and 0.5 kg of $KOCH_{3}$ suspended in 14 L of methanol, the per pass conversions of syngas is 6 %, maximum concentration of methyl formate 3.088 mol% and maximum synthesis, rate of methanol 0.8 gmole/kg ${\cdot}$ hr. It is a significant evidence that copper chromite powder as heterogeneous catalyst didn't active for the hydrogenolysis of methyl formate to methanol, resulting copper chromite powder was not efficiently suspended in a slurry mixture. To enhance the hydrogenolysis of methyl formate in liquid-phase methanol synthesis process, the designed SBCR have need to use the higher specific gravity solvent and/or decrease the catalyst particle size.