• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.105.1-105.1
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• 2010

Korea Electric Power Research Institute (KEPRI) has developed a compact coal-gasification system to accumulate our experiment skills. The combustion furnace for residual oil was modified as a small size coal gasifier. Recently, coal feeding system was also upgraded to control coal feed rate more accurately. Our research group has conducted several experiments to find out the effect of $O_2$/coal ratio on the cold gas efficiency. Furthermore, the effect of $N_2$/coal ratio on the transport characteristics was also studied. According to the calculation of heat and mass balance, the cold gas efficiency was estimated to the maximum at $O_2$/coal ratio of around 0.73. But small size gasifier such as ours required higher value of $O_2$/coal ratio than that of the theoretical estimation. On the optimal $N_2$/coal ratio, we noticed that the coal feed rate was intimately related with the transporting gas pressure and the pipe diameter.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.437-440
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• 2007

Gasification converts coal and other feedstocks into a very clean and usable gas, called syngas, that can be used to produce a wide variety products such as electricity, chemicals, transports fuels, hydrogen production, etc. This paper was studied the gasification performance effects with the variation of the gasification operating parameters such as the feeding amounts of oxygen, steam and coal. When $O_2/coal$ ratio was below 0.8, $H_2$ mole % was increased as increasing $O_2/coal$ ratio. CO mole % was increased when $O_2/coal$ ratio was below 1.2 as increasing the $O_2/coal$ ratio. As increasing steam/coal ratio, $H_2$ mole %was increased and CO mole % was decreased. The $O_2/coal$ and steam/coal ratio was $0.8{\sim}0.9$ and $0.0{\sim}0.4$, respectively, to keep the proper gasification condition that the gasifier temperature was $1300^{\circ}C{\sim}1450^{\circ}C$ and the cold gas efficiency was over 76%.

• 한국수소및신에너지학회논문집
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• 제21권5호
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• pp.470-477
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• 2010

The IGCC (Integrated gasification combined cycle) is known for one of the highest efficiency and the lowest emitting coal fueled power generating technologies. As the core technology of this system is the gasifier to make the efficiency and the continuous operation time increase, the research about different coal's gasification has been conducted. Our research group had set-up the coal gasifier for the pilot test to study the effect of different coals-Shenhua and Adaro coal- on gasification characteristics. Gasification conditions like temperature and pressure were controlled at a fixed condition and coal feed rate was also controlled 30 kg/h to retain the constant experimental condition. Through this study we found effects of coal composition and $O_2$/coal ratio on the cold gas efficiency, carbon conversion rate. The compounds of coal like carbon and ash make the performance of gasifier change. And carbon conversion rate was decreased with reduced $O_2$/coal ratio. The optical $O_2$/coal ratio is 0.8 for the highest cold gas efficiency approximately. At those operating conditions, the higher coal has the C/H ratio, the lower syn-gas has the $H_2$/CO ratio.

• 한국세라믹학회지
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• 제46권6호
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• pp.548-553
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• 2009

This study is on the application of ceramic body and art glaze by using coal ash according to each wt%. Body color was turned red and dark as increasing coal ash contents in the body and art glaze because of the effect of noncombustible carbon in $Fe_2O_3$ and coal ash. Not only pore and black core were generated but also absorptance and shrinkage were increased as increasing coal ash contents. The glaze of coal ash 20 wt% showed blue absorption band, turned red band as increasing coal ash contents, $Al_2O_3\;to\;SiO_2$ ratio got lower and became mat because glaze is estranged from $Al_2O_3\;to\;SiO_2$ mol ratio 1:10 of transparent glaze as increasing coal ash contents. Glaze showed unstable dissolving condition in the more coal ash contents.

• 분석과학
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• 제5권4호
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• pp.433-441
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• 1992

국내의 23개 무연탄을 대상으로 석탄회의 화학분석 및 용융특성분석을 수행하여 석탄회의 화학조성과 용융온도와의 상관성을 고찰하였다. 또한 이들 무연탄을 미분탄 연소의 연료로 사용시 야기될 수 있는 slagging, fouling성을 예측하여 보았다. 국내 무연탄회는 대부분 $SiO_2$와 $Al_2O_3$를 80% 이상 함유하고 있는 반면 1% 이하의 적은 양의 $Na_2O$를 함유하고 있으며, 또한 비교적 높은 용융온도를 갖는다. 따라서 이 무연탄들을 미분탄 연소의 연료로 사용시 slagging 및 fouling 발생 가능성은 낮을 것으로 예측되었다. 국내 무연탄회의 용융특성은 base/acid ratio와 비교적 높은 상관성을 갖는 것으로 나타났다.

• 한국수소및신에너지학회논문집
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• 제21권3호
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• pp.227-240
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• 2010

Coal gasification is heading for a great future as one of the cleanest energy sources, which can produce not only electricity and heat, but also gaseous and liquid fuels from the synthesis. The work focuses on 300MW shell type one-stage entrained flow coal gasifier which is used in the Integrated coal Gasification Combined Cycle(IGCC) plant as a reactor. As constructing an IGCC plant is considerably complicated and expensive compared with a pulverized-coal power plant, it is important to determine optimum design factors and operating conditions using a computational fluid dynamics (CFD) model. In this study, the results of numerical calculations show that $O_2$/Coal ratio, 0.83, Steam/Coal ratio, 0.05, coal particle diameter, $100{\mu}m$, injection angle, $4^{\circ}$ (clockwise) are the most optimum in this research.

• 한국환경과학회지
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• 제28권6호
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• pp.553-559
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• 2019

In this study, zeolitic materials at $Na_2CO_3/CFA$ ratio of 0.6 - 1.8 were synthesized from coal fly ash from a thermal power plant using a fusion/hydrothermal method. The zeolitic materials were found to have cubic crystals structure and X-ray diffraction (XRD) peaks of Na-A zeolite by XRD and SEM analysis. When the zeolitic materials were synthesized from the coal fly ash, the XRD peaks of the zeolitic materials at $Na_2CO_3/CFA$ ratios of 0.9-1.8 had the same location as the XRD peaks of commercial Na-A zeolite. The XRD peaks of the Na-A zeolite ($Na_{12}Al_{12}Si_{12}O_{48}27.4H_2O$) were confirmed in the $2{\theta}$ in the range of 7.18-34.18. However, it was also confirmed that peaks of $CaCO_3$, an impurity inhibiting synthesis of Na-A zeolite from CaO and $Na_2CO_3$ in the coal fly ash, occurred in the XRD peaks of the zeolitic materials at $Na_2CO_3/CFA$ ratio of 1.5-1.8. The crystallinities of the zeolitic materials tended to increase gradually within the $Na_2CO_3/CFA$ ratio range of 0.6-1.8.

• 한국수소및신에너지학회논문집
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• 제23권3호
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• pp.274-284
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• 2012

Recently, gasification technology for coal blended with biomass has been an issue. Especially, An advantages of coal blended with biomass are 1) obtaining high cold gas efficiency, 2) obtaining syn-gas of high-high heating value (HHV), and 3) controlling occurrence of $CO_2$. In this study, the efficiency and characteristic of 300 MW Shell type gasifier were predicted using CFD simulation. The CFD simulation was performed for biomass coal blending ratios of 0~0.2, 0.5, 1 and $O_2$/fuel ratios of 0.5~0.84. Kinetic parameters (A, $E_a$) obtained by $CO_2$ gasification experiment were used as inputs for the simulation. In results of CFD simulation, residence times of particle in 300MW Shell type gasifer presented as 7.39 sec ~ 13.65 sec. Temperature of exit increased with $O_2$/fuel ratio as 1400 K ~ 2800 K, while there is not an effects of biomass coal blending ratios. Considering both aspects of temperature for causing wall slagging and high cold gas efficiency, the optimal $O_2$/fuel ratio and blending ratio were found to be 0.585 and 0.05, respectively.

• 한국세라믹학회지
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• 제43권4호
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• pp.235-241
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• 2006

Mullite short fibers have been fabricated by adapting the Kneading-Drying-Calcination (KDC) process and characterized. The effect of the addition of foaming agent and calcination temperature on the formation of mullite fibers from coal fly ash, was examined. In the present work, ammonium alum $NH_4Al(SO_4)_2\;12H_2O$ synthesized trom coal fly ash and sodium phosphate $Na_2HPO_4\;2H_2O$ were used as foaming agents. After calcination at $1300^{\circ}C$ for 10 h and then etching with 20% HF solution at $50^{\circ}C$ for 5 h using a microwave heating source, the alumina-deficient $(AI_2O_3/SiO_2$ = 1.13, molar ratio) orthorhombic mullite fibers with a width of ${\sim}0.8mm$ (aspect ratio >30), were prepared from the coal fly ash with $AI_2O_3/SiO_2$ = 0.32, molar ratio by the addition of $NH_4AI(SO_4)_2\;12H_2O$, and with further addition of 2 wt% sodium phosphate. The excessive addition of sodium phosphate rather decreased the formation of mullite fibers, possibly due to the large amount of liquid phase prior to mullitization reaction.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2001년도 추계 학술발표회 논문집
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• pp.69-76
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• 2001

The coal gasification process of a slurry feed type, entrained-flow coal gasifier was numerically predicted in this paper. By divding the complicated coal gasification process into several simplified stages suh as slurry evaporation, coal devolitilisation and two-phase reactions coupled with turbulent flow and two-phase heat transfer, a comprehensive numerical model was constructed to simulate the coal gasification process. The k-$\varepsilon$turbulence model was used for the gas phase flow while the Random-trajectory model was applied to describe the behavior of the coal slurry particles. The unreacted-core shrinking model and modified Eddy Break-Up(EBU) model were used to simulate the heterogeneous and homogeneous reactions, respectively. The simulation results obtained the detailed informations about the flow field, temperature inside the gasifier. Meanwhile, the simulation results were compared with the experimental data as function of $O_2$/coal ratio. It illustrated that the calculated carbon conversions agreed with the measured ones and that the measurd quality of the atngas was better than the calculated one when the $O_2$/coal ratio increases. The result was related with the total heat loss through the gasifier and uncertain kinetics for the heterogeneous reactions.