• 공업화학
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• 제22권5호
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• pp.566-574
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• 2011

석탄가스화기는 석탄가스화복합발전과 석탄간접액화 공정에서 고효율을 얻기 위한 중요한 설비 중 하나이다. 현재 여러 종류의 석탄가스화기가 성공적으로 사용되고 있지만, 간단하면서도 신뢰도를 높일 수 있는 다양한 설계 변경이 가능하다. 건식 분류층 가스화기 4종류의 형태를 제시하고 이들을 체류시간, 가스화기 출구 합성가스의 온도, 합성가스 조성을 중점으로 비교하였다. 설계개념이 적정한지를 우선 파악하고자 반응을 배제한(cold-flow) CFD 해석을 먼저 수행하였고, 실제 가스화기 조건을 반영한 화학반응이 고려된(hot-flow) 해석을 수행하여 비교하였다. 가스화기 설계에 CFD를 적용하는 데는 슬랙의 거동과 슬랙탭 설계 등 측면에서 제한적이기는 하지만, 다양한 설계개념 중에서 가능성이 높은 가스화기 형태의 범위를 좁히는 데 매우 유용하게 사용될 수 있다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.368-371
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• 2008

The optimal operation condition of gasifier is one of the most important parameters to increase efficiency and reliability in IGCC plant. Also the prediction of the syngas composition and quantity must be predicted to carry out process design of the gasification plant. However, the gasifier process licensor are protective with information on process design and optimal gasifier design conditions. So, the most of process studies in the engineering company for gasification plant have carried out to look for key parameters and optimal design conditions using several prediction methods. In this paper, we present the estimated preliminary optimal operation condition of the 300MW Demonstration Entrain Flow Gasifier using Aspen Plus. The gasifier operation temperature considering slag flow was predicted by FactSage software and Annen Model.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.265-266
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• 2014

Due to global economic growth, there is an increasing need for energy. Fossil fuels will continue to dominate the world energy supplies in the 21st century and coal will play a significant role. Since coal is one of the most important fossil fuels in the world, coal gasification technology appears to be an inevitable choice for power and chemicals production and has a leading place in Clean Coal Technology (CCT). The most eminent environmental advantage of coal gasification lies in its inherent reaction features that produce negligible sulfur and nitrogen oxides, as well as other pollutants in a reducing atmosphere. The gasifier was operated for a throughput of 1.0 ton & 10.0ton coal per day at pressures of 1~20Bar. Gasification was conducted in a temperature range of $1,100{\sim}1,450^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.417-423
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• 2007

Oxy-gasification or oxygen-blown gasification, enables a clean and efficient use of coal and opens a promising way to CO2 capture. The coal gasification process of a slurry feed type, entrained-flow coal gasifier was numerically predicted in this paper. The purposes of this study are to develop an evaluation technique for design and performance optimization of coal gasifiers using a numerical simulation technique, and to confirm the validity of the model. By dividing the complicated coal gasification process into several simplified stages such as slurry evaporation, coal devolatilization, mixture fraction model 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 influence of turbulence on the gas properties was taken into account by the PDF (Probability Density Function) model. A numerical simulation with the coal gasification model is performed on the Conoco-Philips type gasifier for IGCC plant. Gas temperature distribution and product gas composition are also presented. Numerical computations were performed to assess the effect of variation in oxygen to coal ratio and steam to coal ratio on reactive flow field. The concentration of major products, CO and H2 were calculated with varying oxygen to coal ratio (0.2-1.5) and steam to coal ratio(0.3-0.7). To verify the validity of predictions, predicted values of CO and H2 concentrations at the exit of the gasifier were compared with previous work of the same geometry and operating points. Predictions showed that the CO and H2 concentration increased gradually to its maximum value with increasing oxygen-coal and hydrogen-coal ratio and decreased. When the oxygen-coal ratio was between 0.8 and 1.2, and the steam-coal ratio was between 0.4 and 0.5, high values of CO and H2 were obtained. This study also deals with the comparison of CFD (Computational Flow Dynamics) and STATNJAN results which consider the objective gasifier as chemical equilibrium to know the effect of flow on objective gasifier compared to equilibrium. This study makes objective gasifier divided into a few ranges to study the evolution of the gasification locally. By this method, we can find that there are characteristics in the each scope divided.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.913-924
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• 2011

A steady-state analysis has been conducted to predict the behavior of the slag layer in the entrained-flow slagging coal gasifier. The analysis takes into consideration the composition dependent slag properties such as density, viscosity, heat capacity, thermal conductivity, and temperature of critical viscosity. The amount of added flux to the design coal and the variation of syngas temperature inside the gasifier have been adopted as calculation parameters. The predicted results are the local thickness of the molten and the solid slag layers, and the slag viscosity and the velocity distribution across the molten slag layer along the gasifier wall near the slag tap.

• Korean Chemical Engineering Research
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• 제48권2호
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• pp.129-139
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• 2010

석탄으로부터 수소, 일산화탄소 등의 가스 연료를 생산하기 위하여 개발된 석탄 가스화 공정은 이산화탄소 저장, 환경 유해 물질 저감 등의 우수성으로 인하여 최근 세계 각국에서 앞다투어 개발에 나서고 있다. $75{\mu}m$ 이하의 미분탄을 이용하는 분류층 가스화 공정은 용량의 대형화가 쉽고, 에너지 전환 효율이 우수하여 석탄가스화복합발전(IGCC) 등에 널리 이용되고 있다. 특히 석탄슬러리를 원료로 사용하는 습식 분류층 가스화 공정은 기술적으로 성숙되어 가장 많이 보급되고 있다. 본 논문에서는 습식 분류층 가스화 공정을 이루는 석탄전처리, 버너, 가스화기, 슬래그용융, 가스화 운전 특성과 설계 및 해석을 위한 수치모사 등의 요소기술 개발 현황을 고찰하였다. 습식 석탄가스화는 IGCC 플랜트에서 뿐만 아니라 합성석유, SNG, 화학원료 제조용으로 활용될 수 있으며 융합 공정, 연료 다변화 등에 대응하기 위하여 요소기술별 추가적인 기술개발이 이루어져야 할 것으로 판단된다.

• 대한기계학회논문집B
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• 제21권12호
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• pp.1690-1700
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• 1997

Entrained coal gasification tests with Datong coal were performed to assess the influence of oxygen/coal ration and pressure. When gasification condition in oxygen/coal ratio has changed from 0.5 to 1.0, optimal gasification condition from low pressure runs was oxygen/coal ratio of approximately 0.9 where CO was produced about 40% and H, about 20%. Under the pressure condition of 12-14 atmospheres, optimal oxygen/coal ratio value was in the region of 0.6 where CO was produced about 55% and H2about 25%. From these results, it was found that the oxygen/ coal ratio for the maximum production of CO and H, was decreasing with the increase in gasifier pressure and also, with increasing oxygen content, carbon conversion was increased. For the Chinese Datong coal, cold gas efficiency was in the range of 40-80%.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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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.

• Korean Chemical Engineering Research
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• 제52권5호
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• pp.592-602
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• 2014

석탄 가스화 복합 발전(coal-based IGCC power plant)에서 가스화기의 동적 상태와 성능이 플랜트 전체에 큰 영향을 미치므로, 가스화기가 문제 없이 운전 되도록 제어 하는 것은 전체 플랜트의 가동률을 높이는 데 있어 매우 중요한 일이라 할 수 있다. 가스화기의 안정적인 운전을 위해서는 고체 슬래그 층의 두께가 일정하게 유지되어야 하는데, 고체 슬래그 두께는 실시간 측정이 불가능하기 때문에 상태를 추정하여 추론 제어해야 한다. 본 연구에서는 Shell-type 가스화기의 동적 모사 모델을 개발하고 다변수 시스템의 추론 제어를 위한 방법으로 두 가지 선형 예측 제어 기법을 적용하여 그 특성을 분석하였다. 측정되지 않는 변수의 상태 추정을 위해 Kalman 필터 기법을 이용하였다. 측정 불가능한 1차 변수를 대신하여 측정 가능한 2차 변수를 제어하는 전통적인 추론 제어 기법으로는 외란의 종류에 따라 추론 제어가 불가능 할 수 있음을 확인하였고, 측정되지 않는 슬래그 두께를 Kalman 필터 기법을 이용하여 추정하여 성능 예측에 반영하고 외란 모델을 사용하여 예측 제어하는 경우 두 가지 측정 불가능한 외란 모두에 대해 추론 제어가 가능함을 확인하였다.

• 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.