• Clean Technology
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• v.26 no.3
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• pp.211-220
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• 2020

This experimental study investigates the design parameters to achieve ultra low NOx combustion of coal using a 80 kW capacity single-burner furnace. The influence of key design parameters such as SN, overall and burner-zone equivalence ratios, primary/secondary air ratio, overfire air (OFA) ratio were tested for a total of 81 cases. The results showed that weak swirl intensity of the burner leads to higher NOx emission whereas strong swirl intensity accompanies increased CO concentration desipte lower NOx emission. Therefore, finding an appropirate swirl intensity is essential for the burner design. Larger flow rate of secondary air increased NOx emission, whereas smaller flow rate stretches the flame and increased CO emission. The lowest NOx emission of 82 ppm (6% O₂) was achieved at the optimal condition of the present burner deisgn. It is expected to furrther lower the NOx emission by introducing splitting the burner secondary air into three or four streams.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.96-104
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• 2013

Coal gasification is considered as one of the best alternatives among clean coal technology and new concept next generation technologies are under being developed to achieve low cost as well as high efficiency. In this study we have developed double swirl multi-burner as part of the development of low cost compact gasifier. We installed new concept multi-burner with pulverized coal distributor to the body of existing gasifier for burner test. Gasification test was performed under the condition of $6.4{\sim}7.2kg/cm^2$ and $1170{\sim}1300^{\circ}C$ by using Indonesian ABK (sub-bituminous) coal to get operation condition of new concept multi-burner. Our interest was focused to ensure a stable operating condition rather than the gasifier performance evaluation. As a result, we were able to achieve the carbon conversion of 84% and the cold gas efficiency of 52.1% at the stable operating conditions.

• Clean Technology
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• v.29 no.1
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• pp.22-30
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• 2023

Mongolia is experiencing some of the world's most serious air pollution problems. The air pollution is especially severe during the winter when raw coal and low-grade fuels are used to heat homes in Ger villages. The impact of this pollution has created significant health and socioeconomic challenges for the country. In order to mitigate this air pollution, this study analyzed the fuel quality of the low-grade fuels and Mongolian waste cooking oils used in Ulaanbaatar, Mongolia. Then the environmental characteristics of traditional stove combustion and a prototype combustion heating device were compared and analyzed. In addition, the effect of replacing the heating devices was evaluated by analyzing their risks to humans. Analysis of the fuel characteristics showed that briquettes had relatively low environmental properties as a result of their high ash, N and S content. Also, after analyzing the combustion characteristics, it was found that the air quality improvement effect was higher when waste cooking oil was burned compared to the three types of coal that were analyzed. Finally, this study evaluated the impact of replacing the Mongolia traditional stove with a prototype stove that uses waste cooking oil. The results of this study are expected to help to mitigate the air quality problems currently observed in Ulaanbaatar, Mongolia.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.372-380
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• 2011

Char gasification is affected by operating conditions such as reaction temperature, reactants gas partial pressure, total system pressure and particle size in addition to chemical composition and physical structure of char. The aim of the present work was to characterize the effect of coal particle size on $CO_{2}$ gasification of chars prepared from two different types of bituminous coals at different reaction temperatures(1,000-$1,400{^{\circ}C}$). Lab scale experiments were carried out at atmospheric pressure in a fixed reactor where heat was supplied into a sample of char particles. When a flow of $CO_{2}$(40 vol%) was delivered into the reactor, the char reacted with $CO_{2}$ and was transformed into CO. Carbon conversion of the char was measured using a real time gas analyzer having NDIR CO/$CO_{2}$ sensor. The results showed that the gasification reactivity increased as the particle size decreased for a given temperature. The sensitivity of the reactivity to particle size became higher as the temperature increases. The size effects became remarkably prominent at higher temperatures and became a little prominent for lower reactivity coal. The particle size and coal type also affected reaction models. The shrinking core model described better for lower reactivity coal, whereas the volume reaction model described better for higher reactivity coal.

• Clean Technology
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• v.2 no.1
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• pp.69-79
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• 1996

Sulfur emission control in coal gasification plants implies the removal of $H_2S$ from the fuel gas in the gas clean-up system. In this study, the effects of particle size of sorbents, temperature of sulfidation and sorbent characteristics on the $H_2S$ removal efficiency of manganese ore were investigated. Experimental results showed that the removal efficiency of $H_2S$ was optimum when the temperature was about $700^{\circ}C$. And that the smaller particle size, the higher the $H_2S$ removal efficiency, but that was not effective very much. As the temperature increases, the reactivity of sorbents has lowered because agglomeration of sorbents increased the intraparticle transport resistance. This phenomenon was confirmed by SEM photographs. The equilibrium ratio ($P_{H_2O}/P_{H_2S}$) obtained by experiments is represented as a ${\log}(P_{H_2O}/P_{H_2S})=5653/T-3.7909$. It was showed that the natural manganese ore could be used as a sorbent because its capacity for $H_2S$ removal is equivalent to the eariler developed sorbents.

• Advances in Energy Research
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• v.4 no.2
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• pp.163-176
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• 2016

Rapid depletion of fossil based oil, coal and gas reserves and its greater demand day by day necessitates the search for other alternatives. Severe environmental impacts caused by the fossil fire based power plants and the escalating fuel costs are the major challenges faced by the electricity supply industry. Integration of Distributed Generators (DG) especially, wind and solar systems to the grid has been steadily increasing due to the concern of clean environment. This paper focuses on a new simple and fast load flow algorithm named Backward Forward Sweep Algorithm (BFSA) for finding the voltage profile and power losses with the integration of various sizes of DG at different locations. Genetic Algorithm (GA) based BFSA is adopted in finding the optimal location and sizing of DG to attain an improved voltage profile and considerable reduced power loss. Simulation results show that the proposed algorithm is more efficient in finding the optimal location and sizing of DG in 15-bus radial distribution system (RDS).The authenticity of the placement of optimized DG is assured with other DG placement techniques.

• Clean Technology
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• v.9 no.2
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• pp.71-79
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• 2003

The selective catalytic reduction (SCR) process is the most widely applied technology for the denitrification of coal-fired power plant flue gases due to its selectivity and high efficiency. In order to attain the optimum design of SCR process, it is required to consider various catalysis characteristics as well as various operating conditions. A systematic study to elucidate the effects of the design conditions(reaction temperature, $NH_3/NO$ mole ratio, space velocity and linear velocity) on the reduction of NOx using the SCR pilot plant with maximum flue gas flow rate of $1,000Nm^3/hr$ was carried out and employed to identify the optimum design parameters. Design approaches of SCR process with test results were also presented.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.1
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• pp.31-37
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• 2016

Co-firing of biomass with coal is a promising combustion technology in a coal-fired power plant. However, it still requires verifications to apply co-firing in an actual boiler. In this study, data from the Thermogravimetric analyzer(TGA) and Drop tube furnace(DTF) were used to obtain the combustion characteristics of biomass when co-firing with coal. The combustion characteristics were verified using experimental results including reactivity from the TGA and Unburned carbon(UBC) data from the DTF. The experiment also analyzed with the variation of the biomass blending ratio and biomass particle size. It was determined that increasing the biomass blending ratio resulted in incomplete chemical reactions due to insufficient oxygen levels because of the rapid initial combustion characteristics of the biomass. Thus, the optimum blending condition of the biomass based on the results of this study was found to be 5 while oxygen enrichment reduced the increase of UBC that occurred during combustion of blended biomass and coal.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.657-666
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• 2014

Coal gasification technology is considered as next generation clean coal technology even though it uses coal as fuel which releases huge amount of greenhouse gas because it has many advantages for carbon capture. Coal or pet-coke slurry gasification is very attractive technology at present and in the future because of its low construction cost and flexibility of slurry feeding system in spite of lower efficiency compared to dry feeding technology. In this study, we carried out gasification experiment using bituminous coal slurry sample by integrating coal slurry feeding facility and slurry burner into existing dry feeding compact gasifier. Especially, our experiment was conducted under fairly lower operation temperature than that of existing entrained-bed gasifier, resulting in partial slagging operation mode in which only part of ash was converted to slag and the rest of ash was released as fly ash. Carbon conversion rate was calculated from data analysis of collected slag and ash, and then cold gas efficiency, which is the most important indicator of gasifier performance, was estimated by carbon mass balance method. Fairly high performance considering pilot-scale experiment, 98.5% of carbon conversion and 60.4% of cold gas efficiency, was achieved. In addition, soundness of experimental result was verified from the comparison with chemical equilibrium composition and energy balance calculations.

• Journal of Energy Engineering
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• v.9 no.4
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• pp.295-302
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• 2000

증발열량 석탄가스 연료를 사용하는 석탄가스와 복합 발전 플랜트의 성능 및 NOx 배출량을 동시에 예측하기 위한 모사 방법을 제시하였다. 본 방법은 복합 사이클의 열역학적 해석 기법을 토대로, 석탄가스화 복합발전 플랜트의 시스템 연계 및 석탄가스 연소에 의한 탈설계점 효과를 예측하는 모델들을 포함하고 있다. 본 방법에 의한 전산 모사 결과와 천연가스를 사용하는 복합발전소의 실제 시험 결과를 비교함으로써, 본 방법의 예측정확도를 검증하였다. 본 모사 방법을 이용하여, 서로 다른 4가지 석탄가스 연료에 대해, 공기 분리장치와의 다양한 연계 설계 조건에 따른 석탄가스화 복합발전 플랜트의 전체 성능, 운전 안전성 및 NOx 배출 특성들을 비교, 검토하였다.