• Journal of Biosystems Engineering
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• v.25 no.3
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• pp.187-194
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• 2000

One of effective utilization technique of rice husk is known to carbonize it for using as the culture materials. A series of study on the production of carbonized rice husk by a cyclone combustor shows that the carbonized rice husk produced have a strong alkalinity. Therefore, carbonized rice husk produced by a cyclone combustor is required to neutralize with proper normality. This work is the third part of a series on the production of carbonized rice husk by a cyclone combustor. In this work, the development of neutralization process was carried out in the range of experimental conditions recommended in the previous study. Those include the preheat temperature of combustion chamber of T1b=1273∼1373K, equivalence ratio =1.68∼2.17, auxiliary gas flow rates Qg=5.15∼6.43$\ell$/min. The injection technique of dilute acid was employed for neutralization. At the lower position of the outside of combustor, a dilute nitric acid selected as neutralization liquid was injected to the carbonized rice husk exhausted from the combustion chamber. The normalities of dilute nitric acid were varied to 0.01, 0.03 and 0.05N, respectively. The injection flow rates of the solution were changes from 1.7∼4$\ell$/min. The required carbonized and neutralized rice husk could be obtained at the dilute nitric acid with normality of 0.3N and flow rate of dilute nitric acid of 2∼3.5$\ell$/min. However, the carbonized and neutralized rice husks of about 10∼20% were destroyed by spray with high injection pressure.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.82-89
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• 2001

This paper concerns lean gas cyclone combustion system adopting distributed inlets with different velocity to promote ignition and burnout properties. Detailed temperature measurements have been achieved under different operating conditions and flue gas compositions and NOx have been measured. Experimental results show that cyclone combustor provided increasing combustion stability and reduction NOx emission level to negligible level.

• Journal of Energy Engineering
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• v.13 no.2
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• pp.112-117
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• 2004

Volatile organic compounds (VOCs) are low calorific value gases (LCVG) emitted from chemical processes such as painting booth, dye works and drying processes etc. Characteristics of VOCs are low calorific values less than 150kcal/㎥, high activation energy for ignition and low energy output. These characteristics usually make combustion unstable and its treatment processes needs high-energy consumption. The cyclone combustion system is suitable for LCVG burning because it can recirculate energy through a high swirling flow to supply the activation energy for ignition, increases energy density In make a combustion temperature higher than usual swirl combustor and also increases mixing intensity. This research was conducted to develop optimized cyclone combustion system for thermal oxidation of VOCs. This research was executed to establish the effect of swirl number with respect to the combustion temperature and composition of exhausted gas in the specific combustor design.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.225-230
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• 2004

Volatile organic compounds (VOCs) are low calorific value gases (LCVG) emitted from chemical processes such as painting booth, dye works and drying processes etc. Characteristics of VOCs are low calorific values less than 150 kcal/$m^3$, high activation energy for ignition and low energy output. These characteristics usually make combustion unstable and its treatment processes needs high-energy consumption, The cyclone combustion system is suitable for LCVG burning because it can recirculate energy through a high swirling flow to supply the activation energy for ignition, increases energy density to make a combustion temperature higher than usual swirl combustor and also increases mixing intensity, This research was conducted to develop optimized cyclone combustion system for thermal oxidation of VOCs. This research was executed to establish the effect of swirl number with respect to the combustion temperature and composition of exhausted gas in the specific combustor design.

• 한국연소학회:학술대회논문집
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• 1997.06a
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• pp.103-112
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• 1997

In the combustion of the pulverized coal compared with that of liquid fuel or gaseous fuel, serious pollutants such as ash, $NO_x$ and $SO_x$ are released to surroundings. The objective of this study is the reduction of such pollutants in the combustion process. The modeling of cyclone combustor which uses the method of two stage combustion was carried out. The main burner length, scattering angle and air/fuel ratio were considered as parameters. The results show that the shorter the main burner length is, the less the amounts of coals which exit the combustor directly are, but the scattered input of coal is required anyway in order to collect all ashes. It is recommended that the shorter the main burner length is, the less the scattering angle is. And in the case of the scattered input compared with no scattering, the temperature in the combustor is more uniform and the amount of volatile is more reduced.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.5
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• pp.401-410
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• 2002

Concerns for energy conservation, environmental pollution, and the fact that organic wastes account for a major portion of our waste materials, have created the interest of biogas, which usually contains about 60 to 70 percent methane, 30 to 40 percent carbon dioxide, and other gases, including ammonia, hydrogen sulfide, mercaptans and other noxious gases. Cyclone combustors are used for homing a wide range of fuels such as low calorific value gas, waste water, sludge. coal, etc. The 3-dimensional swirling flow, combustion and emission in a tangential inlet cyclone incinerator under different inlet conditions are simulated using a standard k-s turbulence model and ESCRS (Extended Simple Chemically-Reacting System) model. The commercial code Phoenics Ver.3.4 was used for the present work. The main parameters considered in this work are inlet velocity and air to fuel ratio. The results showed that the change of operating conditions had an influence on the shape and size of recirculation zones, mixture fraction and axial velocity which are important factors for combustion efficiency and emission behavior. The application of this kind of computer program seams to be promising as a potential tool for the optimum design of a cyclone combustor with low emission.

• Journal of computational fluids engineering
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• v.2 no.1
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• pp.93-108
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• 1997

This paper describes several computational results on the various energy and environmental problems using Patankar's SIMPLE method. The specific problems included in this study are : pollutant and flammable material dispersions in open and confined areas, buoyancy-driven flow in a lake, primary clarifier for water and waste water treatment, hood ventilation in workplace. cyclone combustor and Dow chlorination reactor. A control-volume based finite-difference method is employed together with the power-law scheme. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, says SIMPLER and SIMPLEC. The Reynolds stresses are closed using the standard or RNG κ-ε models. A nonequilibrium turbulent reaction model is developed for the application of the chlorination process in the Dow thermal reactor. Other important empirical models and physical insights appeared in this study are presented and discussed in a brief note. The computational method developed in this study is considered, in general, as a viable tool for the design and determination of the optimal operating condition of various environmental engineering system of interest.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.337-344
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• 1994

Two coals which have a quite different properties were selected to compare the combustion characteristics in a cyclone combustor. The capacity of the combustion test rig is about 75kW and total volume is 5.7 liters. The pulverized sample coals are well burned from fuel rich(air ratio 0.4) to fuel lean(airs ratio 1.6). Two different property coals show quite different patterns of ash collection in slag pot, dust separator and combustion chamber. Combustion temperature of subbituminous coal is about $100^{\circ}C$ lower than bituminous coal at the entire region, and in case of bituminous coal, hot spot appeared at the lower part and axial line of the combustion chamber.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.07a
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• pp.16-21
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• 1999

국민소득의 증대와 더불어 향상된 우리의 식생활 문화는 양보다 품질을 선호하게 되어 청정 농산물의 수요가 증대하였는데 이로 인하여 농작물의 유해성을 감소시킬 수 있으며 기후의 영향을 덜 받아 연중재배 및 생산이 가능한 수경재배 및 양액재배 기술이 등장하였으며, 이를 위한 첨단 시설하우스의 설립도 매우 많이 증가하였다. 또한 점점 더 확산되는 집단육묘 체계에서 살균 처리하여 사용되고 있는 관행 상토를 대체할 수 있는 무균의 배양토 재료의 개발이 관심 대상으로 떠올랐다. 토양 및 광물질, 유기물류가 혼합된 대부분의 상토재료(피트모스, 나무껍질)와 양액재배 지주물질은 매우 많은 양이 수입에 의존하고 있는 실정이다. 이러한 고가의 수입자재를 대체하기 위한 일환으로 우리 농촌에서 농업부산물로 생겨나는 왕겨를 탄화시켜 상토재료 및 양액재배용 지주물질로 사용하려는 연구가 다수 시행되었다. (중략)

• Journal of the Korean Society of Combustion
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• v.6 no.2
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• pp.36-42
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• 2001

Usually, we use the flame thickness and turbulence scale to classify the flame structure on a phase diagram of turbulent combustion. The flame structure in turbulence is still in debate, and many studies have been done. Since the flame motion is rapid and its reaction zone thickness is very thin, it is difficult to estimate the flame thickness. Here, we propose a new approach to determine the reaction zone thickness based on ion current signals obtained by an electrostatic probe, which has enough time and space resolution to detect flame fluctuation. Since the signal depends on the flow condition and flame curvature, it may be difficult to analyze directly these signals and examine the flame characteristics. However, ion concentration is high only in the region where hydrocarbon-oxygen reactions occur, and we can specify the reaction zone. Based on the reaction zone existing, we estimate the reaction zone thickness. We obtain the thickness of flames both in the cyclone-jet combustor and on a Bunsen burner, compared with theoretically predicted value, the Zeldovich thickness. Results show that the experimentally obtained thickness is almost the same as the Zeldovich thickness. It is concluded that this approach can be used to obtain the local flame structure for modeling turbulent combustion.