• 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.

• Clean Technology
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• v.25 no.1
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• pp.74-80
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• 2019

Thermochemical treatment of sewage sludge is an energy-intensive process due to its high moisture content. To save the energy consumed during the process, the hydrothermal carbonization process for sewage sludge can be used to convert sewage sludge into clean solid fuel without pre-drying. This study is aimed to investigate co-firing characteristics of the hydrothermally carbonated sewage sludge (HCS) to a pulverized coal combustion system. The purpose of the measurement is to measure the pollutants produced during co-firing and combustion efficiency. The combustion system used in this study is a furnace with a down-firing swirl burner of a $80kW_{th}$ thermal input. Two sub-bituminous coals were used as a main fuel, and co-firing ratio of the sewage sludge was varied from 0% to 10% in a thermal basis. Experimental results show that $NO_x$ is 400 ~ 600 ppm, $SO_x$ is 600 ~ 700 ppm, and CO is less than 100 ppm. Experimental results show that stable combustion was achieved for high co-firing ratio of the HCS. Emission of $NO_x$ and $SO_x$ was decreased for higher co-firing ratio in spite of the higher nitrogen contents in the HCS. In addition, it was found that the pollutant emission is affected significantly by composition of the main fuel, regardless of the co-firing ratios.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.60-60
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• 2011

염색폐수의 정화에는 필연적으로 다량의 슬러지 폐기물이 발생한다. 염색폐수 슬러지는 그간 인근 공해 해상에 투기하는 해양 배출로 저렴하게 처리하였으나, 해양오염을 우려하는 국제협약(1972년 런던협약, 1996년 교토의정서)에 의하여 2008년 8월부터 배출기준이 강화되고 2012년 2월부터는 해양배출이 금지 될 예정이다. 염색폐수 슬러지의 해양 배출이 금지되면 대체 처리방법으로는 지정매립장을 통한 매립처리 방법이나 고온 소각시설에서의 소각처리 방법이 거론되고 있다. 그러나 매립처리는 슬러지 내 함유 수분으로 인한 침출수의 문제와 더불어 장기간 안정적으로 저렴하게 사용할 수 있는 대규모 처분장을 확보하기 어려운 실정이며 소각처리는 슬러지의 높은 함수율로 인해 소각 시보조 연료의 투입이 필연적으로 최근 원유가 급등 등 에너지 비용이 지속적으로 상승함을 고려할 때 소각처리비용 또한 상당한 고가가 될 것으로 예측된다. 이와 같이 슬러지 해양배출이 금지되면 섬유 염색업체들은 많은 환경비용 부담을 안을 것이다. 본 연구에서는 대규모 염색산업단지 공동폐수처리장에서 발생하는 염색폐수 슬러지의 효율적인 건조를 위해 산업단지 내의 열병합발전소에서 발생하는 보일러 폐열을 이용하였으며, 조건 특성 및 효율을 파악하기 위해 보일러 폐열의 특성을 고려하여 슬러지 두께 및 체류시간 등 건조공정 운영조건에 따른 변수별 연구를 수행하였다. 열병합발전소 보일러에서 배출되는 폐열은 온도가 $150^{\circ}C$ 정도로 기존의 슬러지 건조에서는 사용되는 $700^{\circ}C$에 비해서는 매우 저온이다. 하지만 보일러 배가스의 경우, 온도에 비해 많은 풍량을 가지고 있으므로 열량으로 환산시 충분히 가치가 있는 것으로 조사되었다. 염색폐수 슬러지의 경우, 함수율 70% 이내의 탈수 Cake 형태이므로 두께가 두꺼울수록 건조효율이 감소하였으며, 체류시간이 길어질수록 건조효율은 증가하나 20mm 이상에서는 건조효율이 급격히감소하였다. 이를 바탕으로 5톤/일 규모 슬러지 건조 Pilot Plant를 제작하여 운영하였는데, 염색폐수슬러지의 투입공정에서 슬러지와 열풍의 접촉면적을 넓혀 건조효율을 높이기 위하여 슬러지를 압출노즐을 이용하여 슬라이스 칩 형태로 제조하여 건조공정에 투입하였으며, 건조실 내에서도 건조효율의 상승을 위하여 내부열풍순환팬을 설치하여 운영하였다. Pilot 운영결과, 체류시간 52분에서 슬러지의 함수율은 70%에서 10%이하로 감소하였다.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.1
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• pp.88-95
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• 2009

This study is for understanding the domestic possibilities of the high temperature incineration of waste containing Polychlorinated Biphenyls (PCBs) with the analysis of normal operation case and waste gas, fly ash, dioxin about bottom ash, Total-PCBs, Co-PCBs, and the for analysis the heavy metal leaching feature included by bottom ash and fly ash, heavy metal leaching experiment was implemented. The result shows the dioxin density of the waste gas from waste containing PCBs was $0.00699{\sim}0.00763ng-TEQ/Nm^3$, which is lower than $0.0192ng-TEQ/Nm^3$ from the normal operation case. And each Co-PCBs and total PCBs shows $0.00043{\sim}0.00112ng-TEQ/Nm^3$ and $3.06{\sim}3.87ng/m^3$ respectively. The bottom ash test result shows Dioxin 0.00225~0.00630ng-TEQ/g, Co-PCBs 0.00027~0.00082ng-TEQ/g, Total PCBs 0.9~2.6ng/g, and the fly ash shows Dioxin 0.00164~0.00344ng-TEQ/g, Co-PCBs 0.00053~0.00054ng-EQ/g, Total PCBs 0.64~0.84ng/g. The bottom ash and fly ash experiments for heavy metal leaching did not show any leaching but when it comes to the ingredients of the fly ash, Pb elements shows 31.01~237.7ppm, higher than leaching criterion. The analysis of the density of all air pollution material from the waste gas shows the lower value than permissible criterion.

• Clean Technology
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• v.20 no.4
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• pp.390-397
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• 2014

This study was performed to investigate the effects of fluidizing media on $N_2O$ production in fluidized bed incineration of sewage sludge. The fluidized media were prepared in a form of 2 mm bead by mixing zeolite powders in our lab. Sand having 0.4 mm of the mean size showed 0.44 m/s of minimum fluidization velocity ($U_{mf}$), while the prepared zeolite media 0.5 m/s. When the ratio of fluidizing media height to the inside diameter of the incinerator (bed aspect ratio) increased from 1.4 to 3.1, it was found that $U_{mf}$ of the zeolite media was varied from 0.5 m/s to 0.7 m/s. Under the operation conditions in 1.79 of excess air ratio, $909^{\circ}C$ of bed temperature and ca. 1.65 m/s of superficial velocity, as the weight of fluidizing meadia was increased, $O_2$ concentration in the flue gas was slightly decreased, and $CO_2$ increased. Above 6 kg of fluidizing media weight (1.98 of bed aspect ratio), it was observed that $N_2O$ concentration was significantly reduced, which might result from the decomposition of $N_2O$ on the zeolite media rather than transformation of $N_2O$ to NOx. On the other hand, in a variation of the zeolite media mixing ratio to sand and bed temperature at a constant total bed height, significant difference was exhibited in $N_2O$ emission concentration according to the temperature. Considering the operation temperature in the incineration, the effective calcination temperature of the zeolite media was suggested to be around $900^{\circ}C$.