• 청정기술
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• 제22권4호
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• pp.299-307
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• 2016

These days, coal is one of the most important energy resources used for transportation, industry, and electricity. There are two types of coal: high-rank and low-rank. Low-rank coal has a low calorific value and contains large amounts of useless moisture. The quality of low-rank coal can be increased by simple drying technology and it needs to be stabilized by hydrocarbons (e.g. palm acid oil, PAO) to prevent spontaneous combustion and moisture re-adsorption. Spontaneous combustion becomes a major problem during coal mining, storage, and transportation. It can involve the loss of life, property, and economic value; reduce the quality of the coal; and increase greenhouse gas emissions. Besides spontaneous combustion, moisture re-adsorption also leads to a decrease in quality of the coal due to its lower heating value. In this work, PAO was used for additive to stabilize the upgraded coal. The objectives of the experiments were to determine the stabilization characteristic of coal by analyzing the behavior of upgraded coal by drying and PAO addition regarding crossing-point temperature of coal, the moisture behavior of briquette coal, and thermal decomposition behavior of coal.

• 한국식품영양과학회지
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• 제30권1호
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• pp.1-5
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• 2001

This study was carried out to isolate saponin compounds from red-ginseng efflux, which was produced during the industrial processing of red-ginseng from fresh ginseng. We isolated crude saponin from the efflux extract (moisture content 35.0%) by using Diaion HP-20 adsorption method. Non-saponin fraction, which was adsorbed on Diaion HP-20 resin, was removed by eluating with $H_{2}O$ and 25% spirit. Then crude saponin was eluated with 95% spirit, continuously. Saponin in the eluated fractions was confirmed by TLC analysis. Crude saponin isolated from red ginseng efflux extract contained 12.10% of saponin. whereas those of white ginseng and red-ginseng were 3.30 and 3.39%, respectively. Ginsenoside contents showed the highest contents kin crude saponin from red ginseng efflux extract. Expacilly, the ginsenoside-$Rb_{1}$ and Re showed the highest contents in red-ginseng efflux extract when compared with those of white ginseng and red ginseng crude saponins. And the other ginsenosides except ginsenoside-$Rb_{1}$ and -Re also showed the highest contents in red ginseng efflux extract. However, the ratio of PD saponin (Panaxadiol saponin: $Rb_{1}+Rb_{2}$+Rc+Rd) to PT saponin (panaxatriol: $Re+Rg_{1}$) showed almost the same level when compared with those of ginseng saponin fractions. Ratio of PD/PT from red ginseng efflux extract was 1.99. Ratios of PD/PT from white ginseng and red ginseng were 1.85 and 1.84, respectively. Saponin purity, which was calculated by ratio percent of total ginsenoside to curde saponin content, was 45.90%. In case of white ginseng and red ginseng, the purities were 35.50 and 36.00%, respectively. However, by PHLC analysis, we confirmed that crude saponin isolated from red ginsengs. It suggested that crude saponin isolated from red ginseng ellux also would be useful component as ginseng saponins.

• Korean Chemical Engineering Research
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• 제51권5호
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• pp.609-614
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• 2013

본 연구에서는 유기용매를 이용하여 표면처리한 저등급 석탄의 물성과 자연발화성 변화를 알아보았다. 석탄은 인도네시아 갈탄인 KBB탄과 SM탄 그리고 아역청탄인 Roto탄을 사용하였으며, 비극성 유기용매인 1-methyl naphthalene (1 MN)과 혼합한 후 단순 회전 임펠러 또는 초음파를 이용하여 일정 시간동안 교반하였다. 1MN 처리탄의 물성 변화는 공업 분석, 발열량 분석, FT-IR 분석, XPS 분석, 그리고 수분 재흡착 실험을 통해 알아보았으며, 자연 발화성 변화는 Crossing-Point Temperature 분석과, 산화에 의해 발생되는 CO, $CO_2$ 가스 분석을 통해 확인하였다. FT-IR 분석 결과 처리탄들의 수소와 산소를 포함한 결합기들이 줄었다. XPS분석 결과 원탄들에 비해 처리탄들의 C-O, C=O 그리고 COO- 피크는 감소하고 C-C 피크는 상대적으로 증가하였다. 그리고 수분 재흡착성 측정 결과 처리탄들 표면의 소수성이 증가함을 확인하였다. CPT 측정 결과 원탄들에 비해 처리탄들의 CPT 값이 $20^{\circ}C$ 이상 증가하였는데, 단순 기계적 교반보다 초음파 교반 방식으로 처리한 석탄의 CPT 값이 높았다. 이때 배출되는 가스의 분석에서도 처리탄들이 원탄들에 비해 CO와 $CO_2$ 가스 발생량이 적고 발생 시점이 늦어져 자연발화성이 억제되는 것으로 나타났다. 이는 석탄을 유기용매로 처리함으로써 미리 산화반응에 참여하는 표면의 기능기들이 제거되어 자연발화성이 억제되는 것이며, 이에 단순 기계적 교반 방식보다는 초음파 교반 방식이 보다 효과적임을 확인하였다.