Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Comparative Characterization of AFC Precipitated Using Vacuum Drying, Dilution Precipitation and Spray Drying

감압건조, 희석침전, 분무건조 방식으로 제조된 무회분석탄의 특성

  • Kwon, Ho Jung (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Choi, Ho Kyung (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Jo, Wan Taek (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Kim, Sang Do (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Yoo, Ji Ho (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Chun, Dong Hyuk (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Rhim, Young Joon (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Lim, Jeong Hwan (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Lee, Si Hyun (Clean Fuel Laboratory, Korea Institute of Energy Research) ;
  • Rhee, Young Woo (Graduate School of Energy Science and Technology, Chungnam National University)
  • Received : 2015.06.10
  • Accepted : 2015.10.01
  • Published : 2016.04.01
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Abstract

Solid ash-free coal (AFC) samples recovered from solvent-extracted solution by vacuum drying, dilution precipitation and spray drying methods were compared in terms of physical properties and chemical structure. AFC was prepared by using Kideco coal (Indonesian sub-bituminous coal) and polar N-methyl-2-pyrrolidone (NMP) solvent as raw materials. The physical properties of the AFCs were characterized with proximate, ultimate, and calorific value analysis. In analyzing the chemical structure, FTIR and NMR were used. the proximate analysis showed much reduced ash in the AFCs compared to parent raw coal. The FTIR result showed that the extraction solvent was not fully removed from the AFC prepared by vacuum drying. However, the solvent was not detected in the AFC recovered by using dilution precipitation. Dilution precipitation has advantages over the other two methods, since it can be done at relatively low temperature and separate ash-free coal from extraction solvent more effectively.

본 연구에서는 용매추출 공정 중 최종 건조 과정에서 회수방식을 달리하여 무회분석탄을 제조한 후 물리적 특성과 화학적 구조를 비교하였다. 무회분석탄 제조에는 아역청탄 등급의 Kideco coal과 극성용매인 N-methyl-2-pyrrolidone(NMP)를 사용하였으며, 회수방식으로는 감압건조, 희석침전, 분무건조 방식을 사용하였다. 제조된 무회분석탄의 물성변화를 확인하기 위해 공업분석, 원소분석, 발열량분석을 실시하였고, 화학적 구조를 알아보고자 FT-IR, NMR 분석을 하였다. 공업분석을 통해 무회분석탄의 회분함량이 원탄에 비해 줄어든 것을 확인하였다. FT-IR 분석 결과 감압건조로 회수한 샘플은 추출용매의 피크가 나타나는 반면 희석침전방식으로 제조한 무회분석탄에는 추출용매 피크가 사라지는 것을 확인하였다. 희석침전방식을 사용할 경우 다른 회수방식에 비해 저온공정이 가능하였고, 추출용매로부터 무회분석탄을 보다 확실하게 분리할 수 있었다.

Keywords

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