Clean Technology (청정기술)

The Korean Society of Clean Technology (한국청정기술학회)
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Experimental Study on the Agglomeration Characteristics of Coal and Silica Sand by addition of KOH

KOH 첨가에 의한 석탄 및 유동사의 응집특성에 대한 실험적 연구

  • Cho, Cheonhyeon (Carbon Neutral Technology R&D Department, Korea Institute of Industrial Technology) ;
  • Gil, Eunji (Carbon Neutral Technology R&D Department, Korea Institute of Industrial Technology) ;
  • Lee, Uendo (Carbon Neutral Technology R&D Department, Korea Institute of Industrial Technology) ;
  • Lee, Yongwoon (Carbon Neutral Technology R&D Department, Korea Institute of Industrial Technology) ;
  • Kim, Seongil (Carbon Neutral Technology R&D Department, Korea Institute of Industrial Technology) ;
  • Yang, Won (Carbon Neutral Technology R&D Department, Korea Institute of Industrial Technology) ;
  • Moon, Jihwan (Samcheok Thermal Power Plant, Korea Southern Power (KOSPO)) ;
  • Ahn, Seokgi (Samcheok Thermal Power Plant, Korea Southern Power (KOSPO)) ;
  • Jung, Sungmook (Samcheok Thermal Power Plant, Korea Southern Power (KOSPO)) ;
  • Jeong, Soohwa (Carbon Neutral Technology R&D Department, Korea Institute of Industrial Technology)
  • 조천현 (한국생산기술연구원 탄소중립산업기술부문) ;
  • 길은지 (한국생산기술연구원 탄소중립산업기술부문) ;
  • 이은도 (한국생산기술연구원 탄소중립산업기술부문) ;
  • 이용운 (한국생산기술연구원 탄소중립산업기술부문) ;
  • 김성일 (한국생산기술연구원 탄소중립산업기술부문) ;
  • 양원 (한국생산기술연구원 탄소중립산업기술부문) ;
  • 문지환 (한국남부발전 삼척빛드림본부 기술지원실 연소기술부) ;
  • 안석기 (한국남부발전 삼척빛드림본부 기술지원실 연소기술부) ;
  • 정성묵 (한국남부발전 삼척빛드림본부 기술지원실 연소기술부) ;
  • 정수화 (한국생산기술연구원 탄소중립산업기술부문)
  • Received : 2021.12.06
  • Accepted : 2021.12.22
  • Published : 2022.03.31
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Abstract

The agglomeration characteristics of coal and silica sand were investigated under various conditions using mixed samples consisting of coal, silica sand, and potassium hydroxide, which is an agglomeration accelerator. The samples were prepared by either physically mixing or using aqueous solutions. The experiments using the physically mixed powder samples were performed with a two hour reaction time. The results showed that the number of aggregates generated increased as the reaction temperature and the total potassium content increased. The experiments using aqueous solutions were performed at 880 ℃, which is the operating temperature of a fluidized bed boiler, and at 980 ℃, which assumes a local hot spot. The amount of agglomeration generated as the reaction time increased and the total potassium content increased was identified. In the experiment performed at 880 ℃, the amount of aggregate generated clearly increased with the reaction time, and in the experiment performed at 980 ℃, assuming a local hot spot, a large amount of aggregate was generated in a relatively short time. The aggregates became harder as the potassium content increased. When the total potassium content was less than 1.37 wt.%, the aggregates were weak at both temperatures and collapsed even with a slight impact. Additionally, the surface characteristics of the silica sand and ash aggregates were observed by SEM-EDS analysis. The analysis revealed a large amount of potassium at the bonding sites. This result indicates that there is a high possibility of aggregation in the form of a eutectic compound when the alkali component is increased.

본 연구에서는 석탄과 유동사 그리고 응집가속물질인 수산화칼륨(KOH)을 혼합한 시료를 이용하여 다양한 조건에서 응집특성을 파악하였다. 응집실험은 전기로에서 수행하였으며 샘플시료는 두 가지 방법으로 제작하였다. 첫 번째 방법은 수산화칼륨 분말시료를 석탄과 유동사에 물리적으로 혼합하는 방법이며 두 번째 방법은 수산화칼륨을 수용액으로 만들어 석탄과 유동사에 혼합하여 만드는 방법으로 제작하였다. 물리적으로 혼합한 분말시료 실험조건의 경우 동일 반응시간인 2시간 조건에서 다양한 반응온도와 총 칼륨 함량에 따른 실험을 수행하였다. 실험 결과 반응온도 및 총 칼륨 함량이 증가할수록 응집물 발생량이 증가하는 결과를 나타내었다. 수산화칼륨 수용액을 이용한 실험 조건은 일반적인 유동층 보일러의 운전온도인 880 ℃와 보일러 내 국부적인 고온 영역을 가정한 980 ℃ 조건에서 각각 수행하였다. 분말실험과 동일하게 반응시간 및 총 칼륨 함량 증가에 따라 생성되는 응집물 발생량을 파악하였다. 실험 결과 반응온도 880 ℃ 조건에서는 반응시간 증가에 따라 응집물 발생량 증가가 뚜렷하게 나타났다. 국부적인 고온 영역을 가정한 980 ℃ 조건에서는 상대적으로 짧은 시간 안에 많은 양의 응집물이 발생하는 결과를 보였다. 응집물의 굳기는 칼륨 함량이 증가할수록 점점 단단해지는 특성을 나타내었다. 총 칼륨 함량이 1.37 wt.% 이하일 경우 두 반응온도 모두에서 굳기가 약해 약한 충격에도 부서지는 결과를 보였다. 추가적으로 SEM-EDS 분석을 통해 유동사 응집물과 재 응집물의 표면특성을 관찰하였다. 분석 결과 융동사 응집물과 재 응집물 내 결합 위치에서 다량의 칼륨 성분이 검출되었다. 이 결과를 통해 알칼리성분이 많아질 경우 공융화합물 형태의 응집이 발생할 가능성이 높음을 파악하였다

Keywords

Acknowledgement

본 논문은 환경부의 재원으로 한국환경산업기술원의 "감염 우려 의료폐기물 처리 기술개발사업(No.2021003350008)"의 지원을 받아 수행되었으며 일부 남부발전에서 지원하는 "CFB 보일러 연료 유연성 확보를 위한 혼탄/바이오매스 운영 기술개발(과제번호 : IJ200024)"사업의 일환으로 진행되어 이에 감사드립니다.

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