Properties of Cenosphere Particle in the Fly Ash Generated from the Pulverized Coal Power Plant

석탄화력 발전소에서 생성되는 석탄회에서 Cenosphere 입자의 특성에 관한 연구

Cenosphere particles of different fly ash formed at the pulverized coal power plant were hollow sphere or filled with small particles inside solid particles. And size was relatively larger than other fly ash particles as well as specific gravity was small to suspend in the water. In this paper, it was demonstrated to contain a variety of morphological particle type, and the physical and chemical properties related to the cenosphere and fly ash particles. Furthermore it was estimated the possibility to reuse the cenosphere particles on the base of cenosphere properties. Cenosphere formation resulted from melting of mineral inclusion in coal, and then gas generation inside the molten droplet. As the aluminosilicate particle was progressively heated, a molten surface layer developed around the solid core. Further heating leaded to cause the formation of fine particles at the core. The mass median diameter(MMD) of cenosphere particles was $123.11{\mu}m$ and the range of size distribution was $100{\sim}200{\mu}m$ with single modal. It was represented that specific density was $0.67g/cm^3$ fineness was $1135g/cm^3$. The chemical components of cenosphere were similar to other fly ash including $SiO_2$, $Al_2O_3$, but the amount of the chemical component was different respectively. In the case of fly ash, $SiO_2$ concentration was 54.75%, and $Al_2O_3$ concentration was 21.96%, so this two components was found in 76.71% of the total concentration. But in the case of cenosphere, it was represented that $SiO_2$ concentration was 59.17% and $Al_2O_3$ concentration was 30.16%, so this two components was found in 89.33% of the total concentration. Glassy component formed by the aluminosilicate was high in the cenosphere, so that it was suitable to use insulating heat material.

석탄화력 발전소에서 석탄이 연소되면서 생성된 석탄회 중 Cenosphere는 속이 비어 있거나 미세 입자들로 채워져 있고 입자의 크기가 큰 구형의 입자로 물에 부유할 정도로 비중이 작을뿐만 아니라 입자의 벽면에 유리질 성분이 많은 입자이다. 본 연구는 Cenosphere 입자에 대한 형성메카니즘을 분석하여 형태적, 물리적, 화학적 특성을 파악하였다. Cenosphere는 석탄이 연소하면서 입자의 내부에서 발생된 가스가 밖으로 방출되면서 형성되기 때문에 입자가 부풀어져 크게 되고 가스의 분출로 입자의 표변에 구멍이 발생하며 알루미노실리케이트 (Aluminosilicate) 성분에 의해 형성된 기포가 용융표면층에 부착되어 Cenosphere내부에 미세 입자들을 형성한다. 이와 같온 입자의 형성메카니즘 특성 때문에 분말성이 좋으면서 가볍고 큰 입자를 형성한다. Cenosphere의 입도분포는 $100{\sim}200{\mu}m$에 집중된 Single Modal로 질량중앙직경은 $123.11{\mu}m$이고 비중은 $0.67g/cm^3$, 분말도는 $1,135g/cm^3$으로 분석되었다. 또한 Cenosphere의 입자를 구성하는 성분 중 $SiO_2$는 59.17%, $Al_2O_3$는 30.16%로 전체의 89.33%를 차지하고 있고 있어 알루미노실리케이트 성분, 즉 유리질 성분이 높아 열절연성이 뛰어나다. 따라서 Cenosphere 입자를 실리카 바인더로 입자를 결합하면 다양한 온도에서 사용할 수 있는 우수한 열절연체를 만들 수 있어 재활용 원료로 활용이 가능하다.