가압반응기를 이용한 배연탈황석고로부터 α형 반수석고의 생성

박승수; 김기형; 안희수; 박광규; Seung-Soo Park; Ki-Hyoung Kim; Hi-Soo An; Kwang-Kyu Park

Journal of the Korean Industrial and Engineering Chemistry, Vol.17, No.6, 619-624, December, 2006

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가압반응기를 이용한 배연탈황석고로부터 α형 반수석고의 생성

Preparation of Calcium Sulfate α-Hemihydrate from FGD Gypum in the Autoclave

박승수^†, 김기형, 안희수, 박광규

한국전력공사 전력연구원 환경구조연구소 환경화학그룹

Seung-Soo Park^†, Ki-Hyoung Kim, Hi-Soo An, and Kwang-Kyu Park

Environment & Chemistry Research Group, Environment Structure Engineering Laboratory Korea Electric Power ResearchInstitute, Korea Electric Power Corporation, Daejeon 305-380, Korea

E-mail:

초록

유연탄을 연소하는 화력발전소의 탈황설비에서 생산된 배연탈황석고를 대상으로 가압반응기를 이용하여 수열반응을 통한 알파형 반수석고의 생성과정을 살펴보았다. 실험 결과 첨가제를 사용하지 않아도 반응온도 120∼140 ℃ 범위 하에서는 용해-재석출 기구에 의하여 알파형 반수석고가 생성되었으나 아스펙트 비가 매우 높은 침상형 결정이 생성되었다. 호박산나트륨을 첨가제로 주입한 결과 결정형상은 침상형에서 각주형으로 변화되었으며 혼수 비(water/powder ratio)는 33%까지 감소하였다. 호박산나트륨의 농도는 20 mM이 적정하였으며 반응도중 성형체의 붕괴를 방지하고 성형체의 기공부피에 의한 모세관 효과를 최대화하기 위한 최적의 성형체 성형압력은 30 kgf/cm2이었다.

This study was performed to investigate the formation process of calcium sulfate α-hemihydrate from FGD gypsum produced at thermal power plant burning bituminous coal. The experimental results showed that calcium sulfate α-hemihydrate with a large aspect ratio was produced in the temperature range of 120 ℃ and 140 ℃ in the absence of additives through dissolution-recrystallization mechanism. It was also observed that addition of Na-succinate as a catalyst changed crystal shape from acicular to prismatic, resulting in decreased water/powder ratio down to 33%. Optimum concentration of Na-succinate was 20mM. It was confirmed that the optimum moulding pressure and moisture content of moulded body from FGD gypsum were 30kgf/cm2 and between 10% and 15% respectively, which prevent moulded body from collapsing and maximize the capillary effect by given pore volume while autoclaving.

Keywords:FGD;gypsum;α-hemihydrate;moulded body;autoclave

[References]

Park SS, The present state of FGD system and development of technological standard for FGD, proceedings of 2006 KEPICWEEK conference (2006)
US Patent 5,273,581 (1993)
US patent 5,015,450 (1991)
Kudo Y, Yamazaki A, Gypsum & lime, Low cost α-calcium sulfate hemihydrate manufacturing process, 241, 35 (1992)
US patent 0164281 (2002)
Freyer D, Voigt W, Crystallization and phase stability of CaSO4 and CaSO4-based salts, Chemical Monthly, 134, 693 (2003)

[1] Park SS, The present state of FGD system and development of technological standard for FGD, proceedings of 2006 KEPICWEEK conference (2006)

[2] US Patent 5,273,581 (1993)

[3] US patent 5,015,450 (1991)

[4] Kudo Y, Yamazaki A, Gypsum & lime, Low cost α-calcium sulfate hemihydrate manufacturing process, 241, 35 (1992)

[5] US patent 0164281 (2002)

[6] Freyer D, Voigt W, Crystallization and phase stability of CaSO4 and CaSO4-based salts, Chemical Monthly, 134, 693 (2003)