화학증기침투에 의한 촉매지지체용 C/SiC 복합체 제조에 관한 수치모사 연구

Studies on the Modeling of the Preparation of the C/SiC Composite for catalyst support by CVI

  • 이성주 (홍익대학교 화학공학과 대학원) ;
  • 김미현 (홍익대학교 화학공학과 대학원) ;
  • 정귀영 (홍익대학교 화학공학과)
  • 발행 : 2000.08.01

초록

본 연구에서는 촉매지지체의 내구성과 내산화성을 향상시키기 위해 활성탄소에 SiC층을 형성하는 것에 관한 수치모사가 수행되었다. 이염화이메틸규소(DDS)로부터 탄화규소를 활성탄소 기공의 내부에 침투 증착시켜 기공성 구조를 유지하면서 활성탄소에 SiC층이 형성된다. 여러 다른 증착 조건에서 모사된 탄화규소의 물성을 연구함으로써 지지체 제조의 최적 증착 조건을 결정하였다. 정상상태하의 등온 반응기 안에서 대류, 확산 및 반응을 모사하여 시간의 경과에 따른 증착량, 기공 반경, 표면적의 변화 등을 구하였다. DDS의 농도가 낮고 반응압력이 작을수록 시료 기공내에 고른 증착이 얻어졌다. 또한 기공내부 증착에서 입자외부 표면 증착으로 바뀌므로 기공직경과 표면적들이 어느 시점에서 변곡점을 갖는 것이 관찰되었다.

In this research, the mathematical modeling of the formation of SiC layer on the activated carbon was studied to improve the durability and the oxidation resistance of catalyst supports. SiC layer on the activated carbon was formed by permeating SiC from dichlorodimethylsilane(DDS) into pores and depositing while the porous structure was kept. The best conditions of manufacturing the support were found by studying the characteristics of SiC/C which was modelled under various deposition conditions. Changes of the amount of deposition, the pore diameter, the surface area with time were obtained by simulating convection, diffusion and reaction in an isothermal reactor at a steady state. The uniform deposition in the pores of samples was obtained at a lower concentration of the reactant and a lower pressure. Additionally, it was observed that the pore diameter and the surface area have points of inflection at certain times of deposition, because deposition occurred on the inside surface of the pore at first and then on the outside surface of the particle.

키워드

참고문헌

  1. Application of Chemical Vapour Deposition in Catalyst Design (1st Ed.) Moene R.
  2. J. Chem. Phys. v.67 The Impotance of Active Surface Area in the Carbon-Oxygen Reaction Laine N.R.;Vastola F.J.;Walker P.L.
  3. Proc. Carbon '88, Internt. Carbon Conf. v.27 no.3 The Effect of Acid Treatments on Subsequent Reactivity of Carbon-Carbon Composites Murdie N.;Hippo E.J.;Kowbel W.
  4. J. Proc. Carbon '88, Internt. Carbon Conf Vast P.;Palavit G.;Montagne;L. Boulliez;J.L.
  5. Scientific bases for the Preparation of Heterogeneous Catalysts (4th ed.) v.1 Moene R.;Kramer L.F.;Schoonman J.;Maakkee M.;Moulijin J.A.
  6. Chem. Eng. Sci. v.47 no.2 Chemical vapor infiltration;Modelling solid matrix deposition for ceramic composites with layered deposition for ceramic Chung G.Y.;McCoy B.J.;Smith J.M.;Cagliostro D.E.
  7. J. Am. Ceram. Soc. v.74 no.4 Modelling of chemical vapor infiltration for ceramic compos-ites reinforced with layered woven fabrics Chung G.Y.;McCoy B.J.
  8. J. Mater. Sci. v.27 Pulsed Chemi-cal Vapour Infiltration of TiN into a Fine Silica Capillary Sealed at One End Sugiyama K.;Kurisu Y.