Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Study on the Stability of NaBH4 Solution during Storage Process

NaBH4수용액 저장과정 중 안정성에 관한 연구

  • Sim, Woojong (Department of Chemical Engineering, Sunchon National University) ;
  • Jo, Jaeyoung (Department of Chemical Engineering, Sunchon National University) ;
  • Choi, Daeki (Fuel Cell Research Center, Korea Institute of Science and Technology) ;
  • Nam, Sukwoo (Fuel Cell Research Center, Korea Institute of Science and Technology) ;
  • Park, Kwonpil (Department of Chemical Engineering, Sunchon National University)
  • 심우종 (순천대학교 화학공학과) ;
  • 조재영 (순천대학교 화학공학과) ;
  • 최대기 (한국과학기술연구원 연료전지센터) ;
  • 남석우 (한국과학기술연구원 연료전지센터) ;
  • 박권필 (순천대학교 화학공학과)
  • Received : 2010.02.04
  • Accepted : 2010.03.01
  • Published : 2010.06.30
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Abstract

Stability of sodium borohydride solution during storage was studied. In order to enhance the $NaBH_4$ stability, NaOH and KOH were added to the $NaBH_4$ solution. The effect of concentration of the borohydride and alkaline solution, temperature and materials of storage vessels on the rate of borohydride hydrolysis was investigated. The rate of hydrogen evolution decreased as the concentration of alkaline increased due to increase of $NaBH_4$ stability in the solution. The stability of $NaBH_4$ solution decreased when the borohydride concentration raised from 10 to 15 wt% and then increased when the $NaBH_4$ concentration increased above 15 wt% due to increase in the pH of the concentrated solution. The activity coefficient of hydrolysis of $NaBH_4$ solution(NaOH 3.0 wt%, $NaBH_4$ 25 wt%) was 115.1 kJ/mol and this value was 1.5~4.0 times higher than that of hydrolysis of $NaBH_4$ solution with catalyst. The borohydride solutions in glass and stainless-steel vessel were more stable than the solution in plastic(PE) vessel.

수소발생용으로 사용되는 $NaBH_4$ 수용액의 저장과정 중에 $NaBH_4$ 안정성에 대해 연구하였다. $NaBH_4$의 안정성을 증가시키기 위해 NaOH와 KOH를 사용하였으며, $NaBH_4$의 저장 중 가수분해반응에 미치는 알칼리와 $NaBH_4$ 농도, 온도 그리고 저장 용기 재질의 영향을 실험하였다. 알칼리농도가 증가할수록 $NaBH_4$가 수용액 중에서 안정화되기 때문에 수소발생 속도가 감소하였다. $NaBH_4$ 농도를 10에서 15 wt%로 증가시켰을 때 안정성이 감소하다 15 wt% 이상으로 농도를 증가시켰을 때는 pH의 증가에 의해 안정성이 증가하였다. $NaBH_4$ 농도를 25 wt%, NaOH 3.0 wt%일 때 수소발생 활성화 에너지 값은 115.1 kJ/mol 로 촉매를 사용했을 때보다 활성화 에너지 값이 1.5~4.0배 높았다. 유리나 스텐리스-스틸에 저장된 $NaBH_4$ 용액의 안정성이 플라스틱에 저장된 $NaBH_4$ 용액의 안정성보다 더 높았다.

Keywords

References

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