Korean Chemical Engineering Research

  • 제45권1호
  • /
  • Pages.73-80
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  • 2007
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  • 0304-128X(pISSN)
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  • 2233-9558(eISSN)
한국화학공학회 (The Korean Institute of Chemical Engineers)
권호 표지

연속 회분식 반응기에서 최적 질소 제거를 위한 최적 궤적 찾기와 재최적화

Optimal Trajectory Finding and re-optimization of SBR for Nitrogen Removal

  • 김영황 (포항공과대학교 화학공학과) ;
  • 유창규 (경희대학교 환경응용화학대학 환경학 및 환경공학/환경연구센터) ;
  • 이인범 (포항공과대학교 화학공학과)
  • Kim, Young-Whang (Dept. of Chemical Engineering, POSTECH) ;
  • Yoo, ChangKyoo (Dept. of Environmental Science and Engineering/Center for Environmental Studies, College of Environmental and Applied Chemistry, Kyung Hee University) ;
  • Lee, In-Beum (Dept. of Chemical Engineering, POSTECH)
  • 투고 : 2006.10.09
  • 심사 : 2007.01.04
  • 발행 : 2007.02.28
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초록

본 연구는 생물학적 폐수 처리 공정인 연속 회분식 반응기(sequencing batch reactor, SBR)에서 질소 제거 최적화를 위해 활성 오니 공정모델(activated sludge model, ASM No.1, ASM1)과 반복 동적 프로그래밍(iterative dynamic programming, IDP)을 이용하여 SBR의 처리 기준을 만족하면서 최적 운전 조건을 탐색하고 하는 것을 목적으로 하였다. 연속 회분식 반응기의 최적화를 위해 에너지 최소화와 최소 회분 시간이 질소 처리의 농도 그래프의 면적과 비례하는 점을 이용하여 이를 고려한 새로운 performance index를 제안하였다. 회분 시간과 에너지에 대항하는 면적에 적절한 비중(weight)을 줌으로써 최소 회분 시간과 최소 에너지 문제를 동시에 고려하였다. SBR에서 IDP를 이용한 최적 운전서 최적 용존 산소 농도의 설정치가 전체 회분 시간과 전체 에너지 비용에 동시에 영향을 미침을 알 수 있었고 최적 운전시 기존의 운전 방법과 같은 유기물과 질소 제거가 가능하고 동시에 전체 비용을 20％까지 줄일 수 있었다. 더 나아가 공정이상으로 실제 공정이 모델과 다른 모델링 에러에 의해 잘못된 모사의 경우에도 IDP를 이용하여 다시 재최적화할 수 있음을 보였다.

This article aims to optimize the nitrogen removal of a sequencing batch reactor (SBR) through the use of the activated sludge model and iterative dynamic programming (IDP). Using a minimum batch time and a maximum nitrogen removal for minimum energy consumption, a performance index is developed on the basis of minimum area criteria for SBR optimization. Choosing area as the performance index makes the optimization problem simpler and a proper weighting in the performance index makes it possible to solve minimum time and energy problem of SBR simultaneously. The optimized results show that the optimal set-point of dissolved oxygen affects both the total batch time and total energy cost. For two different influent loadings, IDP-based SBR optimizations suggest each supervisory control of batch scheduling and set-point trajectory of dissolved oxygen (DO) concentration, and can save 20% of the total energy cost, while meeting the treatment requirements of COD and nitrogen. Moreover, it shows that the re-optimization of IDP within a batch can solve the modelling error problem due to the influent loading changes, or the process faults.

키워드

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