Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Energy Conservation and Exergy Comparison of a Fully Thermally Coupled Distillation Column

열복합 증류탑의 에너지 절감과 엑서지 비교

  • 김병철 (동아대학교 화학공학과) ;
  • 김영한 (동아대학교 화학공학과)
  • Received : 2011.04.20
  • Accepted : 2011.05.31
  • Published : 2012.02.01
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Abstract

The energy conservation and exergy loss of a fully thermally coupled distillation commercialized as the divided wall column are compared with those of a conventional two-column system for ternary separation. The used example for the comparison is the benzene-toluene-m-xylene separation process widely used in a petrochemical plant. The design procedure of the fully thermally coupled distillation column is explained, and the energy requirement is compared using the HYSYS. When the same numbers of trays are utilized, the fully thermally coupled distillation column uses 28.2% less energy and 10.4% more exergy loss. The increase of the exergy loss is due to the additional mixing from the bidirectional inter-linking and the temperature elevation in the reboiler from the increased pressure at the bottom of the main column.

분리벽형 증류탑으로 상용화된 열복합 증류 시스템의 에너지 절약효과와 엑서지 손실을 기존의 3성분 분리 시스템인 2 탑 증류탑의 에너지 사용량 및 엑서지 손실과 비교하였다. 비교에 사용한 예제공정으로 석유화학 공장에서 보편적으로 사용하는 벤젠-톨루엔-m-자일렌 분리 공정을 대상으로 하였다. 본 연구에서는 열복합 증류탑의 설계방법을 제시하고 HYSYS를 이용하여 계산된 에너지 사용량을 비교하였다. 동일한 증류단수를 사용하였을 때 열복합 증류 시스템이 에너지 사용량을 28.2% 절감할 수 있음을 알았으며, 엑서지 손실은 10.4% 더 많았다. 엑서지 손실의 증가는 열복합 증류탑의 양방향 연결 흐름에 의한 증류단 내에서의 추가적인 혼합과 주탑 하부에서의 압력상승에 의한 재비기에서의 온도 상승이 주요 원인이다.

Keywords

Acknowledgement

Supported by : 동아대학교

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