Title: Analysis of thermal system network of an ammonia plant using genetic algorithms - part II: network modification

Authors: N.K. Chavda; P. Prabhakaran

Addresses: Mechanical Engineering Department, Madhuben and Bhanubhai Patel Women's Institute of Engineering, New Vallabh Vidyanagar – 388 121, Anand, Gujarat, India. ' Mechanical Engineering Department, Faculty of Technology and Engineering, The M.S. University of Baroda, Kala Bhavan, Vadodara, Gujarat, India

Abstract: This part of the paper examines two options of modification of the HEN of the ammonia plant based on two methods of pinch analyses, viz., network pinch method (NPM) and retrofitting analysis (RA) using genetic algorithms for both ΔT_min and Q_min approaches. Using NPM with ΔT_min and Q_min approaches, it is seen that there is a scope for reduction in hot and cold utilities by 1,758 kW and subsequently reduction in area of HEN by 368 m² and 136 m² which results in decrease of total annual cost by 1.71% and 1.30% respectively. Amongst the combination of modification, it is also found that using NPM with ΔT_min approach, the hot and cold utility requirements for existing area efficiency and ideal area efficiency can be reduced with a payback period of 1.69 years and 0.80 years respectively.

Keywords: thermal system network; heat exchanger networks; network modification; pinch technology; genetic algorithms; GAs; modification techniques; ammonia plant; network pinch method; retrofitting analysis; heat exchangers.

DOI: 10.1504/IJPSE.2012.051010

International Journal of Process Systems Engineering, 2012 Vol.2 No.2, pp.111 - 134

Received: 13 May 2011
Accepted: 22 Aug 2011
Published online: 16 Aug 2014 *

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