R. Lakshmanan et R. Banaresalcantara, RETROFIT BY INSPECTION USING THERMODYNAMIC PROCESS VISUALIZATION, Computers & chemical engineering, 22, 1998, pp. 809-812
Although grassroots Heat Exchanger Network (HEN) Synthesis has receive
d much attention in the literature, relatively little research has foc
used on the retrofit problem, which comprises the vast majority of rea
l industrial cases. Attempts at rigorous automation (Ciric and Floudas
, 1989; Yee and Grossmann, 1991) have met with limited success primari
ly because of the excessive computational costs associated with this p
roblem when formulated as a Mixed-integer Nonlinear Program (MINLP). O
ther approaches (Briones and Kokossis 1995; Tjoe, 1986; and Asante, 19
96) make simplifying assumptions which are only appropriate for restri
cted classes of problems. The research described here has focused on t
he development of a visualisation tool, the Retrofit Thermodynamic Dia
gram (RTD), and a set of guidelines for developing retrofit solutions
by inspection. The method relies heavily on the ingenuity of the desig
ner, but has proved to be very flexible - handling a wide variety of p
roblem formulations. It has produced designs that are significantly su
perior to published solutions, ranging from 85% additional energy savi
ng - for the same payback period - (Lakshmanan and Banares-Alcantara,
1996) to a 70% reduction in capital cost (for the same level of energy
saving). (C) 1998 Elsevier Science Ltd. All rights reserved.