An Extended Pinch Analysis and Design procedure utilizing pressure based exergy for subambient cooling

A new methodology for process synthesis extending traditional Pinch Analysis with exergy calculations is described. The methodology shows great potential for minimizing energy requirements (total shaft work) in subambient processes. This is achieved by optimizing compression and expansion work for the process streams together with the work needed to create necessary cooling utilities. The procedure, referred to as Extended Pinch Analysis and Design (ExPAnD), is illustrated by two examples, first in a simple example on how to utilize pressure based exergy in a cold stream for subambient cooling of a hot stream, then in the main example describing the use of the design methodology to develop a novel process for liquefaction of natural gas to LNG.