Pinch Analysis is a methodology that allows the calculation of minimum hot and cold utilities consumption in a process from the knowledge of some data of the hot and cold streams. These energy targets are calculated through the Problem Table Method, that is based on the description of the process using constant heat capacity flowrates. This hypothesis is not valid in certain situations, particularly when phase changes are involved. A modification to Problem Table Method is proposed, that allows the use of enthalpies rigorously calculated from thermodynamic correlations. One case study is provided, where an error of 240% in hot target is verified if phase changes are neglected.
Pinch analysis; phase changes; enthalpies
