Integrating pinch analysis and process simulation within equation-oriented simulators

Process integration techniques may increase productivity and profitability while, at the same time, reducing environmental impacts. In this work, pinch analysis (one of the most popular energy-integration methodologies) was integrated into an equation-oriented simulator, providing energy integration in simulation time, without an external convergence loop. Based on four case studies, pinch analysis was showed to overestimate the optimal total annual cost within a maximum deviation of 10.7%, compared to superstructure-based optimization approaches, providing a near-optimal solution. This is well suited for the initial stages of process synthesis, where only rough estimates of process costs are sought. The methodology was also applied to a bioethanol biorefinery, containing more than 27,000 variables. Energy integration reduced steam consumption by up to 12.8%, increasing plant productivity. An additional advantage of the integrated pinch analysis is that it increased the robustness to the process simulation, by replacing heat exchangers by the pinch formulae. (C) 2019 Elsevier Ltd. All rights reserved.