**Selected Papers from PRES 2018 The 21st Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction**

Printed Edition of the Special Issue Published in *Energies* Jiří Jaromír Klemeš, Petar Sabev Varbanov, Paweł Ocłoń and Hon Huin Chin Edited by

www.mdpi.com/journal/energies
