Application of the bio-inspired Krill Herd optimization technique to phase equilibrium calculations

• Krill Herd and modified Krill Herd algorithm applied to phase equilibria problems.
• Phase stability and equilibrium for non-reactive and reactive problems are considered.
• Algorithms benchmarked against metaheuristic techniques.
• The original Krill Herd algorithm yielded best performance.

The Krill Herd optimization technique, which is based on the simulated herding behaviour of the krill crustacean, is applied to calculations involving phase equilibrium and phase stability, as the application of this emerging technique is extremely limited in the literature. In this work, the Krill Herd algorithm (KH)1 and the modified Lévy-flight Krill Herd algorithm (LKH)2 has been applied to phase stability (PS)3 and phase equilibrium calculations in non-reactive (PE)4 and reactive (rPE)5 systems, where global minimization of the total Gibbs energy is necessary. Several phase stability and phase equilibrium systems were considered for the analysis of the performance of the technique that includes both vapour and liquid phase conditions.The Krill Herd algorithm was found to reliably determine the desired global optima in PS, PE and rPE problems with generally higher success rates and lower computing time requirements than previously applied metaheuristic techniques such as those involving swarm intelligence and genetic and evolutionary algorithms.