Ranking the Efficiency of Gas Hydrate Anti-agglomerants through Molecular Dynamic Simulations
Stephan Mohr, Felix Hoevelmann, Jonathan Wylde, Natascha Schelero, Juan Sarria, Nirupam Purkayastha, Zachary T. Ward, Pablo Navarro Acero, Vasileios K. Michalis
Abstract
Using both computational and experimental methods, the capacity of four different surfactant molecules to inhibit the agglomeration of sII hydrate particles was assessed. The computational simulations were carried out using both steered and non-steered molecular dynamics (MD), simulating the coalescence process of a hydrate slab and a water droplet, both covered with surfactant molecules. The surfactants were ranked according to free energy calculations (steered MD) and the number of agglomeration events (non-steered MD). The experimental work was based on rocking cell measurements, determining the minimum effective dose necessary to inhibit agglomeration. Overall, good agreement was obtained between the performance predicted by the simulations and the experimental measurements. Moreover, the simulations allowed us to gain additional insights that are not directly accessible via experiments, such as an analysis of the mass density profiles, the diffusion coefficients, or the orientations of the long tails.