Design of natural gas hydrate inhibitors from a mechanistic understanding

I&EC 129

Brian Anderson, Brian.Anderson@mail.wvu.edu1, Gian Paolo Borghi2, Jefferson W. Tester2, and Bernhardt Trout, trout@mit.edu2. (1) Dept. of Chemical Engineering, West Virginia University, Morgantown, WV 26506, (2) Department of Chemical Engineering, MIT, Cambridge, MA 02139
With the charge of designing novel hydrate kinetic inhibitor molecules, a two-step mechanism for hydrate inhibition was proposed. Within this mechanistic framework, the energy of binding of four inhibitor molecules (PEO, PVP, PVCap, and VIMA) to a hydrate surface was estimated with molecular dynamic simulations. One key feature of this proposed mechanism is that the binding of an inhibitor molecule to the surface of an ensuing hydrate crystal disrupts growth and therein crystallization. It is found through the molecular dynamic simulations that inhibitor molecules that experimentally exhibit better inhibition strength also have higher free energies of binding, an indirect confirmation of our proposed mechanism. Inhibitors increasing in effectiveness have increasingly negative (exothermic) binding energies and binding free energies of increasing favorability. Equipped with this molecular-level understanding of the process of hydrate inhibition via low-dosage kinetic hydrate inhibitors we can design new, more effective inhibitor molecules.