3 years ago

Molecular Dynamics Analysis of Anti-Agglomerant Surface Adsorption in Natural Gas Hydrates

Molecular Dynamics Analysis of Anti-Agglomerant Surface
Adsorption in Natural Gas Hydrates
Bernhardt L. Trout, Michael A. Bellucci, Matthew R. Walsh
We have used molecular dynamics simulations to examine the surface adsorption of a model anti-agglomerant inhibitor (quaternary ammonium salt) binding to a hydrate surface in both aqueous and liquid hydrocarbon phases. From our molecular dynamics simulation data, we were able to identify the preferred binding sites on the (111) crystal face of a methane–propane sII hydrate as well as characterize the equilibrium binding configurations of the inhibitor and their associated binding energies. In the aqueous phase, we observed that the inhibitor proceeds through a two-step surface adsorption mechanism, whereas in the liquid hydrocarbon phase surface adsorption occurs through a single-step mechanism. To characterize the extent of surface adsorption in each liquid phase, we calculated the standard binding free energy using the free energy perturbation method following a double decoupling thermodynamic cycle. We found that the surface adsorption in the liquid hydrocarbon phase is an exergonic process, whereas the surface adsorption in the aqueous phase is an endergonic process. Our results demonstrate that the extent of surface adsorption is much larger in the liquid hydrocarbon phase relative to the aqueous phase and suggest that the inhibitor is less effective in the aqueous phase because the surface adsorption is less favorable. Finally, we examine the effect of the inhibitor on the water structure in the liquid phase and in the hydrate phase, with the results highlighting the difference between the nature of anti-agglomerant/hydrate interactions as compared to kinetic inhibitor/hydrate interactions.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b09573

DOI: 10.1021/acs.jpcc.7b09573

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.