Due to their high computational efficiency, the coarse-grained water models are of particular importance for practical molecular simulations of gas hydrates. In these models, the mW model is successfully used to study many thermodynamics and dynamics of methane hydrate. Yet, despite several decades of intense research, the mW model is still found to overestimate the melting temperature of methane hydrate. We here employ the minimum mean squared error estimation to revisit the key parameter of the mW model, which determines the strength of the tetrahedral angle of the water system. Relying on the free energy calculations, we first estimate the chemical potentials of water in the liquid phase for temperatures at which methane hydrate forms. We then turn to the mean squared error to describe the chemical potential deviation between the mW model and the TIP4P/ice model (the latter could reproduce the experimental phase diagram of methane hydrate). By minimizing the mean squared error, we finally have an optimized parameter for the mW model. In this part, we also discuss the pressure effect on such reparameterization procedure. Moreover, relying on the direct coexistence method, the melting temperature determined using the reparameterized mW model is found to be consistent with the experimental data. This strategy provides a means to improve the coarse-grained model to match the experimental observations for temperatures in the range of interest.
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http://dx.doi.org/10.1063/5.0228522 | DOI Listing |
Microorganisms
December 2024
Sanya Institute of South China Sea Geology, Guangzhou Marine Geological Survey, China Geological Survey, Sanya 572025, China.
In this study, we use petroleum systems modeling (PSM) to quantitatively simulate the uncertainty of biogenic gas generation modes and their impact on the spatial distribution and resource assessment of gas hydrates in the Baiyun Sag, South China Sea. The results are as follows: (1) Biogenic gas generation is significantly affected by thermal state and organic matter type. Low temperature is a primary reason for gas hydrate occurrence in shallower sediments when sufficient methane gas is present.
View Article and Find Full Text PDFGels
December 2024
Shandong Engineering Laboratory for Preparation and Application of High-Performance Carbon-Materials, College of Electromechanical Engineering, Qingdao University of Science & Technology, Qingdao 266061, China.
Developing an exceptional reaction medium with high promotion efficiency, desirable biodegradability and good recyclability is necessary for hydrate-based methane storage. In this work, a kind of eco-friendly hydrogel, polyvinyl alcohol-co-acrylic acid (PVA-co-PAA), was utilized to absorb dilute sodium p-styrenesulfonate (SS) solution, for constructing a hybrid reaction medium for methane hydrate formation. Hydrogels or dilute SS solutions (1-4 mmol L) had weak or even no promoting effects on hydrate formation kinetics, while the combination of them could synergistically promote methane hydrate formation.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Laboratory of Theoretical Biophysics, School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China.
The formation of natural gas hydrates presents significant economic and safety challenges to the petroleum and gas industry, necessitating the development of effective prevention strategies. This study investigates an environmentally sustainable Tenebrio molitor antifreeze protein (TmAFP) modified to be a potential kinetic hydrate inhibitor. The aim of this study was to enhance the inhibitory activity of TmAFP by systematically substituting threonine (Thr) residues with glycine (Gly), alanine (Ala), or serine (Ser) at positions 29, 39, and 53.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Faculty of Metals Engineering and Industrial Computer Science, AGH University of Krakow, Mickiewicza 30, 30-059 Krakow, Poland.
The modern metallurgical industry produces approximately 90% of the volume of all produced steel; for this, integrated technology based on fossil materials such as coal, fluxes, and especially iron ore is used. This industry generates large amounts of waste and by-products at almost all stages of production. Alternative iron and steel production technologies based on iron ore, methane, or pure hydrogen are also not waste-free.
View Article and Find Full Text PDFSci Total Environ
January 2025
Research Centre of Ecology & Environment for Coastal Area and Deep Sea, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, Guangdong University of Technology, Guangzhou 510006, China. Electronic address:
Methane leaking from the deep seabed is a primary source of carbon and energy for various microorganisms, sustaining the evolution and productivity of cold seep ecosystems. However, the dynamics of methane hydrate formation under methane seepage conditions and potential impacts on the evolution of cold seep ecosystems remain unclear. This study investigated the dynamic formation characteristics of gas hydrates within cold seep sediments by simulating the methane leakage process.
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