Impact of environmental variables on hydrate formation kinetics in porous media systems and their contribution to CO_(2) capture and storageOA

Global dependence on fossil fuels has led to escalating atmospheric carbon dioxide emissions.The consecutive greenhouse effect poses a serious threat to the human habitat,rendering carbon dioxide abatement a key focus in contemporary research.Hydrate-based CO_(2) sequestration offers a promising pathway for carbon capture and storage,though its efficiency is strongly influenced by pressure,salinity,and sediment properties.In this study,the kinetic characteristics and occurrence states of CO_(2) hydrates in porous media were systematically investigated under varying pressures(3.0-3.6 MPa),NaCl concentrations(0-3.5%),and sediment types(quartz sand vs kaolinite).Results reveal a non-linear pressure dependence—gas storage capacity increases by 16.3%as pressure rises from 3.0 MPa to 3.3 MPa,but diminishes to 9.4%with further increase to 3.6 MPa.NaCl exhibits dual inhibitory effects:Thermodynamically shifting the phase equilibrium leftward in the P-T domain and kinetically suppressing growth,with 3.5%NaCl systems exhibiting persistently slow hydrate formation.Sediment type also plays a critical role,as kaolinite''s low-permeability clay structure substantially impedes hydrate formation compared to quartz sand while altering hydrate distribution patterns.Understanding the interplay between pressure-driven efficiency gains and inhibitor-mediated stability control across diverse geological environments is essential for optimizing hydrate-based CO_(2) storage strategies.