Molecular Dynamics Study Of Thermophysical Properties Of H₂ And H₂O/CO₂ Mixed Working Medium Under Supercritical Conditions

For the current energy structure in our country,the clean utilization of coal is an urgent problem to be solved,and the special physicochemical property of using supercritical water can be that the carbon in the coal quickly and efficiently reduces the hydrogen in the water to generate hydrogen,thus avoiding the coal Energy loss in the conventional conversion process and direct conversion of coal chemical energy to hydrogen energy.High concentrations of H₂ and CO₂ in the gasification products can be conveniently separated,enriched and used for producing high value-added chemical products.However,the PVT properties of the mixed working fluid after coal gasification are the preconditions for the optimization of the thermal system operation and the calculation of the variable working conditions of the mixed fluid turbine.However,no research has been done on the PVT properties of the mixed working fluid of H₂O/H₂ and H₂O/H₂/CO₂.In this paper,the PVT properties of H₂O/H₂ mixture were studied by molecular dynamics simulation and theoretical model prediction based on P-R equation.The molecular dynamics simulation was used to calculate the properties of H₂O/H₂/CO₂ternary mixed working fluid PVT nature.The main work of this paper is as follows:?1?PVT properties of pure water system are calculated by using the current water molecular force field model,and the calculation results are compared with the experimental results and IAPWS-IF97 series formula.Simultaneously,the simulation method is verified The water molecular force field model needed for further research is also optimized.?2?The system model of binary and ternary mixed working fluid is established,and the interaction model of binary and ternary mixed working fluid is established by using the mixing law and molecular force field model.?3?PVT properties of binary mixed working fluid were calculated by theoretical predictive model and molecular dynamics simulation based on PR equation,and the calculated results were compared with the experimental results to verify the simulation method used in this study,The validity of force field model and state equation.?4?For the first time,the molecular dynamics simulation of PVT properties of ternary mixture of H₂O/CO₂/H₂ was carried out,and the energy variation and RDF of the ternary mixed system were calculated and analyzed.