Masataka Kosaka

Dew and frost point estimation of residual water in high pressure hydrogen for conditions of hydrogen filling stations.

In hydrogen stations for fuel cell vehicles, a rapid filling process of high pressure hydrogen to a tank on the vehicle is requested, and there are some concerns that possible condensation of residual water at a low temperature section in the fuelling system leads to occlusion in pipes or instability of flow system. In the present investigation, dew and frost point measurement system for residual water in high pressure hydrogen utilizing cooled mirror technique with original image analysis had been designed and developed. Frost point measurements with hydrogen-water standard gases under conditions of 5~10 MPa, 1.5~55 ppm were carried out systematically. Frost point estimation procedures were also developed utilizing two types of equations of states, and experimental data with conditions of low water concentration and high total pressure were quite well in agreement with prediction data. Interaction parameters in the equations of states were also determined by new frost point data. [

Dew and Frost Points Measurements and Estimation for Residual Gases in High-Pressure Hydrogen

Dew and frost points estimation procedure for phase equilibrium systems with solid phases as condensed phases was developed utilizing Peng-Robinson equation of state (PR-EOS), and estimation for H2 +H2 O systems corresponding to actual hydrogen stations of pressure up to 70 MPa were carried out. It became clear that condensable components in hydrogen stations were only water. Dew and frost point measurement system with high pressure test cell utilizing cooled mirror technique with original visible image analysis were designed and produced. The system was designed available for frost point temperature below −50 °C, and total pressure of system up to 10 MPa. Pressure tight test cell with view port was installed separately from the optics, and had extensible design available for higher pressure experiments up to 40 MPa. Dew and frost points measurements with several compositions of H2 +H2 O standard gases were carried out. Frost point data obtained by the present measurement system with pressure tight test cell had good repeatability, and obtained binary interaction parameter kij was small value with the negative sign for about 5 MPa, 50 ppm conditions.Copyright