Conductivity of dilute aqueous electrolyte solutions at high temperatures and pressures using a flow cell

A flow-through electrical conductance cell was assembled in order to measure molar conductances of dilute aqueous electrolytes with a high degree of accuracy at high temperatures and pressures. The design of the cell is based on the concept developed at the University of Delaware and built in 1995, with modifications that will allow the cell to operate at much higher temperatures (to 600 degrees C) and pressures (to 300 MPa). At present, the cell has been tested successfully by measuring aqueous (10(-4)-10(-3) mol-kg(-1)) solutions of LiCl, NaCl, and KCl at temperatures 25-410 degrees C and pressures 9.8-33 MPa. The results are in good agreement with reported values, including those measured with the Delaware flow-through cell. These new results are also complementary to our previous results. which were measured with a static high-pressure cell. Measurements at temperatures near the critical point of water (374 degrees C, 22.1 MPa) require the use of lower solution concentrations that were unachievable in the past with the static cell.