An isothermal flow calorimeter designed for high temperature, high pressure operation

Abstract

An isothermal flow calorimeter suitable for measuring either endothermic or exothermic heats of mixing from 373 to 673 K and from 0.1 to 40.5 MPa is described. An automatically controlled pulsed heater and a highly stable heat leak path are used to maintain the reaction zone at a constant temperature. Energy effects from 0.15 to 120 J min −1 can be measured to an accuracy of ±0.8% at a constant temperature and pressure. The calorimeter was tested by measuring the heat of mixing of water—ethanol at 413 K and 1 MPa and was found to produce data in good agreement with previously measured values.