Redesign of a flow calorimeter and total enthalpy measurements on ethylbenzene, ethylcyclohexane, and isooctane.

摘要

A boil-off flow calorimeter was re-designed and automated for rapid and highly accurate total enthalpy measurements. Details of the modifications to the apparatus design and the measurement procedure are presented. The calorimeter is presently capable of operating at temperatures from 300 K to 600 K and pressures from 1.5 bar to 200 bar with an ultimate upper design pressure of 2000 bar and temperature of 700 K. A micro-computer is employed for the data acquisition and data translation, requiring less time from the operator during an experiment. The calorimeter is capable of running a pure compound or a premixed mixture in any phase. The only limitation for the sample fluid is that it must not solidify at the operating conditions or at room temperature.;Enthalpies of a ultra-pure compressed water and the superheated steam were measured and compared with the values from the most recent steam tables to test the performance of the calorimeter. The results of the performance test showed that the calorimeter would provide total enthalpy data of ;The data set presented in this investigation seems to be internally consistent and should aid in the development of correlations and/or equations of state which can be used to accurately predict enthalpies of hexane-plus fractions and similar compounds.