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One‐ and two‐phase isochoric heat capacity measurements of aqueous solution of nacl near the critical point of pure water
Author(s) -
Abdulagatov Ilmutdin M.,
Dvoryanchikov Vasilii I.,
Kamalov Abdurakhman N.,
Abramova Elena G.,
Abdurashidova Madina A.
Publication year - 2000
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450780314
Subject(s) - isochoric process , heat capacity , thermodynamics , supercritical fluid , critical point (mathematics) , calorimetry , calorimeter (particle physics) , mole fraction , phase transition , chemistry , phase (matter) , adiabatic process , analytical chemistry (journal) , materials science , chromatography , physics , mathematical analysis , mathematics , organic chemistry , detector , optics
Isochoric heat capacities of H 2 O+NaCl solutions (0.0031 and 0.0063 mole fraction of NaCl) were measured with a high temperature and high pressure adiabatic calorimeter near the sub‐critical and near the supercritical point of pure water. Temperatures ranged from 361 to 677 K. Measurements were made at six densities, namely: 367.07 and 485.59 kg·m −3 for x = 0.0031 mol fraction of NaCl and 388.65, 560.03, 607.05, and 973.70 kg·m −3 for x = 0.0063 mol fraction of NaCl. Measurements were conducted in the two‐and one‐phase regions including near phase transition temperatures T S (ρ). The phase transition temperatures T S (ρ) and saturated isochoric heat capacity values C VX have been determined for each isochore. The uncertainty in heat capacity measurements is estimated to be 3.5% to 4.5% near the phase transition and critical points. Present and previous results of heat capacity measurements were compared with predictions from the crossover (CREOS) and Pitzer—Tanger–Hovey equations of state (PTH EOS). Our previous heat capacity measurements were found to deviate systematically from crossover‐model predictions. The present results show good agreement with the crossover model for the composition x = 0.0031 mol fraction.