Measurements of the volatilities of solutes from aqueous solutions and their application to water/steam cycles

Conference · Wed Feb 01 00:00:00 EST 1995

OSTI ID:10120117

Jensen, J P ^[1]; Palmer, D A; Simonson, J M ^[2]

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1. Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering
2. Oak Ridge National Lab., TN (United States)

Partitioning of NaSO{sub 4} and NaHSO{sub 4} between the liquid and vapor phases was measured at 300, 325 and 350{degrees}C by sampling both phases from a static platinum-lined autoclave. Sample compositions were determined by ion chromatography and acidimetric titrations. The solutions were buffered with either acid or base so that the volatility of individual species was determined. The molal thermodynamic partitioning constants were calculated by taking into account the mean stoichiometric activity coefficient in the liquid phase and the hydrolysis equilibrium constants. The vapor phase species were assumed to be neutral molecules with unit activity coefficients. The strong temperature dependence of the partitioning constant was treated by the isocoulombic method to obtain a linear dependence of the logarithm of the partitioning constant versus reciprocal temperature in Kelvin. A model is described for predicting the composition of the condensate in the water/steam cycle of power plants using drum boilers. Equilibrium between liquid and steam is assumed in the drum during boiling, and in the low pressure turbine on steam condensation. The model is based on the measured partitioning constants of HCl, NH{sub 4}Cl, NaCl, NaOH, H{sub 2}SO{sub 4}, NaHSO{sub 4}, NaSO{sub 4} and NH{sub 3}, the hydrolysis of HSO{sub 4}{sup -} and NH{sub 4}{sup +} and the ionic product of water. Two test cases are given to demonstrate the sensitivity of the pH of the first condensate to the concentrations of various anions relative to the corresponding sodium concentration in the drum. These calculations also indicate that very high concentrations of solutes can be achieved under certain conditions.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); Electric Power Research Inst., Palo Alto, CA (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10120117
• Report Number(s): CONF-9410297-1; ON: DE95007101; TRN: 95:002290
• Resource Relation: Conference: VGB conference on 1994 power plan chemistry,Essen (Germany),26-27 Oct 1994; Other Information: PBD: [1995]
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
SODIUM SULFATES
VOLATILITY
BOILERS
CONDENSATES
CHEMICAL COMPOSITION
AQUEOUS SOLUTIONS
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE DEPENDENCE
REACTION KINETICS
THERMODYNAMIC ACTIVITY
STEAM
WATER
PH VALUE
EQUILIBRIUM
421000
400201
COMBUSTION SYSTEMS
CHEMICAL AND PHYSICOCHEMICAL PROPERTIES