A model of vapor-liquid equilibria for acid gas-alkanolamine-water systems

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:6346766

Austgen, Jr, D M

A physico-chemical model was developed for representing liquid phase chemical equilibria and vapor-liquid (phase) equilibria of H{sub 2}SCO{sub 2}-alkanolamine-water systems. The equilibrium composition of the liquid phase is determined by minimization of the Gibbs free energy. Activity coefficients are represented with the Electrolyte-NRTL equation treating both long-range electrostatic interactions and short-range binary interactions between liquid phase species. Vapor phase fugacity coefficients are calculated using the Redlich-Kwong-Soave Equation of State. Adjustable parameters of the model, binary interaction parameters and carbamate stability constants, were fitted on published binary system alkanolamine-water and ternary system (H{sub 2}S-alkanolamine-water, CO{sub 2}-alkanolamine-water) VLE data. The Data Regression System of ASPEN PLUS, based upon the Maximum Likelihood Principle, was used to estimate adjustable parameters. Ternary system measurements used in parameter estimation ranged in temperature from 25 to 120{degree}C in alkanolamine concentration from 1 to 5 M, in acid gas loading from 0 to 1.5 moles per mole alkanolamine, and in acid gas partial pressure from 0.1 to 1,000 kPa. Maximum likelihood estimates of ternary system H{sub 2} or CO{sub 2} equilibrium partial pressures and liquid phase concentrations were found to be in good agreement with measurements for aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), diglycolamine (DGA), and methyldiethanolamine (MDEA) indicating that the model successfully represents ternary system data. The model was extended to represent CO{sub 2} solubility in aqueous mixtures of MDEA with MEA or DEA. The solubility was measured at 40 and 80{degree}C over a wide range of CO{sub 2} partial pressures. These measurements were used to estimate additional binary parameters of the mixed solvent systems.

• Research Organization: Texas Univ., Austin, TX (USA)
• OSTI ID: 6346766
• Resource Relation: Other Information: Thesis (Ph.D)
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
AMINES
PHASE STUDIES
CARBON DIOXIDE
HYDROGEN SULFIDES
AQUEOUS SOLUTIONS
EQUATIONS OF STATE
EQUILIBRIUM
FREE ENTHALPY
GASES
LIQUIDS
MATHEMATICAL MODELS
QUANTITY RATIO
REGRESSION ANALYSIS
SEPARATION PROCESSES
SOLUBILITY
TEMPERATURE DEPENDENCE
VAPOR PRESSURE
WATER
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
DISPERSIONS
ENERGY
EQUATIONS
FLUIDS
HYDROGEN COMPOUNDS
MATHEMATICS
MIXTURES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SOLUTIONS
STATISTICS
SULFIDES
SULFUR COMPOUNDS
THERMODYNAMIC PROPERTIES
030300* - Natural Gas- Drilling
Production
& Processing