Nonequilibrium modeling of an ammonia-water rectifyng column via fundamental thermodynamic and transport relations



Document title: Nonequilibrium modeling of an ammonia-water rectifyng column via fundamental thermodynamic and transport relations
Journal: Brazilian journal of chemical engineering
Database: PERIÓDICA
System number: 000309064
ISSN: 0104-6632
Authors: 1

Institutions: 1Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica, Campinas, Sao Paulo. Brasil
Year:
Season: Dic
Volumen: 23
Number: 4
Pages: 540-553
Country: Brasil
Language: Inglés
Document type: Artículo
Approach: Experimental, aplicado
English abstract A nonequilibrium heat and mass transfer model is presented for the steady-state operation of a rectifying column, employed in ammonia-water absorption refrigeration systems to dehumidify the ammonia vapor leaving the generator. The thermodynamic state relations of the mixture are derived from two equations representing the Gibbs free energy in terms of temperature, pressure and concentration for the liquid and the vapor phases. Two of the transport properties, surface tension and liquid diffusivity required original relations, as presented here in. The resulting nonlinear system of equations is solved by efficient use of the Newton-Raphson code that minimizes the order of the Jacobian matrix without losing any model information or the quadratic order of convergence of the numerical method. Accuracy tests are performed by grid refinement and by comparison with results in the literature. A sensitivity study is presented showing the influence of some alternative methods for estimation of the transport properties on the temperature and concentration profiles
Disciplines: Química
Keyword: Fisicoquímica y química teórica,
Refrigeración por absorción,
Amonio-agua,
Transferencia de calor,
Transferencia de masa,
Termodinámica
Keyword: Chemistry,
Physical and theoretical chemistry,
Absorption refrigeration,
Ammonia-water,
Heat transfer,
Mass transfer,
Thermodynamics
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