INGAR   05399
INSTITUTO DE DESARROLLO Y DISEÑO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Optimal synthesis of heat exchange networks using enthalpy-temperature functions to describe streams
Autor/es:
DIEGO G. OLIVA; JAVIER A. FRANCESCONI; MIGUEL C. MUSSATI; PIO A. AGUIRRE
Lugar:
Salvador, Bahia, Brazil
Reunión:
Simposio; 10th International Symposium on Process Systems Engineering - PSE2009; 2009
Institución organizadora:
Universidad de Sao Paulo
Resumen:
This work presents a mixed integer non linear programming (MINLP) model for heat
exchanger network synthesis including a detailed description of the process streams
resorting to a mathematical function that matches temperature with enthalpy. This
allows the model to account for non linear behavior of streams by taking into
consideration their composition. To achieve the objective, the energy balance equation
proposed in the synheat model by Yee and Grossmann (1990) is modified but
equations involving temperature are kept the same. A new equation is added to that
model to describe the relationship between temperature and enthalpy by correlation. As
the original model, this modified MINLP model provides the network structure that
minimizes the total annual cost. The mathematical program has non-convex equations,
and only locally optimal solutions can be guaranteed. The approach between cold and
hot streams has more detailed information because describes the real behavior of
streams, and avoids matches that a linear functionality or a classical model may allow.
Correlations between temperature and enthalpy are a function of the components
present in a particular stream. The required information can be collected from
bibliography or public databases as those provided by NIST (National Institute of
Standards and Technology). The proposed methodology is a useful tool when the
minimum temperature approach between streams is small. Examples are presented and
discussed to compare results when streams are described by linear and non linear
functionality between temperature and enthalpy.