DEVELOPMENT OF AN EQUATION-ORIENTED STEADY-STATE EVAPORATION PLANT SIMULATOR
Authors: Márcio R. Vianna Neto 1, Marcelo Cardoso 1, Esa K. Vakkilainen 2, Éder D. Oliveira 1
1 Universidade Federal de Minas Gerais. Brazil
2 Lappeenranta University of Technology. Finland
O PAPEL vol. 81, num. 07, pp. 83 - 89 - JUL 2020
ABSTRACT
An equation-oriented process simulator was developed for
simulating evaporation plants. The simulator graphical user
interface was written in Python 2.7, and its engine, in C++.
The simulator orders and partitions the system of equations
that describe the evaporator system under study and solves
the partitions sequentially using the Newton-Raphson
method. If no good initial estimates can be provided by the
user, the simulator solves a simplified problem to generate the
estimates, which greatly facilitates convergence. Calculations
are based on steam table correlations and on black liquor
enthalpy correlations described in the literature. Two multipleeffect
counter-current evaporator scenarios were extracted
from the literature and used to validate the simulator: a simple
3-effect system and a realistic 6-effect system. The simulator
converged to the solutions with relative ease, provided that
the model equations were written as described, that equations
were ordered and partitioned, and the simplified model was
used to generate good initial estimates. Good agreement was
found between the calculated values and those reported in the
literature, indicating that the proposed simulation framework
could be extended to accommodate more complex systems.
Deviations from the reported values can be explained by the
different choices of physical properties correlations.
Keywords: simulation, multiple-effect, evaporation, equationoriented,
partitioning