Precise mathematical models are not always available for some process
units which are too complicated to be understood clearly in mechanism
and variable relationship. These process units are difficult to be ana
lyzed and simulated in conventional approaches. A rule based approach
is proposed in this paper to model the fuzzy units. Conversion between
fuzzy and crisp numbers at the input and output of fuzzy units is dis
cussed in details and a slicing approach for conversion is proposed A
case study shows that this approach provides a way to incorporate fuzz
y models into conventional process simulators. (C) 1998 Published by E
lsevier Science Ltd. All rights reserved.