Ideally, for the needs of robust process simulation, one would like a
nonlinear equation solving technique that can find any and all roots t
o a problem, and do so with mathematical certainty. In general, curren
tly used techniques do not provide such rigorous guarantees. One appro
ach to providing such assurances can be found in the use of interval a
nalysis, in particular the use of interval Newton methods combined wit
h generalized bisection. However, these methods have generally been re
garded as extremely inefficient. Motivated by recent progress in inter
val analysis, as well as continuing advances in computer speed and the
availability of parallel computing, we consider here the feasibility
of using an interval Newton/generalized bisection algorithm on process
simulation problems. An algorithm designed for parallel computing on
an MIMD machine is described, and results of tests on several problems
are reported. Experiments indicate that the interval Newton/generaliz
ed bisection method works quite well on relatively small problems, pro
viding a powerful method for finding all solutions to a problem. For l
arger problems, the method performs inconsistently with regard to effi
ciency, at least when reasonable initial bounds are not provided.