Reality versus simulation-implementation of heat exchangers with phase changes.

• Heat exchangers in which phase changes occur require simulation models that realistically capture the resulting temperature profiles and heat-transfer rates. • Two industrially important process examples are studied: a steam generator heat exchanger and the two heat exchangers in a compression refrigeration system. • The reality of the process is compared to the approximate simulation implementation. • Effective control structures are developed and tested. The heat exchanger is probably second only to the pipe as the most widely used piece of process equipment. A typical chemical plant has hundreds of heat exchangers that transfer heat from a hot source into a cold sink. The analysis of heat transfer is straight-forward when both the hot and the cold streams do not undergo any change in phase during the heating and cooling. However, the analysis gets more complex when there is vaporization or condensation of either of the streams. Now latent heats are involved and temperatures do not change continuously with axial location. Vaporizers, reboilers, evaporators and condensers are common examples of heat transfer with phase changes. The purpose of this paper is to demonstrate how realistic simulation models can be developed that capture the steadystate and dynamic heat-transfer differential temperature driving forces, vapor-liquid fractions and heat-transfer rates for these important and widely applied exchangers. [ABSTRACT FROM AUTHOR]