DESIGN AND CONTROL OF A HEAT-INTEGRATED REACTOR/COLUMN PROCESS

The dynamics of a heat-integration system, consisting of a reactor which is thermally linked to a reboiler of a distillation column, was studied. In this system, an exothermic reactor acts as the heat source and a reboiler acts as the heat sink. This system is a commonly used design to reduce energy costs.; Two heat-integration schemes were studied. The indirect heat-integration system used steam as the heating medium for the reboiler. The direct heat-integration system used hot reactor liquid as the heating medium for the reboiler. The indirect heat-integration system was found to have several advantages over the direct heat-integration system in terms of its dynamic performance and its overall investment cost.; Both systems are operable for both large and small temperature differences between the reactor and the column base. The heat-integration system with a small temperature difference was found to be more controllable than a system with a larger temperature difference. However the cost of the heat exchanger area increases rapidly as the temperature difference decreases. The minimum economic temperature difference appears to be about 60(DEGREES)F.; Changing one of the kinetic parameters, such as the activation energy, did not have a drastic effect on the overall dynamic performance of either the indirect and the direct heat-integration systems.