Thermal Integration of Reboilers Positioned Close to the Pinch Point of a Process

Reboiler Integration is a common alternative for energy savings in industrial processes. The operating pressure of distillation columns and the level of vaporization inside reboilers can be selected in order to “thermally accommodate” a reboiler stream into the composite curves of a process. The capital cost of the column depends on the operating pressure (i.e. if the design pressure increases, then the number of equilibrium stages required for the separation increases as well). The operational cost also depends on the operating pressure (i.e. the larger the pressure is, the larger the heat load required in the reboiler in order to reach purity specifications. On the other hand, the reboiler design strongly depends on the level of vaporization achieved inside this unit. In this work, the best trade-off between energy savings and heat transfer area of the heat exchangers network is determined in the integration of a reboiler stream close to the Pinch temperature. Several alternatives such as flow direction and temperature difference should be considered during the integration task. These parameters directly affect the thermal-hydraulic behavior of reboilers.