THERMAL INTEGRATION OF REBOILERS POSITIONED CLOSE TO THE PINCH POINT OF A PROCESS

摘要

Reboiler integration has become a common alternative for energy savings in industrial processes. Operational and capital costs of distillation columns are directly affected by large changes in the operating pressure (i.e. if the design pressure increases the heat load in reboilers and the number of equilibrium stages required for the separation increase as well). Moderate changes in pressure allow modifying the internal temperature profile in the column and keep these costing parameters about constant. Moreover, reboiler design strongly depends on the outlet vapor fraction achieved by this unit. Then, operating pressure of distillation columns and the level of vaporization can be selected in order to "thermally accommodate" a reboiler stream into the composite curves of a process. In this work, the best trade-off energy/capital of the heat exchanger network is determined when a reboiler stream is integrated close to the Pinch Temperature. This paper examines the integration of both vertical and horizontal thermo-siphon reboilers.