Distillation is the largest single energy consumer in the chemical process industries. However, distillation does not consume energy but degrades the heat input to the reboiler that is subsequently rejected in the condenser. The most effective way to reduce the energy consumption of distillation is by effective heat integration. However, the distillation design and operation must be considered simultaneously with its heat integration. For single distillation columns it is straightforward to identify appropriate heat integration opportunities. For complex distillation systems, the most appropriate combination of distillation system design and operation and heat integration are far from straightforward. The whole separation system together with its heat integration and utility system must be considered simultaneously. This presentation will explain new approaches to be design of heat integrated distillation systems. Examples will be developed from crude oil distillation and from low-temperature separation in chemicals production. Copyright © 2010, AIDIC Servizi S.r.l.