Heat Integration of Distillation Columns—Summary

The appropriate placement of distillation columns when heat integrated is not across the pinch. The grand composite curve can be used as a quantitative tool to assess integration opportunities. 

The scope for integrating conventional distillation columns into an overall process is often limited. Practical constraints often prevent integration of columns with the rest of the process. If the column cannot be integrated with the rest of the process, or if the potential for integration is limited by the heat flows in the background process, then attention must be turned back to the distillation operation itself and complex arrangements considered. 

Once the distillation is integrated, then driving forces between the composite curves become smaller. This in turn means the capital/energy tradeofiF for the heat exchanger network should be adjusted accordingly. 

Unfortunately, the overall design problem is even more complex in practice. Spare driving forces in the process could be exploited equally well to allow the use of moderate utilities or the integration of heat engines, heat pumps, etc. in preference to distillation integration. 

LinnhoflF, B., Dunford, H., and Smith, R., Heat Integration of Distillation Columns into Overall Processes, Chem. Eng. Sci., 38 1175, 1983. 

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