Heat Integration in an Acetone-Methanol System

The energy requirement in the low-pressure column is 14.79 MW, so the auxiliary reboiler must provide 14.79-5.86 = 8.93 MW (32GJ/h, as shown in the TCI faceplate in Fig. 6.30). Flowsheet equations similar to those described in the THF-water system are needed in this system. The pressure-compensated temperature measurement uses the temperature (411.5 K) and pressure (10.354 atm) on Stage 53. 

These results show that there is no control penalty for going to the partial heat-integrated systems when auxiliary reboilers or condensers are added. This result is to be expected because there is no loss of control degrees of freedom. 

Pressure-swing systems are very amenable to heat integration because of the inherent temperature differences in the two columns. Complete heat integration is the most economical from a steady-state economic point of view. However, a considerable dynamic controllability penalty can occur, which can be greatly reduced by using partial heat integration. 

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