A stream containing 4 metric tons/h of a 20 wt% mixture of benzene in toluene is heated from 20 °C to the bubble point at 4 atm pressure. The mixture is separated in a distillation column to give 99.9% recovery of benzene overhead and toluene in the bottoms. 

1. If the toluene product must be cooled to 20 °C, how much of the feed heat can be supplied by heat exchange with the bottoms? 

2. How many heat exchange shells are needed? 

3. What is the minimum total heat exchange area? 

4. What is the distillation column diameter? 

5. How many sieve trays are needed if the tray efficiency is 70%?