For design of an exothermic reactor with cooling, one needs to choose an approach temperature (the nominal temperature difference between the reaction zone and the cooling medium). One engineer claims that the temperature difference across the tube walls should be as small as possible. Another claims that a large temperature difference is better for heat transfer.

1. Describe the advantages and disadvantages of these two choices from the point of view of capital costs.

2. Describe the advantages and disadvantages of these two choices from the point of view of operating costs.

3. Describe the advantages and disadvantages of these two choices from the point of view of operability of the process.