The smallest values of ∆Tmin in the contractor’s design are 7°C at the cold endof match 9, and 13°C at the cold end of match 7. However, ∆Tmin values in othermatches are much higher than this. Hence it was decided, for the “first look” atenergy targeting to take a global ∆Tmin value of 20°C. Calculating the Problem Tableon this basis gave a hot utility requirement of 60.7MW. The plant prior to upratingwas consuming 68.0MW, and the contractor’s proposals required an extra 13.9MW,that is, a total heat input of 81.9 MW! Hence the calculated target indicated a potential saving of about 35%.From this point in the study, the prospects for finding a revamp which avoidedusing the extra fired heater appeared very good indeed and provided a tremendousstimulus to the operating company’s and the contractor’s engineers to find such adesign.