29,800 lb/hr of a 35API light oil at 340F is used to preheat 103,000 lb/hr of 48 API naphtha from 200F to 230F. The mean viscosity of the oil is 2.3cP and that of the naphtha is 0.5cP. Pressure drops of 10psi across the heat exchanger are allowable. Because the oil may deposit residues, allow a combined fouling factor of 0.005 and use a square pitch tube layout. Plant practice is to use in. O.D. 16 BWG tubes with a length of 160 wherever possible. Design a shell and tube heat exchanger.