The green liquor from a wood pulping unit is required to be preheated from 78 C to 95 C by steam in a tubular heat exchanger before it is fed to the evaporator. It is required to design a shell-and-tube heat exchanger for the purpose. The following data and information are available. Green liquor: flow rate = 9900 kg/h; properties at the mean fuid temperature: density= 1100 kg/m 3 , specific heat = 0.94 kcal/kg C, viscosity = 4 cp, thermal conductivity = 0.3 kcal/h m C. Steam: dry and saturated at 140 C. (Suggested design: 1-6 pass, 38 mm tube, 3000mm long, heating area = 30 m 2 ).