A fruit juice at 20 C with 5% total solids is concentrated in a single-effect evaporator. The evaporator is being operated at a sufficient vacuum to allow the product moisture to evaporate at 80 C, and steam with 85% quality is being supplied at 169.06 kPa. The desired concentration of the final product is 40% total solids. The concentrated product exits the evaporator at a rate of 3000 kg/h. 

Calculate the (a) steam requirements and (b) steam economy for the process, when condensate is released at 90 C. The specific heat of liquid feed is 4.05 kJ/(kg C), and of concentrated product is 3.175 kJ/(kg C).