1 Figure 2.1 (in the next page) shows a double effect evaporator used to concentrate 1000kg/h of salt water solution from 1wt% salt to 5wt% salt with an intermediate concentration of 3wt% after Evaporator 1. The feed salt solution enters the first evaporator at 30C. Evaporator 1 is at 100C, while Evaporator 2 is at 80C. The flow rate of the saturated steam S1 for heating is 800kg/h. Vapour V V1 produced in Evaporator 1 is used to heat Evaporator 2. (Note: Any rise in boiling point due to solid content can be neglected). (If necessary, you may assume that the heat capacity for the feed F1 and L1 is 4.14kJ/kgK.) (a) Determine the pressure of the saturated steam S1. (12 marks) (b) Determine steam economy for the double effect evaporator. (4 marks) Figure 2.1 Schematic diagram of a double effect evaporator