When a chemical plant needs steam at multiple pressure levels, it is often economical to generate all the steam at a high pressure and then to let the steam down through pressurereducing turbines to the desired pressure. This principle is illustrated in Figure 8.6. The downside of this approach is that as the exhaust pressure of the turbine increases, the theoretical (and actual) steam requirements increase, meaning that less energy is extracted. To illustrate this point, plot the amount of energy extracted from 50,000kg/h of 58.6barg steam superheated by 205C as a function of the exhaust pressure (efficiency of turbine 60\%). (10 points)