Question

In a chemical plant, a stream of saturated steam at 15 bar is fed into a turbine at a rate of 300 kg/hr. The goal is to generate work from the turbine. To increase the amount of work, a boiler is added that produces superheated steam at 40 bar and 350 °C. This steam can be fed to the turbine as well, at a flowrate of 200 kg/hr. All of the steam entering the turbine leaves as saturated steam at 250 °C. Unfortunately, there is a hole in the insulation on the turbine, such that 10% of the heat entering the turbine is lost as waste heat, and cannot be converted into work. a. 5 points.

a. Draw and properly label a picture of this system

b. Determine how much heat is lost from the turbine as waste heat

c. Determine how much work can be produced from the turbine assuming no other losses.

Answer 1

This question is based on Vapour Power Plant.

In this question the Inlet and exit conditions of a Turbine are given. Based on these conditions and using the saturated steam table and superheated steam table the enthalpy at each point is obtained.

Heat Generated/Dissipated (Q) = Mass flow rate(m) × change in enthalpy (∆h)

The T-S diagram as well as Schematic Diagram of the system is given with the step by step calculation of the heat loss and power developed by turbine below as following:-