How Much steam is produced when 1 Kg of water at 1650C and 8 bar is flashed into a Vessel at 2 Bar?

Problem I. (a) Steam at a pressure of 0.14 bar has a dryness fraction of 0.92. Find:

(i) its specific enthalphy
(ii) its specific entropy
(iii) its specific volume.

(b) Explain and distinguish between the terms:

(i) isenthalpic process
(ii) isentropic process

In each case give an example to illustrate your answer.

Problem 2. Steam is expanded isentropically from a pressure of 40 bar and a temperature of 300 C to a pressure of 0.05 bar. Find the final dryness fraction by calculation using values from the property tables.

Problem 3. Dry saturated steam at a pressure of 20 bar is throttled to 0.5 bar and then expanded isentropically until it again becomes dry saturated. Use your h - s chart to find the pressure at the final state.

Problem 4. (i) Find the change in specific entropy when saturated water is boiled to produce dry saturated steam at 50 bar.

(ii) What does this change tell you about the reversibility of the boiling process?

Problem 5. How Much steam is produced when 1 Kg of water at 1650C and 8 bar is flashed into a Vessel at 2 Bar?

Problem 6. (a) Explain how air can get into and contaminate a steam supply.
(b) What effect does the presence of air, in steam, have on its quality and properties?
(c) Explain the operating principles of one type of air release trap.
(d) State. giving reasons, the most desirable position for an air release trap.

Problem 7. The partial pressure of saturated steam in a steam/air mixture is 1.40 bar. while the partial pressure of the air is 0.15 bar. Find:
a. the total pressure of the mixture
b. the temperature of the mixture
c. the air concentration

Problem 8. The overall heat transfer coefficient in a process heater is 2.15 kW m-2 K-1, and the temperature of the process fluid is essentially constant at 80 C. Find:
(a) the rate at which heat will be transferred by a square metre of heater surface from steam condensing at 1.2 bar
(b) How much dry saturated steam must be condensed in an hour to provide the above heat transfer?

Problem 9. A heat exchanger, supplied with steam at 2 bar, is designed to maintain a process fluid at 95 C on a continuous basis. Using the data given below, calculate the following: