THERMODYAMICS PROBLEMS

[kenz]

Q2. Pinch technology tutorial 1

A Network of heat exchangers is described below in data table 1.

A) Produce a table showing the energy available from or required by each stream.

[5 marks]

B) Construct the incremental temperature–enthalpy table for the hot and cold streams.

[10 marks]

C) For a minimum temperature difference of 10 ˚C and the data given below construct the composite temperature enthalpy curves.

[10 marks]

D) Construct the shifted temperature curves.

[5 marks]

E) Construct the grand composite enthalpy curve and identify the pinch temperature.

[5 marks]

F) Determine the minimum utility heat input and the minimum heat lost to a heat sink.

[5 marks]

 

G) Use the problem table method to check your answer

[15 marks]

H) Determine the optimum sequence for the exchangers

[15 marks]

Data Table 1

 

Stream Number

1

2

3

4

5

6

7

 

Stream Enthalpy

7

2

3

8

9

2

 

Temperature in ºC

300

150

200

190

90

40

 

Temperature out ºC

150

50

50

290

190

190

 

 

 

PROBLEM 3.

Water at 15 ˚C is fed to the top of a spray column by a centrifugal pump from a bulk storage tank at a rate of 50 kg/min. The storage tank is 15 m in diameter 3 m deep and the level within the tank is maintained at 2 m by a float valve connected to the mains water supply.

The pump draws water from the bottom of the bulk storage tank at ground level and discharges it though a nozzle mounted in the roof of a spray tower 25m high. The pipes connecting the tank, pump and nozzle are all 5cm bore. The nozzle has an outlet diameter of 1 cm and is 3 cm long. The spray tower is vented to atmosphere and is drained at its base.

 

a) Draw a diagram of this process

b) The outlet velocities of the nozzles

c) The pressure at the inlet of the nozzle

d) The Power input by the pump assuming 100% efficiency

e) The pump actually operates at 80 % efficiency, recalculate the power input to the pump.

 

 

 

 

 

 

 

 

Edited June 17, 2014 by kenz

[Ophiolite]

The problems do not appear to be attached.

 

Edit: thank you. I'm not sure I can help, but even if I could I would be reluctant to do so by providing answers. The idea of the Homework Help section is to provide guidance, to help put you on the right track. It is not intended to have someone else do your work for you.

 

So what have you done so far in attempting to answer these? What difficulties are you having?

Edited June 18, 2014 by Ophiolite