chapter 13 pinch technology don scott 3/9/6 ench 430

7
Chapter 13 Pinch Technology Don Scott 3/9/6 ENCH 430

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Page 1: Chapter 13 Pinch Technology Don Scott 3/9/6 ENCH 430

Chapter 13Pinch Technology

Don Scott

3/9/6

ENCH 430

Page 2: Chapter 13 Pinch Technology Don Scott 3/9/6 ENCH 430

Pinch Point

• In a system, a point where energy or mass exchange is at a minimum is the pinch point.

• A pinch point needs to be located and used to design the system.

Page 3: Chapter 13 Pinch Technology Don Scott 3/9/6 ENCH 430

Heat Integration- Matching points of heat addition and heat loss

1. Choose a minimum approach temperature.

2. Construct a temperature interval diagram.

3. Construct cascade diagram-minimum utility requirement, pinch temperatures.

4. Calculate minimum no. of heat exchangers above and below pinch.

5. Construct the heat exchanger network.

Pages 462-473

Page 4: Chapter 13 Pinch Technology Don Scott 3/9/6 ENCH 430

Estimate Area

• A=(Q)/(U*delta Tlm*F)

• A: heat transfer area

• Q: amount of heat to be transferred

• U: film heat transfer coefficient

• delta Tlm: log-mean temperature.

• F: log-mean temperature correction factor

Page 5: Chapter 13 Pinch Technology Don Scott 3/9/6 ENCH 430

Equivalent Annual Operating Cost

• EAOC=FCI(i(1+i)n)/((1+i)n-1)+utility costs

• FCI= total cost of network

• ‘n= number of years

• i=before tax hurdle rate

Page 6: Chapter 13 Pinch Technology Don Scott 3/9/6 ENCH 430

Other considerations

• Material

• Operating pressure

• Multiple Utilities

• Phase Changes

Page 7: Chapter 13 Pinch Technology Don Scott 3/9/6 ENCH 430

Mass Exchange

• Analogous to heat exchange.

• Pages 500-509