Transcript Chapter 13 Pinch Technology - UTC Engineering Lab Web

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.
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
Estimate Area
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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
Equivalent Annual Operating Cost
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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
Other considerations
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Material
Operating pressure
Multiple Utilities
Phase Changes
Mass Exchange
• Analogous to heat exchange.
• Pages 500-509