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 Choose a minimum approach temperature. Construct a temperature interval diagram. Construct cascade diagram-minimum utility requirement, pinch temperatures. Calculate minimum no. of heat exchangers above and below pinch. Construct the heat exchanger network. Pages 462-473

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

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

Other considerations Material Operating pressure Multiple Utilities Phase Changes

Mass Exchange Analogous to heat exchange. Pages 500-509