Question

14. In Chapter 15, the concepts of heat-exchanger networks and pinch technology are discussed. When designing these networks to recover process heat, it is often neces- sary to have a close temperature approach between process streams, which leads to large heat exchangers with multiple shells. Multiple-shell heat exchangers are often constructed from sets of 1-2 shell-and-tube exchangers stacked together. For costing considerations, the cost of the multiple-shell heat exchanger is best estimated as a number of smaller 1-2 exchangers. Consider a heat exchanger constructed of carbon steel and designed to withstand a pressure of 20 barg in both the shell and tube sides. This equipment has a heat exchange area of 400 m2. Do the following a. Determine the bare module cost of this 4-shell and 8-tube pass heat exchanger as 8 four, 1-2 exchangers, each with a heat-exchange area of 100 m2. b. Determine the bare module cost of the same exchanger as if it had a single shell. c. What is the name of the principle given in this chapter that explains the difference 8 between the two answers in (a) and (b)?

Answer 1

Add Equipment Unit Number 100 Edit Equipment CEPCI 500 Remove All Equipment User Added Equipment Exchanger E-101 E-102 Exchanger Type Shell Pressure(barg) Tube Pressure(barg) MOC Floating Head Floating Head Area(sq. m) Purchased Equipment Cost(S) Bare Module Cost(S) 128,000 74.900 20 20 20 Carbon Steel/Carbon Steel 20 Carbon Steel/Carbon Steel 400 400 435,000 256,000

Solution The ptoblem ienae Solved by iing hand Calea given Can be The patablen h been olwe n CAPCOST uing The bat module cast a. and b. und od the answes bet tha to ost s 15 the . PRINCIPLE-OF THE ECO NOALL_ OF SALE -. Shells