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hwk-2 Solution

The assignment involves constructing a Pinch Tableau to identify minimum utility and pinch temperature based on given data. It requires drawing composite curves for a selected HRAT value and plotting minimum utility and pinch temperature as a function of temperature difference. Additionally, it discusses optimizing utility usage and determining the outlet temperature of cooling water while considering constraints on maximum temperature return to the cooling tower.

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11 views6 pages

hwk-2 Solution

The assignment involves constructing a Pinch Tableau to identify minimum utility and pinch temperature based on given data. It requires drawing composite curves for a selected HRAT value and plotting minimum utility and pinch temperature as a function of temperature difference. Additionally, it discusses optimizing utility usage and determining the outlet temperature of cooling water while considering constraints on maximum temperature return to the cooling tower.

Uploaded by

melkud
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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CHE 4253

ASSIGNMENT 2
ROBLEM #1(Individual)

Consider the following data

FCp Initial Target


Temperature Temperature
(KW/C)

1.5 170 60

2 45 30

2.7 20 132

1.5 80 140

0.4 160 195

2.5 70 30

a) Construct your Pinch Tableau in Excel so that you can identify minimum utility and pinch temperature
b) Draw composite curves for one selected value of HRAT.
Remember to use the combined FCp for streams that overlap in temperature when making composite curves.
c) Make a graph of the minimum utility and pinch temperature as a function of the minimum temperature difference
(HRAT) in the network.

Pretty straightforward. Just redo what was done in Part a() for different Delta Temp. Then plot them as shown
above.
d) Choose one value of minimum temperature difference (HRAT) (pick one that will render decent overlap) and draw
the grand composite curve. Consider that you have available utility at 100 oC, at 120 oC and at 260 oC where you have
increasing price with increasing temperature. Determine the optimum utility usage.
e) Assume that your cooling water is available at 15 oC. Determine the outlet temperature that will minimize its
flowrate. What is the cooling water outlet temperature in that case? Discuss solutions in the case where the cooling
water to be returned to the cooling tower cannot exceed 30 oC.

Sol) The Cooling Water Line cannot cross the Grand Composite Curve and only touch one of the points on the graph. The
Line should start at the end of the Grand Composite Curve and end at the median of the first pocket on the y axis. This
provides a temperature of 45˚C.

If the cooling water cannot exceed 30˚C, adding a refrigeration system would provide the solution but the utility of the
system would also go up.

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