1. Cyclohexane Production Unit
Presented by Brian Clifton

2. Executive Summary
The cyclohexane production plant is not economically feasible unless the price of cyclohexane is more than double the price of benzene.
Yellow does not recommend IRI to proceed with the plans to build and operate this facility.

3. Outline Process Overview Economic and Risk Analysis Pipe Network
Pump System
Heat Exchanger
Distillation Column

4. Process Overview
Benzene is hydrogenated in a Gibbs reactor at high temperature and pressure to form cyclohexane

5. Process Overview

6. Total Equipment Cost (2005)
Economic Analysis
Equipment
Cost
Distillation column
$53,200
Heat Exchanger E1
$14,800
Heat Exchanger E2
$1,230
Heat Exchanger E3
$6,610
Reactor
$5,040
Mixer
$2,500
Splitter
Compressor
$150,000
Flash
$42,600
Total Equipment Cost (2005)
$344,200

7. Economic Analysis Production Cost: $7.14/gal Revenue: $3.60/gal
TCI: $2.5 million
NPW: negative $1 billion
Accuracy: ±10%
Required ROI: 8%

8. Strauss Plots/Propagation of Error
Strauss plots for FCI, product cost, and product cost
Propagation of error method

9. Monte Carlo Simulation

10. Piping System Piping materials made of stainless steel
Insulation thickness of 1 inch
Schedule 40 pipes increased to schedule 80 to operate under bursting strength
FCI of $900,000 for piping system

11. Piping Specifications
Stream
Type
Length (ft)
Elbows (90o)
Valves (globe)
Pressure Drop (psia)
Hydrogen
8'' Sch 80
700 3
Benzene
4'' Sch 80
500 5
Recycle
350 4 1
Feed
6'' Sch 80
150 6 2
Top
Bottom
Purge
300 S1
10'' Sch 80 S2
100 S3 S4 S5 S6 S7 S8

12. Pumping Section
Cyclohexane is pumped from the process to a storage tank at 555 psia which is 35 feet above the flash tank

13. Pumping Section

14. Pump Section Piping All pipe are stainless steel schedule 40
ability to resist corrosion

15. Pump Section Pump Positive displacement pump 9 hp required
415 ft head available
All components are stainless steel

18. Pumping Section
Cost for installation of the pumping section, including the pump, pipes, and valves, was determined to be $105,000
Total fixed capital investment for the cyclohexane plant up to $2.4 million.

19. Heat Exchanger Network
There are three heat exchangers in the cylcohexane plant
The heating utility required by the plant is minimized by using the hot product stream to pre-heat the incoming reactant stream.

20. Heat Exchanger Network
Heat exchanger 1 was designed rigorously
A temperature – heat diagram was created

21. Heat Exchanger: Design

22. Heat Exchanger: Design
The single pass, countercurrent design was selected
No baffles were
used, in order to
maintain the
shell-side pressure
drop under 5 psi

23. Heat Exchanger: Design
By Hand
Pro/II
Area (ft2)
2730
2980
U [Btu/(hr*ft^2°F)]
9.6
126.8
Number of tubes
326 x 2” OD
40 x 1” OD
Length (ft) 16
284

24. Heat Exchanger Design Triangular pitch Stainless steel heat exchangers
Hot streams were maintained tube side in all heat exchangers
Heat exchanger 2 uses steam to heat the reactant stream
Heat exchanger 3 uses cooling water to cool the product stream

25. Distillation Column 30 theoretical trays
Optimal feed location: 16th tray
Column height:
32 feet
Column diameter:
42 inches

26. Distillation Column Valve trays 94 valves / tray Tray spacing:
24 inches
Condenser heat duty:
-1.9 MM Btu/hr
Reboiler heat duty:
3.01 MM Btu/hr

27. Summary
After the detailed designs were conducted, the cyclohexane plant was shown to not meet IRI’s criteria for profitablity.
Yellow does not recommend IRI building and operating this facility.

28. Questions ?