Cyclohexane Production Unit Presented by Brian Clifton.

Cyclohexane Production Unit

Presented by Brian Clifton

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.

Outline

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

Process Overview

Benzene is hydrogenated in a Gibbs reactor at high temperature and pressure to form cyclohexane

MIXER E1

C1

SPLITTER

E2

E3

R1FLASH

P1

V1

SO1

PI1

PI2

PI3

1

30T1

BENZENE

HYDROGEN

RECYCLE

S4S5

S6

S7

S9

S1

S11

PURGEGAS

S13

PRODUCT

1PRODUCT

S3 1S3S10

1S10

S2

S8S12

S14

Process Overview

Economic AnalysisEquipment 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 $2,500

Compressor $150,000

Flash $42,600

Total Equipment Cost (2005) $344,200

Economic Analysis

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

Strauss Plots/Propagation of Error

Strauss plots for FCI, product cost, and product cost

Propagation of error method

NPW vs. Product Cost

y = -3E+08x + 1E+09

($1,500,000,000.00)

($1,000,000,000.00)

($500,000,000.00)

$0.00

$500,000,000.00

$1,000,000,000.00

$1,500,000,000.00

$0.00 $1.00 $2.00 $3.00 $4.00 $5.00 $6.00 $7.00 $8.00

Product Cost ($/gal)

NPW

($)

Product Cost

Linear (Product Cost)

2Cost

2

)Cost(

)(2Price

2

)Price(

)(22

)(

)(2

NPWNPWFCIFCI

NPWNPW

Monte Carlo SimulationMonte Carlo Simulation for NPW

500 data points

0

20

40

60

80

Net Present Worth(millions of dollars)

Fre

qu

en

cy

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

Piping SpecificationsStream Type Length (ft) Elbows (90o) Valves (globe) Pressure Drop (psia)

Hydrogen 8'' Sch 80 700 3 3 0.1623535

Benzene 4'' Sch 80 500 5 3 0.0568027

Recycle 8'' Sch 80 350 4 1 0.1724243

Feed 6'' Sch 80 150 6 2 0.1095886

Top 8'' Sch 80 500 2 2 0.0748854

Bottom 6'' Sch 80 500 2 2 0.1420422

Purge 6'' Sch 80 300 2 1 0.0448303

S1 10'' Sch 80 150 2 1 0.5344238

S2 10'' Sch 80 100 2 1 0.643341

S3 10'' Sch 80 150 4 2 0.9095154

S4 10'' Sch 80 150 4 2 0.7703857

S5 10'' Sch 80 100 2 1 0.4255066

S6 10'' Sch 80 150 4 2 0.6598205

S7 10'' Sch 80 150 4 0 0.0444946

S8 10'' Sch 80 100 2 1 0.039032

Pumping Section

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

Pumping Section

Pump Section

Piping All pipe are stainless steel schedule

40 ability to resist corrosion

Pump Section

Pump Positive displacement pump

9 hp required 415 ft head available

All components are stainless steel

NPSHA

1240

1260

1280

1300

1320

1340

1360

1380

0 200 400 600 800 1000 1200 1400 1600

flow rate, ft^3/hr

NP

SH

A

System Head

0

100

200

300

400

500

600

700

800

900

1000

0 200 400 600 800 1000 1200 1400 1600

flow rate, ft^3/hr

hea

d, f

t

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.

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.

Heat Exchanger Network

Heat exchanger 1 was designed rigorously

A temperature – heat diagram was created

Heat Exchanger: Design

Duty, x 10^6 BTU/hr0 2.0 4.0 6.0 8.0 10.0

Tem

per

atu

re, F

100.0

140.0

180.0

220.0

260.0

300.0

Heat Exchanger E1 Zones Analysis

Shell Side

Tube Side

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

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

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

Distillation Column

30 theoretical trays Optimal feed location:

16th tray Column height:

32 feet Column diameter:

42 inches

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1

30T1

TOP

BOTTOM

FEED

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

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.

Questions

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