Green GroupKathryn Knopinski

Kara SheldenKim Fink

Justin SneedMark Shreve

Assignment 3

Financial Analysis of Cyclohexane Plant

Purchased Equipment CostComponent Specifications Cost ($) in 2002 Cost ($) in 2005 Flash Drum 1.4 ft diameter $3,200 $3,430Mixer 0.5 ft diameter $2,000 $2,144Splitter 0.5 ft diameter $2,000 $2,144Compressor 71.5 hp $50,000 $53,595Heat Exchangers Surface area

Unit 3 - E-1 2,220 ft2$24,000 $25,725

Unit 4 - E-3   613 ft2$6,500 $6,967

Unit 8 - E-2   195 ft2$2,200 $2,358

Distillation ColumnColumn 7.6 ft diameter $80,000 $85,752Trays 30 sieve trays $28,500 $30,549Tubular Reactor L=20 ft Volume=73.6 ft^3 $150,000 $160,784

Total Purchased Equipment $348,400 $373,000

 

Fixed Capital Investment

Fixed Capital Investment

Total Product Cost

Total Product Cost

Sales Income

Gross Product Income Current prices: $160 million 3x current prices: $480

million ½ current prices $80 million

Majority of profits come from the sale of cyclohexane

Benzene, hydrogen, and methane were also sold

Profits after 10 years

Cash Flow Current prices: $108 million 3x current prices: $2,491 million ½ current prices $-487 million

Net Present Worth Current prices: $63 million 3x current prices: $1,490 million ½ current prices $-461 million

Analysis of Profits

Based on current prices Return on investment

489% Pay-out time

57 days Discounted cash flow rate of return

430%

Assignment 4

Risk Analysis and Piping Analysis of Cyclohexane Plant

Sensitivity Analysis

Strauss plots determined NPW sensitivity

Strauss plots NPW vs. FCI NPW vs. Product Costs NPW vs. Product Price

Strauss Plot for FCI

Strauss Plot (FCI)

y = -1.1084x + 65.056

$61.50

$62.00

$62.50

$63.00

$63.50

$64.00

$- $0.50 $1.00 $1.50 $2.00 $2.50 $3.00 $3.50

FCI (million $)

Ne

t P

res

en

t W

ort

h

(mil

lio

n $

)

Strauss Plot for Product Costs

Straus Plot (TPC)

y = -4.476x + 714.28

R2 = 1

-600

-400

-200

0

200

400

75 125 175 225 275

Total Product Cost (million $)

Net

Pre

sen

t W

ort

h (

mil

lio

n $

)

Strauss Plot for Product Price

Strauss Plot (Product Sales)

y = 172.0403x - 582.0071

$(300.00)

$(200.00)

$(100.00)

$-

$100.00

$200.00

$300.00

$400.00

$500.00

0 1 2 3 4 5 6

Cyclohexane Sales Price ($/gal)

Net

Pre

sen

t W

ort

h

(mill

ion

$)

Risk Evaluation Conclusion

Minimum sale price of cyclohexane: $3.39/gal

NPW: $63 ± 130 million using propagation of

error $63 ± 289 million using Monte-Carlo

Pressure Drop Ranged from 0.84 – 2700 psi

2 pumps and 5 compressors required

Piping for all streams was high-alloy stainless steel Ability to resist corrosion at higher

temperatures

Pipe Material

Bursting Strength

2,480 kPa for all pipes

Operating Pressures 4% - 143% of safe working pressure 3 sections under safe pressure

Error with unit conversion: all pipes should be safe

Piping Insulation Thickness

Varies from 1 – 1.5 inches

Material: mineral wool Low thermal conductivity

Standard metal finish to reduce maintenance and heat loss

Fixed Capital Investment

New Piping Design System $3,670,000

Optimized Piping System $2,890,000

Assignment 5

Simulation and Fluid Transport

Heat and Material Balances

Simulated using SIMSCI PRO/II using the Saove-Redelich-Kwong thermodynamic package

Stream summaries, material balances, and heat balances obtained

           

Table 1. Heat Balances on Heat ExchangersHx Name E1 E2 E3

Hx DescriptionDuty MM BTU/HR 7.129 7.6808 3.9265

Heat and Material BalancesTable 3. Material Balances on Cyclohexane UnitStream Name BENZENE HYDROGEN S3 S5 S4 S9

Stream Description

Phase Liquid Vapor Vapor Mixed Mixed Mixed

Temperature F 99.99994659 99.99994659 189.4477692 121.8623047 223.8749695 249.9999695Pressure PSIA 14.69594288 514.6959839 514.6959839 400.0000305 395 370.0000305

Flowrate LB-MOL/HR 396.6185913 1581.09668 1708.878906 3686.593994 3686.593994 2532.243408

Composition BENZENE 1 0 0.001006522 0.108050577 0.108050577 0.007864989 HYDROGEN 0 0.975000024 0.900769353 0.835696876 0.835696876 0.761562705 METHANE 0 0.025 0.082961343 0.049177725 0.049177725 0.070953541 CH 0 0 0.015262667 0.007074837 0.007074837 0.159618795

Heat and Material BalancesTable 3. Material Balances on Cyclohexane Unit (Continued)Stream Name S1 S10 S11 S13 S12 S6 S7

Stream Description

Phase Mixed Liquid Vapor Vapor Vapor Vapor Vapor

Temperature F 119.9999542 119.9999542 119.9999542 119.9999542 119.9999542 299.999939 434.999939Pressure PSIA 365 365 365 365 365 390.0000305 375.0000305

Flowrate LB-MOL/HR 2532.243408 396.144928 2136.098633 1708.878906 427.2197266 3667.458984 2532.243408

Composition BENZENE 0.007864989 0.044847317 0.001006522 0.001006522 0.001006522 0.108609602 0.007864989 HYDROGEN 0.761562705 0.010929798 0.900769353 0.900769353 0.900769353 0.835367918 0.761562705 METHANE 0.070953541 0.006204838 0.082961343 0.082961343 0.082961343 0.048990767 0.070953541 CH 0.159618795 0.938018024 0.015262667 0.015262667 0.015262667 0.007031692 0.159618795

Reactor Material Selection

High-alloy stainless-steel should be used

Hydrogen not compatible with carbon-steel

Cast-iron not durable at reactor operating conditions (375 psia and 435oF)

Pump Work Requirements

Equivalent pipe lengths were found PRO/II used to find pump work requirements Pump work found to be 12.6HP, or 9.4 kW

Table 5. Pump PropertiesPump Name P1

Pump Description

Pressure Gain PSI 248.413

Head FT 760.313

Work HP 12.5526

Pump Selection

Gear pump chosen Positive displacement pump Stainless-steel case, gears, and shaft Can process liquids containing small

amounts of vapor Handles 83 gal/min flow rate Handles 1.7 MPa pressure gain

NPSHA and System Head vs. Flow Rate

1066.00

1067.00

1068.00

1069.00

1070.00

1071.00

1072.00

1073.00

1074.00

0 100 200 300 400 500 600 700 800 900 1000

Cyclohexane Flow Rate (ft3/h)

NP

SH

A (

ft)

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

Sys

tem

He

ad (

ft)

NPSHA

Hs

Fixed Capital Investment

Table 6: Fixed Capital Investment for Pump Section

Total Pipe Cost (Tees, Elbows) $2,026 Total Valve Cost (Gate, Check) $2,281 Total Pump Cost (Gear) $7,659 Total Purchased Equipment Cost $11,966 Equipment Delivery (10% of Purchased Cost) $1,197 Total Delivered Equipment Cost $13,163 Labor and Materials for Installation (31% of Purchased Cost) $3,709 Total Installed Equipment Cost (FCI for Pump Section) $16,872

Assignment 6

Design of the Heat Exchanger Network

Cyclohexane Production Unit

M1 E1

E2

F1

SP1

C1

R1

E3

BENZENE

HYDROGEN

S3

S5

S4

S6

S7

S9 S10

S11

S12

S13

S1

500 psig

Eff. 80%

Purge Gas

Product

DP=15 psi

300 F

120 F

Recycle

E1

E3

E2

Selection of Material Shell-and-Tube Heat

Exchangers Different stream

composition in each side

CAUTION! Hydrogen causes damage to carbon steel and low alloy metals; stainless steel must be used

Hand Design

Exchanger E1 designed for two cases: Single-Pass Tubes Double-Pass Tubes

Equipment cost determined for each design

T-Q Diagram compared

Overall Heat Transfer Coefficient• U = 52 Btu/hr·ft2·˚F

Heat Transfer Area• A = 1288 ft2

Tubes• Length = 16 ft• OD = 0.750 in• Number = 411

Cost = $22,000

Overall Heat Transfer Coefficient• U = 63 Btu/hr·ft2·˚F

Heat Transfer Area• A = 1119 ft2

Tubes• Length = 16 ft• OD = 0.750 in• Number = 179

Cost = $20,000

Single-Pass Double-Pass

T-Q Diagram for E1

Pro/II Design

Rigorous heat exchanger model used for exchanger E1

Tube length and diameter and shell diameter were varied to produce the smallest heat transfer area

Minimize heat transfer area Minimize cost

Pro/II Design

Shell-and-Tube double-pass heat exchanger Overall heat transfer coefficient, U = 129

Btu/hr·ft2·˚F Heat transfer area, A = 964 ft2

Tubes: Length = 16 ft OD = 0.750 in Number = 19

Cost of Exchanger E1 = $ 21,715

Fixed Capital InvestmentFixed Capital Investment = Direct Costs + Indirect Costs

Based on purchased equipment delivered cost• E1: Stainless steel shell and tubes• E2: Carbon steel shell, stainless steel tubes• E3: Carbon steel shell, stainless steel tubes

Assuming the same heat transfer area for each exchanger as E1 found from Pro/II, the costs are• E1 = $ 21,715• E2 = E3 = $ 20,370• Total purchased equipment cost = $ 62,500

Fixed Capital Investment

Distillation Column Design

Pro/II software used Specified:

Reflux ratio = 24 Bottom stream = 0.985 mole fraction cyclohexane

Resulted in design specifications of Pressure = 14.7 psia Number of stages = 30 Feed tray = 16 Tray Spacing = 24 in Tray type: Valve, 15 in minimum diameter Column diameter = 78 in Column height = 60 ft

THANK YOU!

Questions?