Design Project Spring 2015

Computer-Aided Process Design ProjectDevelopment of a Saturated Gas Plant

Dr. Stephen Dufreche

Spring 2015

Contents1 Project Description 2

1.1 Project Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2 Design Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.3 Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.4 Battery Limit Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.5 Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.6 Site Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.7 Utility Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.8 Miscellaneous Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 61.9 Economic Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2 Written Report Requirements 82.1 Submission Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.2 Section List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

List of Tables1 Product Sale Prices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Product Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Feed Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Naphtha and Diesel Definitionsa . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Utilities Battery Limits Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Motor Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Environmental Site Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Utility Cost Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Based on original design by FLUOR

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UL Lafayette Computer-Aided Process Design Development of a Saturated Gas Plant

1 Project DescriptionA Gulf Coast Oil Company has several gas and liquid streams that contain potentially valuablelight ends. They plan to form a joint venture with your company for processing these streams. Theterms of the joint venture are simple.

The refinery will provide the feed streams as defined.

The refinery will provide all utilities and optional feed streams at the defined tolling costs.

The refinery will purchase all fuel gas produced from the facility. Other products will beshipped via existing pipelines or through the refinery truck loading terminal.

Your company will cover all capital and operating costs.

The open book profits will be split 50/50 between your company and the refinery.

The goal of the project team is to determine the optimum economic products that can be producedform these streams, and design the unit that will produce these product streams. All productspecifications as presented in the design basis must be met.

1.1 Project ApproachThe Project Team will approach the project in two phases.

Phase 1 A preliminary Process Flow Diagram, heat and material balance, major equipment siz-ing, and preliminary cost estimate will be prepared. No commercial process simulator programsmay be used for Phase 1, but spreadsheets and other computer software may be used.

Phase 2 The preliminary process scheme developed in Phase 1 will be optimized so that thedesign reflects the economic optimum unit. A process simulator can be used in this Phase. Thefinal Process Flow Diagrams, heat and material balance, equipment sizing, utility summary, costestimate, and operating costs will be prepared.

1.2 Design BasisThe refinery will operate under the assumption that only products listed in Table 1 will have a viablemarket. This restricts the design of your plant to only producing these streams. Any additionalwaste streams may be sold back to the refinery as fuel gas with its price set by the lower heatingvalue. You are not required to produce all of the product streams. However, all streams must meetthe requirements listed in Table 2 to be considered for sale.

In addition to the feed streams listed in Table 3, you have the option of using up to 30,000BPD of lean oil (diesel) from the refinery. The lean oil can be used to recover additional lightends/naphtha within your process scheme and returned to the refinery crude unit. There is a refineryprocessing fee of $5/bbl of recovered material for this service. Assume that any recovered materialcomes back to your unit as additional material in the crude off gas.

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Table 1: Product Sale PricesProduct Bulk Pricing

Propane 42.50 $/bbliso-Butane 55.00 $/bblCommercial Butane 47.00 $/bblNaphtha 80.00 $/bblFuel Gas 7.00 $/MMBTU

Table 2: Product Specifications

Product Max P at 100 F Max vol% Max H2S[psia] C3 C

4 C4 nC+4 C+5 [ppm]

Propane (HD-5) 208 - - 2.5 - - -iso-Butane - 2.0 - - 2.0 - 4Commercial Butane 70 - - - - 2.0 4Naphtha 10 - 1.0 - - - -Fuel Gas - - - - - - 50

The naphtha content of the rich oil returned to the refinery must be at least as high as in thelean oil from the refinery. Lean oil has a temperature of 100 F, 75 psig, and a maximum flow rateof 20,000 BPD. The stream contains 10% naphtha (C6-350

F) and 90% diesel (350 F-650 F).Specifications for these compounds can be found in Table 4.

1.3 Design ConsiderationsThe following design considerations should be adhered to in determining the unit configurationand specifying equipment:

All compressors must have a knockout drum preceding the compressor inlet.

All hydrocarbon pumps must be fed from a vessel.

Fractionation towers should be designed for a maximum of 80% of flood and use conven-tional trays.

1.4 Battery Limit ConditionsAll process products should leave the unit at 60 psig and 100 F, except for propane, which will be300 psig and 100 F. The required battery limits conditions for utilities are presented in Table 5.Design conditions in this table refer to mechanical requirements. The operating conditions shouldbe used for actual process conditions.

Lean amine is available from the refinery for $4.50/1000 gal while the rich amine is returnedback to the refinery. The amine is 40 wt% MDEA, with a lean amine acid loading of 0.001-0.01mol/mol and a maximum rich amine acid loading of 0.45 mol/mol. The refinery has agreed toprocess any sour water generated by your facility at a charge of $3.80/1000 gal.

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Tabl

e3:

Feed

Spe

cific

atio

ns

Prod

uct

Hyd

rotr

eate

rStr

eam

sC

rude

Stre

ams

Off

-Gas

Wild

Nap

htha

LP

Sepa

rato

rW

ildN

apht

haO

ff-G

as

Phas

eV

apor

Liq

uid

Vap

orL

iqui

dV

apor

Tem

pera

ture

[F

105

105

127

105

105

Pres

sure

[psi

g]80

175

250

100

8

Com

pone

ntFl

ow[l

bmol

/hr]

Wat

er7.

931.

311.

302.

6219

.56

Am

mon

ia0.

260.

150.

030.

030.

02H

2S93

.08

38.3

66.

845.

812.

37H

ydro

gen

106.

950.

9522

9.73

0.04

6.98

Met

hane

108.

636.

3053

.79

0.22

8.36

Eth

ane

104.

9030

.08

22.8

115

.38

41.3

1Pr

opan

e15

3.68

130.

029.

6112

5.45

164.

17is

o-B

utan

e90

.09

138.

43.

4076

.71

34.4

3n-

But

ane

73.4

913

2.32

2.30

230.

9786

.33

iso-

Pent

ane

46.1

616

7.77

1.14

160.

7324

.62

n-Pe

ntan

e18

.99

78.8

70.

3454

0.37

39.0

5H

eavy

Nap

htha

10.5

316

5.18

0.93

2758

.20

26.0

7

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Table 4: Naphtha and Diesel Definitionsa

Liquid Volume [%] Naphtha [ F] Diesel [ F]

0 149 35610 155 42130 163 48650 169 53370 176 56690 272 616100 356 666

Standard Density [ API] 63.7 39.2a)Distillation Method D-86

Table 5: Utilities Battery Limits Conditions

Utility Service Operating Designpsig [ F] psig [ F]

High Pressure Steam 630 725 675 750Medium Pressure Steam 441 627 500 665Low Pressure Steam 165 337 190 425Low Pressure Condensate 25 265 30 275High Pressure BFW 980 250 1100 280Cooling Water Supply 65 90 150 150Cooling Water Return 40 120 (max) 150 150Nitrogen 350 90 610 100Natural Gas 120 100 175 150Lean Amine 250 140 300 165Rich Amine (return) 50 160 (max) 170 200Instrument Air 90 90 135 150Plant Air 100 90 135 110Domestic/Potable Water 140 95 150 120Sour Water (return) 50 120 (max) 100 150

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Table 6: Motor Electrical DataPower Voltage Phase/Hertz

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HP 115 1/6034 HP 200 460 3/60

200 HP 5000 4000 3/60HP > 5000 13200 3/60

Table 7: Environmental Site DataPlant Elevation Above Sea Level [ft] 38Barometric Pressure [psia] 14.68Extreme Maximum [ F] 110Extreme Minimum [ F] 10Maximum Design [ F] 105Minimum Design [ F] 20Design for Winterization [ F] 25Temperature for Air-cooler Design [ F] 95Annual Average Temperature [ F] 68.5Design Wet Bulb Temperature [ F] 80Average Humidity [%] 70

1.5 Electrical DataThe required voltage supply shall be based on the motor size as defined in Table 6.

1.6 Site DataThe unit design shall conform to the most stringent site data shown in Table 7.

1.7 Utility CostsThe utility cost data supplied in Table 8 shall be used for economic evaluations. Note that thesteam and condensate prices apply for either buying from or selling back to the refinery.

1.8 Miscellaneous Design RequirementsInventory: No onsite storage is required for the primary materials, but if additional materials areutilized in the process, sufficient storage should be provided to cater for the expected needs of 30days of operation.

Materials of Construction (MOC) Determine acceptable MOC for this process, and clearlystate what MOC you are using in your cost basis.

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Table 8: Utility Cost Schedule

High Pressure Steam $8.00 / 1000 lbMedium Pressure Steam $6.00 / 1000 lbLow Pressure Steam $4.50 / 1000 lbLow Pressure Condensate $0.51 / 1000 lbHigh Pressure BFW $0.57 / 1000 lbCooling Water $0.08 / 1000 galElectricity $0.08 / kW-hrNitrogen $1.00 / MSCFNatural Gas (100% methane) $8.00 / MMBTUaaCost referred to LHV

Equipment Ratings Maximum allowable working pressure (MAWP) for pressure vessels mustbe specified, including overpressure protection systems.

On-Stream Factor In order to achieve the on-stream factor, all rotating equipment required forunit operation except for centrifugal compressors will require sparing.

Process Structure Document the overall size and cost of the process structure needed to safelysupport the process, and list any applicable assumptions used (e.g., cost per square meter of struc-ture area).

Safety and Environmental Regulations for the U.S. and State of Louisiana must be followed.Wastes are to be handled in a manner that meets all State of Louisiana and Federal regulations.Hydrocarbon emissions to both air and water will be closely monitored and reported to the properauthorities after normal, day-to-day operation is attained after start-up.

HeatX Minimum Approach The Tmin is 15 F when the temperatures are in normal rangesand 5 F when refrigerants are used.

Site Location Plant location is on the Louisiana gulf coast (barge traffic is available).

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1.9 Economic Guidelines Purchased Equipment Cost may be estimated by methods in the course text. Cost factors are

to be based on Louisiana Gulf Coast delivery.

Fuel, steam, cooling water, and electricity are purchased for the plant.

Capital Estimate may be made using methods from the course text.

Working Capital and other Economic Factors may be estimated using the cost factors givenin the course text.

Net present worth should be used to evaluate alternatives.

Depreciation should be based on 10 years straight line for In-Site Boundary Limits (ISBL)and 15 years straight line for off-sites.

Off-sites capital cost are assumed to be 30% of ISBL.

Discounted Cash Flow Analysis should assume:

1. 4Q 2012 startup

2. Ten year project life

3. Tax rates of 34% Federal and 6% State.

Interest rate on capital is 9%.

Maintenance, insurance, and plant overheads are estimated to be 4.0% of fixed investment.

Use a contingency of 20%.

2 Written Report Requirements

2.1 Submission GuidelinesA written report is required as the final deliverable in CHEE408. The report will be submitted inboth paper and electronic formats. A PDF of the entire document, including appendixes, refer-ences, and ASPEN printouts must be uploaded to Moodle on April 27th. A 30-minute presentationwill also be given by each group an May 1st. A panel of judges from industry and academia willbe present to grade each group on their presentation style and technical content.

The written report must be bound with a two-piece report cover having a minimum capacityof 3 inches. Pages larger than standard letter size such as the 11"x17" PFD drawings should befastened in a landscape orientation and folded to fit within the cover. Fonts should be no smallerthan 12 pt double-spaced with the exception of figures and tables which may use 10 pt. Marginsfor single-sided documents should be 1" on top and bottom, 1.5" on the left, and 0.5" on the right.Documents which are printed on both sides of the paper should be 1" on top and bottom, 1.5" onthe spine edge, and 0.5" on the opposite side.

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2.2 Section ListThe following is a list of required sections in the final written report. Follow the order listed belowwhen assembling the document.

1. Letter of TransmittalTo include plant capacity, construction cost, materials cost, yearly profit, and RoI

2. Title Page

3. Table of Contents

4. Abstract

5. Introduction and Customer Requirements

6. Conceptual Design

(a) Preliminary Process SynthesisA listing of previous attempts at flow sheet synthesis. This includes the various itera-tions of design from throughout the semester. Describe why a design was tried and whyit was discarded.

(b) Assembly of Data ValuesA listing of primary physical property information as well as costs and specificationsof products.

7. Feasibility and Development

(a) PFD and Material BalancesA PFD in Dia or another computer-aided design package. Stream tables should beincluded with pressure, temperature, phase, and mass flow rate of each compound.

(b) Process DescriptionThis section walks a reader through the flow sheet. Detailed information is coveredin the section on Equipment Design, but should be referenced here. Alternatives frompreviously-discarded designs can also be mentioned here with the reason for omission.

(c) Energy Balance and Utility RequirementEach equipment which uses a heating, cooling, electrical, or other utility should belisted here. It should include the magnitude of energy required and how the need wasmet (type of utility, how much, etc.).

(d) Equipment List and Unit DescriptionsEvery piece of equipment on the PFD is listed here. The methods of design and cal-culation should be listed for each one along with basis for calculation, difficulties en-countered, limitations in design, etc.

(e) Specification SheetsIn the manner of Figure 26.1 of your textbook, one per page

(f) Equipment Cost Summary

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(g) Fixed-Capital Investment Summary

(h) Operating Cost and Economic Analysis

8. Safety and Environmental

(a) HAZOP AnalysisStandard HAZOP analysis on your final flowsheet

(b) Environmental Regulations and PermittingA list of regulations applicable to the given plant site under which your design may becovered. Detail methods for remaining in compliance with the listed regulations.

9. Conclusions and Recommendations

10. Acknowledgments

11. Bibliography

A: Raw calculations for M&E Balances, Sizing, and Costing

B: Computer programs developed during project (Excel, Polymath, MATLAB)Excel sheets with formulas displayed, Polymath or MATLAB code, etc.

C: Complete Aspen report generated from final designThe full report option in Aspen can be used to generate this appendix. Make sure that thetext is formatted in monospace font and easily readable when printed.

D: Extra printed material not included in the other sections

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