Pressure Vessel [Design]

PRESSURE VESSEL:PRESSURE VESSEL:Perancangan, FabrikasiPerancangan, Fabrikasi

dan Inspeksidan Inspeksi

Ir. Tri Prakosa, M.Eng.Ir. Tri Prakosa, M.Eng.

LAPI-ITB (22-25 Oktober 2009)LAPI-ITB (22-25 Oktober 2009)

11

2. DESIGN OVERVIEW2. DESIGN OVERVIEW

22

33

OVERVIEW PERANCANGAN BEJANA TEKANOVERVIEW PERANCANGAN BEJANA TEKAN((PRESSURE VESSELPRESSURE VESSEL), BERDASARKAN ASME ), BERDASARKAN ASME

CODE SECTION VIIICODE SECTION VIII

ASME International

PengantarPengantar Material Material Pressure VesselPressure Vessel Perancangan (Perancangan (DesignDesign)) Pertimbangam Pertimbangam

Perancangan LainPerancangan Lain Pembuatan (Fabrikasi)Pembuatan (Fabrikasi) Inspeksi dan TestingInspeksi dan Testing

44

Definisi Pressure VesselsDefinisi Pressure Vessels

Wadah fluida yang bertekananWadah fluida yang bertekananDigunakan di beberapa industri, antara Digunakan di beberapa industri, antara lain:lain:– – Perusahaan minyakPerusahaan minyak– – Perusahaan kimiaPerusahaan kimia– – Pembangkit tenagaPembangkit tenaga– – Pabrik pulp dan kertasPabrik pulp dan kertas– – Pabrik makanan, dllPabrik makanan, dll

55

Jenis-jenis pressure vesselJenis-jenis pressure vessel

66

Drum HorisontalDrum Horisontaltumpuan Saddletumpuan Saddle

77

Gambar 2.1

Drum Vertikal tumpuan KakiDrum Vertikal tumpuan Kaki

88Gambar 2.2

1. Sebagian besar head berbentuk kurva lengkung karena alasan kekuatan, tipis dan ekonomi.

2. Bentuk Semi eliptik (Semi-elliptical shape) adalah bentuk yang umum digunakan.

3. Drum kecil vertikal biasanya ditumpu dengan kaki.• Perbandingan maksimum

antara panjang kaki dengan diameter biasanya 2:1.

• Jumlah kaki, ukuram dan detail tambahan tergantung pada besar beban.

Menara Vertikal TinggiMenara Vertikal Tinggi

99Gambar 2.3

1. Nozzel dihubungkan dengan:• Sistem perpipaan• Koneksi instrumen• Manways• Sambungan instrumen

lainnya2. Ujung nozzel biasanya

berbentuk flens.3. Kadangkala nozzel

menjorok ke dalam vessel.

Reaktor VertikalReaktor Vertikal

1010

Gambar 2.4

Tangki BolaTangki BolaPenyimpan (bertekanan)Penyimpan (bertekanan)

1111Gambar 2.5

Vertical Vessel on Lug SupportsVertical Vessel on Lug Supports

1212Gambar 2.6

1 – 10 ft diameter

2:1 to 5:1 height/diameter ratio

Ruang LingkupRuang LingkupASME Code Section VIIIASME Code Section VIII

Section VIII digunakan di seluruh duniaSection VIII digunakan di seluruh dunia

Tujuan: Penyajian syarat minimal untuk Tujuan: Penyajian syarat minimal untuk keamanan konstruksi dan operasikeamanan konstruksi dan operasi

Terdiri dari tiga divisi: 1, 2, dan 3Terdiri dari tiga divisi: 1, 2, dan 3

1313

Section VIII Division 1Section VIII Division 1

15 psig < P ≤ 3000 psig15 psig < P ≤ 3000 psig

Berlaku sampai dengan koneksi pertama ke pipaBerlaku sampai dengan koneksi pertama ke pipa

Pengecualian lainPengecualian lain

– – Peralatan internal (kecuali yang dilas ke vessel)Peralatan internal (kecuali yang dilas ke vessel)

– – Pemanas proses yang menggunakan apiPemanas proses yang menggunakan api

– – Bejana tekan yang bersatu dengan mesinBejana tekan yang bersatu dengan mesin

– – Sistem perpipaanSistem perpipaan

1414

Section VIII, Division 2,Section VIII, Division 2,Aturan AlternatifAturan Alternatif

Ruang lingkup identik dengan divisi 1 tetapi Ruang lingkup identik dengan divisi 1 tetapi berbeda persyaratan dalam hal:berbeda persyaratan dalam hal:

– – Tegangan yang diijinkanTegangan yang diijinkan

– – Perhitungan teganganPerhitungan tegangan

– – PerancanganPerancangan

– – Kontrol kualitasKontrol kualitas

––Fabrikasi dan inspeksiFabrikasi dan inspeksi

Pemilihan antara divisi 1 dan 2 tergantung Pemilihan antara divisi 1 dan 2 tergantung pertimbangan ekonomipertimbangan ekonomi

1515

Division 3, Alternative RulesDivision 3, Alternative RulesHigh Pressure VesselsHigh Pressure Vessels

Applications over 10,000 psiApplications over 10,000 psi

Pressure from external source, processPressure from external source, process

reaction, application of heat, combinationreaction, application of heat, combination

of theseof these

Does not establish maximum pressureDoes not establish maximum pressure

limits of Division 1 or 2 or minimum limitslimits of Division 1 or 2 or minimum limits

for Division 3.for Division 3.

1616

Structure of Section VIII,Structure of Section VIII,Division 1Division 1

Subsection ASubsection A– – Part UG applies to all vesselsPart UG applies to all vesselsSubsection BSubsection B– – Requirements based on fabrication methodRequirements based on fabrication method– – Parts UW (weld), UF (Forged), UB (brazed)Parts UW (weld), UF (Forged), UB (brazed)Subsection CSubsection C– – Requirements based on material classRequirements based on material class– – Parts UCS, UNF, UHA, UCI, UCL, UCD (Cast Parts UCS, UNF, UHA, UCI, UCL, UCD (Cast Ductile Iron), UHT (heat treatment),Ductile Iron), UHT (heat treatment), ULW (layered construction), ULT (low ULW (layered construction), ULT (low temperature)temperature)Mandatory and Nonmandatory AppendicesMandatory and Nonmandatory Appendices

1717

Contoh Mandatory (Wajib)Contoh Mandatory (Wajib)

Rumus-rumus Rancangan tambahanRumus-rumus Rancangan tambahan

Aturan untuk sambungan flens baut, Aturan untuk sambungan flens baut, dengan gasket tipe ringdengan gasket tipe ring

Vessel yang penampangnya bukan Vessel yang penampangnya bukan lingkaranlingkaran

Aturan rancangan untuk sambungan Aturan rancangan untuk sambungan clampclamp

1818

Contoh yang Non-mandatoryContoh yang Non-mandatory

Saran (Saran (good practicegood practice) untuk struktur ) untuk struktur internalinternal

Aturan rancangan tubesheetAturan rancangan tubesheet

dlldll

1919

Kelas BahanKelas Bahan

Material Covering

Code part

Applicable Code

stress value tables

Remarks

Carbon and

low-alloy

steels

UCS Code Section II,

Part D, Table 1A

Basis for establishing stress values—Code Appendix P,UG-23

Low-temperature service requires Pars. UCS-65,UCS-66, UCS-67, UCS-68, UG-84 Code Figs. UCS-66, UCS-66.1,UCS-66.2

In high-temperature operation, creep strength is essential

Design temperature—Code Par. UG-20

Design pressure—Code Par. UG-21, Fn. 8

Temperature above 800°F may cause carbide phase of carbon steel to convert to graphite

Pipe and tubes—Code Pars. UG-8, UG-10, UG-16, UG-31,UCS-9, UCS-27

Creep and rupture properties—Code Par. UCS-151

2020

Kelas Bahan, Kelas Bahan, ((sambungan)sambungan)Material Covering

Code part

Applicable Code

stress value tables

Remarks

Nonferrous

metals

UNF Code Section II,

Part D, Table 1B

Basis for establishing values— Code, Appendix P, UG-23

Metal characteristics—Code

Par. UNF, Appendix NF, NF-1 to NF-14

Low-temperature operation— Code Par. UNF-65

Nonferrous castings—Code Par. UNF-8

High-alloy

steels

Castings

UHA Code Section II,

Part D, Table 1A

Selection and treatment of austenitic chromium–nickel

steels—Code Par. UHA-11, UHA Appendix HA, UHA-100

to UHA-109

Inspection and tests—Code Pars. UHA-34,UHA-50, UHA-

51, UHA-52

Liquid penetrant examination required if shell thickness

exceeds 3⁄4 in—all 36% nickel steel welds—Code Par. UHA-34

Low-temperature service—Code Pars. UHA-51, UG-84

High-alloy castings—Code Pars. UHA-8, UG-7 Code Par. Ug-7

Code Pars. UG-11, UG-24, UCS-8—Code Appendix 7

2121

Kelas Bahan , Kelas Bahan , ((sambungan)sambungan)

Material Covering

Code part

Applicable Code

stress value tables

Remarks

Cast iron

Dual cast iron

UCI

UCI

UCI-23 Vessels not permitted to contain lethal or flammable substances —Code Par. UCI-2

Selection of materials—Code Pars. UCI-5, UCI-12, UG-11,

UCS-10, UCS-11, UCI-3, UCI-1,UG-10

Inspection and tests—Code Pars. UCI-90, UCI-99, UCI-101,UCI-3

Repairs in cast-iron materials— Code Par. UCI-78

Code Pars. UCI-1, UCI-23, UCI 29

Integrally

clad plate,

weld metal

overlay, or

applied

linings

UCL (See Code Pars.

UCL-11, UCL 23.)

Suggest careful study of entire metal UCL section

Selection of materials—Code Pars. UCL-1, UCL-3, UCL 10,

UCS-5, UF-5, ULW-5, UCL-11, UCL-12, UG-10

Qualification of welding procedure—Code Pars. UCL-40 to -46

Post-weld heat treatment—Code Pars. UCL-34, UCS-56 (including cautionary footnote)

Inspection and test—Code Pars.UCL-50, UCL-51, UCL-52

Spot radiography required if cladding is included in computing required thickness—Code Par. UCL-23(c)

Use of linings—Code Par. UG- 26 and Code Appendix F

2222


Material Covering

Code part

Applicable Code

stress value tables

Remarks

Welded and

seamless pipe

and tubes (carbon

and low alloy

steels)

Welded and

seamless pipe

(high-alloy

steels)

UCS

UHA

Code Section II,

Part D, Table 1A

Code Table 1A

Thickness under internal pressure—Code Par. UG-27

Thickness under external pressure—Code Par. UG-28

Provide additional thickness when tubes are threaded and

when corrosion, erosion, or wear caused by cleaning is expected —Code Par. UG-31

For calculating thickness required, minimum pipe wall thickness is 87.5 percent of nominal wall thickness

30-in maximum on welded pipe made by open-hearth, basic oxygen, or electric-furnace process— Code Par. USC-27

2323


Material Covering

Code part

Applicable Code

stress value tables

Remarks

Forgings

Low- temperature materials

Layered

Construction

Ferritic steels with tensile

properties

enhanced by

Hea-ttreatment

UF

ULT

ULW

UHT

Code Section II,

Part D, Table 1A

ULT-23

Code Table 1A

Materials—Code Pars. UG-6, UG-7, UG-11, UF-6, UCS-7 and Section II, Part D, Table 1A

Welding—Code Par. UF-32 (see also Section IX Code Par. QW- 250 and Variables, Code Pars. QW-404.12, QW-406.3, QW- 407.2, QW-409.1 when welding forgings)

Operation at very low temperatures, requires use of notch

tough materials

Vessels having a shell and/or heads made up of two or more separate layers—Code Par. ULW-2

Scope—Code Par. UHT-1

Marking on plate or stamping, use “low-stress” stamps—Code Par. UHT-86

2424

Material Selection FactorsMaterial Selection Factors

Strength

Corrosion Resistance

Resistance to Hydrogen Attack

Fracture Toughness

Fabricability

2525

StrengthStrength

Determines required component thicknessDetermines required component thickness

Overall strength determined by:Overall strength determined by:

– – Yield StrengthYield Strength

– – Ultimate Tensile StrengthUltimate Tensile Strength

– – Creep StrengthCreep Strength

– – Rupture StrengthRupture Strength

2626

Corrosion ResistanceCorrosion Resistance

Deterioration of metal by chemical actionDeterioration of metal by chemical action

Most important factor to considerMost important factor to consider

Corrosion allowance supplies additionalCorrosion allowance supplies additional

thicknessthickness

Alloying elements provide additionalAlloying elements provide additional

resistance to corrosionresistance to corrosion

2727

Resistance toResistance toHydrogen AttackHydrogen Attack

At 300 - 400°F, monoatomic hydrogenAt 300 - 400°F, monoatomic hydrogen

forms molecular hydrogen in voidsforms molecular hydrogen in voids

Pressure buildup can cause steel to crackPressure buildup can cause steel to crack

Above 600°F, hydrogen attack causesAbove 600°F, hydrogen attack causes

irreparable damage through componentirreparable damage through component

thicknessthickness

2828

Serangan HidrogenSerangan Hidrogen

Hydrogen permeated into the steel can react with Hydrogen permeated into the steel can react with carbon, resulting in the formation of methane: C(Fe) + carbon, resulting in the formation of methane: C(Fe) + 2H2 <==> CH4.2H2 <==> CH4.The methane is more or less trapped in the metal The methane is more or less trapped in the metal structure and will accumulate in voids in the metal structure and will accumulate in voids in the metal matrix. The gas pressure in these voids can generate matrix. The gas pressure in these voids can generate an internal stress high enough to fissure, crack or an internal stress high enough to fissure, crack or blister the steel. blister the steel. As the reaction that forms methane consumes the As the reaction that forms methane consumes the carbon that is present in the steel, hydrogen attack is carbon that is present in the steel, hydrogen attack is also called "internal also called "internal decarburization".".Hydrogen attack will result in degradation of Hydrogen attack will result in degradation of mechanical properties, as tensile strength and mechanical properties, as tensile strength and ductility drop dramatically, and can lead to failure due ductility drop dramatically, and can lead to failure due to crack formation.to crack formation.

2929

Brittle FractureBrittle Fractureand Fracture Toughnessand Fracture Toughness

Fracture toughness: Ability of material toFracture toughness: Ability of material to

withstand conditions that could causewithstand conditions that could cause

brittle fracturebrittle fracture

Brittle fractureBrittle fracture

– – Typically at “low” temperatureTypically at “low” temperature

– – Can occur below design pressureCan occur below design pressure

– – No yielding before complete failureNo yielding before complete failure

3030

Brittle Fracture andBrittle Fracture andFracture Toughness, cont’dFracture Toughness, cont’d

Conditions required for brittle fractureConditions required for brittle fracture

– – High enough stress for crack initiationHigh enough stress for crack initiation

and growthand growth

– – Low enough material fracture toughnessLow enough material fracture toughness

at temperatureat temperature

– – Critical size defect to act as stressCritical size defect to act as stress

concentrationconcentration

3131

Factors That InfluenceFactors That InfluenceFracture ToughnessFracture Toughness

Fracture toughness varies with:Fracture toughness varies with:- Temperature- Temperature- Type and chemistry of steel- Type and chemistry of steel- Manufacturing and fabrication processes- Manufacturing and fabrication processes

Other factors that influence fracture toughness:Other factors that influence fracture toughness:- Arc strikes, especially if over repaired area- Arc strikes, especially if over repaired area- Stress raisers or scratches in cold formed thick- Stress raisers or scratches in cold formed thick plateplate

3232

Setup Uji Charpy V-NotchSetup Uji Charpy V-Notch

3333

http://www.twi.co.uk/j32k/twiimages/jk71f2.gif

ASME Code andASME Code andBrittle Fracture EvaluationBrittle Fracture Evaluation

Components to considerComponents to consider– – ShellsShells – Nozzles– Nozzles– – ManwaysManways – Tubesheets– Tubesheets– – HeadsHeads – Flanges– Flanges– – Reinforcing padsReinforcing pads – Flat cover plates– Flat cover plates– – Backing stripsBacking strips – Attachments essential– Attachments essential that remain inthat remain in to structural integrity to structural integrity placeplace that are welded to that are welded to

pressure parts pressure parts (contoh:(contoh:

pressure support)pressure support)

3434

Temperatures to ConsiderTemperatures to Consider

Minimum Design Metal TemperatureMinimum Design Metal Temperature

(MDMT)(MDMT)

– – Lowest temperature at which componentLowest temperature at which component

has adequate fracture toughnesshas adequate fracture toughness

Critical Exposure Temperature (CET)Critical Exposure Temperature (CET)

– – Minimum temperature at which significantMinimum temperature at which significant

membrane stress will occurmembrane stress will occur

3535

Simplified ASMESimplified ASMEEvaluation ApproachEvaluation Approach

Material specifications classified intoMaterial specifications classified intoMaterial Groups A through DMaterial Groups A through DImpact test exemption curvesImpact test exemption curves– – For each Material GroupFor each Material Group– – Acceptable MDMT vs. thickness where impactAcceptable MDMT vs. thickness where impact testing not requiredtesting not requiredIf combination of Material Group andIf combination of Material Group and

thickness not exempt, then must impact test at thickness not exempt, then must impact test at CETCET

3636

Material GroupsMaterial Groups

MATERIAL

GROUPAPPLICABLE MATERIALS

Curve A

•All carbon and low alloy steel plates, structural shapes, and bars not listed in Curves B, C & D•SA-216 Gr. WCB & WCC, SA-217 Gr. WC6, if normalized and tempered or water-quenched and tempered

Curve B

•SA-216 Gr. WCA, if normalized and tempered or water-quenched and tempered•SA-216 Gr. WCB & WCC for maximum thickness of 2 in., if produced to fine grain practice and water-quenched and tempered•SA-285 Gr. A & B•SA-414 Gr. A•SA-515 Gr. 60•SA-516 Gr. 65 & 70, if not normalized•Except for cast steels, all materials of Curve A if produced to fine grain practice and normalized which are not included in Curves C & D•All pipe, fittings, forging, and tubing which are not included in Curves C & D

3737

Material Groups, cont’dMaterial Groups, cont’d

MATERIAL GROUP APPLICABLE MATERIALS

Curve C

•SA-182 Gr. 21 & 22, if normalized and tempered•SA-302 Gr. C & D•SA-336 Gr. F21 & F22, if normalized and tempered•SA-387 Gr. 21 & 22, if normalized and tempered•SA-516 Gr. 55 & 60, if not normalized•SA-533 Gr. B & C•SA-662 Gr. A•All material of Curve B if produced to fine grain practice and normalized which are not included in Curve D

Curve D

•SA-203 • SA-537 Cl. 1, 2 & 3

SA-508 Cl. 1 • SA-612, if normalized

• SA-516, if normalized • SA-662, if normalized

• SA-524 Cl. 1 & 2 • SA-738 Gr. A

Bolting and Nuts

See Gambar UCS-66 of the ASME Code Section VIII, Div. 1, for impact

test exemption temperatures for specified material specifications

3838Table 3.1 (Excerpt)

Impact Test Exemption CurvesImpact Test Exemption Curvesfor Carbon and Low-Alloy Steelfor Carbon and Low-Alloy Steel

3939

Gambar 3.1

Additional ASME Code ImpactAdditional ASME Code ImpactTest RequirementsTest Requirements

Required for welded construction over 4 Required for welded construction over 4 in. thick, or nonwelded construction over 6 in. thick, or nonwelded construction over 6 in.in. thick, if MDMT < 120°Fthick, if MDMT < 120°F

Not required for flanges if temperatureNot required for flanges if temperature

≥ ≥ -20°F-20°F

Required if SMYS > 65 ksi unlessRequired if SMYS > 65 ksi unless

specifically exemptspecifically exempt

4040

Additional ASME CodeAdditional ASME CodeImpact Test Requirements, cont’dImpact Test Requirements, cont’d

Not required for impact tested lowNot required for impact tested low

temperature steel specificationstemperature steel specifications

– – May use at impact test temperatureMay use at impact test temperature

30°F MDMT reduction if PWHT P-1 steel30°F MDMT reduction if PWHT P-1 steel

and not required by codeand not required by code

MDMT reduction if calculated stress <MDMT reduction if calculated stress <

allowable stressallowable stress

4141

FabricabilityFabricability

Ease of constructionEase of construction

Any required special fabrication practicesAny required special fabrication practices

Material must be weldableMaterial must be weldable

4242

Maximum Allowable StressMaximum Allowable Stress

Stress: Force per unit area that resists loadsStress: Force per unit area that resists loadsinduced by external forcesinduced by external forcesPressure vessel components designed toPressure vessel components designed tokeep stress within safe operational limitskeep stress within safe operational limitsMaximum allowable stress:Maximum allowable stress:– – Includes safety marginIncludes safety margin– – Varies with temperature and materialVaries with temperature and materialASME maximum allowable stress tables forASME maximum allowable stress tables forpermitted material specificationspermitted material specifications

4343

Maximum AllowableMaximum AllowableStress, cont’dStress, cont’d

4444ASME Maximum Allowable Stress (Table 1A Excerpt)

Gambar 3.2

Maximum AllowableMaximum AllowableStress, cont’dStress, cont’d

4545

ASME Maximum Allowable Stress (Excerpt), cont'dGambar 3.2, cont'd

Material Selection BasedMaterial Selection Basedon Fracture Toughnesson Fracture Toughness

Exercise 1Exercise 1New horizontal vesselNew horizontal vesselCET = - 2°FCET = - 2°FShell and heads: SA-516 Gr. 70Shell and heads: SA-516 Gr. 70Heads hemispherical: ½ in. thickHeads hemispherical: ½ in. thickCylindrical shell: 1.0 in. thickCylindrical shell: 1.0 in. thickNo impact testing specifiedNo impact testing specified Is this correct?Is this correct? If not correct, what should be done?If not correct, what should be done?

4646

Exercise 1 - SolutionExercise 1 - Solution

Must assume SA-516 Gr. 70 not normalized.Must assume SA-516 Gr. 70 not normalized.

Therefore, Curve B material (Ref. Table 3.1).Therefore, Curve B material (Ref. Table 3.1).

Refer to Curve B in Gambar 3.1.Refer to Curve B in Gambar 3.1.

– – ½ in. thick plate for heads: MDMT = -7°F½ in. thick plate for heads: MDMT = -7°F

– – ½ in. thick plate exempt from impact testing½ in. thick plate exempt from impact testing

since MDMT < CETsince MDMT < CET

1 in. shell plate: MDMT = +31°F1 in. shell plate: MDMT = +31°F

– – Not exempt from impact testingNot exempt from impact testing

4747

Exercise 1 - Solution, cont’dExercise 1 - Solution, cont’d

One approach to correct: Impact test 1 in. plateOne approach to correct: Impact test 1 in. plateat -2°F. If passes, material acceptable.at -2°F. If passes, material acceptable.Another approach: Order 1 in. plate normalizedAnother approach: Order 1 in. plate normalized– – Table 3.1: normalized SA-516 is Curve D Table 3.1: normalized SA-516 is Curve D materialmaterial– – Gambar 3.1: 1 in. thick Curve D, MDMT = -Gambar 3.1: 1 in. thick Curve D, MDMT = -30°F30°F– – Normalized 1 in. thick plate exempt fromNormalized 1 in. thick plate exempt from impact testingimpact testing

4848


Choice of option based on cost, material Choice of option based on cost, material availability, whether likely that 1 in. thick availability, whether likely that 1 in. thick non-normalized plate would pass impact non-normalized plate would pass impact testingtesting

4949

Design ConditionsDesign Conditionsand Loadingsand Loadings

Determine vessel mechanical designDetermine vessel mechanical design

Design pressure and temperature, otherDesign pressure and temperature, other

loadingsloadings

Possibly multiple operating scenarios toPossibly multiple operating scenarios to

considerconsider

Consider startup, normal operation,Consider startup, normal operation,

anticipated deviations, shutdownanticipated deviations, shutdown

5050

Design PressureDesign Pressure

5151Gambar 4.1

Zones Temperature Zones Temperature pada Vessels Tinggipada Vessels Tinggi

5252Gambar 4.2

Additional LoadingsAdditional Loadings

Weight of vessel and normal contentsWeight of vessel and normal contentsunder operating or test conditionsunder operating or test conditionsSuperimposed static reactions from weightSuperimposed static reactions from weightof attached items (e.g., motors, machinery,of attached items (e.g., motors, machinery,other vessels, piping, linings, insulation)other vessels, piping, linings, insulation)Loads at attached internal components orLoads at attached internal components orvessel supportsvessel supportsWind, snow, seismic reactionsWind, snow, seismic reactions

5353

Additional Loadings, cont’dAdditional Loadings, cont’d

Cyclic and dynamic reactions caused by Cyclic and dynamic reactions caused by pressure or thermal variations, equipment pressure or thermal variations, equipment mounted on vessel, and mechanical loadingsmounted on vessel, and mechanical loadings

Test pressure combined with hydrostatic weightTest pressure combined with hydrostatic weight

Impact reactions (e.g., from fluid shock)Impact reactions (e.g., from fluid shock)

Temperature gradients within vessel component Temperature gradients within vessel component and differential thermal expansion between and differential thermal expansion between vessel componentsvessel components

5454

5555

Weld Joint CategoriesWeld Joint Categories

5656

Gambar 4.3

A : Menahan hoop stress (tegangan keliling/tegak lurus sumbu)B : Menahan longitudinal stress (tegangan searah sumbu)C : sambungan flangeD : sambungan nozzle - shell

Weld TypesWeld Types

5757Gambar 4.4

Weld Joint EfficienciesWeld Joint Efficiencies

5858

Gambar 4.5

Summary ofSummary ofASME Code EquationsASME Code Equations

5959Gambar 4.6

6060

6161

TypicalTypicalFormed Closure HeadsFormed Closure Heads

6262Gambar 4.7

HemisphericalHemisphericalHead to Shell TransitionHead to Shell Transition

6363

Gambar 4.8

Sample Problem 1Sample Problem 1

6464

Gambar 4.9

Sample Problem 1 - SolutionSample Problem 1 - Solution

Required thickness for internal pressure of Required thickness for internal pressure of cylindrical shell (Gambar 4.6):cylindrical shell (Gambar 4.6):

Welds spot radiographed, E = 0.85 (Gambar Welds spot radiographed, E = 0.85 (Gambar 4.5)4.5)S = 14,400 psi for SA- 515/Gr. 60 at 700°F S = 14,400 psi for SA- 515/Gr. 60 at 700°F (Gambar 3.2)(Gambar 3.2)P = 250 psigP = 250 psig

6565

Sample Problem 1Sample Problem 1Solution, cont’dSolution, cont’d

For 6 ft. - 0 in. shellFor 6 ft. - 0 in. shell

r = 0.5D + C = 0.5 x 72 + 0.125 = 36.125 in.r = 0.5D + C = 0.5 x 72 + 0.125 = 36.125 in.

t = tp + c = 0.747 + 0.125t = tp + c = 0.747 + 0.125

t = 0.872 in., including corrosion allowancet = 0.872 in., including corrosion allowance

6666


For 4 ft. - 0 in. shellFor 4 ft. - 0 in. shell

r = 0.5 x 48 + 0.125 = 24.125 in.r = 0.5 x 48 + 0.125 = 24.125 in.

t = 0.499 + 0.125t = 0.499 + 0.125


6767


Both heads are seamless, E = 1.0.Both heads are seamless, E = 1.0.

Top HeadTop Head - Hemispherical (Gambar 4.6) - Hemispherical (Gambar 4.6)

r = 24 + 0.125 = 24.125 in.r = 24 + 0.125 = 24.125 in.

t = tt = tpp + c = 0.21 + 0.125 + c = 0.21 + 0.125


6868


Bottom Head - 2:1 Semi-Elliptical (Gambar Bottom Head - 2:1 Semi-Elliptical (Gambar 4.6)4.6)

D = 72 + 2 x 0.125 = 72.25 in.D = 72 + 2 x 0.125 = 72.25 in.

t = 0.628 + 0.125t = 0.628 + 0.125


6969

Design For External PressureDesign For External Pressureand Compressive Stressesand Compressive Stresses

Compressive forces caused by deadCompressive forces caused by dead

weight, wind, earthquake, internal vacuumweight, wind, earthquake, internal vacuum

Can cause elastic instability Can cause elastic instability (buckling`/tekukan)(buckling`/tekukan)

Vessel must have adequate stiffnessVessel must have adequate stiffness

– – Extra thicknessExtra thickness

– – Circumferential stiffening ringsCircumferential stiffening rings

7070

Design For External Pressure andDesign For External Pressure andCompressive Stresses, cont’dCompressive Stresses, cont’d

ASME procedures for cylindrical shells,ASME procedures for cylindrical shells,

heads, conical sections, as function of:heads, conical sections, as function of:

– – Material Material – Temperature– Temperature

– – DiameterDiameter – Thickness– Thickness

– – Unstiffened lengthUnstiffened length

7171

Stiffener RingsStiffener Rings

7272

Gambar 4.10


7373

Gambar 4.11

A tall cylindrical tower is being supplied. The geometry and design conditions are specified in Figure 4.11. The vendor has proposed that the wall thickness of this tower be 7/16 in., and no stiffener rings have been specified. Is the 7/16 in. thickness acceptable for external pressure? If it is not acceptable, what minimumthickness is required? Round your answer upward to the nearest 1/16 in.

7474

L : tangent to tangentSeam

Seam


Calculate L and DCalculate L and Doo of cylindrical shell. of cylindrical shell.

L = Tangent Length + 2 x 1/3 (Head Depth)L = Tangent Length + 2 x 1/3 (Head Depth)L = 150 x 12 + 2/3 x (48/4) = 1,808 in.L = 150 x 12 + 2/3 x (48/4) = 1,808 in.Do = 48 + 2 x 7/16 = 48.875 in. (48 : ID)Do = 48 + 2 x 7/16 = 48.875 in. (48 : ID)

Determine L/DDetermine L/Doo and D and Doo/t/tAccount for corrosion allowance: (CA=0,0625”=1/16)Account for corrosion allowance: (CA=0,0625”=1/16)

t = 7/16 – 1/16 = 6/16 = 0.375 in.t = 7/16 – 1/16 = 6/16 = 0.375 in.Do/t = 48.875 / 0.375 = 130Do/t = 48.875 / 0.375 = 130L/Do = 1808 / 48.875 = 37L/Do = 1808 / 48.875 = 37

7575


Determine A.Determine A.

Use Gambar 4.12, DUse Gambar 4.12, Doo/t, and L/D/t, and L/Doo..

Note: If L/DNote: If L/Doo > 50, use L/D > 50, use L/Doo = 50. = 50.

For L/DFor L/Doo < 0.05, use L/D < 0.05, use L/Doo = 0.05 = 0.05

7676


7777

Factor A

Gambar 4.12


7878

Factor B

Gambar 4.13


Calculate maximum allowable external Calculate maximum allowable external pressurepressure

Where:Where:E = Young's modulus of elasticityE = Young's modulus of elasticityE = 27 x 10E = 27 x 1066 psi (Gambar 4.13) at T = psi (Gambar 4.13) at T = 500°F500°F

PPaa = 9 psi = 9 psi7979

Karena Factor A terletak di sebelah kiri kurva, maka tidak Faktor B tidak ada, sehingga untuk menghitung Pressure, digunakan rumus di samping


Since Pa < 15 psi, 7/16 in. thickness not Since Pa < 15 psi, 7/16 in. thickness not sufficientsufficient

Assume new thickness = 9/16 in.,Assume new thickness = 9/16 in.,

corroded thickness = 1/2 in.corroded thickness = 1/2 in.

8080

Exercise 2 - RequiredExercise 2 - RequiredThickness for Internal PressureThickness for Internal PressureInside Diameter Inside Diameter : 10’ - 6”: 10’ - 6”Design Pressure Design Pressure : 650 psig: 650 psigDesign Temperature Design Temperature : 750°F: 750°FShell & Head Material Shell & Head Material : SA-516 Gr. 70: SA-516 Gr. 70Corrosion Allowance Corrosion Allowance : 0.125 in.: 0.125 in.2:1 Semi-Elliptical heads, seamless2:1 Semi-Elliptical heads, seamless100% radiography100% radiographyVessel in vapor service (no liquid loading)Vessel in vapor service (no liquid loading)

8181

Exercise 2 - SolutionExercise 2 - SolutionFor shell For shell

P = 650 psigP = 650 psigr = 0.5 x D + CAr = 0.5 x D + CA= (0.5 x 126) + 0.125 = 63.125 in.= (0.5 x 126) + 0.125 = 63.125 in.

S = 16,600 psi, Gambar 3.3 for SA-516 Gr. 70S = 16,600 psi, Gambar 3.3 for SA-516 Gr. 70E = 1.0, Gambar 4.8 for 100% radiographyE = 1.0, Gambar 4.8 for 100% radiography

8282


Add corrosion allowanceAdd corrosion allowance

ttpp = 2.53 + 0.125 = 2.655 in. = 2.53 + 0.125 = 2.655 in.

For the headsFor the heads

Add corrosion allowanceAdd corrosion allowance

ttpp = 2.23 + 0.125 = 2.355 in. = 2.23 + 0.125 = 2.355 in.

8383

Reinforcement of OpeningsReinforcement of Openings

Simplified ASME rules - Area replacementSimplified ASME rules - Area replacement

Metal used to replace that removed:Metal used to replace that removed:

- Must be equivalent in metal area- Must be equivalent in metal area

- Must be adjacent to opening- Must be adjacent to opening

8484

Kompensasi (Kompensasi (CompensationCompensation))

Compensation, or Compensation, or reinforcement, reinforcement, is the is the provision of extra stress-transmitting area provision of extra stress-transmitting area in the wall of a cylinder or shell when in the wall of a cylinder or shell when some area is removed by boring a hole for some area is removed by boring a hole for branch attachment.branch attachment.

The principle is sketched. The principle is sketched.

8585


The left sketch shows part of a cylinder's The left sketch shows part of a cylinder's longitudinal section; the major circumferential longitudinal section; the major circumferential stress acts across the critical longitudinal plane. stress acts across the critical longitudinal plane. The nominal thickness is T, and a hole of The nominal thickness is T, and a hole of diameter Ddiameter Dbb is bored - dimensions being is bored - dimensions being

reckoned in the fully corroded condition. The reckoned in the fully corroded condition. The stress-transmitting area removed is A = Dstress-transmitting area removed is A = Dbbt t

where the calculation thickness t is given by where the calculation thickness t is given by ( ( 11). ).

8686


The figure on the right demonstrates The figure on the right demonstrates compensation for area removal by providing compensation for area removal by providing equal area for alternate force paths in otherwise equal area for alternate force paths in otherwise unused material of cylinder and branch. Not all unused material of cylinder and branch. Not all the branch wall can be devoted to compensation the branch wall can be devoted to compensation since the internally pressurised branch is a since the internally pressurised branch is a cylinder in its own right, with calculation and cylinder in its own right, with calculation and nominal thicknesses, tnominal thicknesses, tbb and T and Tbb, determined in , determined in

a manner identical to the main shell. a manner identical to the main shell.

8787


Provided that the longitudinal welds in both shell Provided that the longitudinal welds in both shell and branch do not lie in the critical longitudinal and branch do not lie in the critical longitudinal planeplane, , then - from a compensation point of view - both t then - from a compensation point of view - both t and tand tbb would be reckoned from ( would be reckoned from ( 11) with η = 1. The ) with η = 1. The

thickness differences ( T - t ) and ( Tthickness differences ( T - t ) and ( Tbb - t - tbb ) contribute ) contribute

to compensation - though reinforcement is ineffective to compensation - though reinforcement is ineffective beyond the limits Lbeyond the limits Lnn normal to the vessel wall, and L normal to the vessel wall, and Lpp

from the branch centreline parallel to the wall, as shown from the branch centreline parallel to the wall, as shown below for a set-in branch :-below for a set-in branch :-

8888


8989


9090

AS 1210 gives the limits as :- AS 1210 gives the limits as :- LLnn = maximum [ 0.8 ( D = maximum [ 0.8 ( DbbTTbb ) )1/21/2 + T + Trr , minimum , minimum

( 2.5T, 2.5T( 2.5T, 2.5Tbb + T + Trr ) ] ) ]

or ( D or ( DbbT )T )1/21/2 for a flanged-in head for a flanged-in head

LLpp = maximum [ D = maximum [ Dbb , D , Dbb/2 + T + T/2 + T + Tbb + 2c ] + 2c ]


Usually the first of the LUsually the first of the Lpp limits, D limits, Dbb, controls. , controls.

However However a compensating area cannot a compensating area cannot contribute to more than one branchcontribute to more than one branch, so if the , so if the spacing of two branches Dspacing of two branches Db1b1 and D and Db2b2 is less is less

than ( Dthan ( Db1b1+ D+ Db2b2 ), then by proportion L ), then by proportion Lp1p1 = D = Db1b1 . .

spacing/( Dspacing/( Db1b1+ D+ Db2b2 ). ).

9191


Furthermore, if the branch is attached to a dished Furthermore, if the branch is attached to a dished end, then no compensation area is effective if it end, then no compensation area is effective if it lies outside the aforementioned 80% limits. If the lies outside the aforementioned 80% limits. If the head is torispherical, the hole should lie in the head is torispherical, the hole should lie in the spherical portion and t will be given by ( spherical portion and t will be given by ( vv). If the ). If the head is ellipsoidal, then AS 1210 defines an head is ellipsoidal, then AS 1210 defines an equivalent sphere for the application of ( equivalent sphere for the application of ( vv), since ), since the hole will not lie close to the rim region of sharp the hole will not lie close to the rim region of sharp curvature which dictates the thickness via the curvature which dictates the thickness via the stress concentration factor in ( stress concentration factor in ( viivii). ).

9292


Within the LWithin the Lnn, L, Lpp limits, compensation requires limits, compensation requires

that :- that :-

AA11 + A + A22 + A + A33 + A + A44 + A + A55 ≥ A = D ≥ A = Dbbt t

The inward protrusion '3' is subjected to The inward protrusion '3' is subjected to corrosion on three surfaces but there is no corrosion on three surfaces but there is no pressure differential across it; it will not exist for pressure differential across it; it will not exist for a set-on branch. The sketch indicates that:- a set-on branch. The sketch indicates that:-

AA11 = ( 2L = ( 2Lpp - D - Dbb - 2t - 2tbb ) ( T - t ) ; A ) ( T - t ) ; A22 = 2L = 2Lnn ( (

TTbb - t - tbb ) etc. ) etc.

9393

Cross-Sectional View ofCross-Sectional View ofNozzle OpeningNozzle Opening

9494

Gambar 4.14

Nozzle Design ConfigurationsNozzle Design Configurations

9595Gambar 4.15

Additional ReinforcementAdditional Reinforcement

Necessary if insufficient excess thicknessNecessary if insufficient excess thickness

Must be located within reinforcement zoneMust be located within reinforcement zone

Allowable stress of reinforcement padAllowable stress of reinforcement pad

should be ≥ that of shell or headshould be ≥ that of shell or head

Additional reinforcement sourcesAdditional reinforcement sources

– – PadPad

– – Additional thickness in shell or lower part ofAdditional thickness in shell or lower part of

nozzlenozzle

9696


9797

Gambar 4.16


Calculate required reinforcement area, ACalculate required reinforcement area, A

A = dtA = dtrrFF

Where:Where:d =d = Finished diameter of circular opening, orFinished diameter of circular opening, or

finished dimension of nonradial opening infinished dimension of nonradial opening inplane under consideration, in.plane under consideration, in.

ttrr = Minimum required thickness of shell using = Minimum required thickness of shell using

E = 1.0E = 1.0F = Correction factor, normally 1.0F = Correction factor, normally 1.0

9898

Sample Problem 3 -Sample Problem 3 -Solution, cont’dSolution, cont’d

Calculate diameter, d.Calculate diameter, d.d = Diameter of Opening – 2 (Thickness +d = Diameter of Opening – 2 (Thickness +

Corrosion Allowance)Corrosion Allowance)d = 8.625 – 1.0 + .125 = 7.750 in.d = 8.625 – 1.0 + .125 = 7.750 in.

Calculate required shell thickness, tCalculate required shell thickness, trr (Gambar 4.6)(Gambar 4.6)

ttrr = 0.487 in. = 0.487 in.

Assume F = 1.0Assume F = 1.0

9999


Calculate ACalculate A

A = dtA = dtrrFF

A = (8.625 - 1.0 + 0.125) x 0.487 x 1A = (8.625 - 1.0 + 0.125) x 0.487 x 1

= 3.775 in.= 3.775 in.22

Calculate available reinforcement area in vesselCalculate available reinforcement area in vessel

shell, Ashell, A11, as larger of A, as larger of A1111 or A or A1212

AA1111 = (E = (Ellt - Ftt - Ftrr)d)d

AA1212 = 2 (E = 2 (Ellt-Ftt-Ftrr)(t + t)(t + tnn))

100100


WhereWhere::

EEll = 1.0 when opening is in base plate away from welds, = 1.0 when opening is in base plate away from welds,or when opening passes through circumferentialor when opening passes through circumferential

joint in shell (excluding head to shell joints).joint in shell (excluding head to shell joints).EEll = ASME Code joint efficiency when any part of = ASME Code joint efficiency when any part of

opening passes through any other welded joint.opening passes through any other welded joint.F = 1 for all cases except integrally reinforced nozzlesF = 1 for all cases except integrally reinforced nozzles

inserted into a shell or cone at angle to vesselinserted into a shell or cone at angle to vessellongitudinal axis. See Fig. UG-37 for this speciallongitudinal axis. See Fig. UG-37 for this special

case.case.ttnn = Nominal thickness of nozzle in corroded condition, = Nominal thickness of nozzle in corroded condition, in.in.

101101


AA1111 = (E= (Ellt - Ftt - Ftrr)d)d

= (0.5625 - 0.0625 - 0.487) x 7.75= (0.5625 - 0.0625 - 0.487) x 7.75= 0.1 in.= 0.1 in.22

AA1212 = 2 (E= 2 (Ellt - Ftt - Ftrr) (t + t) (t + tnn))

= 2(0.5625-0.0625-0.487)x(0.5625-0.0625+0.5 -= 2(0.5625-0.0625-0.487)x(0.5625-0.0625+0.5 -0.0625)0.0625)

= 0.0243 in.= 0.0243 in.22

Therefore,Therefore,

AA11 = 0.1 in.= 0.1 in.22 available reinforcement in shell available reinforcement in shell

102102


Calculate reinforcement area available in Calculate reinforcement area available in nozzle wall, Anozzle wall, A22, as smaller of A, as smaller of A2121 or A or A2222..

AA2121 = (t = (tnn-t-trnrn) 5t) 5t

AA2222 = 2 (t = 2 (tnn-t-trnrn) (2.5 t) (2.5 tnn + t + tee))

103103


Where:Where:

ttrnrn = Required thickness of nozzle wall, in.= Required thickness of nozzle wall, in.

r r = Radius of nozzle, in.= Radius of nozzle, in.

ttee = 0 if no reinforcing pad.= 0 if no reinforcing pad.

ttee = Reinforcing pad thickness if one installed, = Reinforcing pad thickness if one installed,

in.in.

ttee = Defined in Gambar UG-40 for self-= Defined in Gambar UG-40 for self-

reinforcedreinforced

nozzles, in.nozzles, in.104104


Calculate required nozzle thickness, trn Calculate required nozzle thickness, trn (Gambar 4.6)(Gambar 4.6)

105105


Calculate ACalculate A22..

AA2121 = (t= (tnn - t - trnrn)5t)5t= (0.5 - 0.0625 - 0.0784) x 5 (0.5625 - 0.0625)= (0.5 - 0.0625 - 0.0784) x 5 (0.5625 - 0.0625)= 0.898 in.= 0.898 in.22

AA2222 = 2 (t= 2 (tnn - t - trnrn) (2.5 t) (2.5 tnn + t + tee))= 2 (0.5 - 0.0625 - 0.0784) [2.5 x (0.5 - 0625) + 0]= 2 (0.5 - 0.0625 - 0.0784) [2.5 x (0.5 - 0625) + 0]= 0.786 in.= 0.786 in.22

Therefore,Therefore,

AA22 = 0.786 in.= 0.786 in.22 available reinforcement in nozzle. available reinforcement in nozzle.

106106


Determine total available reinforcement area, ADetermine total available reinforcement area, ATT;;

compare to required area.compare to required area.

AATT = A = A11 + A + A22 = 0.1 + 0.786 = 0.886 in. = 0.1 + 0.786 = 0.886 in.22

AATT < A, nozzle not adequately reinforced, < A, nozzle not adequately reinforced, reinforcement pad required.reinforcement pad required.

Determine reinforcement pad diameter, DDetermine reinforcement pad diameter, Dpp..

AA55 = A - A = A - ATT

AA55 = (3.775 - 0.886) = 2.889 in. = (3.775 - 0.886) = 2.889 in.22

107107


Calculate DCalculate Dpp

ttee = 0.5625 in. (reinforcement pad thickness)= 0.5625 in. (reinforcement pad thickness)

AA55 = [D= [Dpp - (d + 2 t - (d + 2 tnn)] t)] tee

2.889 = [D2.889 = [Dpp - (7.75 + 2(0.5 - 0.0625)] 0.5625 - (7.75 + 2(0.5 - 0.0625)] 0.5625

DDpp = 13.761 in. = 13.761 in.

Confirm DConfirm Dpp within shell reinforcement zone, 2d within shell reinforcement zone, 2d

2d 2d = 2 x 7.75 = 15.5 in.= 2 x 7.75 = 15.5 in.

Therefore, DTherefore, Dpp = 13.761 in. acceptable = 13.761 in. acceptable

108108

Flange RatingFlange Rating

Based on ASME B16.5Based on ASME B16.5

Identifies acceptable pressure/temperature Identifies acceptable pressure/temperature combinationscombinations

Seven classesSeven classes

(150, 300, 400, 600, 900, 1,500, 2,500)(150, 300, 400, 600, 900, 1,500, 2,500)

Flange strength increases with class numberFlange strength increases with class number

Material and design temperature combinations Material and design temperature combinations without pressure indicated not acceptablewithout pressure indicated not acceptable

109109

Material Specification ListMaterial Specification List

110110

Gambar 4.17

ASME B16.5, Table 1a, Material Specification List (Excerpt)

Pressure-Temperature RatingsPressure-Temperature Ratings

111111

Gambar 4.18


Determine Required Flange RatingDetermine Required Flange Rating

Pressure Vessel Data:Pressure Vessel Data:

Shell and HeadsShell and Heads : SA-516 Gr.70: SA-516 Gr.70

FlangesFlanges : SA-105: SA-105

Design Temperature: 700°FDesign Temperature: 700°F

Design PressureDesign Pressure : 275 psig: 275 psig

112112


Identify flange material specification SA-105Identify flange material specification SA-105From Gambar 4.17, determine Material Group From Gambar 4.17, determine Material Group No.No.Group 1.1Group 1.1From Gambar 4.18 with design temperature andFrom Gambar 4.18 with design temperature andMaterial Group No. determined in Step 3Material Group No. determined in Step 3– – Intersection of design temperature with Material GroupIntersection of design temperature with Material Group

No. is maximum allowable design pressure for theNo. is maximum allowable design pressure for the flange Classflange Class

113113


– – Table 2 of ASME B16.5, design information forTable 2 of ASME B16.5, design information for

all flange Classesall flange Classes

– – Select lowest Class whose maximumSelect lowest Class whose maximum

allowable design pressure ≥ required designallowable design pressure ≥ required design

pressure.pressure.

At 700°F, Material Group 1.1: Lowest Class thatAt 700°F, Material Group 1.1: Lowest Class that

will accommodate 275 psig is Class 300.will accommodate 275 psig is Class 300.At 700°F, Class 300 flange of Material GroupAt 700°F, Class 300 flange of Material Group

1.1: Maximum design pressure = 535 psig.1.1: Maximum design pressure = 535 psig.

114114

Flange DesignFlange Design

Bolting requirementsBolting requirements

– – During normal operation (based on design During normal operation (based on design

conditions)conditions)

– – During initial flange boltup (based on stress During initial flange boltup (based on stress

necessary to seat gasket and form tight sealnecessary to seat gasket and form tight seal

115115

Flange Loads and Moment ArmsFlange Loads and Moment Arms

116116

Gambar 4.19

Stresses inStresses inFlange Ring and HubFlange Ring and Hub

Calculated using:Calculated using:

– – Stress factors (from ASME code)Stress factors (from ASME code)

– – Applied momentsApplied moments

– – Flange geometryFlange geometry

Calculated for:Calculated for:

– – Operating caseOperating case

– – Gasket seating caseGasket seating case

117117

Flange Design andFlange Design andIn-Service PerformanceIn-Service Performance

Factors affecting design and performanceFactors affecting design and performance

ASME Code m and y parameters.ASME Code m and y parameters.

Specified gasket widths.Specified gasket widths.

Flange facing and nubbin width, wFlange facing and nubbin width, w

Bolt size, number, spacingBolt size, number, spacing

118118

ASME Code m and y FactorsASME Code m and y Factors

119119

Gambar 4.20

ASME Code Gasket WidthsASME Code Gasket Widths

120120

Gambar 4.21

ASME Code Gasket Widths(Table 2-5.2 excerpt)

Gasket Materials and Gasket Materials and Contact FacingsContact Facings

121121

Gambar 4.22

Maximum AllowableMaximum AllowableWorking Pressure (MAWP)Working Pressure (MAWP)

Maximum permitted gauge pressure at top ofMaximum permitted gauge pressure at top ofvessel in operating position for designatedvessel in operating position for designatedtemperaturetemperature

MAWP ≥ Design PressureMAWP ≥ Design Pressure Designated Temperature = Design TemperatureDesignated Temperature = Design Temperature Vessel MAWP based on weakest componentVessel MAWP based on weakest component

– – Originally based on new thickness less corrosionOriginally based on new thickness less corrosion allowanceallowance– – Later based on actual thickness less future corrosionLater based on actual thickness less future corrosion allowance neededallowance needed

122122

Local LoadsLocal Loads

Piping systemPiping system

Platforms, internals, attached equipmentPlatforms, internals, attached equipment

Support attachmentSupport attachment

123123

Types of Vessel InternalsTypes of Vessel Internals

TraysTrays

Inlet DistributorInlet Distributor

Anti-vortex baffleAnti-vortex baffle

Catalyst bed grid and support beamsCatalyst bed grid and support beams

Outlet collectorOutlet collector

Flow distribution gridFlow distribution grid

Cyclone and plenum chamber systemCyclone and plenum chamber system

124124

ASME Code andASME Code andVessel InternalsVessel Internals

Loads applied from internals on vessel to Loads applied from internals on vessel to be considered in designbe considered in design

Welding to pressure parts must meet Welding to pressure parts must meet ASME CodeASME Code

125125

Corrosion AllowanceCorrosion AllowanceFor Vessel InternalsFor Vessel Internals

Removable internals: CA = CA of shellRemovable internals: CA = CA of shell

– – Costs lessCosts less

– – Easily replacedEasily replaced

Non-removable internals: CA = 2 (CA of Non-removable internals: CA = 2 (CA of shell)shell)

– – Corrosion occurs on both sidesCorrosion occurs on both sides

126126

Typical Head-to-Shell TransitionsTypical Head-to-Shell Transitions

127127

Gambar 6.1

Typical Shell TransitionsTypical Shell Transitions

128128

Gambar 6.2

Nozzle Neck AttachmentNozzle Neck Attachmentto Thinner Pipeto Thinner Pipe

129129

Gambar 6.3

Stiffener Ring AttachmentStiffener Ring Attachment

130130

Gambar 6.4

Post Weld Heat TreatmentPost Weld Heat Treatment

Restores material propertiesRestores material properties

Relieves residual stressesRelieves residual stresses

ASME Code PWHT requirementsASME Code PWHT requirements

– – Minimum temperature and hold timeMinimum temperature and hold time

– – Adequate stress reliefAdequate stress relief

– – Heatup and cooldown ratesHeatup and cooldown rates

131131

ASME Reference ChartASME Reference Chart

132132

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Pressure Vessel [Design]