Multiwall Vessel

MULTIWALL VESSELSMULTIWALL VESSELSMULTIWALL VESSELSMULTIWALL VESSELS

Heavy Engineering DivisionLARSEN & TOUBRO LIMITED, INDIALARSEN & TOUBRO LIMITED, INDIA

© Larsen & Toubro Limited: April 2010. All rights reserved

AGENDAAGENDA

Various layered construction

Multiwall shellsMultiwall shells

• Applications• Materials of construction• Connection of multiwall shell to head / flange• Design methodology

Proof testing by L&T• Proof testing by L&T• Manufacturing sequence• Advantagesg• In-service monitoring

Reference list

Conclusions© Larsen & Toubro Limited: April 2010. All rights reserved

LARSEN & TOUBRO LARSEN & TOUBRO OPERATING DIVISIONSOPERATING DIVISIONSOPERATING DIVISIONSOPERATING DIVISIONS

Year Established : 1938S l US $ 8 5 BilliSales : US $ 8.5 Billion

No. of employees : > 30,000

MIPD ECC

HED

EBG E&C© Larsen & Toubro Limited: April 2010. All rights reserved

CRITICAL EQUIPMENT FOR PROCESS INDUSTRIESPROCESS INDUSTRIES

710 MT World’s largest

1500 MT World’s largestWorld s largest World’s largest

AMMONIA CONVERTER E.O. REACTOR VERY LARGE SIZE

108 M LongWorld’s tallest

VERY LARGE SIZEEQUIPMENT

1200 MT World’s largest

PRODUCT SPLITTER FCC REGENERATOR © Larsen & Toubro Limited: April 2010. All rights reserved

CRITICAL EQUIPMENT FOR PROCESS INDUSTRIES

DHDT REACTOR METHANOL CONVERTER

HYDROCRACKER REACTOR UREA REACTOR


NEED FOR MULTIWALL CONSTRUCTIONN d l t i t h l i dNew developments in process technology requiredequipment to operate at higher pressures & temperatures.

E i t i d t h dl l th l fl id t i iEquipment required to handle lethal fluids containingHydrogen, Hydrogen Sulfide, Ammonia etc.

Exponential increase in plant capacities.

Consequently equipment sizes increased and requiredConsequently, equipment sizes increased and requiredhigher cross-section thickness.

Multiwall / Multilayer technology developed as a costMultiwall / Multilayer technology developed as a cost-effective alternative to monowall shells.

ASME also recognizes the need & incorporates certainASME also recognizes the need & incorporates certaindetails for such alternate constructions.


VARIOUS LAYERED CONSTRUCTION

Incorporated in ASME Codes:

Fig ULW 2 1 of ASME Concentric W d Fig. ULW-2.1 of ASME

Sec.VIII,Div.1&

Fig 4 13 1 of ASME

Wrapped

Notes:

Fig. 4.13.1 of ASME Sec.VIII,Div.2Coil Wound

Notes:(1) Inner shell(2) Dummy layer, if used(3) Layers

Multiwall(3) Layers(4) Shell layer (tapered)(5) Balance of layers(6) GapsSpiral Wrapped ( ) pSpiral Wrapped


WHAT IS MULTIWALL SHELL ?

FabricatedFabricated byby consecutivelyconsecutively shrinkshrink fittingfitting multiplemultiplecylindricalcylindrical shellsshells overover eacheach otherothercylindricalcylindrical shellsshells overover eacheach otherother

InterferenceInterference fitfit betweenbetween consecutiveconsecutive shellshell layerslayers

ThicknessThickness ofof individualindividual shellshell == 1515 100100 mmmmThicknessThickness ofof individualindividual shellshell == 1515--100100 mmmm

ComplyComply withwith ASMEASME SectionSection VIII,VIII, DivDiv..11 && DivDiv..22


APPLICATIONS OF MULTIWALL VESSELSFERTILIZERFERTILIZERINDUSTRY(Ammonia Converters,

U R t

PETRO-CHEMICAL

PETROLEUM REFINERIES

Urea Reactors etc..)

PLANTS (Solution

Adsorbers etc..)

(Hydrocracker Reactors,

Separators)

CHEMICALINDUSTRIES

(H P Heat Exchangers )

OTHERINDUSTRIES

(H P Exchangers..)

(Storage..)


MATERIALS FOR MULTIWALL VESSEL

Based on application, multiwall vessels are manufactured from any of the following materials :

• Carbon & low alloy steely• High strength quench & tempered steels

For units requiring an alloy interior two types For units requiring an alloy interior, two types of construction are possible:

All l ddi ld l th • Alloy cladding or weld overlay on the innermost layer

• Solid alloy liner backed by Multiwall shell • Solid alloy liner backed by Multiwall shell (e.g. Urea Reactor)


CONFIGURATIONS OF MULTIWALL SHELLS TO HEAD/FLANGE CONNECTIONO / NG CONN C ON

Ref : ASME Boiler & Pressure Vessel CodeRef : ASME Boiler & Pressure Vessel Code© Larsen & Toubro Limited: April 2010. All rights reserved

DESIGN METHODOLOGY FORMULTIWALL VESSELMULTIWALL VESSEL

Multiwall shells are designed as per the code rules given in rules given in

Part ULW of ASME sec VIII div.1 or or

Part 4.13 of ASME sec VIII div.2 for the applicable loading


CONTACT REQUIREMENT BETWEEN LAYERS – ASME CodeS S Code

Ref : ASME Boiler & Pressure Vessel CodeRef : ASME Boiler & Pressure Vessel Code

Ag < Thickness expressed in ‘inAg < Thickness expressed in ‘in22’,’,Gap Length < Diameter, inGap Length < Diameter, in


DESIGN METHODOLOGY : STRESS PROFILE

SHRINK STRESS SHRINK STRESS AFTER STRESS RELIEVING

PRESSURE STRESS RESULTANT STRESS© Larsen & Toubro Limited: April 2010. All rights reserved

FEM ANALYSIS : STRESS PROFILE

Inside radius

Inside radius

Pa Pa

Circumferential stressMULTIWALL VESSELMONOWALL VESSEL

Load case: Design pressure + Shrink-fit stress + Operating temperature



Circumferential stress in the inner layer of multiwall vessel(which is exposed to Hydrogen containing fluid) is muchlower than that of monowall vessel.

Pa Pa

Circumferential stressMULTIWALL VESSELMONOWALL VESSEL

Load case: Design pressure + Shrink-fit stress + Operating temperature


FEM ANALYSIS OF AMMONIA CONVERTER

Vessel ID (mm) 3600

No. of layers 4y

Layer thickness (mm) 46

Total vessel thickness (mm) 184

Start-up cycle

Shut-down cycle

Design pressure (MPa) 22 065 22 065Design pressure (MPa) 22.065 22.065

Syngas temperature (OC) 21 to 440 440 to 21

Rate of temp. variation (OC/hr) 50 50

Total cycle time (hrs) 8.38 8.38


FEM ANALYSIS FOR START-UP CYCLE

Inside radius

OC

Temperature distribution at end of start-up cycle© Larsen & Toubro Limited: April 2010. All rights reserved

FEM ANALYSIS FOR START-UP CYCLEComparison between Monowall & Multiwallp

Inside di Inside radius

radius

OC OC

Monowall vessel Multiwall vessel

OCOC

Temperature distribution at end of start-up cycle© Larsen & Toubro Limited: April 2010. All rights reserved


PPa PaPa

Tangential stress during Start up + Operating +

Multiwall vesselMonowall vessel

Tangential stress during Start-up + Operating + Shutdown cycle


Max. stress occurs at the multiwall shell to head weld

FEM ANALYSIS : STRESS PROFILEMax. stress occurs at the multiwall shell to head weldjoint during shutdown cycle. From fatigue assessment,the fatigue life is approx. 10,200 cycles.

PaPa

Equivalent stress in welds during Start-up + Operating + Shutdown cycle



Inside radius

MPa

Stress intensity near shell-to-head junction at end of start-up



Inside radius

MPa

Stress intensity at circ. seam at end of start-up cycle© Larsen & Toubro Limited: April 2010. All rights reserved


Inside radius

MPa

Stress intensity between two circ. seams at end of start-up cycle


FEM ANALYSIS FOR SHUT DOWN CYCLE

Inside radius

MPa

Stress intensity near shell-to-head junction at end of shut-down cycle


FEM ANALYSIS FOR SHUT DOWN CYCLE

Inside radius

MPa

Stress intensity at circ. seam at end of shut-down cycle


PROOF TEST OF MULTIWALL VESSELS(at L&T)(at L&T)

Multi wall vessel being Multi wall vessel being prepared for destructive testsprepared for destructive tests


MANUFACTURING SEQUENCE

1st layer

• Measurement of actual plate thickness.• Rolling, welding & RT or TOFD UT of shell courses for first layer.• Measurement of actual circumferences• Measurement of actual circumferences.

2nd layer

• Manufacture shell courses for second layer to the dimensionsrequired to achieve predetermined interference (based on actualdimensions of first layer)y

• Clear RT or TOFD UT of long seams for each course.• Shrink fitting of second layer (thermally expanded) on first layer.

Subsequent layers

• Repeat above steps till required number of layers are achieved.• Make weld bevels at the ends and drill vent holes in multiwall

h lllayers shell courses.• Continue subsequent operation as in solid wall construction.



NDT of circ

• RT• Conventional UTcirc.

seams before PWHT

• Conventional UT• PT / MT

NDT after • Conventional UT of all accessible welds.

NDT after PWHT

NDT after Hydrotest

• PT / MT of all accessible welds.

Hydrotest






SEQUENCE OF SHRINK FITTING

(1)(1) (2)(2) (3)(3)© Larsen & Toubro Limited: April 2010. All rights reserved

MULTIWALL CIRC. SEAM

• After welding of Circ. seams for Multiwall,

interpretation of RT can be difficult. However,interpretation of RT can be difficult. However,

welding techniques and RT techniques have

improved, thereby eliminating the need for

inter-layer welding.

• No special steps (such as sealing of gaps by

welding or buttering of the surface) are neededwelding or buttering of the surface) are needed

before circ. seam welding.

• No defects encountered in circumferential seams

at the plate interfaces.

Photograph of circ. seam PTC.


MULTIWALL CIRC. SEAM

Multiwall to Multiwall Multiwall to

Photograph of Circ Seam PTC.

Multiwall to Multiwall Multiwall to Monowall


ADVANTAGES OF MULTIWALL

Theoretically no limitation for achieving any thickness of cross

section.section.

Plates in standard thickness range can be used. (Gives higher

flexibility in sourcing/ availability of plates.)y g/ y p )

Thinner plates permit better metallurgical control & superior

structural homogeneity during manufacturing at mills.

Consequently the same advantages get translated for much

thicker sections by utilizing multiwall constructionthicker sections by utilizing multiwall construction.

Materials of different properties can be used for inner layers &Materials of different properties can be used for inner layers &

subsequent layers, if desired.



Shrink fitting of multiwall induces compression in the innerlayers, which counters the pressure stresses and thus creatingadditional reserve strength.

In-built safety exists against brittle fracture.

additional reserve strength.

Fracture, if initiated in long seams, would be confinedto one layer and would not propagate through the totalthickness.

Fracture is not expected in circumferential seams asthese are half-stressed joints. (In any case, the risk ofbrittle fracture in circumferential seams is same as thatof monowall construction)

Normal stresses due to temperature gradient are lowercompared to monowall due to lower discontinuity stresses for

of monowall construction).

compared to monowall due to lower discontinuity stresses formultiwall construction.


V ti t id l i f bl


Venting system provides early warning for any probleminitiated from the inside surface of the vessel.

In-service monitoring system for Multiwall© Larsen & Toubro Limited: April 2010. All rights reserved

IN-SERVICE MONITORING SYSTEM

Inherent features of multiwall construction gives much superior operational reliability to the much superior operational reliability to the multiwall vessels.

Provision for a continuous monitoring system using the venting arrangement eliminates the g g gneed for carrying out “In-service” NDT during shutdown to detect defects

The intents of stipulations in Clause 4.3 b of API-934 A & C: May 2008) are met with934-A & C: May 2008) are met with.


REFERENCE LIST

L & T has manufactured and supplied 50 + Multiwall vessels for Ammonia, Urea & other Petrochemical services operating for periods up to 20+ years.

Many of such vessels are used for Hydrogen service viz. Ammonia Converter, operating with 50 to 55 mole% Hydrogen at 100 – 140 bar partial pressure y g p pand temperature of 350 to 450 deg C.

Another reputed manufacturer (M/s Struthers Wells) has supplied multiwall vessels like Hydrocracker Reactor H P Separator etc for refineries in the pastReactor, H.P. Separator etc for refineries in the past.


REFERENCE LIST FOR AMMONIA CONVERTERSAMMONIA CONVERTERS

Sr.No Customer / Location Process

Licensor

Design Press.

Kg/Cm2

DesignTemp.

°C

Design Code

Dimensions(ID X L)

mm

Thkmm

Material Of Construction(Multi-Wall)

Year OfSupply

H2 Partial

Press.K2Kg/Cm2 C mm g/cm2

1 Kribhco - Hazira Haldor Topsoe

245 360 ADM 1971 x 16995 110 SA 204 GR. B +

1988-89 179

(40+35x2) SA 533 GR. B CL 2

2 Zuari Agro – Goa Haldor 165 260 ADM 1964 x 72 SA 204 GR B + 1989-90 1002 Zuari Agro Goa (2 Nos)

Haldor Topsoe

165 260 ADM 1964 x 20000

72 SA 204 GR. B + 1989 90 100

(20+25x2) SA 533 GR. B CL 2

3 Chambal Fertliser, Gadepan

Haldor Topsoe

245 370 ADM 3005 x 21455

155 SA 387 GR.11 CL 2 + SA 533 GR. B CL.2

1992 158

(35+40x3)(35+40x3)

4 Tata ChemicalsBabrala

Haldor Topsoe

155 370 ADM 2805 x 23436

98 SA 387 GR.11 CL 2 + 1993 102

(30+34x2) SA 533 GR. B CL.2

5 Tata Chemicals Haldor 155 450 DIV.2 2705 x 145 SA 387 GR. 22 CL.2 1993Babrala Topsoe 21274

(48.5x3)

6 IFFCO – Aonla Haldor Topsoe

245 370 ADM 3000 x 22425

155 SA 387 GR.11 CL 2 + 1996 157

(32+41x3) SA 533 GR. B CL.2

7 NFL – Vijaipur Haldor Topsoe

245 370 ADM 3000 x 22425

155 SA 387 GR.11 CL 2 + 1996 157

(32+41x3) SA 533 GR. B CL.2


REFERENCE LIST FOR AMMONIA CONVERTERS


Licensor

Design Press.

Kg/Cm2

DesignTemp.

°C

Design Code

Dimensions

(ID X L)mm

Thkmm


Year OfSupply

H2 Partial Press.Kg/cm2

8 FACT -Udyogmandal

Haldor Topsoe

158 370 ADM 2700 x 20940

94 SA 387 GR.11 CL 2 + 1996 105

(30+32x2) SA 533 GR. B CL.2

9 IFFCO - Phulpur Haldor T

245 370 ADM 3000 x 22425

155 SA 387 GR.11 CL 2 + 1997 157Topsoe 22425

(32+41x3) SA 533 GR. B CL.2

10 RCF, Trombay -I Haldor Topsoe

120 370 ADM 2000 x 16300

56 SA 387 GR.11 CL 2 + 1998 82

(24+32) SA 533 GR. B CL.2

11 Indo Gulf Haldor Topsoe

245 370 ADM 3000 X 22425

148 SA 387 GR.11 CL 2 + 1998 157

(25+41x3) SA 533 GR. B CL.2

12 Chambal Fertiliser Gadepan

MW Kellogg

188 290 ADM 2800 x 29650

107+ 6 SA 302 GR. A + 1998 116.2Gadepan Kellogg 29650

(27+40x2) SA 533 GR. B CL.2

13 MHI/P.T Kaltim Pasifik Amoniak,

Indonesia

Haldor Topsoe

155 370 ADM 3300 x 22980

110 SA 387 GR.11 CL 2 + 1998 103

(32+39x2) SA 533 GR. B CL.2

14 Petronas Ammonia Syngas Project

Haldor Topsoe

155 370 ADM 2700 x 20600

111 SA 387 GR.11 CL 2 + 1999 111

(25+43x2) SA 533 GR. B CL.2




Licensor

Design Press.

Kg/Cm2

DesignTemp.

°C

Design Code

Dimensions(ID X L)

mm

Thkmm


Year OfSupply

H2 Partial Press. Kg/cm2

15 NFCL, Kakinanda Plant –1

Haldor Topsoe

155 370ADM

2700 x 30400 94 SA 387 GR 11 CL 2 +

2001 1021 Topsoe ADM 30400 94 SA 387 GR.11 CL 2 +

(30+32x2) SA 533 GR. B CL.216 Uhde Gmbh, Germany /

QAFCO-4Uhde 230 300 DIV.2 3010 X

11550192 SA 387 GR.11 CL 2 + 2003 129.5

(48x4) SA 533 GR. B CL.217 Uhde Gmbh, Germany /

QAFCO 4Uhde 230 300 DIV.2 2855 X

10200182 SA 387 GR.11 CL 2 + 2003 105

QAFCO-4 10200(44+46x3) SA 533 GR. B CL.2

18 Snamprogetti, Italy / OMIFCO,Oman-2 nos.

Haldor Topsoe

230 370 ADM 2800 x 21540

142 SA 387 GR.11 Cl.2 + 2004 158.02

(25+39x3) SA 533 Gr.B Cl.2

19 B F tili Pt Ltd KBR USA 16 65 270 DIV 2 3250 174 SA 387 GR 11 CL 2 2004 111 519 Burrup Fertilizers Pty Ltd, Australia

KBR, USA 16.65 270 DIV.2 3250 x 31000

174 SA 387 GR.11 CL.2 2004 111.5(MPA) (4x43.5)

20 IFFCO-Kalol & Phulpur-I: 2 Nos.

Haldor Topsoe

155 380 ADM 2800 X 20,000

96 SA 387 GR 11 Cl 2 +SA 533 Gr B Cl 2

2005 87(24+36x2)

21 IFFCO A l I & II H ld 225 430 ADM 3000 X 169 (42 3+43) 13 C M V910 2006 11721 IFFCO-Aonla I & II Haldor Topsoe

225 430 ADM 3000 X 20,300

169 (42x3+43) 13 Cr Mo V910 as per EN 10028-2

2006 117

Phulpur-II: 3 Nos.

22 RCF-Trombay Haldor Topsoe

225 430 ADM 2400 x 16,210

120 (40x3) 13 Cr Mo V910 as per EN 10028-2

2006 117

23 KBR EBIC E t KBR 103 413 DIV 2 / 3810/3313 135 SA 387 G 11 CL2 2007 55 5323 KBR-EBIC-Egypt KBR 103 413 DIV.2 / U2

3810/3313 x 23470

135 SA 387 Gr. 11 CL2 2007 55.53

24 KBR CFCL1 –India KBR 225 398 ADM 3600 x 17540

184 (47x4) 13CrMov9-10 2008 93.9




Licensor

Design Press.

Kg/Cm2

DesignTemp.

°C

Design Code

Dimensions(ID X L)

mm

Thkmm


Year OfSupply


25 KBR CFCL2 –India KBR 188 398 ADM 3600 x 17540 153 (51x3) 13CrMov9-10 2008 93.925 KBR CFCL2 India KBR 188 398 ADM 3600 x 17540 153 (51x3) 13CrMov9 10 2008 93.9

26 Petrochina Tarim - China Haldor Topsoe

218 325 DIV.2 2600 x 22545 188 SA 387 Gr. 11 Cl. 2 2008 144.8

(47 x 4)

27 Uhde GmbH, Sorfert Uhde 234.5 300 DIV.2 3010 x 16730 247.5 SA 387 Gr. 11 Cl. 2 2009 132.5Algeria (49.5 x 5)

29 Uhde GmbH, Sorfert Algeria

Uhde 234.5 300 DIV.2 2855 x 14725 235 SA 387 Gr. 11 Cl. 2 2009 106.5

(47 x 5)

30 Jianfeng Chemicals & Co L d Chi

KBR 166.29 285 DIV.2 3000 x 26700 158 SA 387 Gr. 11 Cl. 2 2009 110.2Ltd, China. (40x3+38)

31 PIDEC, Iran Ammonia Casale

183.54 300 DIV.2 3100 x 29300 184 SA 387 Gr. 11 Cl. 2 Under Exec

108.1

(46 x 4)


REFERENCE LIST FOR AMMONIA SEPARATORS


Licensor

Design Press.

Kg/Cm2

DesignTemp.

°C

Design Code

Dimensions(ID X L)

mm

Thkmm


Year OfSupply


1 HFCL Namrup (2 nos) Haldor Topsoe

270 -20 DIV.2 1400 x 4220 130SA 516 Gr 70

1983 -

40 + 2 x 45

2 IFFCO Aonla Expansion

Haldor Topsoe

245 50 ADM 2260 x 5460 100 SA 537 Cl 1 + 1995 -

30 + 2 x 35 SA 533 GR. B CL 2

3 NFL Vijaypur Expansion Haldor Topsoe

245 50 ADM 2260 x 5460 100 SA 537 Cl 1 + 1995 -

30 + 2 x 35 SA 533 GR. B CL 2

4 IFFCO Phulpur Haldor 245 50 ADM 2260 x 5460 100 SA 537 Cl 1 + 1996 -Expansion Topsoe 30 + 2 x 35 SA 533 GR. B CL 2

5 QAFCO 4, Qatar Uhde 225 50 DIV.2 2170 x 9725 172SA 516 Gr. 70

2003 -

43 x 4

6 Sriram Fertilizer, Kota 345 70 DIV.2 1130 x 6000 136SA 516 Gr 70

1999 -SA 516 Gr. 7036 + 2x32 + 36

7 Snam-Technip JV / Oman India Fertilizer Co., Oman (2 nos.)

Haldor Topsoe

234.5 75 ADM 2350 x 3640 104 SA537 Cl1 + 2004 -

30 + 2 x37 SA 533 GR. B CL 2

8 Burrup Fertilizers Pty Ltd, Australia

KBR 169 60 DIV.2 2400 x 10740

136SA 516 Gr. 70

2004 -

4 x 34


REFERENCE LIST FOR UREA REACTORS

Sr. Customer / Location Process Design Press

DesignTemp Design Dimensions

(ID X L) Thk Material Of Construction Year Of

H2 Partial PNo Customer / Location Licensor Press.

Kg/Cm2Temp.

°C Code (ID X L)mm mm Construction

(Multi-Wall) Supply Press. Kg/cm2

1 NFL Bhatinda Mitsui 260 210 HPGC + Div 2

2100 x 29000 148 SA 533 Gr. B Cl 2 1996 -Div 2

37 x 4 + Ti Liner

2 Chambal Fertlisers, Gadepan (2 nos.)

TEC 184 220 ADM 2450 x 27300 SA 533 GR. B CL 2 1998 -

84 + 7 SA 240 Gr. 316L

3 NFL NangalExpansion

Urea Casale 240 220 ADM 1200 x 29000 SA 533 GR. B CL 2 2000 -

57 + 8 SS 25 - 22 - 2 Liner


REFERENCE LIST FOR SOLUTION ADSORBERS

Sr. Customer / Location Process Design Press

DesignTemp Design Dimensions

(ID X L) Thk Material Of Construction Year Of

H2 Partial

No Customer / Location Licensor Press.Kg/Cm2

Temp.°C Code (ID X L)

mm mm Construction(Multi-Wall) Supply Press.

Kg/cm2

1 RPL, Hazira Nova 195190

315340

Div 2 2743 x 6463 225 SA 516 Gr. 70 1989 -190 340

23+3, 50 x 4 Monel Clad

2GAIL, Auriya

Nova 195 340 Div 1 2900 x 1610 259 SA 516 Gr. 70 1996 -

32+3, 56 x 4 Monel Clad,

3 RPL, Hazira Nova 195 340 Div 2 2900 x 1610 237 SA 516 Gr. 70 1996 -


4IOCL, Panipat

Nova 190 340 Div 1 3800 x 2900 305 SA 516 Gr. 70 2009 -



REFERENCE LIST….Summary

Ammonia Converters: 35 nos.

Urea Reactors: 4 nos.

Ammonia Separators: 10 nos.

Urea Reactors: 4 nos.

Solution Adsorbers: 4 nos.

Hydrogenation Reactors: 2 nos.; Towers: 2 nos.

Hydrocracker Reactors: 3 nos.; Secondary Reactor: 1 no. (supplied by Struthers Wells)


TO CONCLUDE ...

Multiwall construction is proven design and fabricationtechnology for high pressure vessels in varied processservices including Ammonia Converters, HydrocrackerR t S t tReactors, Separators etc.

Design & manufacture of Multiwall equipment fully conformsto ASME Code.to ASME Code.

Multiwall construction provides higher operational safetydue efficient to venting of diffused gases, such as Hydrogeng g y gand inherent ability to provide an early warning in case ofany failure originating from inside of vessel.

M lti ll t ti f ilit t f thi l t tiMultiwall construction facilitates use of thinner plate sectionswhich have inherent ability to achieve better/superiormetallurgical control /structure and thus, it is not only costff ti b t b b tt lt ti f Hi h Peffective, but may be a better alternative for High Pressure

Vessels / Reactors.


REQUESTS TO API 934A COMMITTEE

For the short-term, we request adding the followingstatement to API 934-A: "This standard addresses solidwall vessels; however, it is not meant to exclude the useof multiwall vessels. For multiwall vessels, the Purchasershould develop a specification similar in scope to API934-A (in addition to following all ASME Code934 A (in addition to following all ASME Coderequirements)."

Request API committee to list out all concerns and testqdata that would be needed for API 934 members toaccept the use of multiwall vessels in Hydro-processingReactor serviceReactor service.

Assuming that the concerns can be addressed, at thattime, multiwall should be added to API 934-A and maybetime, multiwall should be added to API 934 A and maybe934-C in the future, or be a stand-alone separate API934 document.


THANK YOU


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