fDESIGN OFPROCESS EQUIPMENT

SELECTED TOPICS

KANTI K. MAHAJAN P' E.

SECOND EDITTON

PRESSURE VESSEL HANDBOOKPUBUSHING, INC.

P.O. Box 35355 Tulsa, OK 74153

t)tist(iN otr t,tt(x'tiss tiQUt pMtiNT,Scc() (l Ir.(lilion

ERRATA

Page 27Fig. 11 the illegible word should read: Grooves

Page 88reference at the bottom should read; *See note on page 90

Page 113, 1 t5, 117 and 129Equations should read:

d=te+t p=14/ te+lPage I 19Equation #2 should read:

PREFACE

'fhc design of process equipment such as shell-and-tube heat ex-rlrlrrgcrs, pressure vessels and storage tanks requires a familiarity with avirr icty of sources of design data and procedures. The purpose ofthis booki$ to oonsolidate the scattered literature and present the material in simpli-lro(l li)rm so that it can be easily applied to design problems. Typical ex-irrrrplcs have been included to illustrate the application of the relationshipsrrrrtl procedures presented in the text. Therefore, the designer should findtlris book to be a convenient and useful rcference.

This book is based upon the author's several years of design exper-ic ce and extensive researchinto previously published literature. The topicsl)r'cscnted were selected based upon t}le problems most frequently en-crountered by the author.

Every effort has been made to eliminate effors during the develop-0r0r1t of this book. However, should any euors be noted, the reader is en-oouraged to bring them to the attention of the author. In addition anycomments or questions related to the topics within this book are invitedl)y the author. Neither the author nor the publisher, however, can assumetcsponsibility for the results of designers using values or procedures con-tained in this book since so many variables affect every design.

The author wishes to acknowledge his indebtedness to Frank R.llollig for editorial work and to Eugene F. Megyesy for his help in prepar-ing this book for publication.

The author also wishes to express his appreciation to the AmericanSociety of Mechanical Engineers, Gulf Publishing Company, Chemical En-gineering, The James F. Lincoln Arc Welding Foundation, Institution ofMechanical Engineers, The Intemational Conference of Building Officials,Tubular Exchanger Manufacturers Association, Inc., Eneryy ProductsGroup, Chemical Engineering Progress, McGraw-Hill Book Company andto other publishers who generously permitted the author to include mater-ial from their Dublications.

Kanti K. Mahajan

IMYV S,;

M^".:^sn#-zpt u

Page 125Equation should read:

Printed in the United States of America

PREFACEto the Second Edition

ln this second edition several new topics have been incorpo-fatcd. The additions are as follows:

Solved examples have been included for design of majorcomponents in the chaptet of Shell and Tube Heat Exchangers'

Chapter on Flange Deslgn has been expanded to cover design ofllanges with full face gaskets.

A new chapter, entitled Air Cooled Heat Exchangers has beenirrcluded in three parts. It covers fully the design method of Air( ixrlers.

At the request of users of the first edition sevenAppendices havebccn added to Dresent the derivation of various formulas.

Chapter on Deslg n of Tall Stacks has been enlarged and rewrit-fcn under the title: Mechanical Design of Self-Supported Steel Stacks.lt covers more detailed design methods of wide variety of stacks.

And finally, two chapters: Vessel Codes of Various Countriesantl Equivalent Materials ofVarious Countries havebeen deleted dueto the lack of information necessary for updating the data of those( llapters.

The author wishes to acknowledge the assistance of those, whocarefully checked the material of the first edition and called hrsirttcntion to errors and omissions.

Kanti K. Mahajan

CONTENTS

l, Shell-and-Tube Heat Exchangers . . . .... .. .. 92, Flange Design . . . . . . . . . . . . . . 593, Rotauon of Hub Flhnges . . . ...........1334. Stress Analysis of Floating Heads . .......t475, Fixed Tubeslreet DesUn. . . . .... .......1616. Flanged and Flued Expansion Joints . . . . . .1597. Pipe Segment Expansion foints. . . . . .....185E, Vertical Vessels Supported bylugs.. . . . . . . . . . . . . .1959, Vertical Vessel l-eg DeslSn . ..... .......20710. ASME Code, Section VIII, Division 2 and Its Comparison to

Division 1.. . . . . . . . . . . . . . . . . .227ll. Mechanical Design of Self-supported Steel Stacks . . . . . . . . . . . . 233

*,y 12. Vibration Analysis of Tbll Tbwers . . . . . . . . . . .......259.' > [3. Design of Rectangular 'Ibnks . - . : . . . . . . . . . . . . .267

14. Air Cooled Heat ExchangersPart A

-

Co4structional Details.. . .... ..,281Part B

-

Header Box Design.... ,....,...290Fdrt C

-

Coverplate and Flange Design For Header 3s1 . . . . . .302

Appendix I -

Appendix 2 -

Derivation of ASME code formulas for shell and headthicknesses of cylindrical vessels for intemal pressure 313Derivation of fornulas for checking thicloesss at vari-ous levels of vertical vessels. . . . . . . . . , . . . .317

Appcndix 3

Appendix 4

Appendix 5

Appendix 6

Appendix 7

-

Dcriv$tion of formulas for anchor boh chair dcsign forlarSe ve ical vessels .. . .. . . . . .321

-

Derivation of TEMA equation for non-fixed tubesheetthickness or ASME equation for flat unstayed circularheads in bending ......327

-

Derivation of TEMA equation for pressure due to differ-ential thermal expansion for lixed tubesheets . .. .. .333

-

Derivation of TEMA equation for flat channel coverthickness . ...............337

-

Derivation of formulas for calculating allowable bucklingstress in tall cylindrical towers... ......341

ISHELL-AND.TUBf, HEAT EXCHANGERS

lntroduction

A heat exchanger is a device used to transfer heat from one fluidto another. This type of equipment is mostly used in petroehemicalplants and petroleum refineries. Proper selection of such equipmentcannot only minimize the initial plant cost but can also reduce the dailyoperating and maintenance costs' The project or process engineerdoes not have to be familiar with the complete design aspects sincethese exchangers are generally designed by the manufacturer'

The project or process engineer, however, must understand themethods ol designing and labricating heat exchangers in order to obtainthe best suited unit liom the manulacturer. By knowing these methods,he can cooperate more closely with the manulacturer and this can savethem both time and money in exchanger applications.

Several types ol heat exchangers are available but only lhe majortypes along with their design leatures will be discussed in this chapter.

Applications of Heat Exchangers

Heat exchangers are used in a wide variety of applicationspetrochemicai plants and petroleum relineries. The functions ofmajor types are:'

ChillerThe chiller cools a process stream by evaporating a rel'rigerant. lt lstusually employed where required process temperatures are lower thanthose attainable with cooling waler.

lnthe

I)tist(;N ()tr t,tr,(x:liss li(?tI ,MLiN I'(irudcnscrl'hc condenser condenses vapors by rcmoving heat to cooling water,atmospheric air or other media.

Partial Condenser

The partial condenser condenses vapors at a point high enough toprovide a temperature dillerence great enough to preheat a cold streamoi process Uuid. lt saves heat and eliminates the need lbr providing aseparate preheater using a Iurnace or steam.

Final Condenser

The linal condenser condenses vapors to a linal storage temperature olaround l00oF. It generally uses water cooling which means that thetranslerred heat is lost to the process.

Cooler

The cooler cools process streams by removing heat to cooling water,atmospheric air or other media.

Exchanger

The exchanger exchanges heat from a hot to a cold process stream.

Heatr

The heater heats a process stream by condensing steam.

Reboiler

The reboiler connects to the bottom of a distillation column to boilbottoms liquids and supply heat to the column. The heating media canbe steam, hot water or hot process stream.

Thermosiphon Reboiler

With the thermosiphon rboiler the natural circulation ol the boilingmedium is obtained by maintaining sufficient liquid head to provide lbrcirculation of the fluid material.

Forced Circulation Reboiler

The lbrced circulation reboiler uses a pump to lorcc liquid through thcreboiler ol a distillation column.

t0 tl

.s'

SHELL-AND.TUBE HTJAT IjXCHANCERS

Sterm Generator

The steam generator generates stam lbr use elsewhere in th plant byusing high level heat from any available Iuel.

Superheatel

The superheater heats a vapor above the saturation or condensationtemPerature.

!hporizerThe vaporizer is a heater which vaporizes part of the liquid led to it'

Wast Heat Boilel

The waste heat boiler produces steam and is similar to a steam generator'except that the heating medium is a hot waste gas or hot liquid by-product produced within the plant.

To perform these applications, many types of heat exchangers areavailable. However, their design and materials of construction must besuitable for the desired operating conditions. The selection of matrialsof construction is mainly influenced by the operating temPerature, andthe corrosive nature of the fluid being handled. In each case seleclionmust be both economical and practical.

CLASSIFICATION OF HEAT EXCHANGERS

The classification oI heat exchangers is primarily defined by theirtype of construction of which the most common is the shell-and-tubetype. Shell-and-tube heat exchangers are built of round tubes mountedin cylindrical shells with their axis parallel to that ofthe shell. These haveextreme versatility in thermal design, and can be built in practically anysize or length. Tbe majority ofliquid-toJiquid heat exchangers fall in thistyp of construction. These are employed as heaters or coolers for avaiiety of applications that include oil coolers in power plants and theprocess heat exchangers in the petroleum refining and chemicalindustries. This type of construction is also well suited to specialapplications in which the heat exchanger must be made ofglass toresistthe attack of highly corrosive liquid, to avoid alfecting the flavor offoodproducts, or the like. Figure I shows some of the various kinds of mostiommonly used shell-and+ube heat exchangers.2

The general construction features of common shell-and-tube typeexchangers as well as the nomenclature involved is illustrated in Figure.r2

l)lisl(;N ( )l; Pl..(x:liss IIQLJIPMUN'tF igurc 2 shows sections ol typical exchangers. The tube bundle is

made up of tubes, tubshets and cross baflles. The channel at the frontend of the exchanger serves as a header to feed the fluid into the tubes.The tloating head at the back end ofthe tube bundle is the return header.It moves freely with the thermal expansion of the tubes in the bundle.

The shell unit is essentially a cylinder with a bolting flange at eachend. The channel bolts to th front flange, and the shell cover bolts to therear flange. Figure 2 also shows some ofthe variations available in shell-and-tub designs. Each variation has certain advantages, and also hassome disadvantages. The major types of shell-and-tube heat exchangrsdepending on their mechanical conliguration are discussed below.r

FIG.T. SHELL.AND-TUBE HEAT EXCHANGERS(Courresy of Tubular Exchanger Manlfacturers A$ociation-)

FRONT END STATIONARY HEAD TYPES

CHANNELAND REMOVABLE COVER

N

CHANNEL INTEGRAL WTTH TUBE-SHEET AND REMOVABLE COVER

BONNET (INTEGRAL COVER)

D

SPECIAL HIGH PRESSURE CLOSURECHANNEL INTEGRAL WITH TUBE_SHEET AND REMOVABLE COVER

t2 IJ

w,

SHELL.AND.TUEE HI]AI' TJXCHANCERS

STIELL TYPES

ti

ONE PASS SHELL SPLIT FLOW

TWO PASS SHELLWITH LONGITUDINAL BAFFLE

H

DOUBLE SPLIT FLOW

m nr--l----nLfLr_____ilJ

DIVIDED FLOW

K

KETTLE TYPE REBOILER

X

cRoss FLow

REAR END HEAD TYPES

IFIXED TUBESHEET

LIKE "A'' STATIONARY HEADFLOATING HEAD

WTTH BACKING DEVICE

M

FIXED TUBESHEETLtKE "B" STATIONARY HEAD

T

PULL THROUGH FLOATING HEAD

FIG.r. SHELL-AND-TUBE HEAT EXcHANGERS (Continued)(Courtesy of Tubular Exchanger Manufacturers Asociation.)

NFIXED TUBESHEETLIKE "N" STATIONARY HEAD

U

U_iUBE BUNDLE

OUTSIDE PACKED FLOATING HEAD

w

EXTERNALLY SEALEDFLOATING TUBESHEET

l)l1Sl(;N ()lr Pl{()(:liSS l;(.1(,IPMtiN I'

FIG.I. SHELL-AND.TUBE HEAT EXCHANGERS (CONtiNUEd)

NOMENCLATURE OF HEAT EXCHANCER COMPONENTS

SHELL.AND.TUBI] HI.IA'I' IIX(IIIAN(iIJRS

FIG.2. HEAT EXCHANCER CONSTRUCTION TYPES(Courtesy of Tubular Exchanger Manufacturers Association.)

3. Stationary Head Flange-Channel or 22. Floatine Tubesheet Skirt

l. Stationary Head-Channel2. Stationary Head-Bonnet

Bonnet4. Channel Cover5. Stationary Head Nozzle6. Stationary Tubesheet7. Tubes8. Shell9. Shell Cover

10. Shell Flange-Stationary Head End11. Shell Flange-Rear Head End12. Shell Nozzle13. Shell Cover Flange14. Expansion Joint15. Floating Tubesheet16. Floating Head Cover17. Floating Head Flange18. Floating Head Backing Device19. Split Shear Ring

20. Slip-on Backing Flange21. Floating Head Cover-External

23. Packing Box24. Packrr'g25. Packing Gland26. kntern Ring27. Tierods and Spacers28. Transverse Baffles or Suppod Plates29. Impingement Plate30. Longitudinal Baffle31. Pass Partition32. Vent Connection33. Drain Connection34. Instrument Connection35. Support Saddle36. Lifting Lug37. Support Bracket38. Weir39. Liquid I-evel Connection

(Courtesy of Tubular Exchanaer Manufacturers Association.)

AJW

14 t5

I)l1lil(;N ()lr l'R(X:liSS li(.ltllPMliN f

CFU

AKTFIG.2. HEAT EXCHANCER CONSTRUCTION TYPES

(Courtesy of Tubular Exchanger Manufactuiers Association,)16

s Iil,t.-ANl) t.u$ti I.:A,f |]X( t tAN(il,RSl.'ixed-'l'ubeshcca l.loul llxchangeni

F ixcd-tubcshecl oxcbatrgcrs ilrc [scd n]()rc (ttcn thatr r)y otllcf lyltc.-fhcy have stlaight tubes sccured at botlt onds in tubcshccts wcldcd tothe shell. Usually, the tubesheets extend beyond the shell and scrve ersllanges lbr bolting tubeside headers. This construction requires t hat shclland tubesheet materials must be weldable to each other.

_

Because -there are no gasketed joints on the shellside, fixed_

lgbesheet exchangers provide maxrmum protection against leakage of5Sellside fluid to the outside. Since clearance betwe; th; oui..rn.r,lgbes and the shell is only the minimum required for fabrication, tubesmay completely fill the exchanger shell. However, this type haslirnitations such as: (a) the shell side cannor be mechanically cleaned orinspected, and (bl t hereis no provision for dillerential therrnut

"iounrronot rne ruDes and the shell. An expansionjoint may be installed in ihe shell1e provide lbr difl'erential thermal expansion, but this req;ir;;;;retuldesign and high quality fabrication, which for large sizes."rufi.,n osubstantial cost increase. Tubeside headers, channel covers, gaskets erc.,are accessible lbr maintenance and replacement, and tu-bes can bereplaced.and cleaned internally. The shellside can be cleaned onll oy6sckwashing or circulating a cleaning fluid.

_.

Fixed-tubesheet exchangers tjnd use primarily in services where the56ellside fluids are nonfouling, such as steam, refrigerants, gases, certainheat transfer nuids, some cooling waters and clean process streams.

g-Tube Heat Exchangers

In this type, both ends of U-shaped tubes are fastened to a singlestationary tube-sheet, thus eliminating the problem ot aifiereitiatllermal expansion because the tubes are free to expand unJ

"o"i.u",.The tube bundle can be removed from the heat ixchanger shell foiinspectron and cleaning or replacement.

The U-tube bundles provide aboul the same minimum clearancebetween the outermost tubes and the inside ofthe shell as fixed_tubesheetexchangers. The number of tube holes in the tubesheet for anv sivcn5hell, however, is less than for the fixed_tubesheet kind becau,ie oflirnitations on bending tubes. The number of tubeside passes mustalways be an even number, the maximum is limited only by ft" nu.U".of return bends.

.

Tubeside headers, channels, gaskets etc., are accessible lbrmaintenance and replacement. BundG tube replacement i" ifr"

"r,rt"rows presents no problems. Tlrc others can be replaced only when sDeclaltube supports are used, which allow the U _ tu bes to be spread apart so as

l'1

l)llsl(;N olr Pl{(x)liss [(lulPMtiN'l'to gain acccss to tubcs insi

t)lisl(;N ( )1, l,l((x:l.ss liQt,lPMIN'l

1&_!. Q9Z

^x

pF(,zF

F

c0>

oo

J

e

d

20

SItIil,I,-ANI).TUBL I It]AT EXCHANCERS

FABRICATION OF SHELL-AND-TUBEHEAT EXCHANGERS

Standards

The TEMA'? (Tubular Exchanger Manufacturers Association) haspublished detailed standards for the design and construction of.shell-and-tube heat exchangers. The mechanical standard has been dividedinto three parts rePresenting the following three diflerent classes of heatexchangers:

l. Class "R" Exchangers This type is specified for the generally severerequirements of petroleum and related processing applications'Equipment fabricated pr this class is designed for safety andduraLi[ty under the rigoroirs service and maintenance conditions rnsuch applications.

2. Class "C" Exchrngers This is specified for the generally moderaterequirements of commercial and general process applications'Equipment fabricated in accordance with this class isdesigned for theeconomy and ove.all compactness consistent with safety and servicerequirements in such applications.

3. Class "B" Exchangers This cl4ss is specified for chemical processservice. The equipment is designed for the maximum economy andoverall compactness consistent with safety and service requirementsin such applications.

Fabrication Procedure''s

Shells

The shell portion ofthe heat exchanger is made ofeither seamless pipe orrolled and welded cylinder. These are fabricated from pipe with nominalpipe diameters up to 12" as given in Table 1. Above 12" and including 24"the actual outside diameter and the nominal pipe diameter are the same.Shells above 24" in diameter are fabricated by rolling and welding steelplates in accordance with the ASME Code Section VIII, Division l, forFressure Vessels. Automatic welding is used almost exclusively on thelongitudinal sams and also on most of the circumferential seams.

zz

v

t

F

E]zX()F'JJ3,.1

z

z

ti$,i

srs *x- l:I* l*,S r,-.l.o.l*.- lE:ellll--l---l'''{.'xEx!

lroo croo laroS,+or l.r IGovr @ o o I u, o .r I t\ r| | N . , l . , ..'lclc I c?111 !99 l9\e lq , Iooo I ooo I ooo tooo o I

anz

Ll

lxoo lo-- l.'o l-.- --.

.6-lo I q|6r I t\ cr ! l{rN- od- loorao ro!l-.r(\ l(\drt I ct.a . l(|at\ 6-c) l!(|N lonlcjcjct |

l6] 3*:88 1 &trEX(d)(4,

l)l,Sl( iN ()lrl'lt(X:l.Sli li(l(lll'MIN l

(b) (c)FIG. 4 - TUBE HOLE PATTERNS

FIG. s ' BAFFLE SPACER DETAIL (Enlarsed) +

Shell flange

Channel flange

ffi*ss-$ 6gmFs88888? *,*ttj\oooooo/ ./N9-,/-o'ittihg

FIC. 6 - SEGMENTAL BAFFLE DETAIL"

(l,r')rI "l'ft'c{ss l-lcnt Transfer" rv Donald Q. Kern - Copvdghr r9s0I'v Mfl irnw llill ll.x)k Cornprny)

24 25

SHF]LT--AND-'t'UI]F: }IDAT LXCIIAN(;T':RS

are screwed into the tubesheets placcd secttrcly at thc eorrect spacing lorthe given exchanger. Baffles are then slipped onto the tie rods and Iirmlylocated in their proper place by use ol spacers between I hem as shou n inFig.5.

There are several types of baffles which are employed in heatexchangers, but by far the most common are the segmnt baffles asshown in Fig. 6. Segmental baffles are drilled plates which are general-ly cut to some percentage of the shell inside diameter' Baffles may bearranged, ur rho*rr, for "up-and-down" flow or may be rotated 90oto prJuid" "side-to-side" flow, the later being desirable when a mix-ture of liquid and gas flows through the shell' The baffle pitch not thepercentage cut detlrmines the effective velocity of the shell fluid'

Other types of bames are the disc or donut, and the orifice baflles asshown in Figs.7 and 8 respectively. Although additional types aresometimes employed, they are not of general importance.

Tubes

Heat-exchanger tubes are also referred to as condenser tubes and shouldnot be confused with steel pipes or other types of pipes which areextruded to iron pipe sizes. The outside diameter of heat exchanger orcondenser tubes is the actual outside diameter in inches within a verystrict tolerance. Heat exchanger tubes are available in a variety ofmetalswhich include steel,copper, admiralty, muntz metal, brass, 70-30 copper-nickel, aluminium bronze, alurninium and stainless steel. They areobtainable in a number of wall thicknesses defined by the BirminghamWire Gage, which is usually referred to as the BWG or gage of the tube.These tubes are available in various sizes, of which i" O.D. and 1" O.D.are most common in heat exchanger design.

The choice of a tube material for any particular application maypresnt no problem at all in many cases but may be a dilficult andcomplex problem in severely corrosive envitonments. All the knownfactors which influence or contribut to corrosion such as pastperformance of materials under similar service condition, type ofcorrosion experienced in similar units, etc. would aid an engineermaterially in selection of most economical and most serviceable tubematerial for the job.Duplex Tubes

It is not uncommon to find conditions where the fluids both inside andoutside the tubs are extremely corrosive, and in addition require adilferent amount of corrosion on each side. Tubes which combine two

r)rlsl(;N ()lr Pl{(x;liss lxll.J IPML|NT

orific\[lr------l

irr--1nl(a) Detail

FIG. ? - ORIFICE BAFFLE *

FIG. 8 , DISC AND DOUGHNUT BAFFLE '

O. D. of tubes

FIG. TODUPLEX TUBE AND TUBESHEET

JOINT

Donald Q. Kern - Copyrisht 1950

(b)

FIG.9I)UPLEX TUBE

(lr,'rn '11rxrcss lltl't Transfer"hv M, (;rxw llill lr,xrk (l)mpany)

Doughnut

FERRULE(Same materialas inner tube)

26

SI IELI,.AND.'TUBE HtsAT I]XCHANCERS

differrent metals called duplex tubes can be used to meet this problem'Duplex tubes are manufactured by mechanically bonding tubes. of twodifferent metals or alloys so that they are in intimate contact' In this wayit is possible to choose various combinations of ferrous or non-ferrousalloys to combat successfully a certain type of corrosion at the^outsidesurface and entirely different type of corrosion at the inside surface'

Ferrules

Where contact of the ends of th outer tube with the fluid passingtfriough tlt" toUe isconsidered objectionable, these ends may be replacedwith flrrules of the same alloy as that of the inside tube' These ferrulesneed be only long enough to ensure their bing held in place when the

tube ends are rollid into the tubesheets' It is a distinct advantage to haveiil."-1".tut". furnished as an integral part of the tube to facilitateir,.Lttutiott. The construction of duplex tubes with attached ferrules isshown in Fig. 9 and 10 before and after installation respectively'

Tube Rolling

Tubes are passed through the tubeshets and baffles, and are fixed inplace by an expanding operation. They are set in a preliminary.fashionLy forcing u piog ug"intt the tubes. The plug preYents the tube fromturning when the roller expander is inserted' The roller is a rotatrngmandr-il having a slight taper. It is capable ofexceeding the elastic limit ofthe tube metai and transforms it into a semiplastic condition so that itflows into the grooves and forms an extremely tight seal A simple and

"ornrnon ""u.ll. is shown in Fig. 11. Tube rolling is a skill,since a tube

-rv- U. Ou-og"O by rolling too thin and leaving a seal with littlestructural strength.

FI6. 1T . TUBE ROLL(From "Process He.t Transfer"by Mccraw-Hill Book ComPany)

FIG. I2 - FERRULEDonald Q. Kern ' Copyright r95O

27

TurningSlot \

Tube wall

l)lisl(;N olr Plt.( )(il'lss llQtrlPMuN'lln some industrial uses it is desirable to install tubes in a tubesheet

so that they can be removed easily as shown in Fig. 12. The tubes areactually packed in the tubesheet by means of ferrules using a soft metalpacking ring.

After completion ofthe bundle assembly, it is brought to a test rackwhere a hydrotest is applied. Bundles are then lowered vertically into theexchanger shells and linal hydrotest of the exchanger is made. After theoutside ofthe shell is painted with a rust-preventive paint and all flangesare covered to prevent damage, the unit is ready for shipment.

Design of rnajor shell and tube heat exchanger components isillustrated in the examples given below.

EXAMPLE NO. 1

Usinghand calculation method, mechanically design all the components ofacarbon steel, 56 inch inside diameter having 16 feet long tubes, TEMA'AET" type of shell and tube heat exchanger for the following conditions.

Design Pressure, PsigDesign Temper'ature,'FCorrosion Allowance, In.Number of Passes

SHELL SIDE TUBE SIDE50 420

400 250Va '/al4

Provide solid soft steel gasket at the floating head and steel j acketed asbestosgaskets at all otherjoints. Use ASME Section VIII, Division l6 and TEMA"R" design criteria in calculations. Also, check the reinforcement require-nrcnt for an 8 inch 300# R.F. nozzle on the tubeside.

28

sllDl,l--ANl)-ltJttli llliAl lix( l{AN(il:Rs

DESIGN CAI,CULATIONS

Shell CylinderReference: ASME Section VIII, Division 1' Paragraph UG-27(c)

P = Design Pressure, Psig : 50 PSign = C..t A"i inside radius, in. = 28 125 in'J : eilo*uuf" stress at design temperature' psi = 13'800 psiE = Welcl joint efficiencY : 85

C.A.: Corrosion allowance, in : .125 in'Now

t = Minimum cylinder (hickness' in'PR: >* C.A.

SE _ ,6P

_

50(28.125) _i

.12513s00(.85) - .6(50)

= .1202 + .125 : '2452 in , use 72" (SA-285-C)

Shell Cover CYlinderReference: same as shell cylinder

5O(28.t25) + .2513300(.85) - .6(s0)

: .1202 + -125 : '2452 in , use /2" (SA-285-C)

Shell Cover Head (2:1 ElliPsoidal)Reference: ASME Section VIII, Division l' kragraph UG-32(d)

P : Design Pressure, Psig : 50 PsigR : Corr;ded inside radius, in = 28 125 in'S : Allowable stess at design temPeratue' psi = 13'800 psiE = Weld joint efficiency = '85

C.A. = Corroiion allowance, in = 125 in'

l)liSl(;N ( )lr I'l{(XilrSS lQtJlPMIN'l'

Now

r = Nominal head thickness, in.PR

st -

.lP

50(28.125\-F

.125 + .u02513800(.85)

- .1(s0)

: . i 199 + .125 + .0625

- .3O'14 in., use 26" nom. (SA-285-C)

Channl CylinderReference: Same as shell cylinder

420(28.125\t =

-+

C.A.17500(.8s)

- .6(420)

: .8078 + .125 = .9328 in., use 1" (54-516-70)

Channel Flanges at Cover and Thbesheet

Reference: ASME Section VIII, Division 1, Paragraph UA-48Welding neck flanges are used in design. Both channel flanges will be

identical as they are independent because tube side design pressure isconffolling the design.

Referring to the nomenclature, figures, tables and design steps forindependent hub flange in chapter 2 and using SA- 105 flanges and SA-193-87 bolts, we have

p : 420 psiS' : 25'000 PsiS" = 25,000 PsiSr" = 17,500 psiSr" = 17,500 psi

Also in uncorroded condition8:56in.

80: t': l0in'Assume

gr : 1.5(go) = 1.5(1.0) = 1.5in.Thus in corroded condition

B : 56.25 in.8" : 875 in'

SHTJI,I--AND"TUBE HEA'I' T.:XCTIAN(itJRS

itn(l8r : l '375 in

Nowh : 1.5(eo) = 1.5( 875) : 1.3125 in. (min'), use 2'25 in'

k, -

2^l (1.375 -

R75)(rone =E ---:------------- = o.2222 < 0.333h 2.25Therefore, the flange can be designed as an integral type as shown in

Fig. 1a of Chapter 2. Now assume (64) lVt in. dia. bolts. From Table 3. inChapter2, for lVq in. dia. bolts, we have

R : 1.75 in.E = 1.25 in.

Nowc = B + 2(g t) + 2(R'):56.25 + 2(1.375) + 2(1.75) = 62.s in-

andA: C + 2(E) = 62.5 + 2(r.25) = 65 in.

Gasket and Bolting Calculations

From lhble I in Chapter 2, for an iron jacketed asbestos filled gasketm = 3.75

andv : 7600

AssumeN = 0.625 in.

Fig. la. of Table 2 in Chapter 2,applies to our situation. So,A/ n 6t56 =:::: = 0.3125 in.22Therefore

Vb^ Vc.:t sh : -:-

: U.L|YJ n.-22

NowG : C

- a

- 2(0.25)

- 2(b) : 62.s

- 1.2s

- 2(0.2s)

- 2(2195)

= 60.191 in.Assume rib area : RA :

'{0.7018 in.2Therefore W.r: 10.2795 (n) 60.191 + .5(40.7018)l 7600

: 556,344 lb.Ho = 12 (n) 0.279s(60.19r) + 40.70181 3.7s(420)

= 230'590 lb.

3t

l)lisl(;N ( )tr plt(x:liss uQUlpMtrNT1tIt = -(60.1910), 42o = t,t95,097 tb

W^, = |,195,097 + 230,590 = 1,425,68l. tbthus

. r,425.687".

=J5poo = 57.0275 in.zFrom Table 3 in Chapter 2, the root area of a 1 ya in. dia. bolt having g threadsper inch is .929 in.2 which gives

Ao = 64(.929) = 59.456 tn.2Since A, ) A-, therefore (64) lVq tn. dia. bolts are adequate. Now

W : 0.5 (57.02'15 + 59.4s6) 25,000 = r,456,044 rband

.. (59.456) 2s.000

'"-t =zrr?oooioo.rsl = o5l7l inSince N > N-r, therefore chosen gasket width is adequate.Flange Moments Calculations

HD:- \56.25)2 42O = 1.043.j23 tb4H6 = Ho = 230,590 lbHr= 1,195,097

- |,043,723 = t5t,3j4 tbhp:1.75 + .5(1.375) = 2.4375 n.

hc= .5 (62.5 -

60.191) : t.1545 in.hr=.5 (r.75 + 1.375 + 1.1545) : 2.1398 in.

Mo= 1,043,723 (2.4375) : 2,544,07 5 in-tbMc = 230,590 (1.154s) = 266,216 in-IbMr:151,374 (2.1398) : 323,910 inlb

Mo = 2,544,0'15 + 266,216 + 323,910= 3,134,201 in-lb

Now, for the gasket seating condition

Now

Therefore,

Hc: W : 1,456,044lb.

33

SHELL.AND.TUBE HEAT EXCHANGERS

'l'hcrclurc,

Mo = 1,456,044 (1.1545) = 1,681,003 inlbt(O tr(62.5\Actual bolt spacing =-: 64 = :.00S in.Assumet:5.0625in.

Miximum bolt spacing = 2(1 .25) + *9 ^ : g.e+l in.(J. /J + U.)'Normal bolt spacing : 2(1.25) + 5.0625 = 7.5625 in.

Since, Actual bolt spacing ( maximum bolt spacing, the chosen bolt spacingis O.K. and also actual bolt spacing < normal bolt spacing, the correctionlactor CF = 1.0.'I'hus, the calculation factors are

" ='u#-= 55.ite

tu t.681.003 ( t.0)56.25

Deiermining Shape Constants

Z:1.8565z = 6.9647Y : 13.487 |

U:14.8209Now

L = r.57l4

8o

fr\^

: _

--:l= l.t))o)b.ziFrom Table 4 in Chapter 2, for rK : 1.1556

29,884

and

ho :\6r.25.r;, = 7.0156

l)Hst(;N ( )tr PR()cEss EQUIPMENT

h=2.25: ^rnho 7.0 t56

From Fig. 4 in Chapter 2, for

P, h"

- 1.51 t4 and

- = .320i8o ho

we have

F = 0.8736Similarly from Fig. 5 in Chapter 2,

V = 0.3488and ftom Fig. 8 in Chapter 2,

f = r.20r9

0.8736p =-: l)A\- 7.0156

and

14.8209d : laRR (7.0156t (.875)2 = 228.2333

Calculating Other Stress Factorsc = 5.0625 (.1245) + | : 1.63

B =14 \s.oozsr.l245) + t= l.E4\ 3/I .63

^, =-= R7R,' 5.062s

-

(5.0625)3d =-= .5685

i: .8782 + .5685 = 1.4467Calculating StressesOperating Condition

^ 1.2019(55.719)," :lZOt,r:tsr, = 24,484 psi

and

l)tist(;N oF Pt{o(iEss EQUTPMENTThus, in the coroded condition

8r : 0.6875 in.Assume

h = 2.0 in. > 1.5 Go)> 0.5625 in. O.K.ro 6R?5

-

n 17slSlope :--:

.1563

r)Esl(;N oF PR(rcESS EQUIPMENT

h:2'o : o.+zssho 4.5928From Fig. 4 in Chapter 2 for grl80 = 1.8333 and hlho : 0.4355 we have

F : 0.8442Similarly from Fig. 5 in Chapter 2

V : 0.2671and from Fig. 8 in Chapter 2

Now

and

f = 1'2179

0.8442e =-= 0.18384.5928

14.8209d = 0.26j 1@.5928) (0.375)'z : 35.8386

Calculating Other Stress Factorscr = 4 8125(0.1838) + I = 1.8846p :( r )a.8l2s(0.1838) + I :2.t794r =@: t.ot:t' 1.8565

(4.8125)l; =-: J.ii- 35.8386

I: 1.0151 + 3.11 = 4.1251Calculating StressesOperating Condition

-

|.2t79(33,17t) ^

,S.. =

-

= 20.720 psi

r )tjtit(;N ()tr t,R(xIiss ti.ltJ ,MINT('.r'1.

- Cornrsion allowancc or dcpth ol pass partition groove, whichever isgreater, in. : .1975 in.

C = A factor for method of cover attachment = .3S., = Allowable stress for cover materi2l ar ar-^.^r.-,;^ ,---^-^...-_^

: 17,500 psi naterial at atmospheric temperature, psiJ"o : Allowable stess for cover

: 17,500 psi material at design temperature' psiE : Elastic modulus of cover material at design temperature, psi: 28.4s(10)6 psilV : Design bolt load for sasket

w-, : legu_,r9g bort road ror

"0"#l';":"::?fl,i:' rb = r,4s6,044 rb

= 1,425,687 tb

TEMA Equation

,=l*y".r#y1,, + cA_lt -422-$0.l9l)4 420+0.5(t.1545) 59.456(60.t91) l06 j,,t

,^L 28.45( 10)6 28.45( t0)6 t/i$ -

J + l87s= 7 .1744 in.

ASME EquationsOperating Condition

t=G cP r.9lw_,) h-r- *.;;* to'

= 60.191

= 5.5177 in.

Gasket Seating Condition

-

/t.9twh-t=U., l a+aAV s., (ct, - "'= 60.191 C.A.

: 1.9288 in.TEMA F4uation Conhols: Use 7.25 in. thk. (5A-516-70)

17.s00 (60.191)3

| .9fl,456.044) 1.ts4517,s00 (60.19t)3

sHttlL-ANt),',t ulrlt IiAI Ix(]]tAN(]trRs

'lbbesheet

l{cference: TEMA Paragraph R-7.1P = Design pressure, psig = 420 psigS : Allowable stress for tubesheet material at design temperature, psi

= 17,500 psiG: Mean gasket diametet in. = 60.191 in.F: Tirbesheet constant : 1.0 (for tubesheets having straight tubes)

C.A. : Shell side corrosion allowance plus tube side corrosion allowance ordepth ofpass partition groove, whichever is greater, in. = .3125 in.

Now7 : Effective thickness of tubesheet, in.

FG Tp:iv;*_

1.0(60. 191)2

+ .3125

C.A.

= 4.6624 + 0.3125 : 4.9749 in.Use 5" thick tubesheet (5,4-516-70)Notes: (l) Ihbesheet thickness for bending only is calculated and it is

assumed that shear does not control the desisn.(2) Floating tubesheet will have sma er valui of G but both

tubesheets of the same thickness are used.

Floating HeadReference: ASME Section VIII, Division l, hragraph l-6 & Appendix 5

P: Intemal design pressure, psig = 420 psigPc = Extemal design pressure, psig = 59 nritS" = Allowable bolt stress at atrnospheric temperature, psi = 25,000 psiSr: Allowable bolt stress at design temperature, psi = 25,000 psi

Sra = Allowable stress for flange material at atmospheric temperature, psi: 25.000 osi

Sn: Allowable stress for flange material at design temperature, psi= 25,000 psi

Srr = Allowable stress for head material at design temperature, psi= 17,500 psi

C.A. = Shell or tube side corrosion allowance, in. = .125 in.

41

DESIGN OF PR@ESS BQUIPMBNT

Materials of ConsnuctionBolts SA-193-87Flange SA-105Head 5^4-516-70Gasket Solid Soft SteelUse 7r in. x 7a in. single nubbin for gasket facing.

trlange DesignAllolving % in. clearance between the LD. of the shell and the O.D. of theflange, we get

A = Outside diameter of flange, in. = 56 -

.375 = 55.625 in.Assume (56) I % in. dia. bolts. TEMA recommended minimum wrench andnut clearances are not used for the flange design since this is an intemal jointand exchanger design does not require to comply with ApI 660requirements.

C : Bolt circle diameter, in.=A - Nut dimension across comers:55.625

- 2.0 = 53.625 in.

From Table I of Chapter 2, for solid soft stel gasket, we haven = Gasket factor : 5.5) = Gasket seating stress, psi = 18,000 psi

Assume N = Gasket width. in. = .375 in.also w = Nubbin width, in. = .125 in.Fig. (2) of Table 2 in Chapter 2 applies to this situation, so

bo = Basic gasket seating width, in.w+N .125 + .375:

.125 in,

D = Effective gasket seating width, in. : bo : .125 n.Also

G = Diameter at location of gasket load reaction, in.= C

- Bolt hole dia.

- .375

- N

= 53.625 -

1.25 -

.375 -

.375= 51.625 in.I = Inside diameter of flange, in.:G_N= 51.625

- .3?5 = 51.25 in.

SHELL.AND.TUBE HEAT BXCHANOENS

L = Inside radius fo( dished only head, in'=.8(B) = '8(51.25) = a1.0 in.

Rr = Rib area, in.2 = 19.22 in.2

Flange and head will be designed using corroded dimensions becguseconoded condition results in greaier thickness. Thus in corroded condition

A = 55.625 - 2(.125) = 55.375 in'B = 51.25 + 2.\.125') = 51.5 in.L= 41 + .125 = 41.125 rn.

W., = Minimum required bolt load for gasket seating, lb= (bnG + .5Ra))= [.12s(tt) 51.625 +.5(19.22, 18000= 537.896 lb

Il, = Total joint-contact surface compression load, lb= (2ttbG + R)mP:12(tr)

.r2s(51.62s) + 9.nls.s@n)= 138,060 lb

Il = Total hydrostatic end load, lb

=loct p

= -.(5r.625)2 420

= 879,143 lb.W-r = Required bolt load for operating condition, lb

=H+HP: 879,143 + 138,060= 1,017.203 lb

A,, : Total required cross-sectional area of bolts, in.2^ ^W,a W^r: Urearcr oI -:-or-;-J" J,_ _537,896 t,Ot7 203

= Greatr d ztmo - zsooo= 40.6881 in.2

From Table 3 in Chapier 2, the root area ofa I % in. dia. bolt having 8 threadsper inch is .728 in.2 which gives

Aa = Actual total ooss-sectional area of bolts, in2= 56(.728) = 40.768 in.2

Since A, ) A-, therefore (56) l% in. dia. bolts are adequate. Now

l' n

DEStcN oF PROCESS BQUTPMBNT

W = Flange design bolt load for the operating condition or gasket seat_ing, as may apply, lb

= .5(A^ + A) S"= .5(40.6881 + 40.768) 25,000= r,018,201 lb

and

.lf-, : Minimum required width of gasket, in.:Aus"

2ryG_

40.768(2s,000)2r(18,000) 51.625

: .1746 in.

Since N) N,,r, therefore chosen gasket width is adequate.flange Moments Calculations

11o = Axial component ofmembrane load in the spherical segment actingat the inside of the flange ring, lb

:!8, p4

1T= -(51 .5)2 420

= 874,890 lbIlc = Gasket load in operating condition, lb

:Ho= 138,060 lb

1{. = Difference between total hydrostatic end force and hydrostatic endforce on area inside of flange, lb:H-Ho

:879,143 -

874,8m= 4,253 lb

Ilr = Radial component of the membrane load in the spherical segment,tb

_- f v_4L, - B'r _ _^^f vai.nf=,7;rv1:""L- a I =874,8e0L--=;:J: I,089,471 lb

44 45

55.375 -

51.5

SHBLL-AND.TUBE HBAT EXCHANOERS

io = Radial distance ftom the bolt circle to the inside of the flange ring,m,

=.5(C - a) = .5(53.62s - 51.5) = 1.0625 in.ic = Radial distance from gasket load reaction to the bolt circle, in.

= .5(C - G) = .5(53.62s - 51.625) = 1.0 in.frr = Radial distance from bolt circle to circle on which Ii. acts, in.

=,s(hD + he) = .5(1.0625 + 1.0) = 1.0313 in.hn = I-ever arm of force 11^ about centroid of flange ring, in.

=0 in.NowMa = Moment due to I/r, in-lb

=Hoho = 874,890 (1.0625) = 929,571 in-lbMc = Moment due to llc, in-lb

= He hc = 138,060(1.0) : 138,060 in-lbMr : Moment due to I1r, in-lb

= Hr hr = 4,253(1.0313) = 4,386 inlbMn = Moment due to llR, in-lb

: Hn hn = 1,089,471(0) = 0 in-lbMo : Total moment acting upon the flange for the operating condition, in-

lb=MolM6+Mr+MR=929571 + 138,060 + 4,386 + 0: |,072,017 in-lb

Mt:Mal moment acting upon the flange for the gasket seating, in-lb:WC: 1,018,201(1.0) : 1,018,201 in-lb

Flange Thickness CalculationsIntemal hessure

P8\,6I;-;8S&(A

- A)

4206r.s\v4(4r.125)2 -

(5 1.5)28(17s00) (55.37s

- 5l.s)

=2.557

M.o/A+B:"+(^-"= 32.81

) =;iff#ft( 55.375 + 51.5

DESIGN OF PROCESS EQUTPMENT

, = Rcquilgg_qEe thickness for opcrating condition, in.=F +\/F7=2.557 +\EmTffir = 8.83 in.

, = Required flange thickness for gasket seating condition, in.

#;"r->

= 5.5821 in.

Extemal hessure

p :YoG, p,

:f,u.azsl,5o = ru,66o lb

no:!SP r"

=itsr.sy so : lo4,l53 rbHr=H

- Ho

= 104,660 -

104,153 = 507 lb

hp"= ho -

h6= 1.0625 - 1.0 :

hre: hr -

hc= 1.0313 - 1.0 =

ha=oMo= Ho ho,

: 104,153(.062s) =

.0625 in.

.0313 in.

6,510 in-lb

= t*,'slfV{4#l : r2e,6e8 rbL 5t.5 I

1,018,20r,,55.3755l i(lr5oo)(553?5

46 47

SHELL.AND.TUBE HEAT EXCHANOERS

Mr= H, hr"= 507(.0313) = 16 inlb

Mp: Ho h^:129,698(0) = 0 in-lb

Moe = Ibtal moment acting upon the flange due to extemal pressure, psi=Mo*M,rM*=6,510 + 16 + 0 = 6,526in-lbp.B\/trL

- B,

8 Sf" (A -

B)50(51.5) v4(41.12s\2

- 51.52

8(17500) (55.375 -

51.5)= .3044

J =Moe1e + n

B S/"\A -

B

6.526 .,55.375 + 51.5=

sr J(r?Joor(5si?s -

sl.s:0.20

t : Required flange thickness for extemal pressure, in.:F +!F2 + l= 30da f/(304o2 + .?I : .8454 in.

Thus the flange thickness for operating condition controls. Adding %o in. forcounterbore and ys in. for shell side corrosion allowance, we get,Total thickness of flange= 8.83 + .1875 + .125

= 9.1425 in., Use 9.25 in.

Ilead Thickness CalculationsIntemal Pressure

/azr = Minimum required thickness of head plate, in._

.833 PLsl{

.833(420) (41.125)= 0.8222 in.. sav 0.875 in.

17,500

Extemal Pressure

tno = 0'875 in'L = 41.125 in.

t)t.:st(;N ( )tr t,t((xltjss lt(lrJ ,MtjN,t.Lltt

, = 41.1251.875 = 47A = Code factor to obtain B

, .125 .. .l2s:{* l= * =.0021\LnHD/ +rFrom ASME Section VIII, Division l, Appendix 5, Fig. UCS-28.2

B = 13,900P" : Maximum allowable external pressure for bead, psi/ B . 13.900

=l* l_-=2e5psi\LlrHD/ +rMaximum allowable pressure Po is greater than the extemal design pressureP" of 50 psi thus the head thickness is adequate.Total.head thickness =,r/D + shell side C.A. + tube side C.A. * formingor thinning allowance:

.875 + .125 + .125 + .125: 1.25 \n. nominal thk.

Calculation of Reinforcement for Thbe Side NozzleReference: ASME Section VIII, Division l, paragraph UG-37 and Appen_

dix LP = Design pressure, psig = 420 psig

C.A. : Corrosion allowance, in. = .125 in.R : Conoded inside cylinder radius, in.

- 28.125 in.R,: Corroded inside nozzle radius, in. = 3.9375 in.d: Corroded inside nozzle diameter, in. = 7.g75 in.

Er = Channel cylinder joint efficiency : 1.0E: Nozzle neck joint efficiency : 1.0S: Allowable cylinder stress at design temperature, psi = 17,500 psiS": Allowable nozzle stress at design temperature, psi = 15,000 psit: Corroded cylinder thickness, in. = 0.875 in.t,: Corroded nozzle thickness, in. : 0.375 in.

S, : Allowable reinforcing pad stress at design temperature, psi:17,500 psis- 15.000

"/,, = (max = 1.0)=-=.8571J 17,500f..r = (lesser of S, or Sp)/S (max - 1.0, =

-!f, - ttt'I /,)UU

sHIit-1.-ANI)-ltJBli I tAt lixcltAN(itsRs

17.500(max = 1.0):-:1.017,500

a = Outward nozzle weld leg size, in. : 375 in.F : Correction factor = 1.0

t,: Required cylinder thickness, in.PR

sEt -

.6P

_

420(28.r2s) :0.6849 in.17500(1.0)

- .6(420)

/,,- Required nozzle neck thickness. in.: PR"

s"E -

.6P

420(3.931s)= u. r rZr rn.

15000(1.0) -

.6(420)A = Area of reinforcement required, in.2

:dt,F + Zt"t,F (1 - f,r)

:7.87s(.6849) (1.0) + 2(.375) (.6849) (1.0) (l -

.8571)= 5.467 in.z

A, = Excess area in cylindet in.2: Larger of the following: d(EJ

- Ft,)

- 2t, (EJ Ft,) (.1

- f,)= 7.875 {l(.875) - l(.6849)} - 2(.375){l(.875) - l(.6849r(l -

.8571): 1.4767 in.z

of:2(t + t.) (Ert

- Ft.)

- zt"(EJ

- Ft)(l

- f,)= 2(.875 + .37s) {l(.875) - l(.6849)} - 2(.375) U(.875) -

l(.6849)) (l -

.8s71):

.3369 'n.242: Excess arca in nozzle, in,2

: Smaller of the following:5(t"

- t,") f1 t

= 5(.375 -

.1121) .8571(.875)= .9858 in.2

or:5(t"- t,")fit,=5(.375 - .1121) .8571 (.375)

49

DESIGN OF PROCESS EQUIPMENT

: .4225 in.z

Ar = Area of outward nozzle weld= (a)2 fa= (.375)2 (.8571) : .1205 in.2

Total available area of reinforcement : A, -t A, ! Ao:1.4767+.4225+.1205= 2.0197 in.2

Since Ar + Az+ A4

ff1

DESIGN OF PROCESS EQUIPMENT

do = Outside diameter of tubes, in. = 0.75 in.," = Corroded shell thickness, in. = 0.25 in.,r ='IUbe wall thickness, in. : 0.083 in.G: Corroded shell I.D., in. = l9.5in.

N = Number of tubes = 284E": Elastic modulus of shell material at metal temperature, psi: 28.21(10)6 psi4= Elastic modulus of tube material at metal temperature, psi

= 28.26(10)6 psiE : Elastic modulus of tubesheet malerial at metal temperature, psi

= 28.63(10)6 psid" : Coefficient ofthermal expansion of shell material at metal tempera-

ture, in./in. "F : 6.596(10)-6 in./in "Fa, : Coefficient of thermal expansion of tube material at metal tempera-

ture, in./in. 'F = 6.576(10f6 in./in. "FO" = Shell metal temperature

-

70"F = 228'FO, = Tub" metal temperature

- 70"F = 218"F

Mr = Total flange moments in operating condition, in- lb = 0M2 = Total flange moments in gasket seating condition, in

- lb= 0

F = Thbesheet factor : I (for tubesheets with straight tubes)J: Rctor : I (for shell without expansion joint)S = Allowable tubesheet stress at design temperature, psi = 17,500psi?= Assumed thickness of tubesheet, in. = 1.25 in.Z = lbbe length between inner tubesheet faces, in. = 141 in.

D; = Expansionjoint inside diameter, in. = 0 (since there is noexpansion joint)

Now

,, E" t" (Do - t")Et\N (4

- t)

=@=.,..28.26fl0)6 (.083) 284 (.75 -

.083)1300 r. E- ,G, 31ttaF.= .25 + (F

- .6) l=:-{;l IL KLE \t/ J

" ?rn/ ?s) 28.21(10)6 zl9.5ri-lt/a ^ ^^:.25+t-.6t1--

l.rrsrr+rr-e-orffi (,*) I : 3'62P, : Equivalent differential expansion pressure, psi

_

4./ E, t" (oc" O" -

a, O,)(Do_3t")(t+JKFq)

4(r) 28.21(10)6 (.2s) [6.s96(10)-6 (228) - 6.[20 - 3(0.25t [1 + (1) .3135 (3.82)]

SHELL-AND.TUBB HEAT EXCHANOBRS

= 216.89 psi

Pr, = Equivalent bolting pressure when tube side is under pressure' psi

= u ?-

',t = o (since M, = g;(n2 (G)3Pr" : Equivalent bolting pressure when tube side prcssuro is zero' psi

= 6'? M"-:

o (since M" = g;(n2 (G)3

forir,s * rrr.t

,L- +/")) - :J(e'(t + .lKF q\_ 75r.4(1) u.5 + .3135 (1.5 + .5799)l - 5 = 29.379 osi

-L 1+l(.3135)(3.82) IP = Effective shell side design pressure, psi (will be the greater absolute

value of the follorings)P=.5(P"'

- P) = .5(29.379 - 46.89) : - 8.76psi

P =P: = 29.379 psiP=Pas=0P=.5(P!

- Pa- Pns) = .5(29'379 - 46.89 - 0) = - 8.76 psi

P = .S(Pas + P7) : .5(0 + 46.89) = 23.45 psiP : P"'

- Pes = 29.379 - 0 : 29.379Psi

The maximum absolute value of effective shell side design pressue will be29.319 psi.

Now

f"=t-"fo)':1-2s4(4,J2:.Siee

P! = P

f,=1-*(+')J

DESIGN OF PROCESS EQUIPMENT

r.75 -

2 (.083Ir 'z

=l-284l-ler I =.74s

Since P,' is positiveP = Effective tub side design pressure, psi (will be the greater absolute

value of the followings)P =.s(Pi + PE, + P) = .5(75.87 + 0 + 46.89) = 6l.38psiP = Pt! + Pat : 75.87 + o = 75.87psi

Thus the effective tube side pressure will be 75.87 psiT : Requircd tubesheet thickness

FC IF2y s

Where P is tlle gxeater of effective shell or tube side design pressure

= ''[uffiffi@]:zs'sznsr

r(rg.5\ EE2 V l75oo

= .642 in., use 1.25 in (min.) + shell side C.A. + greater of tube side C.A.or groove depth

or use r = 1.25 + .125 + .125 : 1.5 in. (54-516-70)It is O.K. to \se ly2 in. thick since tubesheets thicker than computed arepermissible provided neither sheU nor tubes are overloaded.

She[ Longitudind Stnecs CalculationsPr

-Pr - P,'= 130 - 75.87 = 54.13 psiP,* = Pr = 54.13 Psi

or P,* =p I - 29.379 psiorPr+=

- Pa = - 46.89psi

or Pj* = Pr + P"' = 54.13 + 29.379 = 83.5 psiorPr*:Pr

- Pa = 54.13 - 46.89 = 7.24 psi

or Ps:* =Ps' - Pa = 29.379 - 46.89 : - 17.511 psior Prt =Pr + P"' - Pd = 54.13 + 29.379 - 46.89 = 36.62 psiUsing maximurn positive value of P"* we have

54 55

SHELL.AND"TUBE HEAT EXCHANCEN,S

Cs = 1.0 (from TEMA kragraph R-7.22)Ss = Maximum effective longitudinal shell sness

_

(D. -

r") (C" P"'*)4t"

_

(20 -

.25) (l) (83.5)4(.2s)

= I,649 psi (tensile)S" (allowable) = 15,000 psi (tensile)S" < S, (allowable), shell is O.K. in tension

Using rnaximum negative value of P"t we haveC. = 1.0 (from TEMA Paragraph R-7.22)

(20 -

.25\ | //'6.89).4(.25'l

: 926 psi (compressive)A= .r25 | (DJzt")

: .125 t (2O1.5) = .003l

From ASME Section VIII, Division l, Fig. UCS-28.2B : 14,900

S" (allowable) = B = 14,9000 psi (compressive)S,

rDBSIGN OF PROCESS BQUTPMENT

ot P,r = p, + Po = 59.52 + 46.89 = 97.41 psiot P,4 =-P3+Pd:

-17.99 + 46.89 = i8.9psior P,* = p, - P3 + Pd = 50.52 - 17.99 + 46.89 =Using maximum positive \alue of P,* we have

C, = 0.5 (From TEMA hragraph it-7.23)S, = Maximum effective longitudinal tube stess

_

Fo G2 Ct Pt+4N4@o- t)

3.82 (19.5)2 .5 07.4tl4(284) (.083) (.7s

- .083)

= 1,125 psi (tensile)S, (allowable) = 10,000 psi (tensile)S, < S, (allowable), tubes are O.K. in tensionUsing maximum negative value of P,+ we have

C,:1.0 (from TEMA kragraph R-7.23)^ 3.82 (19.5\2 | (17.99\''

= +,2g4) ("08ilJ5:ls3): 416 psi (compressive)

: lhbe maierial yield stress : 26,000 psi: Radius of glration of tube: 0.25Vdo2 + (do

- 2r)z

= 0.25 V.75)2 + t .75 - .t66)2 : .2376 in.

79.42 psi

.s,

r

Kkt

= Maximum unsupported tube span= 60 in. (span between two baffles)= 1.0 (For unsupported span between two baffles): Equivalent unsupported buckling length of the tubes: 1(60) = 60 in.

IGFE.vs.

kl 60r .2376

2(n)2 28.26(10)626,000

56 57

SHELL-AND-TUBE HEAT EXCHANOERS

Since c" JS. = Allowable tube compressive stress

_

tP E, _tr2 (28.26)106=r@y=

,eoLory : 3'417 Psi\r,S, (allowable) = smaller of S, (allowable) in tension or Sc

= 3,417 psi

S,

I )rist(;N ( )tr t,l{( x:lis:i ltlutPMtN't

/;. : Pactor for reliability ofjoint= 0.70 (for rolled joints having two or more grooves)

4, : Ratio of tubesheet yield stress at metal temperature to the tube yieldstress at metal temperature or 1.0, whichever is less, for rollerexpanded joirts

= 1.0

17, (allowable) = Maximum allowable tube-lo-tubesheet joint load= A, (s") f" (f) fy:

.1739 (10,000) l (0.70) I= | ,217 lb

17,

t)tist(;N ( )t t,t{(xjiss l1(?lIIt,MIrNI.AWWA (Anrcricarr Watcr Works Association) Standard C207-55.classcs B, D and E, in sizes 6" through 96".

The flanges included in the API Standard and the several TaylorForge Standards are designed in accordance with the requirements ofthecode. When flanges to other standards are considered, only allowableratings in accordance with the code need to be checked instead of thedevelopment of an individual design.

Taylor Forge Catalog No. 722 lists all of the above and also otherlarge diameter flanges. A lot of unnecessary flange design time can besaved by choosing the appropriate flange from this catalog. Howevcr,due to the variety of sizes and pressure and temperature combinationsrequired for process equipment, manual designing ofthese flanges is notvery uncommon. The design analysis of various types of flanges alongwith the sample design calculations for eash kind are included in thischapter.

We will cover the design ofcircular flanges under internal pressure withgaskets entirely within the inrer edges of the bolt holes and with the outerrims of the flanges not touching under the applied loading as discussed rnASME Boiler and Pressure Vessel coder and EPG Bulletin No. 502,2 Thescare classified as circular flanges as illustrated in Appendix 2 of 1983 editionof the ASME code Section VIII, Div l, Paragraph 2-4 and Fig. 2-4. Thefollowing are types of such flanges:1 Intgral Type Flanges. This type covers designs where the flange rs

integral with the neck or vessel wall, butt-welded to the neck or vesselwall, or attached to the neck or vessel walt by any other type of weldedjoint that is considered to be the equivalent to an integral structure. Inwelded construction, the neck or vessel wall is considered to act as ahub.

Fig. la through ld represent flanges of this type. For flangcshaving tapered hubs, the dimension 9o is defined in the code as thehub thickness at the small end, but for calculation purposes it is moreconvenient to let go equal the wall thickness of the attached cylinder.Also, th hub length I extends exactly to the point where its slopelinemeets the O.D. of the vessel or nozzle and thus ft may actually beshorter or longer than the hub length as manufactured.

The dimension B in this case will be the inside diameter of boththe flange and the vessel or nozzle.

2- Loose Type Flanges. This type covers designs where the flange hasno dirct attachment between the vessel or nozzle and those wherethe method of attachment is not considered to be equivalent rointegral structure.

60 6l

Irl.AN(il; l)rlsl(;N

l-ig. lc shows the original application of this type. The hub canho made of any length or omitted entirely. Bsides lapjoint, slip on,threaded and socket type flangs are also classed as loose typ. Forhubbed flanges ofthis type, there is no minimum limitation on i or go.I{owever, values oI go less than 1.5t, and i lcss than go are notrecommended. Ifthe hub is too small to meet these limits, it is best todesign it as in Fig. 1f, but ofintegral type, using hub thickness equal to(t r + t,) at large end, t, at small end and B as the inside diameter ofthevessel or nozzle.

While designing loose type flanges, B should be taken as theinside dianeter of the flange but not the vessel or nozzle.

Optional Type Flanges. This type covers designs where theattachment of the flange to the vessel or nozzle wall is such that theassembly is considered to act as a unit which should be calculated asan integral flange, with the vessel wall taking on the functions of thehub. This obviously includes welded construction with no apparenthub, as shown in Fig. 1g and lh, or constructions with such smallhubs that do not merit inclusion in the loose typ group. The term"optional" is used because the designer may calculate theconstruction as a loose type flange provided none of the followingvalues is exceeded:

B .^^

,o:i Incn. ..i

:J(^JDesign pressure :300 psi

Operating temperature : 700"F

Thus the integral flanges that come within the above restrictionscan also be designed as loose type flanges. This simplifies the calcula-tions and may result in som economy.

BOLT LOAD AND GASKET REACTIONIn bolt-up condition the bolt load is balanced only by the gasket

reaction as shown in Fig. 2a. As internal pressure is applied, the boltload is balanced by lhe sum of gasket reaction and the hydrostatic endforce due to pressure as shown in Fig' 2b. Thus, while designing aflange, both the above conditions should be analyzed separately.

INTEGFAL TYPE FLANGES TOOSE TYPE FLANGES

whete Hub Stope Adiacen! To FlangeE ceeds 1:3 Use Dataits (1b) ot (1c)

f. 8. tu1., At Nii-p.irt Ot Carocr B.-1..., n@0. Ard Lop t.d.p.nd.nt Of

OPTIONAL TYPE FLANGES

| ^=-,4Fu Pcr.r.o ;A Ba.k.hle ILoodlnt And Dlhutto.s At. fha SoD. As

FIG. I . TYPES OF FLANGES(Courtesy of Energy Produds croup)

62 63

lrl.AN(ili l)l1Sl(;N

Itr.qrir(d llolt Lords

{rl lflet Disc-Type Gaskets: Operatirg Conditionsllrt: r'cquired bolt load, tIl.r, shall be sufficient to resist the hydrostaticr'|l(l li)rcc, H, exerted by the internal pressure on the area bounded by the,lrrrrrrctcr of gasket reaction G, and, to maintain on the gasket or joint-, {,ntircl surface a compression load. tl, Thus'

w^t:H+He::G2P+2bncn? (l)

llolt-up or Gasket Sating Condition

lkrlilrc a tight joint can be obtained it is necessary to seat the gasket orro!nt-contact surface properly by applying a minimum initial load, l/,r,wr tlrout the presence of internal pressure. This load is a function of theprrskct material and the effective gasket area to be seated and can ber'U)rcSSed aS:

W^z:brGY

FIG.2a

(2)

FIG' 2bFIG. 2-BOLT LOAD AND CASKET REACTION

(Courtesy of Energy Products Group)

tk.w

l.t.AN(iti Dl1st(;N

,:

'd

?.Y

iE>iE .;

; I *r E5i+;, *:Ei i s:tj. E?.iE:{:i Ei i+ rz L-3FE I, IiE.s i ; IErrij I;h.:::'z=E !.= A5!E ti ;F='d:

=- >,+!: >

): ti 5 iE7i-, a=

i *!! c;: i;; F:E:'9n ar!g=t= E1'r' vE I e

:o,Y3E*.i=3::5 5 (!i.,i:>6

E

,r. =

ii

F F';=i,i.

]. Ya6 .:=

E;-E9

-1 i:

6564

o

F

ts

=I;

!o Eyc7-9'Z

5a$#' g

iisd'j: ;ts

.= 3-;r,,ib

Jo 3

.9

o i9

J -o

=9:-.o o-< !l: O;:EtE:6

rr1

t

- !.n

cc.

3i

-'

ai93

!l

3P

?.aiE

t )lisr(;N olr Pl{(xtLss LQUTPMEN'I'

-azt4a

FLANGE DESI(]N

/:b

i;5>:5

.-E .:

a>

2A;= L?: r,tT: Ez7 a

a^ !

vll

*:=+i+tdj o:< r! ce{'s i.9 E= oE r;: ; 1"s"{!!: !r, t o L-E

Ei;*:i[; EI

l-'-*' ;.$| (,*II

cl']i l-"'lc

67oo

l)lrsl(;N ()F PI{O(ILSS tiQUIPMENT

--\al+ l'+{:..-sj"+ 16l

-l-l

\z$

ZF

=lg-

- l^r^l

-l< l.rvtl

INiNNRB-{1tzN

'|| rtrtlrl

_'t]*1.r_,=

z

;

z

aIv

FT

,Fr{M

E]FHEl

3F

T+

ZN

,iFtil{FflaF3N

$z

t)list(;N ( )tr pR(xitiss l]Q(itpMI]NT

For flange pairs having a tubesheet in the middle as in exchangerapplication or for any other similar application wher the flanges andor gaskets are not the same, W^, shall be the larger of the valuesobtained from above formula as individually calculated for eachflange and gasket, and that value shall be used for both flanges.

Code suggested values of gasket factor ,|| and minimum designseating stress / for various gaskei materials are tabulated in Table Iand effective gasket seating widths for different contact facings aregiven in Table 2.

(b) Self-energizing Gaskets: Operating ConditionsThe required bolt load for the oprating conditions, t/,,, shall besufficient to resist the hydrostatic end force, H, exerted by the internalpressure on the area bounded by the outside diameter ofthe gasket. H, isto be considred as zero for all self-energizing gasket except certainseal configurations which generate axial loads which must be con-sidered.Bolt-up or Gasket Seating ConditionSelf-energizing gaskets may be considered to require an inconsequen-tial amount of bolting force to produce a seal. So ttl.2 can be assumedequal to zero. Bolting, however, must be pretightened to provide abolt load sufficient to withstand the hydrostatic end force I/.

Determination of Bolt Area

If S, denotes the allowable bolt stress at the operating temperature,and S, the allowable bolt stress at atmospheric temperature, thenthe minimum required total bolt area,4- is obtained as follows:

. w^, w^A.: !' or '2. whicherer is greaterJn J,Selection oibolts to be used shall be made such that the actual total

cross-sectional area of bolts, lr, will not be less than 1.. Excessrvebolting may have to be provided while designing relatively thin flangesfor low pressure service because of the following,l. Due to the danger of over-stressing smaller size bolts during

tightening, a minimum bolt size of /z " is usual in most piping andpressure vessel work,

2. For practical construction reasons, bolting is mostly provided inmultioles of four.

68 69

trt.AN(;li I)|]st(;N

I lk)lts must be spaced close enough to assure adequate gasket pressurel)clwcen bolts.

Seltction of Bolt Spacinglhc minimum bolt spacing based on wrench clearances limits therrrrrrrbcr of bolts that can be placed in a given bolt circle. The maximumlxrll spacing is limited by the permissible deflection that would existlr('twocn flanges. If the deflection is excessive, the gasket joint will leak.lil'(i Bulletin 502 "Modern Flange Design" recommends the followingfrrrpirical relationship for maximum bolt spacing:

Bolt spacing (maximum):2a +. 6-L' (m + 0.5)l,lstsblishing Bolt CirclI lrc thickness of hub at back of flange g, should first be calculated asIr)llows:

g L: 1.25 g o to 2.590Table 3 lists the root area, minimum bolt spacing, radial distance

rrd edge distance etc. as functions ofbolt size. The minimum bolt-circletliirnreter will be either the diameter necessary to satisfy the radial' lcirrances,i.e. B * 2(tr + R) or the diameter necessary to satisfy the bolt-

rpircing requirement,i.e. N(Bolt spacing)/z, whichever is greater. The,rptimum design is usually obtained when these two controllirrg(lr meters are approximately equal.l,'lange Design Bolt Load, Wlhc bolt loads used in the design of the flange shall be the values()btained from the following forrnulas:

For operating conditions

W:W^,For gasket seating

t 4,-r Ab\5.u,:. .^ i g)ln formula (4) S, shall not be less than that tabulated in Subsection C ofthc ASME Section VIII, Division t code. In addition to the minimumfcquirements for safety formula (4) provides e margin against abuse ofthc flange from overbolting since margin against such abuse is neededplirnarily for the initial, bolting-up operation which is done at

(3)

|)tist(;N otr PR(xtuss tiQtjlt,MUN'I'

F

ztrFI

JF

6z:

I)llsl(;N ()lr l,l{(xil-ss li(.ltJll'MliN f

h.:= (ll)These lever arms also apply to optional type flanges when they are

designed as loose-type flanges. However, exception to the above is takenin the case of lapjoint flange Fig. 1e in which the lever arm ho is given byequation (9) and lever arms lrr and lo are identical and are given byequation (11).

For gasket seating, the total flange moment Mo is based on theflange design bolt load of formula (4), which is opposed only by thegasket load in which case

Mo:I'Yq:G) ir2)The moments obtained by the above formulas are valid only if the

bolts are spaced sufliciently close to produce a reasonably evendistribution of gasket load. This spacing can be called normal spacingand is assumed to be equal to (2d+ t). Thus, ifthe actual spacing exceedsthe normal bolt spacing, the flange thickness must be increased in orderto maintain an even distribution ofgasket load. This necessary increasein thickness can be determined by giving the total moments acorresponding increase, the thickness increase being proportional to thesquare root of the moment increase as derived from formulas forcalculation of S^ and St, the radial and tangential stresses in the flangerespectively. So the total moment can be multiplied by a correctronfactor as derived from the above relationship and given by:

^ / actual bolt spacingtr: a/ 116rmar uort .spacins

FIG. 3 - FORCES AND LEVER ARMS FOR INTEGRAL FLANGEIN OPERATINC CONDITION

'ra 73

trt.ANCll l)tisl(;N

ii t-o l.E" I- ;tr i

'rP 3'a ...'

Eo

u)

3E3

'-iPE

.3-

:go

d

o P9

; !5-

vE6i !+

9,'i

o

lrl -AN(;li I)liSl(;N

''oooo o o.o(o dr N _qq9c? n'co@sc) N

-

ooooo :33 33 3E-do c; ci oo

-J

E

3 ,no SB 3ci oOo ci

7574

Itl:Sl(,N ()l l,ltrx:l SS tirlll ,MtlNt

,1

E

6

E

35 3^ >d 5: cas E

.rI 3>r -.: !- ,u

o

3

'.q

o

A

I )list(;N otr pt{(xjliss IiQtJtpMuN'1.

Frc. E _ VALUES OF/(UA-51.6)(Hub Stress Correction Factor)

(Reproduced from ASME CODE Section VIII, Div. t )

Calculation of Flange Strsses

.The stresses in the flange shall be determined for both the operatingcondition and gasket seating condition, whichever controls. In order tosimplify calculations, the following factors are introduced in operatingas well as gasket seating conditions bydividing their respective momentsby the flange inside diameter B:

M:MocrB

76 77

it ||(l

trl.AN(iu l)lisl(;N

M : MocrB

l{adial flange stress,-:0!-" fu2

'I angential flange stress

.MY-^5-: .,

_ ZSj'1

For loose type flanges without hubs or with hubs which are notconsidered in design and for optional type flanges calculated as loosetype without hubs or with hubs which are not considered in the design'the flange stresses in operating condition are:

MYand S": ,'t'

Factors T. Z. y and U can be determined from Table 4 as a functionol K, the ratio of the outside to inside diameter of the flange.

Factors F, \ Fr,Vrandf canbe obtained from Figures 4 through 8.l,irctors F and Iz apply in designing integral type flanges while F" and I/,rrlc used for loose flange calculations. The hub stress correction factor jfis of significance only when tapered hubs are involved, as its value is I forhu bs of uniform thickness.

Flange thickness t must be initially assumed. Using the assumedvalue of r, the various factors c, B, y, d and ,t can now be determined (seethc attached calculation sheets) and used in the formulas for calculatinglhc flange stresses.

For integral fype flanges &s well as for optional type flangesctlculated as integral type and for loose type with a hub which isconsidered in the design, the stresses in the flange for the operatingcondition are:l.onsitudinal hub stress

sI| fM: .-2^gr

Sa:0Sr:0

The stresses for gasket seating condition in either case can be foundby substituting M in place of M in the above equations.

l)l,Sl(;N ( )l l'R( X liSliTAI]LU 4 - T.'ACTOITS

ll(.!( Jll,MriN lINVOLVING K "

K T z U K z Ur.oo I|.002l.oo3|.004r.005

r.9l

r.9l| 9lr.9l

r000.50500.50333.83250.50200.50

l91l.t6956.16637.85178.71383.22

2100.181050.72

700.93526.05a21.12

1.016t.o171.0a8l.or9r.050

r.90t.901.90I.90r.89

12.O521 .7921.3520.92?0.5 |

42.7541.87at.o210-2139.43

46.9946.0345.0911.2143.34

r.0061.OO7r.008r.009r.ot0

9l9l9l9l9l

67.1713.3625.50I t.6l00.50

319.55271.09

239.952 t 3.4Cr 92.1 9

351.16301.20263.75231.122r r.l9

t.051L05 21.053t.0541.055

1.891.891.89t.89t.89

20.1219.7119.38r 9.03r 8.69

38.6837.9637.2736.6035.96

42.514t.7340.9640.2339.64

l.0t Ir.012r.0t 3l.0l ar.015

r.9ll.9l1.9 |r.9lr,91

9t.rl8 3.8177.1371.9 3.67.17

171.A3160.38148.06137.69r28.61

| 92.1317 6.?5t62.81I51.30I { r.33

1.0561.0571.0581.0s91.060

t.891.89t.891.891.89

I8.38I 8.0617.7617.1717.18

35.3 434.7 434.1733.6233.04

3 8.8438.r 937.5636.9536.34

t.0t.0t_01.01.0

t6

t8t9lo

t.901.901.90r.90t.90

63.0059.3356.0653. r,(50.51

II r r.98r 07.36tot.7296.73

20.56 132.19| 24.8l| | 8.00I r 1.78106.30

1.06t1 .062r .0631.064t.065

1.891.891.89L891.89

16.9116.64I6.40l6.t 5r 5.90

3 2.5532.0431.5531.0830.61

35.78

31.6434.1733.65

.021

.o22

.023

.o2a

r.901.901.90r.90|.90

18.t245.964 3.9812.17,(0.5 |

92.2 |88.0t81.3080.8 |77.61

r0t.3396.7592.6t88.8lI5.29

1.0661 .0671.0681.069|.o70

r.891.891.89r.89r.89

1 5.6715.451 5.22I5.0214.s0

30.1729.7 429.3228.9128.5r

33.1732.6932.2231.7931 .34

|.026t.o271.028LO2 9t.030

t.90t.90r.90t.90t.90

38.973/.5136 223 r.993 3_8,1

7 A.707 t .9769.1367.1|61.9 |

82.0979.O87 6.3073.7571.33

1.0711.0721.073t.o741.O75

t.891.891.891.88r.88

14.6114.41I4.22I4.Ol13.85

28.1327.7627.3927.0426.69

30.9230.5r30.1I

29.34

1.03 |r.0321.03 3r.034r.035

1.90|.90t.90|.90r.90

31.7 630.8 |29.9229,08

62.8560.9?59. r I57.115 5.80

69.0666.9161.9563.086r.32

1.076LO771.o781 .079

r.080

t.881.881.88I.881.88

13.68

13.35l3.t 8r 3.02

26.3626.0325.7225.4025.10

2 8.9828.692A.2727.9227.59

r.036t.o37t.0381.039r.0r0

1.901.90t.901.901.90

24.2927.5126.8326.1525.51

51.29

51.5050.2 |48.97

59.6658.0856.5955.1753.82

1.081t.082r.083t.084t.085

1.881.881.881.88r.88

12.87

| 2.4312.29

24.8124.5224.2124.0O23.69

27.2726.9 5

26.3426.05

l-0411.0a2|.0131.0a 4t.0t5

1.90r.90l.9o|.90r.90

21.9021.3223.77

22.71

n7.8116.7115,6111.6A,t 3.69

50.15r9.0514.O2

1.0861 .O87L0881.0891.090

t.881.881.881.881.88

12.15| 2.O2I1.8911 .761 1.63

23.1423.1822.9322.6822.44

25.7725.4825.2024.9324.66

(Courtesy of Energy Products Group)

78 79

l l AN( ilr l)l Si( iNTAULU 4 - I.',\CTOlts INVOLVING K (Continucd)

T Z K T z Ur.oer I|.0e2

llr.093 lr.oe4

1l|.oe5 Itl

r.096 || .o97 |r.0e8

ll

i?33 l-xI l0l

r.102 ll

r.r 03 Ir.r04 ll

r.t 05 ll---{

r.r 06 It.r 07

It.108r.t 09

I1.rr0 ]

r.rrr It.ll2

t.n31.114| 'lLl

l r.n6lr. Zll. 8ll.u9tl.l20

1.88I .88t.881.881.88

I 1.5211.401 l.2E1 I.l6I 1.05

21 .9921.7621.5421 .32

21.1124.1623.9123.6723.11

1.1361.137l.t 381.1 391.140

1.86r .861.861.86L86

7.88

7.787.737.6a

15.26r 5.1515.05r 4.951 4.86

16.77I6.6516.5416.4316.35

1.88r.88r.881.88L88

10.91r 0.8310.7310.6210.52

2l.r r20.9120.7120.5120.3t

23.2022.97

22.3922.14

l.l4l1.142l.l 431.1441.145

1.861.861.86r.86r.86

7.627.577.537.487.43

| 4.76| 4.6614.5714.4814.39

16.22t6.lIr 6.0115.9115.83

1.881.881.881.88r.88

't0.4310.3310.23l0.l 410.05

20.1519.9419.7 619.5819.38

22.122l .9221 .7221 .5221.30

1.t 46I .1 47'l .l 48

1.1 491.150

1.86t.861.86r.861.86

7.387.347.297.257.20

1 4.291 4.20| 4.1214.0313.95

15.7115.6115.5l15.42I5.34

1.881 .871 .471 .871 .87

9.969.879.789.709.62

19.3319.07r s.9014.74r 8.55

21.1120.9620.7720.5920.38

l.l 5l1.1521.1531.154l.t 55

1.861.861.861.861.86

7.117.077.O36.99

13.8613.77r 3.6913.61

15.23l5.t 415.0514.9614.47

1 .871 .87| .471.87'| .a7

9.549.469.3 89.309.22

14.1214.2718.1317.9717.81

20.2520.08t 9.9119.7 519.55

1.1561.157l.l 58r.159r.160

r.861.86L86L861.86

6.956.916.876.836.79

13.45

I3.30

I3.t5

14.7814.7014.6114.5314.45

1.871.87t.871 .871 .87

9.1 59.079.008.918.86

t7.6817.5417.40| 7.27t7.13

19.4319.2719.12i 8.9818.80

Ll611.1621.1.63l.t 641.165

t.851.851.85r.85r.85

6.716.676.646.60

13.0713.0012.9212.8512.78

1 4.3614.2414.2014.1214.04

r.t 2l| .122r.1231.124Ll25

1 .a7| .871.871 .871 .57

8.79

8.668.598.53

| 7.OO16.87'| 6.7416.6216.19

I 8.6818.54I 8.4018.26l8.l I

1.1661.1671.1681.t 691.170

1.85

1.851.851.85

6.566.536.496.466.42

12.7112.6412.5812.5112.43

13.97I3.89| 3.a213.7 4r 3.66

1.1261.127t.1281 .129l.t 30

| .a71 .871.871.871 .87

8.178.408.318.2 88.22

| 6.3716.25l6.l 416.0215.91

17.9917.46

17.6017.48

1 .1711.1721.1731 .1741.175

1.851.851.851.851.85

6.396.356.326.296.25

12.3812.31t2.25I2.18t2.t0

13.60r 3.5313.46

I3.30

l l3lt.132t.133t.134t.135

1.87| .87r.86t.uo1.86

8.168.1I

7.997.94

1 5.79I 5.68I J.a/| 5.46I5.36

17.3517.21l7.t Ir 6.99t 6.90

1.176't.1771.1741.1791.180

1.851.851.851.851.85

6.226.196.166.136.10

12.0612.00I 1.9311.8711.79

I3.2513.18l3.l l'13.05| 2.96

| )l,l.il(;N ( )tr t,t{( X:liSS Ii(ltJ )MtiN I.'l AllLlj 4 - IJAC'IOtts INVOLVING K (Continued)

K T Z Y U K T z ULt821.1841.1861.188r.t90

1.851.851.85t.851.84

6.045.985.92J.605.8r

| 1.70I 1.58

I1.3611.26

12.8612.7312.61t 2.19| 2.37

1.278I.28t|.2441 .2871.290

r.8lt.8lr.80r.801.80

4.t 64.124.O84.054.01

8.057.987.9 |7.81

8.858.778.698.618.s3

1.1921.194l.t 96l.l 981.200

1.841.841.84t.a41.84

J./ Js.70J.O55.60

I l.l511.0510.9510.8510.7 5

12.2 5t2.t 4I 2.0311.92I l.8l

11 .71I l.6lI l.5lI l.4l11.32

1.2931.2961 .2991.302r.305

1.801.801.80r.801.80

3.983.9 43.9r3.8I3.84

7.70

7.577.507.41

8.468.398.318.248.18

1.2021 .2041.2061.208r.210

1.841.841.841.841.84

5.505.455.40

I 0.65r 0.5610.47t 0.38r 0.30

1.308l.3l I1.3141.3171.320

1.791.79t.791 .791.79

3.8r3.78J./ J

3.69

7.387.327.267.207.1 1

8.1 I8.057.987.927.85

1 .2121 .21 41.2161.2t 81.220

1.83r.83r.83r.83r.83

5.27

5.185.1 45.t0

I0.21l0.r 2I 0.049.969.89

11.22ll.l2I r.03t0.9410.87

t.3231 .3261.329t.332I.JJ5

1 .791 .791.7at.7al.7a

3.673.613.61J.J63.56

7.097.036.986.926.87

7.797.73

7.617.s5

1.222| .2241.226| .22a1 .230

r.83

r.831.83L83

J.UJ5.014.984.944.90

9.809.729.659.579.50

I o.77I 0.6810.6010.5210.44

r.338r.3411.3111.317r.350

| .781.781.781.78|.78

3.533.5 |3.483.463.43

6.A26.776.726.646.63

7.507.417.397.337.28

1 .2321.2341.2361 .2381.240

r.831.831 .82t.a21 .e2

4.864.834.794.7 64.72

9.439.369.299.229.1 5

r 0.3610.2810.2010.13t 0.05

1.3541.3581 .3621.3661.370

1.771.771 .77

t.77

3.40

3.3 4

3.2I

6.576.506.446.386.32

7.2 17.t 17.O87.O l6.9 5

1.2421.241t.246|.24a1.250

1.821.821 .821.82| .82

4.694.651.624.594.56

9.089.O28.958.898.83

9.989.919.819.779.70

1 .3711.378t.3a21.3861.390

|,/61.761.761.76

3.203.173.15

6.276.216.166.1 |6.06

6.896.826.776.726.66

1.2521.2541.2561.2581.260

1.821 .821.82l.8lL8l

4.524.494.464.434.40

8.778.718.658.598.53

9.649.579.519.419.38

1.3941.3981 .4021.4061.410

1.761.751.751.751.75

3.103.O73.053.O2

6.0r5.965.925.475.82

6.60o.556.496.446.39

1 .2631.266t.2691 .272r.275

l.8lr.81r.8lt.8lr.8l

4.364.324.284.244.20

8.458.378.298.218.t 3

9.289.r 99.i I9.O28.93

1.414L4181.422| .4261.430

t -/51.7 51.75|,/4| .71

3.002.942.962.9 42.91

5.68s.615.60

6.346.296.2 56.206.15

80 8l

l l AN(;li l)lrSl( iN'fAIJLIj 4 - ITACTOII.S INVOLVING K (Continucd)

t( T Y K T z Y U|.434L438t.412t.446r.450

t.454t.458t.462t.466t.470

|.475L 480r.485r.490,u7:t.5001.5051.510r.515r.520

1 .525t.530t.535r.540t_545

t.551.56| .57r.58t.59

r.60t.6l1 .62r.63r .64

r.65I .66| .67t.68]ot1.701 ,711.72t.731.74

1.741.7 41 .711.74

2.892.A72.852.832.81

5.525.485.445.40

6.106.0s6.0r5.975.93

1.751.761.771.7e1 .79

r.60r.60r .60I .591.59

1.97r.95t.941.92l.9l

3.613.61

4.003.963.933.89

1.731.731.731.731.72

2.802.752.7 62.7 42.72

5.36

5.215.805.765.71

t.80t.8l1.821.831.84

L581.581.581 .571 ,57

r.89r.88r .861.851.84

t.83l.8lt.801.79t.78

3.473.443.413.3 83.3 5

3.823.783.7 53.723.69

1.721.721.721.721 .71

2.702.682,662.642.62

5.1 65.12

5.045.00

5.665.615.57

5.49

r.85r.86| .871.881.89

r.56r.56r.561.551.55

3.3 3

3.273.243.22

3.6 53.623.5 93.5 63.s 4

1 .711 .711 .711 .711.70

2.602.5a2.56

2.s3

4.964.924.884.844.80

5.415.375.335.29

t.90t.9l1.92t.931.94

1,54

| .54r.53r.53

t.77|.751.741.731.72

3.193.173.1 43.123.09

3.513.483.453.433.40

1.701.701.701 .69I .69

2.512.492.472.462.44

4.774.7 44.704.664.63

5.21

5.1 35.09

r.95l 96| .97I .98I.99

t.53i.521 .52r.5lr.5l

1 .711.70t.69t.68I .68

3.07

3.033.Ol2.98

3.3 8

3.3 33.303.2I

1.69r.691.681.68t.6/

2.432.402.372.312.31

4.604.544.484.124.36

5.0s4.994.924,864.79

2.002.012.022.O42.06

t.5t1.501.501.491.48

1 .67t.66I .65L63t.62

2.9 62.9 42.922.882.85

3,26

3.?13.173.t 3

1 .67

t.651.65l -65

2.262.232.212.18

4.314.254.204.154.10

1.734.67

4.561.50

2.O82.102.122.142.16

L481 ,171.461 ,46

1.60r.591 .571.56

2.812.7I2.7 42.712.67

3.093.053.012.972.9 4

r.651.641.641.63t.oJ

2.162.14

2.102.08

4.054.013.963.923.47

4.454.40

4.304.26

2.182.202.222.242.26

1 ,441.441.431 .42t.4t

1 .52l.5lt.501 .49

2.6 42.612.582.562.53

2.902.872.842.8l2.74

1.631 .621 .62t.6ll.6l

2.062.042.022.OO1.99

3.833.793.7 53.723.68

4.211.174.124.084.O4

2.282.302.322.3 42.36

t.4l1.40t.401.39t.3B

1.48

1.461.451.44

2.502.482.452.432.40

2.752.7 22.692.672.6 4

I )list(;N otr pt{(x;tiss IiQtJ ,M[.N't.'fAllLE 4 - F'ACTOIIS INVOLVING K (Continued)

K T z U K T z U2.382.402.422.442.46

r.381 .37

1.361.35

l 431 .42l.4lr.40t.40

2.3 82.362.3 3

2.29

2.612.592.562.542.52

3.5 03.5 43.583.623.66

t.r0t.o9t.0B1 .071,07

l.t81 .17|,17t.l6t.t6

1 .62l.6lL59t.57

1.78

t./ J1.731 .71

2.4a2.502,532.562.59

L35L34t.331.32r.3l

t.39L381 .37

2.272.2 52.222.192.17

2.502.472.442.412.3I

3.703.7 43.783.823.86

1.06t.05r.05r.041 .03

r .16r.t5l.r5t.l5t.t4

t.)51.531.521.50| .49

1 .701.681 .67

r.642.622.6 52.6A2.712.74

r.30r.30r,291 .28L27

1.34r.331.32t.3lL3l

2.1 42.122.O92.O72.04

2.3 52.322.302.272.25

3.903.9 43.9 84.004.05

1.031 .O2t.0lt.0091.002

Lt41.r4t.t3l.t31.1 3

1 .481 .461.45

t.43

1 .621.6 |t.60i.59| .57

2.802.8 32.862.89

1.261.26t.251.24r.23

1.301 .291.28r .281 .27

2.022.O01.98I .961.94

2.202.172.15

4.t 04.154.204.254.30

.996

.989

.982

.968

1.13t.l21.12t.l2t.t I

1.42t.401.39t.38

r.56r.54

l,5i1.50

2.922.952.983.0 23.06

1 .221.22r .21'l .20

l.t9

1 .271.26r.251.251.24

1.92r.90r.881.861.83

2.1 12.O92.O72.O42.01

4.404.454.5 04.55

.962

.955

.94

.911

.9U

Ll ll.r.t.t0l,t0

r.341.33r.31t.30

1.48

I.461,44L43

3.t 03.t 43.t 83.223.26

l.t 8l.t7l.t6l.t6t.l5

1 .231.231 .22l.2lt.21

1.811.791 .771.751.73

r.991 .971.941.921.90

4.604.654.70

4.8 0

.n8

.nl.911.908.9m

t.t0l.t01.09r.091.09

| .29t.2a1 .271 ,261.25

1 .421.41I.39t.3d

3.303.3 43.3 83.423.46

l t4l.l3l,t2l.t I1.lr

1 .201 ,20l.t9l.l 9l.l8

1 .71r.691 .671.661.61

r.88r.86t.84r.82r.80

4.8 54.904.955.00

.893

.887

.880

.873

1.091.091.081.08

L241.231.221.21

8283

III,ANGI DLSI(iN

l l(;. 9a - TWO PASSARRANGEMENT

FIG,9b, FOUR PASSARRANGEMENT

FlG. 9c - SIx PASSARRANGEMENT

FIG. 9 . MOST COMMON PASS ARRANGEMENTSFOR MULTIPASS CHANNEL

Allowable Flange Dsign Stresses

l hc flange stresses as calculated above shall not exceed the followingvalues:

l. Longitudinal hub stress Sr should not be greater than 1'5 S/" in theoperating condition and 1.5 S/" in the gasket seating condition.

l. Radial flange stress SR shall not exceed S/, in the oprating conditionand S/. in the gasket seating condition.

I. Tangential flange stress Sr shall not be greater than S/" in theoperating condition and S/, in the gasket seating condition.

4. The greater of 0.5(srf + Sr) or 0.5(Sr, * Sr ) shall not exceed Sr" in theoperating condition and S/" in the gasket seating condition.

If any of the stresses other than S, exceeds the allowable' the flangeI hickness r can be revised till the stresibs are within allowable. However,if S,, xceeds the allowable, the increase in flange thickness will not helpand it may be necessary to lengthen the hub, increase the 9r thickness oralter both of them.

Considering Pass Rib Area in Flenge DeignIn certain application of flanges, especially in shell-and-tube heatcxchangers where multipass channels are specified, the area for pass ribsalso contributes to required bolt load in the operating as well as in thegasket seating conditions. Its effect may be negligible in some cases but itis advisable to consider it in flange design wherever applicable. The mostcommonly used pass arrangements for two, four and six pass channelsare indicated in Fig. 9. In order to simplify the calculations, the rib areasfor each case and for exchanger sizes 6" through 100" inclusive are givenin Table 5. Use ofrib area in llange design is illustrated in the calculationsheet.

r )lis t(;N ()|l Pl((xiliss riQUIpMl.iN't'

Table 5 -

Pass Rib AreaNomlnal

Vessel SizePass Rib Area, Rr, in.2

Two Pass Four Pass Six Pass68

1012l116l8202224252627282930JI

33343536

38394041424344454647484950

2.843.594.365.105.536.287.037.788.539.289.94

10.3110.6911.0611.4411.8 t12.1912.5612.9413.3113.6914.06t4.4414.8115.1915.5615.9416.31t6.6917.0617.4417.8118.1918.5618.9419.31

5.27o.oz

8.079.38

10.2111.5612.9514.30t).o)16.9918.23r8.9219.6220.2720.93zt .oz22.3223.0r23.7124.3625.062J. t)26.4s27.1527.8028.4929.r929.8930.543t.2431.8932.5933.2833.9434.6't35.33

8.3610.3612.44t4.4315.60t't.5919.5821.63zt.oz25.6127.4128.4329.4630.423t.4s32.4133.4434.4635.4336.4637.4838.4539.4'l40.504t.5242.4943.5144.4845.5046.5347.5048.5249.5550.5151.5452.56

84 d5

!.LANCE DBSICN

Table 5 -

Psss Rib Area (Continued)N omlna

Vessel Sizein.

Pass Rib Area. Rr, in.2Two Pass Four Pass Six Pass

515253545556575859606l6263646566676869707l72

74757677'18'79

80818283848586

19.6920.0620.4420.8121.t921.5621.9422.3122.6923.0623.4423.8124.1924.5624.9425.3125.6926.0626.4426.8127.1927.5627.9428.3128.6929.0629.4429.8130.1930.5630.9431.3131.6932.0632.4432.81

36.0236.685t-3t38.0738.7739.4240.1140.814t.4642.1642.8643.5544.2144.9045.6046.2s46.9547.6448.3048.9949.6950.3851.0451.7352.4353.1353.7854.4855.1755.8256.s257.2257.9r5 8.5759.2659.96

53.5954.5555.5856.6057.6358.6059.6260.5961.6162.5863.6064.6365.6566.686'1.6468.6769.08'70.66

71.6972.6573.68'74.'10

7 5.6'l76.6977.72'78.'74'19.7'l

80.7381.7682.7383.7584.'7285.7486.7787.7988.76

l)list(;N Olr Pt{( x:Ess EQUTPMENT

Tsble 5 -

Pass Rlb Arer (Conrinued)Nomlnal

Vessel Sizein.

Pass Rib Area. Rr, in.2Two Pass Four Pass Six Pass

Et8889909l9293949596979899

100

33,l933.5633.9434.3134.6935.0635.4435.8136.t936.5636.9437.3137.6938.06

0u.6561.3562.W62.'7063.3564.0564.7465.4466.0966.7967.4968.1868.8469.53

E9.7E90.8191.8392.8093.8394.8595.8296.8497.8798.8399.86

100.82101.85102.87

EXAMPLE NO. 1

Design a pair of welding neck flanges to be used to contain atubesheet ofa TEMA BKU type of exchanger. The 4l in. I.D. two passchannel designed for 150 psi at 500.F is built ofI in. thick A_515_70 piateinclusive offin. corrosion allowance. Theshell sideflangeis to be weldedto a 41 in. I.D. x 75 in. LD. cone designed for 460 psi at 650.F. The coneconsists of l; in. thick 4_515_20 plate inclusive of$ in. corrosionallowance. Assume ironjacketed asbestos filted gasket on'Uotf,.iO", unOuse A-105 flanges with A-193-87 Bolts_

86

and

87

F'LANC!: DESIGN

SOLUTION

ln this case we will have two flanges bolted together but designed fordiffcrent conditions. The required bolt load in the operating conditionlbr the shell side will govern the design of both flanges because of lhehigher design pressure. Since the gaskets on both sides are of the samenraterial, the required bolt load for gasket seating will be greater for thelow pressure flange. Since such a high design pressure is involved, gasketscating probably will not control the design. Tberefore, the shell sidellange will be the independent flange while the channel side will be thedcpendent flange.

Independent flange has to be designed first so that we can carry overthe bolt load for the design ofthe dependent flange. Both the flanges willbc designed here in detail, but the attached calculation sheets can be usedto save time. Both these flanges will be designed using corrodeddimensions because the corroded condition results in greater thicknels.

Design of Independent FlangeRefer to Figure and design steps on Weld Neck Independent FlangeDesign Calculation Sheet. Now we have,

p:460 psiSa:25,000 PsiS":25,000 Psi

Sr' : 17'500 PsiSr": 17,500 Psi

Also in uncorroded condition

Assume

B :41 in'go:t^:l'25ln'

9 t: 1.25(s o\: 1.25(1.251:1.5625 in.Thus in corroded condition

B'41.25 in.9o:1.125 in.

g r:1.4375 in.

DESIGN OF PROCESS EQUIPMENT

Now,t = 1.s(gJ- 1.5(1.125)= 1.6875 in. (minimum)

stope =!9r:sd: $431s--!r25) -0.1852 < 0.333' h 1.6875

Therefore, the flange can be designed as an integral type as shown inFig. la- Now assune (48) 1| in. dia. bolts. From Table 3, for lf in. dia.

FLANOB DESION

n =f,tu.t sF +oo = 7 23,4s2.t tb

W : 123,492.1 + t2t 255.7 : 844,747.8 lb

.4.:Greareror'## * t*,ltl't=rr.tri".'

From Table 3, the root area ofa l| in. dia. bolt having 8 threads per inchis 0.728 in.2 which gives

A t : 48 (0'7 28l, : 34'9 44 in'2

Since 74, > .4., therefore (48)lI in. dia. bolts are adequate. NowW:0.5(33.79 + 349,14)25,000 : 859,1 75 lb

r^,,:ffi,=0.4088in.Since N > N,ir", therefore chosen gasket width is adequate.

Flange Moments Calculatiom

H D:;@l.2512 460 =614,745.9 lb

Hc:HP-121,255.7 lbH r:723A92.1 - 614,745.9 = 1O8,746.21b

h D: 1.5 + 0.5(1.437 5) = 2.21 88 in.he :0.5(47.r25

-44.75): 1.1375 in.fir:0.5(1.5 + 1.4375 + 1.1875) =2.0625 in'

Now

M o= 6t4,7 45.9(2.21 88) : 1,363998 in- lbM e =121,255.7 (!.1875)= 143991 in-lbM r = 1O8,7 46.2 (2.06251 : 224 289 in-lb

Therefore,

bolts. we have

R : 1.5 in.E = 1.125 in.

Nowc : B + 2(s ) + 2(R) : 41.25 + 2(r.437 5) + 2(r.5) : 47 .125 io.

andA

- C + 2(E) : 47.12s + 2(t.t25l : 49.37 s in.

Gaslet and Bolting C,alculatiomFrom Table 1, for an iron jacketed asbestos lilled gasket

andm:5- I)

v=76WAssume

N :0.5 r!.Fig. la. of Table 2.applies to our situation. So,

u.:!=!=o.zsn;

D:0.25 in.Now

G:C -

a-2(0.375)-2(Q:a7.p5 -

1.rzs -2(0.375) -2(o.2s)

:44.75 in.Therefore

W^z* :0.25(n)44.7 5(7600) = 267,1t4 lbH, : 2(n) 0.2s (44.7 5X3.7 5) 460 : r2r,25 s.7 tb

and

Therefore

' See note on page 58

88

Mo= 1,363,998+ 1 43991 +224,289 :1,732,278 in-lb

t)list(;N ()lr pt{(xjriss ltQUlpMIiNTNow, for lhe gaskct seating condition

ThereforeH e : W:859,175 lb

Mo : 859,175(1.187s) : 1,020,270 in-lb

Actual borr spacing -

r(l) =

r{4J-125t :3.0843 in.

-n48

and

Assume t:2.75 in.

Maximum bolt spacing:2(t.l 251 , -6975L-:6.Ij2J in.{J. /) +U.)l

Normal bolt spacin E:2(l.t25l +2.j5:5 in.Since,