Shell & Tube Heat Exchanger

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Page 1 of 10

JACOBS H&G

QUALITY WORK INSTRUCTION

SHELL & TUBE HEAT EXCHANGER DESIGN BY USING HTRI PACKAGE

DOCUMENT NO: P WI 05

PREVIOUS DOC No: NONE

Rev No. Issue Date Pages Rev Description Prepared

By CheckedBy ApprovedBy

A 25th_{April 2004} _{10 + 2}

Annex. For Comments SPP RGP VVD

0 1st_{June 2004} _{10 + 2}

Annex. Issue for use SPP RGP VVD

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3.0 DEFINITIONS 4.0 METHOD (PROCEDURE) 4.1 GENERAL 4.2 FORMAT 4.3 CONTENT 4.4 VALIDATED SOFTWARE 4.5 CHECKING AND APPROVAL 4.6 ISSUING, FILING, AND STORAGE

5.0 RELATED DOCUMENTATION (REFERENCES)

6.0 RECORDS

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JACOBS H&G LTD

DATE: 01 June 2004 QUALITY WORK INSTRUCTION

PAGE: 3 of 10 SHELL & TUBE HEAT EXCHANGER DESIGN BY HTRI PACKAGE

REVISION NO: 0

1.0 PURPOSE

The purpose of this procedure is to define the workflow, format, and procedure of Shell & Tube Heat exchanger Design by using HTRI Package.

2.0 SCOPE

This procedure applies to all Shell & Tube Heat Exchangers performed by the Process Department.

3.0 DEFINITIONS

none.

4.0 METHOD (PROCEDURE)

4.1 GENERAL

It is the responsibility of the individual to design Shell & Tube Type heat Exchanger in accordance with this procedure.

4.2 FORMAT

None.

4.3 CONTENT

Shell & tube Heat exchanger Design steps

Input all data, which is required for heat exchanger design. 4.3.1) Process Parameters

Input Flow rate, Temperature & Vapor fraction at Inlet/Outlet condition. Input Allowed Pressure drop for shell & tube side.

For liquid vapor fraction is "0", for gas it is "1" & for two phase it is in between 0 & 1.

4.3.2) Geometry

Input following configuration

TEMA type As per given in Data sheet(If not given then it depend upon

Fluid type, condition etc.)

Orientation Orientation may be Horizontal, Vertical or Inclined with some

Angle in between 0 to 90 Deg.

Hot fluid side Either Shell side or Tube side.

Tube type Plane or finned.(for shell & tube generally plane tubes are used )

Tube

length In design mode you can enter length & design exchanger

for various shell ID, Tube length, Pitch.

In FPS Units 4,6,8,10,12,14,16,18,20,22,24 ft. are std.Tube length

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& Calculate effective tube length

Tube length, which is used for heat transfer.

(Total tube length - Tube sheet thickness - Tube projection)

Surface area Gross Total installed area.

( no of tubes x total tube length x PI x Tube OD) Surface area Effective Total installed area.

( no of tubes x Effective Tube length x PI x Tube OD) Shell

ID In design mode this input is not required. HTRI will calculate.

IF you want to design exchanger for fixed Shell ID then input ID. IF you want to design exchanger from 'xx' mm to 'xx' mm shell ID IF you want to design exchanger from 'xx' mm to 'xx' mm Tube Length

IF you want to design exchanger for Single or double segmental baffle or NTIW Design. IF you want to design exchanger Various Tube OD or Various Tube Pitch

IF you want to design exchanger Various TEMA Type Shell (i.e. F shell,J-shell,Floating head etc.) then We can enter All these option in Grid design.

Tube OD Generally 19.05,25.4,31.75,38.1,50.1 mm

Tube Pitch Generally 1.25 times tube OD

Tube layout 30,60,45,90

Flow Direction Flow Direction

30 O _Layout ₆₀O _Layout ₉₀O _Layout ₄₅O _Layout

Tube passes For design case not required.

(for floating head even no of passes, for U-tube 2,4,6,8 etc.) Tube

count

For design case not required.

Tube material Select from HTRI data bank

Baffle type For design case not required.(Single,Double,NTIW,None,Rod)

Baffle cut For design case not required.(Vertical & Horizontal)

Baffle cut is with respect to shell inlet nozzle axis.(i.e. if baffle cut is perpendicular to nozzle axis then cut is horizontal and if cut is parallel to nozzle axis then it is vertical cut)

Baffle spacing For design case not required.

Parallel pass lane For design case not required.(Refer HTRI help)

Perpendicular pass

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JACOBS H&G LTD

REVISION NO: 0

Sealing strips For design case not required.(Refer HTRI help)

Sealing strips reduces leakage in bundle & shell, which Increases cross flow fraction.

Shell side inlet / outlet nozzle Std., Schedule,Nos,ID,Type,Position For design case not required.

Tube side inlet / outlet nozzle Std., Schedule,Nos,ID,Type,Position For design case not required.

Impingement plate For design case not required.

If Shell side nozzle inlet / outlet RV2 is more than allowed limit then HTRI will consider Impingement plate. For gas & two phase flow Imp. Plate is required, For Liquid Phase it depends on RV2.Generally rectangular Imp. plate are used for Exchanger. There is some optional data, which is not required for design purpose. But this data Should be corrected at the time of rating & fine-tuning, which is given below.

Total tube sheet thickness, Floating head support plate, Support at U-bend, Design temperature & pressure etc.

4.3.3) Piping

4.3.4) Process

Exchanger Duty Enter Actual exchanger duty.

Duty Multiplier if 10% Over design on duty then you have to enter 1.1.

Fouling resistance Input, which is given in data sheet. If not given in data sheet

then use process heat transfer by D.Q.Kern for guidance.

4.3.5) Physical properties for Hot & Cold fluid

Physical properties input Three options are available, first is mixture property via grid, Second is component by component, Third is Grid & Component.

Heat release curve Three options are available, first is user specified, Second is

Specified dew/bubble point, Third is programmed calculated.

Composition units Moles, mass

Flash type Differential (Separate & not in contact), Integral (Well mixed and in thermal &

chemical equilibrium)

4.3.6) Design

Geometry

a)Shell ID You have to enter minimum, maximum Shell ID and no of steps

in nos or step size in mm or Inch.

b)Baffle spacing You have to enter minimum, maximum baffle spacing and no of steps

c)Tube passes You have to enter minimum, maximum no of passes and odd or

even nos.

d)Tube length You have to enter minimum, maximum tube length and no of steps

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g)Shell type All TEMA shell type.

TEMA E,F,G,H,J12,J21,X,K type shell

h)Baffle type Single,Double,NTIW,None,Rod

In Design mode we are not varying Shell ID,Baffle spacing, Pitch ratio, Shell type, Baffle type. HTRI gives various design with different shell ID with optimum baffle spacing for given various tube length & tube passes.

HTRI gives shell ID in STD. Inch format. We are suppose to fine-tune for nearest round number which is divisible by 5 in Rating mode.

We are varying only Tube length, No of passes in design mode. For special case you can very all other parameters.

Constraints You can give constraints of Hot fluid velocity, cold fluid velocity,

Pressure drop etc.

Options You can give options as given In HTRI Program.

Warnings You can give warnings as given In HTRI

Constraints,options,warnings are not required for simple design.

4.3.7) Control

Name Here you can give name of client, Exchanger, Project No. etc.

Case Here you can give case description (Design case, Rating Case,

With ___ Length, With ____ Shell Type etc.)

Methods,Safety,User defined methods,Vibration,F & J curve etc are not required for Simple design.

4.3.8) Design & rating

Once you enter all above Data you can run case by claiking run option on tool bar. Programme gives various designs for given options. Typical design table is given below

4.3.9) Selection of optimum design from various design reported by HTRI.

Take printout of various designs. Analyze and evaluate % over design, Pressure drop, No of Shell in series, No of shell in parallel, Area, H.T. Coefficient, Velocity etc.

Select one case for rating.

Select Optimum case from various design & Click right button of mouse and save input as rating file with different file name.

Open rating file and run case again.

Analyze result for Pressure drop, Over design, Warnings, H.T.Coefficient etc.

If Over design is more then 5.0 %( Our standard) you can reduce tube no’s, or tube length. Check Flow

fractions.

a)Try to increase B-stream flow fraction and minimize leakage stream flow fractions. In actual practice, it is not possible or necessarily desirable to eliminate leakage streams completely because clearances are required to construct the heat exchanger. B-stream fraction

C as e O ve r D es ig n % To ta l Ar ea ( m 2) D u ty ( M M E M TD ( C ) U Sh el l h (k ca l/ m 2-Tu b e h (k ca l/ m 2-S h el l V el o ci ty Tu b e V el o ci ty S h el l D P (k g f/ cm 2) Tu b e D P (k g f/ cm 2) S h el ls I n S er ie s S h el ls I n P ar al le l S h el l ID (m m ) B af fl e S p ac in g Tu b e P as se s Tu b e L en g th Tu b e D ia . (m m ) Tu b e P it ch C ro ss P as se s S h el lT yp e B af fl e Ty p e S ho rt cu t D es ig n 1 1. 66 13 19 .8 7 12 .8 51 8 59 .0 20 1. 06 11 44 .2 4 39 8. 42 2. 48 5. 45 0. 82 0 0. 49 7 9 1 15 24 .0 0 2 10 00 .0 20 .0 00 1. 30 00 ₂ E S ng . S eg . S ho rt cu t D es ig n 10 61 .5 0 13 49 .6 5 12 .8 51 8 45 .7 34 5. 75 14 66 .4 1 10 01 .6 2 4. 50 17 .7 6 0. 83 6 1. 63 2 3 1 12 19 .2 0 46 4. 52 2 4 49 99 .9 20 .0 00 1. 30 00 10 E S ng . S eg . S ho rt cu t D es ig n 11 1. 58 75 1. 00 1 12 .8 51 8 46 .7 37 8. 15 19 75 .5 1 10 63 .0 0 6. 06 19 .1 5 1. 40 2 1. 08 5 3 1 86 3. 60 2 47 7. 57 3 2 59 99 .9 20 .0 00 1. 30 00 12 E S ng . S eg . S ho rt cu t D es ig n 18 24 0. 42 31 58 .8 1 12 .8 51 8 46 .2 30 4. 86 12 77 .8 8 81 4. 16 3. 45 13 .6 6 0. 87 7 1. 51 1 3 1 13 71 .6 0 54 2. 57 7 4 89 99 .9 20 .0 00 1. 30 00 16 E S ng . S eg . Xi st R at in g 1 49 .4 1 77 9. 73 6 12 .8 51 8 50 .0 49 9. 95 20 28 .5 9 22 80 .8 1 5. 17 17 .6 9 1. 19 7 1. 64 3 3 1 86 3. 60 2 47 7. 57 3 2 59 99 .9 20 .0 00 1. 30 00 12 E S ng . S eg .

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JACOBS H&G LTD

REVISION NO: 0

should be more than 40 %.(for viscous fluid it less & Shell side condensing fluid it is less) B-stream can be increased by increasing baffle cut, Reducing no of baffles, and also reducing other leakages.

b)The magnitude of the tube-to-baffle clearance affects the size of the "A" leakage stream. Because the "A" stream is thermally effective, a significant "A" stream does not have a large negative impact on thermal performance of the exchanger.

c)C-stream bypassing can result because of bundle to shell clearance, which can be reduced by using sealing strips. For floating head exchanger this stream is on higher side which can be reduced up to some extent by using sealing strIps.HTRI calculate sealing strip pairs, but you can use one pair for every 5 tube rows which are in overlap region. d)"E" stream is not thermally effective, a large "E" stream has a large negative impact on the

Exchanger’s thermal performance."E"stream is because of baffle to shell clearance. HTRI uses TEMA Std.You can vary This clearance with the help of fabricator advise. e)The F stream travels along tube pass partition lanes. Because these bypass streams can

affect heat transfer and pressure drop performance, they must be modeled accurately. Thus, usually you do not run a case with these streams blocked. HTRI block this stream by using seal rod of same OD of tube or smaller OD.

4.3.10) Tips to decide optimum & good design of Shell & Tube Heat exchanger

a)Find out which coefficient is governing.

If shell side coefficient is governing then check All DP is used or not. If all DP is not used then increase no of baffles or reduce Baffle cut.

If DP is Higher than allowed then reduce no of baffles or increase Baffle cut. Some time you can go for Double segmental Baffle for very low DP in shell side. b)When you are specifying no of baffles ensure shell side Inlet / Outlet nozzle location. if you want shell side nozzle on opposite side then no of baffle cross passes are odd.

c)Generally for horizontal shell nozzles are on opposite side. For vertical shell Nozzle can be on opposite side or same side.

d)Inlet / Outlet Baffle spacing is dependent on nozzle ID.Baffle should not foul nozzle. Generally Inlet / Outlet spacing is Equal to or More than Mid Baffle Spacing. Try to set baffle spacing divisible by 5 mm in MKS unit or 1 Inch in FPS units.

Check % Contribution of DP in Nozzle, Cross Flow. If DP In nozzle is high then go for Higher nozzle size.

e)If shell side coefficient is very low you can increase it by using fin tube, but shell side fluid should be very clean.(Special Design)

f)If tube side coefficient is governing then check All DP is used or not.

If all DP is not used then increase tube length & reduce no of tubes at the same time by kipping same H.T.area.

If all DP is not used & actual DP is very less then increase tube passes.

You can go for smaller tube OD but you have to run Design mode again with two different tube OD & fine-tune.

g)For single phase on shell side you can use vertical as well as horizontal cut baffles. For two phase flow on shell side mostly use vertical cut baffles. some time you can use horizontal baffles with cutout at bottom.

h)Nozzle orientation should be such that we get counter current flow in 1st tube pass. i)U-tube exchanger is cheaper because only one tube sheet is required.

(for U-tube type exchanger Tube side cleaning is not possible.)

j)Specify Location of nozzle at U-bend for U-tube Exchanger. Options are At U-bend, Before U-bend & After U-bend.

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m)For U-tube exchanger generally bend radius is 2 times tube OD.HTRI is considering 1.5 times tube OD. We are supposed to enter Pass lane manually.

n)If there are more shell in series then at the time of rating & fine tuning you should input shell side inlet/outlet nozzle location for each shell.(i.e.at top or bottom, at front end or rear end)

o)You can use different geometry for shells in series.

4.3.11) Procedure for preparing Shell & Tube heat exchanger process data sheet

First copy standard Shell & Tube Heat exchanger process data sheet from standard format. a) Read following points when updating standard process data sheet.

a1) Marked cells to be checked / rewritten / deleted as per requirement.

b1) Please note that for fixed tube-sheet exchanger mean metal temperature to be given for various conditions as in sheet-4.

c1) Copy Tube Layout from HTRI output on sheet-6.

d1) When Shells in series are more than one, then we are supposed to give detailed Interconnection drawing on separate sheet.(sheet-3)

e1) When Shells in series are more than one & MOC for Tubes & Shells are different for different shells then give table for MOC.( sheet-3 )

f1) If we require Duty or Flow margin then we are supposed to specify in remark. G1) For double segmented baffle there is no provision to specify cut for inner baffle

& outer baffle. We suppose to include this point in to remarks.

h1) There is no provision in HTRI to specify whether Exchanger is IBR approved or not. We suppose to include this point in remarks.

b)Copy from TEMA-1 Sheet from Row -9 to Row-58 & Paste only the Values at location given in standard data sheet.(Sheet-2)

c)Copy Sketch of Individual shell from individual & connect to each other.(Sheet-3)

Please check inlet & outlet nozzle location are correctly shown for shell side & Tube side. This sheet is required when there are more than one shells in series or parallel.

In Design pressure, Design temperature, Material of construction are different for different shell then Specify in Sheet-3.

d)Mean Metal Temperature : This is required For Fixed Tube Sheet Exchangers Only. If no of shells in series are more than one then we are supposed to specify mean metal temperature for All shell's. Specify Nozzle schedule in Sheet-4.

e)Draw sketch of reboiler & piping details in Sheet-5.

Sheet-5 is required when Exchanger is reboiler & piping details are required to ensure pressure drop in inlet / outlet Piping.

f)Copy Tube layout from HTRI Output (Drawing-Tube layout) & paste in Sheet-6.

If tube layout is not fitting width wise then reduce size of tube layout by changing object size. Remove Shell side nozzle ID from tube layout. We are specifying nozzle schedule in Sheet-4. g)Delete Sheets & data depending on type of exchanger.

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JACOBS H&G LTD

REVISION NO: 0

This work instruction is prepared for Shell & Tube type Heat exchanger by using HTRI package.

4.5 CHECKING AND APPROVAL

None.

4.6 ISSUING, FILING, AND STORAGE

None.

5.0 RELATED DOCUMENTATION (REFERENCES)

None.

6.0 RECORDS

Calculation no to be given to Shell & Tube Heat Exchanger Design.

7.0 ATTACHMENTS / APPENDICES

7.1 Standard Process data sheet for Shell & tube heat exchanger.

"Standard Data

Sheet For Shell & Tube Heat Exchanger.xls" 7.2 Scanned drawings from HTRI Help file.

Shell & Tube Exchanger Drawings.pdf