Inspection of Heat Exchangers

Saad G.AL-Dufairi

BGP-Inspection Unit

July4,2005

Outline

• Objective.

• Types of Heat Exchangers.

• Saudi Aramco Specifications, F175 Forms.

• Industrial Standards & Codes.

• TEMA Classifications.

• Air-Cooled Heat Exchangers.

• Primary Process Functions of Heat Exchangers.

• Fabrication steps through ITP.

Objective

• Identify the main types of heat exchangers and their primary components..

• Inspection, and testing procedures for heat exchangers.

• Saudi Aramco Specifications and F175 Forms.

• Industry Standards And Codes.

• Evaluate vendor fabrication drawings for suitability, using 32-SAMSS-007, 32-SAMSS-011, TEMA, and API standards.

• Describe the use of 32-SAMSS-007, 32-SAMSS-011, and industry codes and standards to determine heat exchanger inspection and testing requirements.

Types of Heat Exchanger

• Shell-and-tube heat exchangers

• Air-cooled heat exchangers

• Double-pipe heat exchangers

• Plate-and-frame heat exchangers

The main types of heat exchangers that are used by Saudi

Aramco are as follows:

Types of Heat Exchanger

Figure 1. Shell-and-Tube Heat Exchanger

Shellside

Flow Out

Tubeside

Flow In

Tubeside

Flow Out Shell

Tube Bundle

Shellside

Flow In

Shell-and-Tube Heat Exchanger

Types of Heat Exchanger

Nozzle

Header

Tube spacer Side Frame

Fins

Tube Support

(bottom)

Tube

Air Seal

Header

Lifting Lug Tube Keeper

(top) Air Seal

Air Seal

Typical Air-Cooled Heat Exchanger

Types of Heat Exchanger

Double-Pipe Heat Exchanger

Shell Cover Gasket

Shell

External Fin Pipe

Shell End Piece Twin Flange

Return Bend (welded)

Shell Cover

Vent

Drain Sliding Support

Fixed Support

Types of Heat Exchanger

Cin

Plate-and-Frame Heat Exchanger2

Separating Sheet

Bin Aout Nozzle

Header

Corrugated Sheet

Side Bar

Distributor

Effective Length

Effective Width

Heat Transfer Section

Distribution Section

Cout

Ain Bout

B

A

SA Specifications

• 32-SAMSS-007 Manufacture Of Shell And Tube Heat Exchangers

• 32-SAMSS-011 Manufacture Of Air-Cooled Heat Exchangers Inspection

• 32-SAMSS-028 Manufacture of Double Pipe Heat Exchangers

• SAES-E-004 Design Criteria Of Shell And Tube Heat Exchangers

• SAES-E-006 Design Criteria of Double Pipe Heat Exchangers

• SAES-E-007 Design Criteria Of Air-Cooled Heat Exchangers

• SAES-E-014 Design Criteria Of Plate And Frame Heat Exchangers

• SAES-E-015 Design Criteria Of Electric Heat Exchangers

Saudi Aramco Inspection Requirements Forms

SA F 175

• Form 175-323100 Manufacture of Shell And

Tube Heat Exchangers

• Form 175-323500 Floating Heads or Tube

Bundles

• Form 175-323600 Manufacture of Air-Cooled

Heat Exchangers

• Form 175-323300 Manufacture of Plate &

Frame

• ASME SEC VIII Rules for Construction of

D1/D2 Pressure Vessels

• TEMA Standards of the Tubular

Exchanger Manufacturer's

Association

• API 660 Shell and Tube Heat Exchangers

for General Refinery Services

• API 661 Air-Cooled Heat Exchangers for

General Refinery Service

Industrial Standards

TEMA Classifications

TEMA Class Application Example __________________________________________________________________________________________________________________________________________

R Severe environments Refineries

C Moderate service Building

services,

commercial,

and general

process

industries

B Chemical process Chemical

manufacturing

TEMA Classifications

Design Item Class/Service

R/Refinery C/General B/Chemical

Corrosion Allowance

(carbon steel) 1/8 in. 1/16 in. 1/16 in.

Minimum Thickness of Shell See Table R-

3.13

See Table

CB-3.13

See Table

CB-3.13

Minimum Tie-Rod Diameter 3/8 in. ¼ in. ¼ in.

Gasket Contact-Surface Tolerance 1/32 in.,

max. None None

Minimum Bolt Size ¾ in. ½ in. 5/8 in.

TEMA Designation System Example

Type “S” Split-Ring

Floating Head

Type “E” Shell

Single-Pass

Type “A” Channel

23”

Shell

I.D.

Straight Tube

Length 192”

(16’ – 0”)

TEMA Size and Type Normally Written: 23–192 AES

TEMA Types

Acceptable Exchanger Components

Materials for Carbon and Alloy Steels

Exchanger

Component

Design Temperature (Note: The numbers in ( ) refer to the specific notes at the end of the table)

-100ºC - 47ºC

(-150ºF - 51ºF)

-46ºC - 0ºC

(-50ºF - 32ºF)

1ºC - 425ºC

(33ºF - 800ºF)

351ºC - 645ºC

(651ºF -

1200ºF)

Shells, Channels,

Dished Heads,

Tube sheets,

Rolled Nozzle

Necks, Covers,

and Reinforcing

Pads

SA-203

Grades D or E

SA-516

Grade 70N,

or

SA-537 Class 1

SA-516 Grade

70

or

SA-537 Class 1

or

SA-285

Grade C (1)

SA-387 Grade

11

Pips, Nozzle

Necks

SA-333 Grade 3 SA-333 Grade 6 SA-106 Grade

B

SA-53

Grade B (1)

SA-335

P11, 12 or 22

Shell and Tube Heat Exchangers

Air-Cooled Heat Exchangers

• Forced-draft

Air forced across tube bundle by fan located in air plenum

below bundle.

• Induced-Draft

Fan located above hood covering tube bundle.

Air pulled across tube bundle and exhausted through hood.

• Humidified Forced-Draft

Air humidified before forced across tubes.

Evaporation draws heat from air and cools air below

temperature of process fluid.

Air-Cooled Heat Exchangers

Typical Forced-Draft Air-Cooled Heat Exchanger

Supports Plenum

Fan Ring

Fan

Outlet

Nozzles

Inlet

Headers

Drive

Assembly

Outlet

Headers

Inlet Nozzles Tube Bundle

Return

Header(s)

Horizontal Tube, Induced-Draft Air-Cooled Heat Exchanger

Inlet Nozzles

Return Headers

Fan Ring

Supports

Drive Assembly

Tube Bundle

Outlet Nozzles

Outlet Headers

Inlet Headers

Hood or Plenum

Fan

Air-Cooled Heat Exchangers

Air-Cooled Heat Exchangers

Humidified Forced-Draft Heat Exchanger

Tube Bundle

Fine Water Mist

Hot Air

Header

Plenum Chamber

Forced Draft Fan

Water Header Nozzles (above

fan Typical)

Header

Partition Plate

Process Nozzle

Process Nozzle

Water Header Nozzles (below fan Sometimes)

Acceptable Materials for Fin fan cooler

Exchanger

|Component

Design Metal Temperature (Note: The numbers in ( ) refer to the specific notes at the end of the table)

-46ºC to 0ºC

(-50ºF to 32ºF)

1ºC to 425ºC

(33ºF to 800ºF)

351ºC to 645ºC

(651ºF to 1200ºF)

Header Plates,

Pass Partition Plates

and Stiffener Plates

SA-516 Grade 70N

or

SA-573 Class 1

SA-516 Grade 70,

or

SA-537 Class 1

or

SA-205 Grade C (1)

SA-387

Grades 11, 12 or 22

Nozzle Necks SA-333 Grade 6 SA-106 Grade B

SA-53 Grade B (1)

SA-335

P11, 12 or 22

Tubes (inner) (2) SA-334 or SA-249

Type 304

SA-179 or SA-214 SA-179 or SA-214

or SA-213 Type 304

Forged Flanges,

Forged Fittings,

and Plugs

SA-350 LF2 SA-105N SA-182 F11, 12, or

22

Wrought Fittings SA-420 WPL6 SA-234 WPB SA-234 F11. 12. pr

22

Studs/Nuts for

Pressure

Connections

SA-320 L7 w/

SA-194 Grade 2H

SA-193 B7/

SA-194 Grade 2H

SA-193 B5, or

B16/SA-194 2H, or 3

Primary Process Functions of Heat

Exchangers

• Change temperature of a fluid

• Change phase of a fluid.

Fabrication steps through ITP

• Fabrication drawing should be issued for constriction.

• Welding Procedure Specification (WPS) & Procedure Qualification Record (PQR) shell be approved by CSD.

• Material certificates to be 3.1B for pressure parts plus NACE TM0284 for HIC service.

• Certificate should include material chemical analysis & mechanical test.

• Verification of heat number between certificate and actual material.

• Material traceability. (hard punching prior to cutting)

Fabrication steps through ITP (2)

• Layout marking for cutting of shell and header box.

• Rolling & edge preparation of long seam & circ seams.

• Re-rolling after long seam.

• Fit-up of long seams then circ seams.

• Layout marking of all nozzles pipe.

• Fit-up of flange to neck pipe.

• Marking of all nozzles on shell & channels.

• Bevel edge preparation of nozzle opening.

• Fit-up of nozzles to shell & Channels.

Fabrication steps through ITP (3)

• Layout & drilling of baffle plate & tube sheet .

• Tube bundle preparation & assembling of tubes, tie-rods, spacers etc, to tube sheet.

• Tube expansion to be between 5.0% to 10%.

• Post Weld Heat Treatments (PWHT) if required.

• NDE (RT, UT, MT & PT) and Hardness test.

• Final visual & dimensional test.

• Pneumatic test of all reinforcements pads at 30 KPA.

• Hydrotest of shell side, tube side then channels side.

Fabrication steps through ITP (4)

• Draining the whole equipment.

• Verification of “U” stamp and name plate.

• Surface preparations, blasting then coating.

• Fin-fan coolers shall be completely drained with dry air

to an exit dew point of less than -1°C.

• Internal surface protection by corrosion inhibitor such

as CORTEC VCI-309, VCI-307 or 5 PSIG of nitrogen

blanket.

• Shipment release.

Thank you