Heat Exchanger

HEAT EXCHANGERHEAT EXCHANGER

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Heat Exchanger is a device to transfer of heat from one medium to other medium.

Two fluids of different temperatures, one flows through the tubes and other flows out side tubes but inside the shell.

Heat is transferred through the tube walls.

1. Tubular Exchanger a. Shell – and – Tube Exchanger b. U - Tube Exchanger c. Kettle reboiler Type Exchanger d. Double pipe Type Exchanger

2. Extended Surface a. Plate type Exchangers b. Finned Tube

1. Shell2. Front End Head 3. Rear End Head4. Inlet / Outlet Nozzles5. Tube sheets 6. Tubes 7. Baffles8. Tie Rods9. Stiffener Plate10. Impingement plate

U- Tube bundle

U- Tube bundle

Kettle re -boiler Type

Kettle re -boiler Type

Double Pipe Exchanger

Double Pipe Exchanger

Typical Example of Shell and Tube

1. Cross Flow to Tubes

2. Parallel Flow to Tubes

TEMA –Tubular Exchangers Manufacturer's Association

ASME Codes Sec-VIII-Div I and IIASME Sec –II A , B ,C ,D- Materials , Welding

consumables, propertiesASME Sec –IX – Welder qualificationASME Sec –V - NDTANSI standardsNACE standards/ recommended practicesAPI standards 660Process Licensor's guidelines

ShellFront endstationary head type

Rear endhead type

Alphabetical Letters given for the front end, shell and rear end types.

Exchanger designated with three letter .

Example : AES, BES, AKT ... Etc,

They support the tubes during assembly and operation.Help to prevent vibration from flow induced eddies. Two types of baffles : 1. Plate type 2. Rod type

Baffle Cut : Cut in each baffle to permit the shell side fluid to flow across the baffle . Baffle cut can vary between 15% - 45 % of the shell ID

A triangular or rotated triangular pattern will accommodate more tubes than a square or rotated square pattern. A triangular pattern produce a high heat-transfer coefficient.Typical tube pitch of 1.25 times the tube OD.Mechanical cleaning of triangular tubes pattern is very difficult.Square pattern must be used where mechanical cleaning is required.

TUBE PITCH : It is defined as the shortest distance between two adjacent tubes. Minimum tube pitch is 1.25 times of tube OD.

To join tubes and tubesheet and keep the tubes structurally stable and support the skeleton assembly under design conditions.To prevent intermixing of shell and tube sheet fluids.To take care of Longitudinal, Compressive, Mechanical and Thermal axial loads coming on tubes.

Expansion

•Tubes are attached to the tube sheet by Pneumatic or hydraulic pressure or by roller expansion.

Strength weld is one in which the design strength of the weld is greater than or equal to the maximum allowable axial tube strength.

Seal weld is used to supplement an expanded tube joint to ensure tube joint leak tightness.

Where the fluid velocity for the nozzle diameter is high, an impingement plate is specified.To distribute the fluid evenly to the tubes.To prevent fluid enduced erosion, cavitations and vibration

Shell : CS / SS / Non-ferrous typesTubes : CS / AS / SS / Non-ferrousTube Sheet : Forgings / PlatesNozzle Pipes : CS / AS / SSNozzles : CS / AS / SSGaskets : CAF, Spiral Wound, IJA,

Ring Joint typeFasteners : CS / AS / SSName Plate : SS

Material Identification (Pressure parts)FormingWeldingReview of WPS / PQR / Welder QualificationNDTStage and Final InspectionsMock-up AssemblySkeleton AssemblyTube BundleInsertion of Tube Bundle into ShellTesting (Hydro testing / Pneumatic testing)PaintingDocumentationPacking / Protection / Dispatch

Provided to seal the joints against leakSpiral wound with asbestos fill or graphite fillMetal jacketedRing joint typeCamprofile typeCAF – only for less critical servicesMaterial SS 304, SS 316

Identify leak type and location: hydrotestingAttend leak :

gasket leak- re-tighten or replace retubing or plugging leaky tubes re-expansion of tube sheet joint/ re-welding

Cleaning of tube side /shell side as per requirementsInstall new bundles/ shell as per requirementOffer statutory tests as per schedule (IBR Etc.)Timely modifications in shell side/ tube side as per CTS/CES/FDC/Licensor requirements

Civil jobs : foundation / pedestal/ structuresInspection as received condition- check for N2 purging of shell & tube sidesPhysical installation : LevelingSite Checks: ITP format fill upAlignment to upstream downstream tube side / shell side pipingInsulation wherever necessary