Industrial cooling · Semi-welded replacement

Discontinued TM10-BFT Replacement in Propene Service

A semi-welded drop-in replacement for a discontinued fully welded exchanger without piping modification.

TM10 BFT fully welded plate heat exchanger replacement by HEXNOVAS semi welded design for propene service — Original image from the legacy HEXNOVAS project record

Project summary

Challenge

Replace discontinued equipment in propene service while retaining existing piping and meeting elevated pressure requirements.

Engineering response

A compatible semi-welded arrangement was engineered for the existing interface, 26 bar design pressure and 30 bar test pressure.

Outcome

The replacement avoids piping modification while restoring serviceability and documented pressure capability.

Propene service
26 bar design pressure
30 bar test pressure
No piping modification

Original project record

Replacement of Discontinued TM10-BFT in Propene Service

Project Background

The client was operating a fully welded plate heat exchanger — Alfa Laval TM10-BFT — in propene service.

Medium: Propene
Design Pressure: 26 bar
Hydrostatic Test Pressure: 30 bar
Fully welded structure
Fixed piping layout
Model discontinued

When the unit required replacement, the original model was no longer available. The plant requirements were strict:

No reduction in pressure rating
No modification to existing piping
Safe operation in hydrocarbon service
Maintain mechanical reliability

HEXNOVAS proposed a semi-welded plate heat exchanger retrofit solution .

Engineering Challenges & Solutions

This project required solving three critical engineering constraints simultaneously.

Challenge 1

Propene Compatibility in Transition Sealing Area

Although semi-welded plate heat exchangers use welded cassettes on one side, the port transition area still contains a ring gasket exposed to process media.

In propene service, elastomer selection becomes critical due to:

Hydrocarbon swelling risk
Permeation sensitivity
Pressure cycling
Safety considerations

After material compatibility evaluation, we selected high-performance FKM (Viton) ring gasket .

Excellent resistance to light hydrocarbons
Stable compression under 26 bar operating pressure
Reduced swelling and diffusion risk
Controlled maintenance interval

Challenge 2

Nozzle Center Alignment — No Piping Modification Allowed

The client required that the existing piping layout remain unchanged. However, nozzle centerline positions did not match between the original TM10 and a standard semi-welded frame.

Redesigned flange welding position
Adjusted nozzle neck extension length
Applied flange offset geometry
Matched port center elevation

Result: drop-in replacement with no field welding and minimal shutdown duration.

Challenge 3

Achieving 26 Bar Design Pressure in Semi-Welded Structure

Matching the original unit integrity (26 bar design / 30 bar test) required structural optimization.

Reinforced frame structure to reduce deflection under compression load
Upgraded plate thickness and reduced stress at port area
High-strength bolts and uniform compression distribution

Verification: 26 bar achieved, 30 bar hydrostatic test passed, stable ring gasket compression.

Technical Advantages of the Retrofit Solution

Serviceable plate pack
Lower lifecycle cost
Easier inspection access
Equivalent hydrocarbon sealing integrity
Maintained mechanical rating

Project Outcome

The retrofit was completed without piping modification and without compromising safety.

Engineering Insight

Replacing a discontinued fully welded plate heat exchanger is not only a thermal exercise. It requires addressing chemical compatibility, mechanical equivalency, structural integrity, and field installation constraints.

Our engineering team can provide a customized solution.

Downloads

Put the PDFs here for easy conversion.

Semi-Welded PHE Catalogue (PDF) Specs, applications, and selection guidance.
GPHE Catalogue (PDF) Service-friendly plate heat exchanger portfolio.