The client was operating a fully welded plate heat exchanger — Alfa Laval TM10-BFT — in propene service.
The original unit specification:
When the unit required replacement, the original model was no longer available.
The plant requirements were strict:
HEXNOVAS proposed a semi-welded plate heat exchanger retrofit solution.
This project required solving three critical engineering constraints simultaneously.
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:
After material compatibility evaluation, we selected:
High-performance FKM (Viton) ring gasket
Key characteristics:
Result:
✔ Long-term sealing reliability
✔ Equivalent safety level to welded structure
✔ Controlled maintenance interval
The client required that the existing piping layout remain unchanged.
However:
The centerline positions did not match.
Rather than requesting piping modification, we redesigned:
Maintained:
Result:
✔ Drop-in replacement
✔ No field welding
✔ No piping relocation
✔ Minimal shutdown duration
The original unit was rated:
Matching mechanical integrity was mandatory.
Semi-welded structures require precise structural optimization to reach high pressure ratings.
We implemented:
Reinforced Frame Structure
Optimized Plate Configuration
Enhanced Bolt Compression System
✔ 26 bar design pressure achieved
✔ 30 bar hydrostatic test passed
✔ No excessive frame deformation
✔ Stable ring gasket compression
Compared to the original fully welded design, the HEXNOVAS semi-welded solution provides:
The client successfully replaced the discontinued welded unit with:
The retrofit was completed without piping modification and without compromising safety.
Replacing a discontinued fully welded plate heat exchanger is not only a thermal exercise. It requires addressing:
This project demonstrates that with proper structural design and material selection, a semi-welded plate heat exchanger can safely and reliably replace fully welded units in hydrocarbon service — even at 26 bar design pressure.
If you are facing similar replacement challenges in:
Our engineering team can provide a customized solution.
