Speak to a specialist about improving propylene gas quality and compressor reliability with proven liquid gas coalescer technology.
Customer challenge
A polypropylene unit within an integrated refinery petrochemical complex experienced operational challenge in its propylene gas handling system. A legacy liquid gas coalescer supplied by another vendor was unable to efficiently remove liquid hydrocarbons, oil and traces of triethylaluminium (TEAL) catalyst from the propylene gas stream.
As integrated refinery petrochemical complexes continue to expand globally, maintaining propylene purity and reliable compressor operation is critical. In this case, inadequate contaminant removal caused frequent compressor trips, unplanned shutdowns and significant propylene losses.
Operating conditions
- Propylene gas flow rate: 15,600 kg/hr
- Gas density: 2 kg/m3
- Gas viscosity: 0.01 cP
Propylene losses reached approximately 4 tonnes per hour with product valued at $625 per tonne. Over 208 hours of operation, this equated to 832 tonnes of lost propylene per year or $520,000 in direct product losses, excluding downtime, spare parts and maintenance costs.
Pall solution
Pall engineers designed a targeted liquid gas coalescer upgrade to address contamination and reliability issues.
The solution replaced the existing coalescer with a Pall system comprising:
- Seprasol® Plus coalescer elements, 6 × 40 in
- 99.999% efficiency at 0.3 µm aerosol rating
- 99.7% solids removal efficiency for particles >0.3 µm
- 1500 mm diameter filter vessel installed downstream of an internal demister pad
This configuration was engineered to manage residual liquids and fine aerosols in the propylene gas stream and deliver consistent gas cleanliness ahead of compression.
Results
Following installation, the customer reported immediate operational and economic improvements:
- Operational stability: The Pall liquid gas coalescer eliminated shutdowns linked to liquid and solid contamination and enabled consistent production of clean propylene gas.
- Compressor reliability: Effective contaminant removal significantly improved compressor reliability and reduced maintenance frequency and unplanned downtime.
- Extended element life: Element life was initially estimated at three months based on a clean differential pressure of 300 mbar. Actual performance demonstrated run lengths of six to nine months, reducing operating costs.
- Fast payback: By eliminating product losses and minimizing downtime, the solution achieved a payback period of less than six months.
Conclusion
This installation shows how a carefully engineered liquid gas coalescer solution can resolve contamination challenges in polypropylene production. Customer confidence in the solution was demonstrated through the purchase of an additional standby coalescer vessel, an uncommon practice for liquid gas coalescer applications.
The solution has since been replicated at multiple refinery petrochemical complexes. By improving propylene recovery, enhancing compressor reliability and delivering rapid economic return, Pall coalescer technology supports more efficient and resilient polypropylene operations.
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