Tailored for success: compact heat exchangers solve space and performance challenges in Singapore petrochemical plant

The challenge

The absorption-stripping system at SPC's ethylene oxide plant is designed to separate ethylene oxide from carbon dioxide and unreacted ethylene. The process involves two critical heat exchanger positions: the interchanger and the lean cooler. The interchanger recovers heat at the bottom of the stripper, while the lean cooler reduces the temperature of the regenerated absorption medium before it re-enters the absorption tower.

SPC needed to maximize heat recovery while minimizing the heat transfer area. Standard shell-and-tube heat exchangers were not suitable due to their inability to achieve counter-current flow and handle crossing temperatures in a single unit. This would have required several large units installed in series, which was impractical given the space constraints.

Our solution

SPC concluded that a compact plate heat exchanger with a counter-current flow pattern capable of handling crossing temperatures was the most practical solution. The turbulent flow achieved in a compact heat exchanger results in exceptional heat transfer efficiency, allowing maximum heat recovery with minimal area and fewer units.

Given SPC's long-standing relationship with Alfa Laval, they chose Compabloc welded plate heat exchangers for both critical positions. Mr. Chen, Equipment Manager of the EO/EG Plant, stated:

We have great confidence in Alfa Laval products because we have been using them for more than 20 years. Our experience with the Compabloc welded plate heat exchanger gave us even greater peace of mind. We believe that it will have a long lifetime and that we don’t have to worry about leakages.”

Process implementation

In 2002, SPC installed Compabloc heat exchangers at the ethylene oxide plant. The Compabloc units replaced the existing shell-and-tube heat exchangers, providing trouble-free operation and significantly improving efficiency.

The interchanger and lean cooler positions were optimized with the Compabloc heat exchangers, which offered superior heat transfer efficiency and compact design. This allowed SPC to achieve maximum heat recovery while minimizing the space required for the heat exchangers.

Impact and benefits

The installation of Compabloc heat exchangers at SPC's ethylene oxide plant brought several key benefits:

• Efficiency: The compact design and counter-current flow pattern of the Compabloc heat exchangers resulted in exceptional heat transfer efficiency, maximizing heat recovery.
• Space savings: The compact nature of the Compabloc units allowed SPC to replace several large shell-and-tube heat exchangers with fewer, smaller units, freeing up valuable space within the plant.
• Reliability: The Compabloc heat exchangers provided trouble-free operation since their installation, with no concerns about leakages or maintenance issues.
• Cost savings: The improved efficiency and reduced maintenance requirements led to significant cost savings for SPC.

Alfa Laval's Compabloc heat exchangers have proven to be a reliable and efficient solution for critical heat exchanger positions within SPC's ethylene oxide plant, enhancing overall plant performance and profitability.