Hairpin Heat Exchangers

An efficient alternative to conventional shell and tube heat exchangers.

Chart IMB hairpin heat exchanger

Hairpin Heat Exchangers use true counter-current flow. Unlike multi-pass shell and-tube designs where correction factors are used to account for inefficiencies resulting from counter current passes, this process maximizes temperature differences between shell-side and tube-side fluids.

Owing to having fewer sections and less surface area, a hairpin heat exchanger is the most efficient design when a process requires a temperature cross i.e. the hot fluid outlet temperature is below the cold fluid outlet temperature.

Process conditions particularly suited to hairpin heat exchangers:

  • Process requires a temperature cross
  • Applications with high pressure on the tube-side
  • Cyclical service
  • High flowrate ratios between shell-side and tube-side fluids
  • High terminal temperature differences (300°F/149°C or greater)
  • The exchanger is subject to thermal shock
  • Heating or cooling vapors
  • Complete vaporization is required
  • Solids are present in the process stream

Chart IMB hairpin heat exchanger

Double-Pipe and Multi-Tube Exchangers

Double-Pipe heat exchangers utilize a single pipe-within-a-pipe design and are commonly used for high fouling services such as slurries where abrasive materials are present, and for smaller duties. Standard shell diameters range from 2” to 6”.

Multi-Tube heat exchangers are used for larger duties with standard designs for shell diameters up to 30” and surface areas in excess of 10,000 ft2 per section. Free floating U-tube bundles allow for differential expansion and eliminate the need for expansion joints. 

Chart IMB multi-tube hairpin heat exchanger

  • Separate tubesheets handle large temperature differences and cycling duties more effectively than shell and tube units
  • Durable baffle cage construction welded directly to the tie rods removes the need for sleeves or internal nuts
  • Movable support brackets allow thermal expansion and contraction of the shell
  • Tube- and shell-side connections are at the same end for simplified installation and pipework connection
  • No inetrnal bolting
  • Double-pipe exchangers utilize pipe instead of thin wall tubing for enhanced integrity

Heat Transfer Augmentation

Longitudinal fin pipes and fin tubes provide augmented heat transfer surface area for both double pipe and multi-tube hairpin exchangers. This provides further space saving in applications where the shell side heat transfer coefficient is the limiting factor, for example with low pressure gases and highly viscous fluids.

IMB has also engineered peripheral baffles that further enhance extended surface effectiveness, without increasing pressure drop.

Clean Energy Applications

Hairpin heat exchangers are the preferred design to withstand the demanding process requirements associated with increasing capacity at LNG storage and processing plants. IMB has a proven track record in this field with the design and manufacture of large units (ND > 20").

Chart IMB hairpin heat exchanger for LNG

Twin 28" and 33" ND IMB multi-tube heat exchangers replaced eight conventional shell and tube units at two concentrated solar plants, delivering investment cost savings, together with more efficient performance and reduced maintenance.

Chart IMB hairpin heat exchanger for concentrated solar power plant

Hairpin heat exchangers are also widely used in oil and gas processing.

  • Features

Features Include:

Superior closure design permits simple removal of the tube bundle for a variety of design conditions, cleaning and routine maintenance.

External split rings are used to lock the bundle to the shell. This avoids the split rings coming into contact with the shell-side fluid, which happens with internal split rings..

Separate tube- and shell-side gaskets prevent inter-stream leakage. In addition, IMB gaskets do not seat on the tubesheet face, where misalignment can occur and the potential for erosion exists. On the shell-side, our gaskets are easier to remove than wedge gasketing.

Round flanges seal gaskets more effectively than square ones.

 

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IMB

Imbagnolo, Italy

+39 0373 237611

+39 0373 237611

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