Alfa Laval has introduced the T45 plate heat exchanger, suited for general heating and cooling duties on offshore oil and gas installations.
The T45 is the latest in the company’s series of gasketed plate heat exchangers (PHEs). It is almost 4 m (13 ft) high, providing a maximum heat transfer surface of 2,360 sq m (25,400 sq ft) and throughput of up to 1,000 kg/sec.
In common with the company’s previous PHEs, the T45 consists of a pack of corrugated metal plates with port holes for the passage of two fluids. The plate pack is assembled between a fixed frame plate and a movable pressure plate and compressed by tightening bolts. Gaskets seal the inter-plate channels and direct the fluid into alternate channels.
Alfa Laval’s new compact T45 heat exchanger.
Offshore, PHEs provide space and weight savings compared with conventional shell and tube (S&T) heat exchangers, says Peter Rose, Alfa Laval’s marketing manager for the UK & Ireland. A PHE might occupy just 20% of the space required for an S&T unit of equivalent heat transfer capacity. Alfa Laval has widespread offshore installations of PHEs for duties such as cooling utility water, lube oil, and drilling mud.
Like most PHEs, the T45 provides temperature approaches of 1ºC – in other words, following heat transfer, the temperature of the cooler liquid is within 1ºC of the warmer liquid, says Rose. Corrugations in the plates form the channels for the liquids to flow through, in the process promoting turbulence, which in turn improves heat transfer. Turbulence also helps to prevent fouling in the exchanger and keeps the channels clear.
The number of plates in a given unit is determined by the flow rate, physical properties of the fluids, pressure drop and temperature program. Since the design is essentially modular, the capacity of the T45 can be increased or reduced simply by adding or subtracting the appropriate number of plates. This ensures that the exchanger can be sized precisely for a given duty and eliminates the need for expensive over-engineering, Rose says.
Depending on the duty and the nature of the working environment, the T45 can be supplied with plates in stainless steel (alloy 316 or 254) or titanium. Other exotic materials are available on request. Gaskets are generally made from nitrile or EPDM rubber. •
For more information contact Peter Rose, Alfa Laval. Tel +44 1276 63383, fax +44 1276 413524.[email protected], www.alfalval.com.
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