Efficiency focus on heat exchangers

Paul Boughton

With users from oil and gas companies to the food industry demanding greater efficiency from their heat exchangers, manufacturers are having to rise to the challenge. Sean Ottewell report.

HRS Heat Exchangers has supplied Barbery in Somerset, UK, with its MI series and industrial multi-tube K series heat exchangers to heat whey protein concentrate.

Whey proteins are used extensively in food products because of their good functional and nutritional properties and their appeal to a whole range of consumers. Heat treatment is commonly used to improve the utilisation of valuable food components and to ensure safety assurance.

The MI series is used for preheating feed to Barbery's spray dryer, providing sensible heat more efficiently than in the drying process. HRS has also supplied an industrial multi-tube K series heat exchanger in order to produce hot water at 68°C, using steam as the service medium.

The MI and K series are ideal heat exchangers for whey heating as corrugated tubes are used to increase heat transfer rates - making them much more efficient than normal smooth tube heat exchangers.

HRS has also supplied two KH 225 273/12 4.0m shell and tube heat exchangers to the Waste Recyling Group's (WRG) Eastcott energy-from-waste plant in Nottingham, UK. The installation of heat exchangers ensured waste heat recovery in the high pressure hot water for the incinerator that feeds a turbine. The capability of HRS heat recovery systems to retrofit into existing systems encouraged WRG to replace existing units. HRS matched up to the existing site connections and designed to suit the space left by the failed parts.

The HRS K series heat exchanger is an all stainless steel shell and tube heat exchanger for industrial use and an ideal heat exchanger for steam to water applications such as CIP heating. The four-metre long units were supplied with AEL headers that allow the customer to visually inspect the tube side of the heat exchanger, without having to remove site pipe work.

In another development, HRS has won a EUR1m grant from the European Commission-Research Executive Agency (EC-REA) towards the development of a new evaporation technology and better processes for volume reduction of environmental waste (Fig. 1).


Pig manure is a huge problem across Europe and has been identified as a major environmental issue in Brussels. The large volume of pig manure and its daily use as fertiliser for agriculture is responsible for causing serious environmental problems. The project is aimed at developing an integrated and cost-effective solution to reduce the volume of pig slurry, minimise the pollutant emissions and process energy consumptions.

The main technology to be used here is the special version of the Unicus for evaporation applications. Unicus is a scraped surface heat exchanger for high fouling and viscous fluid applications. During evaporation, in case of the Unicus, the scraping action keeps the heat transfer surface clean and maintains heat transfer high. This allows the Unicus to concentrate to levels where traditional technologies fail. HRS says that this makes the Unicus the ideal solution for concentration of environmental waste where volume reduction is vital.

Alfa Laval has launched a new plate heat exchanger called FusionLine. It features a novel design with a truly open flow and no contact points. The company says that FusionLine offers the best of both worlds, combining the energy efficiency, accessibility and modularity of plate technology with the viscous and particulate-handling capabilities of tubular technology. As such the company says it is a great choice for viscous and particulate products such as juices, prepared foods, soups and sauces, which have traditionally been processed in tubular heat exchangers (Fig. 2).

By extending beyond technology boundaries, FusionLine enables food and beverage manufacturers to optimise their performance without compromising on end-product quality, characteristics or economy. Combining benefits in this way adds an extra dimension in freedom of technology choice. Now the process and the customer can dictate the solution to a much greater extent.

Achim Heiming, competence centre manager thermal, Alfa Laval, says: "FusionLine is an excellent complement to traditional technologies, providing a new level of flexibility. It's a solution that should help keep production costs down and end-product quality up."

FusionLine features a 4-6 mm open channel on the product side, which is easy to CIP and fully accessible. The open-channel design is made possible by bonded plate cassettes on the media side. The cassettes are bonded using Alfa Laval's patented AlfaFusion technology, which bonds two stainless plates together into one piece with no joints.

The AlfaFusion technology allows the use of thin plates providing optimum heat transfer, and thus maintains a high resistance against product pressure. The unique channel geometry ensures gentle product treatment. Plates can be easily added and removed, providing the flexibility to react to changes in production volume. The footprint is also 30-40 per cent smaller than a tubular heat exchanger.

In summary, FusionLine is different because: there are zero contact points on the product side; it has a low pressure drop, requiring low pumping power; it has a small footprint; and it is easy to clean and inspect.[Page Break]

Welded plate supplier chosen

During 2012, Dutch state-owned company Gasunie will complete work on a gigantic nitrogen buffer storage facility. Nitrogen is required as an additive for gas delivered directly to Dutch households. The site of the buffer facility is located in an area of now defunct salt mines.

Gasunie and Petrogas gas-systems, who are managing a glycol dehydration and regeneration unit through BTE Technische Handelsonderneming, have chosen Tranter as their preferred supplier of welded plate heat exchangers. Petrogas Gas-Systems is a globally active turnkey gas facilities contractor and is also able to handle servicing and maintenance requirements.

All-welded plate heat exchangers are able to withstand both very high pressures and high temperatures. The contract in the Netherlands was awarded to Tranter due in no small part to the many advantages that welded plate heat exchangers have over tube heat exchangers.

"Firstly, Tranter's welded plate heat exchangers take up significantly less space than the tube heat exchanger alternative, possibly as much as 50 per cent less installation space. Secondly, these welded plate heat exchangers require almost no maintenance at all, which of course is a major financial benefit in both the short and long term," says Hans de Groof, head of the team responsible for Petrogas' installation and implementation at Gasunie in Zuidbroek.

The Petrogas installation at Gasunie's nitrogen storage facility is an advanced multi-pass solution with a long thermal length. In Tranter's solution, glycol passes through the welded plate heat exchangers no fewer than five times. This ensures that the necessary process of regenerating glycol for the dehydration of the huge quantities of nitrogen involved is made as efficient as possible.[Page Break]

True dual evaporator for chillers

SWEP has launched the DP700, a brazed plate heat exchanger with the function of an evaporator and condenser for chillers. It is designed for R410A chillers, with a cooling capacity range up to 700 kW.

The DP700 enables high performance and low pressure loss on the secondary side, and is short and compact which creates space for other system components.

SWEP's AsyMatrix plate design for high performance is another feature of the product. The AsyMatrix channel configuration increases thermal performance, reduces refrigerant charge and decreases the pump power needed for the circulation of chilled media.

Meanwhile the company also has launched its e-business shop to the US market. This features fast and secure online orders, a user-friendly web interface, a delivery scheduling system and live expert advice from SWEP's local support. "The shop provides a comprehensive overview of our products and accessories and makes it easy for our customers to plan their orders and deliveries. It makes the business of selling brazed plate heat exchangers easy," said Pär Björkman, company segment manager dealer.

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