Milestone: Thermal Processing Improving Sustainability through Innovation: Excellence in Thermal Processes

Author / Editor: Ulla Reutner / Dominik Stephan

With separators, heat exchangers and fluid handling equipment, Alfa Laval helps deliver efficient processes in production, and during heating and cooling. The invention of a cream separator was the first milestone on the company’s journey. Over decades, it gathered experience and built up expertise in the field of heat transfer. After eventful times, rapid growth now demonstrates clearly that Alfa Laval has found its way — by concentrating on core competencies, customer requirements and sustainability.

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Heat transfer is one of the three mainstays of Alfa Laval. In the 21st century, the service sector is continually growing in importance.
Heat transfer is one of the three mainstays of Alfa Laval. In the 21st century, the service sector is continually growing in importance.
(Source: Alfa Laval)

When it came to heat exchange processes, the Romans were ahead of the game. Unlike other cultures, they heat their baths with a fire in the same room. Instead, they used separate heating chambers from which hot air flowed into underfloor and in-wall heating systems. This was an early example of what we now call a heat exchanger or, more specifically, a recuperator. However, this technology fell into the shadows in subsequent centuries. It was not until 1716 that it resurfaced, with the oldest known hot water heating system. Marten Trifvald, a Swede, devised it to heat a greenhouse. The patent for the first plate heat exchanger was eventually awarded to the German Albrecht Dracke in 1878.

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At a much earlier date — around the turn of the first millennium — the principle of indirect heat exchange was applied in a production process. It was used to produce more or less pure drinking alcohol. To do this, the gaseous ethanol released when alcoholic beverages are heated was re-liquefied with the aid of a cooler. The principle remains unchanged to this day. Two material flows at different temperatures flow through an apparatus, separated by a heat-permeable wall, with the aim of transferring thermal energy from one material to the other.

Heating, Cooling, Tempering: It Depends on the Task

Heating rooms and cooling material flows are two early heat exchanger applications. Since then, a vast number of new applications have been added, and there is no way we could list them all here, even if we were to limit ourselves to indirect heat transfer applications. Refrigerators contain this type of system, as do thermal solar systems and heat pumps. Heat exchangers can also be found in numerous industrial processes. Applications range from biotech and beverage processing, to the oil and gas, and chemicals industries, to paper manufacturing, wastewater treatment and marine applications.

The range of designs used is equally huge. Plate and tube heat exchangers are among the most common design principles used in the industry. In addition, heat exchangers differ in terms of how the material flows are controlled and guided. Examples of this include counterflow, parallel-flow, cross-flow and vortex heat exchangers, as well as combinations of them all.

This results in a vast range of different designs, applications and industries, all of which are covered by Alfa Laval. Few competitors can keep pace. And the number of genuine rivals decreases further if you consider the complete package that Alfa Laval offers. Alongside heat transfer, separation systems and fluid handling (with pumps and valves) make up the three parts of its core business. These are products often used in the same industries as heat exchangers, and they all serve the same goals: to support materials handling and conversion in the most efficient manner and to thus improve the day-to-day living conditions of people.

Alfa Laval’s current offering is based on over a century’s worth of experience and derives from the initial idea of Swedish engineer Carl Gustaf Patrik de Laval. He took the cream separator invented by the German Wilhelm Lefeldt and significantly refined the idea in 1878. De Laval contributed the drive mechanism — a constant pressure steam turbine. The centrifuge for separating cream from milk that was improved by de Laval gave the company which he founded with Oscar Lamm in 1883 its name: AB Separator. In the same year, De Laval Cream Separator Co. was founded in the USA. AB Separator supplied pumps to the dairy industry from 1888. Another milestone came one year later with the acquisition of a patent owned by the German Clemens von Bechtolsheim, who had optimized the milk centrifuge with sophisticated plate inserts in the separating drum. However, this new design — known as the “Alfa Separator” — met with very little interest in Germany. Things were quite different in Sweden, where the efficiency of the centrifuges from AB Separator was given a significant boost thanks to the “Alfa-Disk”.

When Franz von Soxhlet discovered that the shelf life of milk could be extended through pasteurization, it became clear that the temperatures at which milk is handled play an important role. It is not known how this knowledge made its way to Sweden, but the company history tells us that AB Separator sold its first continuous milk pasteurizer as early as 1889. Clearly, de Laval and his partner had a good eye for the innovations that would shape the future of heat transfer processes, even though their significance for the future portfolio of the company was not yet apparent.

92 Patents for the “Man of High Speed”

Separation processes became the young company’s first expansion into other technologies. The small, inexpensive “Colibri-Separator” (“hummingbird separator”) was launched in 1894, followed by a yeast separator in 1898. But Gustaf de Laval still felt an obligation to his customers in the milk processing industry, so in 1910 he began developing a milking machine. Three years later, the “Man of High Speed” (as the inscription on his gravestone describes him) died at the age of 67. A short but intense life, during which he obtained 92 Swedish patents. The company he founded, AB Separator, continued on its path of dynamic growth, selling one million separators by 1917.

One and a Half Centuries Tempering Expertise
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One other important acquisition can be attributed to the founder. In 1907, AB Separator acquired a majority shareholding in “Bergedorfer Eisenwerk AG Astra-Werke.” After numerous detours involving majority shareholders such as ABB, Sabroe Refrigeration, York, and Johnson Controls, it eventually evolved into what remains the German distribution arm of Alfa Laval in Glinde. The roots of the Hamburg company reach back to 1859. After de Laval’s invention of the milk separator, Bergedorfer Eisenwerk quickly secured the rights for sole distribution in Germany. In 1904, contractual disputes with AB Separator led to the milk separators being sold under the brand name Astra by Bergedorfer Eisenwerk. This contributed to the German company’s liquidity problems, which AB Separator brought to an end by investing a stake of 1.75 million marks. The factory grew steadily in the period afterwards, and Astra refrigeration plants became a real hit. In 1932 the company built its first plate heater with a metallic gasket.

Breaking into New Markets with the First Heat Exchangers

It was around this time that AB Separator entered into the heat transfer business. With its first plate heat exchanger, the company became a player in the market for cooling and heating as well as heat recovery in the 1930s. Designs for industrial applications were launched throughout the 1950s. In 1951 alone the Swedish company was able to sell 182 units.

The separation part of the business made an especially significant impact in 1951 with the first self-cleaning centrifuge and then in 1958 with the first automatic CIP (Cleaning-in-Place). The heat exchanger sector of AB Separator made a splash in 1962, with the acquisition of several patents from AB Rosenblad (today known as RDG — Rosenblad Design Group). That helped the company develop spiral heat exchangers that were not only simple to produce but were also more robust and less susceptible to soiling than standard plate heat exchangers.

High time for a new name! 1963 saw the change from AB Separator to Alfa Laval — first and foremost a tribute to the company founder, but also featuring a nod of recognition to the role played by “Alfa-Disks” in the success of the company’s early years. The change of title made it clear that “Separator” was too limited a name to cover the full scope of the company’s activities. That became even more apposite in 1971, when the company added a majority stake in Danish company LKM — experts in the field of fluid handling. Business with heat exchangers also grew noticeably. In 1976, the company reflected this with a major investment initiative. In Lund, Southern Sweden, a large production center for plate heat exchangers was constructed.

In heat transfer technology, plate heat exchangers were increasingly proving to be superior to the older tube bundle variants. Thanks to new materials, new designs and new production methods, they operated more efficiently and could therefore be built into more compact enclosures. In the 1970s there was a real revolution in terms of unit sizes. Copper-brazed heat exchangers revolutionized the design of the modules for district heating. Another technical milestone was the brand new design of clip-on-gaskets introduced by Alfa Laval in 1978, which enabled customers to replace plate gaskets themselves.

The 90s and the Tetra Pak Era

In the 1980s, the company managed to achieve yet another technical high point with the development of the Compabloc, a welded plate-and-block heat exchanger. Since it requires no gaskets between the plates, it is suitable for controlling the temperature of corrosive media at high pressures and temperatures. It soon became number one on the market for difficult media, thanks to its thermal efficiency (three to five times higher than tube bundle solutions). There are now seven models, all of which offer excellent service life and ease of maintenance.

In 1991, the acquisition of the company by Tetra Pak, which had established itself as the market leader in packaging for beverages and dairy produce, shaped the company’s history. The Tetra Laval group of companies founded in 1993 comprised four industrial groups that operated independently of each other: Tetra Pak, Tetra Laval Food (covering the liquid food activities of Alfa Laval), Alfa Laval Agri (covering the agricultural machinery business), and Alfa Laval (covering all remaining activities.) The joint path with Tetra Pak came to an end in 2000. Investor Industri Kapital purchased the Alfa Laval Group with its core technologies Heat Transfer, Separation and Fluid Handling. After a period of restructuring, the company was relisted on the Stockholm stock exchange in 2002.

Heat Exchangers for the Process Industry

The company went into the new millennium with a renewed sense of energy and vigor. One of the technological highlights from this period was the Alfa Fusion bonding technique, which Alfa Laval developed and patented after years of research in the field of material and soldering technology. Here, corrugated stainless steel plates are connected to each other using a filler material in a high-temperature furnace. In 2003 the technology enabled a world-first: the production of a unique plate heat exchanger, the first in the world to be 100 % manufactured from stainless steel.

Alfa Nova is seen as the first choice for challenging applications in the process industry, since it can be used with aggressive media and at temperatures in a range from -196 °C to 550 °C. Its unique geometry ensures optimized heat transfer and temperature matching as close one or two degrees Kelvin. Its properties are comparable to those of welded plate-and-block heat exchangers. Far more compact than a tube bundle heat exchanger but with a similar output, it is also suitable for on-site cleaning. Alfa Nova has now tapped into a large number of applications in a wide range of sizes.

One of the milestones from the acquisitions that happened during this period was the 2005 takeover of French company Packinox, one of the global market leaders in welded plate heat exchangers for the oil and gas industry and for refineries. In 2007 this was followed by the acquisition of the Dutch company Helpman and the Finnish company Fincoil, both manufacturers of air-to-air heat exchangers used for cooling during the logistics chain and in other industrial applications.

A Flood of Innovations for Plate Designs

A constant stream of new innovations in the heat exchanger sector has further broadened Alfa Laval’s portfolio, which now covers almost any conceivable application with gasketed, brazed, welded and welded plate-and-block heat exchangers. The company also produce spiral heat exchangers with low susceptibility to soiling, and heat exchangers with a scraped surface which are ideal for viscous materials and other challenging products. For foodstuffs, pharmaceuticals and cosmetics, these are often the first choice because the patented rotating scraper technology continuously removes deposits.

In terms of the plate heat exchangers, a major leap in terms of efficiency was achieved with the Flex Flow plate design. With the aid of asymmetrical channels, this solution eliminates the compromise between thermal efficiency and pressure loss, which is particularly important in applications with different hydraulic loads on the two sides of the heat exchanger. The improved flow of media through the plates and increased heat transfer surface area mean that the same performance can be achieved with fewer plates, and therefore with a more compact unit.

The Next Generation of Tempering Devices

The newest generation of industrial gasketed plate heat exchangers from Alfa Laval manages to keep setting new standards. Thanks to the wide range of sizes, plate configurations and gasket materials, the designs can be adapted to a wide range of different requirements. Technical details such as a special distribution area and the non-circular inlet and outlet optimize the flow of media and thermal efficiency.

As a result, these models achieve 30 % higher efficiency than comparable designs. The distribution areas are based on the company’s Curve Flow principle to minimize the risk of deposits. The Clip Grip gasket and many other special features make units much easier to service. In addition, they come with a very small footprint, making them perfect for tight spaces.

Significant improvements have also been made recently in semi-welded heat exchangers. These are used for heating and cooling tasks in applications requiring higher pressures. With these units, it is possible for corrosive media or other critical media to be passed through the welded cassette. In terms of fatigue resistance, these offer significant advantages over welded plate-and-block heat exchanger variants. This has resulted in an increased service life in both industrial cooling plants and industrial heat recovery.

A Swedish Thermal Success Story

However, post-flotation, the story has been about more than expanding the product range. The importance of the service department has also steadily grown. 2011 saw the inauguration of the 100th service center. At that time, more than a quarter of the group’s turnover was already generated by service. More and more customers were focusing on their core business and were happy to leave optimization measures to the experts. This resulted in the creation of the Global Sales & Service Division in 2017, which has since been operating on an equal, closely interconnected footing with the business divisions Food & Water, Energy and Marine. Tom Erixon, CEO of the Alfa Laval Group since 2016, initiated the reorganization, which also coincided with a new strategic realignment.

In the future, the focus will be on organic growth, with a sustainable, long-term effect — a change from recent rapid growth (received rose from around SEK 32 billion (three billion Euros) in 2016 to around SEK 45 billion (4.2 billion Euros) in 2018.)

Regionally, the Asian market brought particular growth. Strong demand for Alfa Laval has also been generated by new international regulations on maritime environmental protection, along with the growing importance of heat recovery. “The heat exchangers we have installed to recover energy have enabled us to save an amount of energy equivalent to the annual installed wind energy output,” explains Erixon in his “President’s Comments” in the current annual report of Alfa Laval.

Modernization and Revamps on the Road to Success

In the new millennium, new developments in the heat exchangers sector are have been (and will likely continue to be) focused on modernization — particularly in Europe. Capacity expansions for brownfield plants are the order of the day. Accordingly, heat exchangers need to be increasingly more compact, and ultimately more efficient. Alfa Laval developers are finding ways to do this with ingenious plate geometries, which ensure turbulent flow even in the partial-load range.

But it is not just expansion that are defining this business area. Industrial companies are increasingly questioning overall process efficiency and striving to make energy savings. This is a trend that is currently being reinforced by climate change and related legislation. The Service Division at Alfa Laval is contributing to this new paradigm with audits and consultancy services that promote energy efficiency or even energy recovery. They also advise customers on how optimized cleaning and maintenance cycles can improve plant uptime.

Sustainable Solutions in the Shadow of Climate Change

What will shape the heat exchanger business over the next decades? If energy transformation is to be a success, the ability to store thermal energy will play a major role. “This is something we feel an obligation toward,” the CEO emphasizes. With involvement in an American energy storage start-up, the company is establishing a network that is fit for the challenge of making renewable energies competitive in the future. Alfa Laval is already contributing in many other ways to sustainability, including in its own production and operations. Alfa Laval is establishing itself as a company that sees arguably mankind’s biggest challenge — tackling climate change — as both an obligation and an opportunity.