Sweden’s Alfa Laval, founded more than 125 years ago by Gustaf De Laval, the inventor of the centrifugal milk separator, has grown into a leading global producer of equipment for heating, cooling, separating and transporting a wide variety of products, from oil and chemicals to foodstuffs and pharmaceuticals. Now the boom in biofuels is opening new markets for the company’s technologies.

Heat exchangers are key to converting organic materials to fuel. The main task of a heat exchanger is to ensure the efficient transfer of energy from one medium (for example air or water) to another without requiring that the two media come in direct contact with one another.

Plate heat exchangers, commonly used in the process industry, are constructed with a stack of metal plates to increase the surface area between the different temperature zones. The plates are designed with various patterns to make the exchange of heat as effective as possible. These plates are usually sealed with gaskets to prevent the liquids from mixing or leaking out, although the seals may be brazed or welded for high heat or pressure applications.

All over the world, interest is growing in biofuels such as ethanol, biodiesel and biogas. Drivers for this trend include concerns over energy security caused by dependence on fossil fuels, and the need to reduce emissions of greenhouse gases and other pollutants. An important factor in cost-effectively producing biofuels is avoiding heat loss during the manufacturing process—and this is where heat exchangers play a crucial role. Alfa Laval, with its long history manufacturing heat exchangers, sees great potential in improving renewable fuels production from a variety of raw materials. The company also sees growing markets in technical solutions for heating, separation of desired products from by-products, and processing of residues.

Energy savings

Production of ethanol is based on processes and equipment used in distilleries: condensers, evaporators, re-boilers, mash heaters, fermentation coolers, centrifuges and separators. Alfa Laval supplies decanter centrifuges and evaporators used to refine distillation residues from animal feed. Separators—the products upon which Alfa Laval was founded in 1883—are used to recover yeast which would otherwise be lost.

Alfa Laval also supplies technical solutions for heating, separation and mixing that can be adapted for manufacturing biodiesel. Pre-treatment removes pollutants from vegetable oil, which is then processed in high-speed separators, mixers and heat exchangers. The core of biodiesel production process is transesterification, in which separators remove glycerin by-products.

These are energy-intensive processes, making optimization of energy use an essential consideration; this is why heat exchangers are key components in the production of biofuels. Alfa Laval manufactures plate heat exchangers of all sizes, including compact models that are extremely efficient at harvesting heat from liquids passing through the exchanger.

Ethanol from cellulose

Producing ethanol from crops such as maize and sugar cane has raised objections over the impact on food prices, and the United States has an objective that, within in ten years, half of all ethanol fuel should be produced from non-food raw materials. These “second-generation biofuels” may be waste organic material, for instance from restaurants or agriculture, but a good deal of research is focused on cellulose from forests as a raw material. A breakthrough in this area would be of great interest for Alfa Laval, as demand for heat exchangers and separators would significantly increase, and the company is naturally following American developments closely. This makes it possible to participate in research projects and influence the development of biofuels in other ways.

Article published in October 2009