Lecithin: When a byproduct slips into the main role

First of all, it should be said that lecithin is an essential nutrient for humans, with no synthetic variant available to date. Among other things, lecithin is an essential component of the cell membrane. Yet lecithin is not only essential for the survival of the human organism. Thanks to lecithin, fat and water can be mixed, making the phospholipid one of the most important players in both the food and pharmaceutical sectors. Without lecithin, there would be no chocolate and no infusion solutions. 

High sales, low margin – what now?

It is firstly necessary to establish what makes the edible oil industry and the associated market tick in order to understand why even small gains in yield are so interesting for our customers, explains Schürmann. The sales generated by edible oil refineries and mills are relatively high, regardless of the size of the operation, not least because a large amount of raw material must initially be purchased. The price of these raw materials also varies considerably – between €500 and €1,500 per metric ton – depending on factors such as crop failure or other circumstances. The war in Ukraine, for example, has led to an exorbitant rise in the price of sunflower seeds. 

The margin is already so slender that most other industries would probably not be satisfied with it. It is clear, therefore, that oil producers are in a very high-risk business, making it all the more important for them to ensure that their production facilities run smoothly – 24/7 on around 330 production days a year, because that is the minimum requirement for being able to work profitably at all. 

As a rough rule of thumb, one day of lost production results in one-month loss of profit. By the same token, this also means that every 0.1% increase in oil yield represents a major benefit: 330 extra tons of oil per year at a plant producing 1,000 tons daily.

Lecithin: 3% with 100% impact

“For these market- and production-related reasons, there is an increasing focus on by-products,” Schürmann continues. These products, known as side streams, include free fatty acids, glycerol and so-called lecithin. They can simply be sold as animal feed or into the oleochemical industry. But if those products are of high quality, significantly better prices can be achieved. To do this, however, businesses must have the process well in hand.

“We are seeing more and more customers looking at the side streams,” Schürmann says. “They have simply reached the limit of what is possible with the rest of their processes. The only way to generate an even higher margin from the purchased raw material is therefore to exploit the side streams more efficiently. The earlier we can extract the lecithin in the process, the better.” In the case of lecithin, the quality can be assessed visually. Fewer solids and suspended matter mean fewer impurities, resulting in a brighter and clearer product. “The cleaner the lecithin, the more versatile it is for applications in the food or pharmaceutical sector, which has an impact on its value and thus also its price,” says Schürmann. “At the same time, the demands are also continually rising, so our challenge is to find solutions that improve the quality of lecithin.” 

Small change, big impact: decanters for press oil clarification

Lecithin only accounts for up to 3% of the raw oil in question – such as sunflower or rapeseed oil. “In order to understand the most efficient way of obtaining this valuable 3%, you firstly need to understand how the edible oil is extracted from crops like the sunflower in the first place,” explains Schürmann. “Like all seeds, sunflower seeds and rapeseed are initially pressed. This is similar to the process used for squeezing oranges, for example, except that instead of juice we get oil, also known as press oil, and instead of orange peel we get something referred to as press cake or oil cake.” A press cake consists of the remaining solids from the seed and the unpressed oil content. Or as in the orange analogy, skin remains with pulp residue and some juice. The precious lecithin is dissolved in the oil – both in the press oil and that still present in the press cake. Ideally, customers extract the lecithin from both streams. That is not always the case though.

It works better with a little water

In the next step, press oil clarification, filters are often used to clean the oil. These filters need to be cleaned regularly using compressed air. The key part of GEA’s new press oil clarification method involves a decanter instead of these filters. For one thing, this saves the customer from having to purchase and maintain filters, with their operating costs and especially high energy costs. What’s more, the decanter works in a more efficient manner, optimally extracting the oil from the solids. “The trick is that we can add a little water to the inflowing oil before cleaning the press oil in the decanter,” says Schürmann. “The addition of water almost completely separates the lecithin from the press oil, which is then transferred to the solid phase of the decanter.” The solid phase is further processed together with the press cake in the extraction process. The press oil, meanwhile, is optimally prepared for the subsequent refining processes following clarification by the decanter.

Miscella and better clarification performance

For the press cake and the solid phase from the decanter, the next stage is extraction to obtain the remaining oil (approximately one-third of the total amount) as well as the lecithin. Hexane must be added as a solvent here. It is later evaporated out in huge distillation columns, leaving behind the extracted raw oil. After a further refining process to eliminate gums, pigments and aromatic substances, the oil is ready.

The lecithin is ultimately obtained in the water degumming process following distillation. Water is added to the extracted oil, dissolving the lecithin from the oil and enabling it to be separated along with the water using GEA separators. Prior to that, however, the entire stream passes through the distillation stages. And this is precisely what determines the quality of the lecithin. “Our preferred method for obtaining the best possible quality is the so-called miscella clarification,” explains Schürmann. “Here, the term miscella refers to the mixture of the organic solvent hexane and vegetable oil. It also contains a relatively high proportion of solids. And it is precisely these solids that are crucial to how the process unfolds further down the line.” High temperatures are used in the distillation stages. The higher the solid content in the extracted oil, the darker the lecithin becomes, while simultaneously increasing the undesirable changes in taste. However, solids removed from the oil as early as possible, yields bright, clear lecithin and potentially a higher price. 

GEA recommends miscella clarification immediately after the first distillation stage not only because of the increased product quality but also to protect subsequent extraction stages from contamination, significantly increasing the service life of the system.

A minor thing for a decanter, a game changer for the industry

For one GEA customer, the investment in a decanter and the resulting change in the process at the press oil clarification stage quickly proved its worth. Schürmann heard reports back from sales to production asking, “What is going on there? We now have to order an extra tanker every week because we have so much more lecithin!” The gains have amounted to 3 extra tons of lecithin every day.

Win-win: more product, less energy

With that increase in lecithin comes a decrease in energy consumption. “The replaced filters used to require considerable amounts of compressed air at our customer’s facilities, with compressed air generation being one of the main energy consumers in the plant,” Schürmann emphasizes. We used to have to run all the oil through the water degumming process, now it is only the extracted oil, which only accounts for one-third of the total amount of oil. On top of that, our solution also saves a lot of space. In other words, our process represents a win-win-win-win situation for our customers. And all of this in a market that is currently booming, providing the best prospects for our customers.”