A new technology to freeze-dry products faster

The start-up Lyophitech has developed a dynamic freeze dryer capable of freeze-drying products between 4 to 5 times faster than conventional static freeze dryers. This new process also makes it possible to reduce the energy consumption of freeze-drying. Meeting with Jean Delaveau, the founder of this company.

Jean Delaveau, the founder of Lyophitech. Credit: Lyophitech

An engineer by training, a graduate of AgroParisTech, Jean Delaveau has worked throughout his professional career in large groups such as Danone, Rhône-Poulenc and Sanofi. At Air Liquide, he uses a static freeze-drying process to preserve lactic acid bacteria, but finds the technology restrictive. He then waited until he was retired to develop a new device and contacted the LAGEPP (Laboratory of Automation and Process Engineering) to help him design it. A year later, at the end of 2017, and thanks to the financial support of Pulsalys, a SATT (Technology Transfer Acceleration Company), he managed to demonstrate the concept of a dynamic freeze dryer. Today, he is about to freeze-dry his first products on behalf of several manufacturers. Interview with Jean Delaveau, the founder of Lyophitech.

Engineering Techniques: Describe the operation of conventional freeze dryers currently in service.

John Delaveau: They operate in static mode and consist of a large stainless steel cabinet in which products are placed on trays or in bottles. They are placed on hollow shelves inside which circulates a heat transfer fluid which initially allows the products to be frozen. Then, a second phase occurs, called sublimation, during which the cabinet is placed under vacuum, which causes the heat transfer liquid to heat up. The water present in the products in the form of ice will then be transformed directly into steam and the product will thus dehydrate at very low temperatures, between -20 and -30 degrees, while retaining its properties.

The disadvantage of this technology is that it is very slow to implement, between 2 and 4 days, and that many energy losses are observed. It also requires the presence of an operator who loads and unloads the products on the shelves.

How did the idea for your new process come about?

It is based on a simple principle: when you stir a product (soups, rice, pasta) in a saucepan with a wooden spoon, you manage to heat it much faster than if you leave it motionless on the heat. Agitation improves heat transfer and provides more consistent temperatures. The time saved is considerable and the energy consumption is much lower, since it is directed towards the product, rather than towards the walls to be heated.

How does your dynamic freeze dryer work?

The first stage of product freezing is carried out separately using separate equipment. Then, we designed a dynamic freeze-dryer consisting of a cylinder which has the particularity of making very slow pendulum movements. We fill it with frozen products, then it is closed to create a vacuum inside. The very slight rotation of the cylinder improves heat transfer and the steam will be extracted much more easily from the product then cross a pipe before being trapped in a second cylinder. In the end, this sublimation phase takes place between 4 to 5 times faster than that observed with static freeze dryers. We are thus able to reduce energy consumption and lower the cost of freeze-drying by between 20 and 40%.

The dynamic freeze dryer developed by the start-up. Credit: Lyophitech

In order to reduce the labor time required to feed this equipment, we are working on the design of a continuous loading system, thanks to the installation of baffles inside the cylinder. Eventually, we will be able to work in bulk with products such as coffee, spices or red fruits, and we will thus be able to freeze-dry large volumes at an unbeatable price.

What stage of development is your project at?

We have protected our technology by filing patents in the main pharmaceutical manufacturing countries (Europe, United States, Japan, China, India, Canada…), because 80% of freeze dryers are sold to the pharmaceutical industry in these countries. On the other hand, it is a very complex industry in terms of its regulations and its quality requirements. We have therefore developed a strategy to gradually reach this market, starting first with the agri-food industry, then the cosmetics industry, then the probiotics industry and finally moving towards the pharmaceutical sector.

We carried out feasibility tests on a pilot unit based on products entrusted to us by future customers and freeze-drying proved to be conclusive.

We won a competition organized by France Relance, and thanks to the financial resources we received, we are currently building a shaping workshop in Vénissieux. From September 2022, we will receive a first dynamic freeze dryer, which we had manufactured, with a capacity of 1,000 litres. It will be able to freeze-dry 250 kg of products in 24 hours, and from the autumn, we will be able to deliver our first freeze-dried industrial batches. We are currently signing processing contracts to freeze-dry products such as bacteria as well as plant extracts for the nutraceutical, food and cosmetics sectors.

Several dynamic freeze dryers with a capacity of 1,000 liters will gradually be delivered to us in our production unit and we intend to be a major player in the processing.

Our factory will also serve as a showroom for future customers and from 2023, we will be selling our first machines to manufacturers who will thus be able to freeze-dry their own products themselves. We will also provide them with services in order to pass on our know-how to them. Our ambition is to move quickly towards the international market.

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