Technology

How the distillation process works

Distillation is a method used to separate the components of a liquid mixture based on their different boiling points. Each substance in a mixture has a specific temperature at which it begins to boil and transform into vapour. Distillation exploits this property to isolate the components.

The process is outlined in the following steps :

  • Heating : the mixture to be separated is heated. The component with the lowest boiling point vaporises first.
  • Condensation : the vapour rises the column and passes through a condenser, which cools it back into a liquid state.
  • Collection : the condensed liquid, now purer, is collected in a separate container.

Alambic representing the simple distillation process with a single equilibrium stage

Isotope distillation is a specialised process used to separate isotopes of the same element with slight differences in their atomic mass. The basic principle of distillation remains the same: it utilises the differences in the isotopes’ boiling points. However, the minimal differences in boiling points add complexity: isotopes of the same chemical element have nearly identical chemical properties, including similar boiling points. This means that separation via distillation requires more precise temperature control and often sophisticated and sensitive equipment.

Due to the minute differences in boiling points, the distillation columns used for isotopes must be taller and equipped with numerous equilibrium stages compared to standard columns. This helps to increase the separation between the isotopes, as each equilibrium stage can provide a minimal increase in separating the more volatile component from the less volatile one.

Isotopic distillation requires a lot of energy, mainly because the minimal differences in boiling points require more extended periods to achieve effective separation.

In summary, isotopic distillation is more delicate and technically demanding than standard distillation. Advanced equipment and high precision are required to manage and exploit the subtle differences in isotope boiling points and achieve effective separation.

For this reason, our choice for the production site is the strategic location of the Seruci mine in Sardinia, an area unique with great potential for industrial development and equipped with deep wells of 350 meters.

We address this aspect with an advanced infrastructure solution that significantly improves production efficiency and scalability, reducing operational costs. Additionally, heat recovery is integrated to optimise energy savings.

The distillation process for our isotopes must be conducted at cryogenic temperatures because substances that are gaseous at room temperature, such as argon, nitrogen, oxygen, carbon monoxide, or carbon dioxide, require very low temperatures to liquefy. Cryogenic columns allow for the reaching and maintenance of the necessary temperatures for the condensation of these gases. The cryogenic columns are designed to minimise heat loss, thus optimising energy consumption.

Why cryogenic distilliation is the ideal solution

There are several techniques for producing stable isotopes, each with advantages and limitations (for more details, see the section “Technologies for the Production of Stable Isotopes”). Still, among all technologies, cryogenic distillation is the most advanced solution for producing stable isotopes. Its advantages are clear :

  • High product purity (>99%);
  • High production efficiency;
  • Industrial scalability.

Our facility will focus on producing stable isotopes, specifically 13C from carbon monoxide (CO) and 15N from molecular nitrogen (N₂).

Scientific Articles Published on the Aria Project

Tecnologies for the production of stabe isotopes

Here is a comparison between the main techniques for separating stable isotopes.

  • Gas diffusion : a traditional method that exploits the different diffusion speeds of isotopes through a semipermeable membrane. While simple, it has low efficiency, requires a lot of energy, and large-scale facilities.
  • Gas centrifugation : uses centrifugal force to separate isotopes based on mass. It is more efficient than gas diffusion but requires complex and expensive infrastructure and consumes a lot of energy.
  • Isotopic separation with lasers : uses targeted lasers to ionise specific isotopes with high precision. This technology is very efficient but extraordinarily costly and difficult to scale industrially.
  • Ion-exchange chromatography : a chemical technique that separates isotopes based on charge using ion-exchange resins. Although it offers high precision, it is suitable only for small amounts of isotopes, making it unsuitable for large-scale production.