Re-inventing the sphere

The ‘EXAct sphere’ technology is a new and innovative approach to create spherical catalyst supports, which are – in spite of all their theoretical drawbacks, such as their dense packing and a low geometric surface area – are still one of the most popular carriers sold on the market.

Exacer’s goal was to invent a technology that would eliminate several of the technical limitations and drawbacks of the established routes:

  • Our technology can be basically applied to all kinds of materials and usually does not require the addition of inorganic binders. Therefore, we are able to create ultra-high purity supports (e.g., from pyrogenic silica or ultrapure alumina).
  • The process naturally provides a very uniform size distribution, without losing large parts in a sieving step (a typical standard deviation is in the range of only 1-2%). CFD studies prove that the carrier behaves like perfect sphere packing with a desirable void volume, leading to a favorable pressure drop and a very homogenous flow distribution across the reactor.
  • We can easily manipulate the physical properties, such BET surface area, pore volume or pore size distribution, so that we can provide a large variety of different supports characteristics. With this technology we can even achieve very extreme parameters, e.g., γ-alumina spheres with a bulk density as low as 500 g/l (the usual standard is ~700 g/l).
  • The EXAct spheres have outstanding mechanical properties. This is illustrated by our zirconia-spheres, which have approx. 1/3rd less attrition, when compared to extrudates of a similar size and properties, which is a huge advantage for the handling, e.g., in subsequent impregnation steps. Another example is a highly pure silica carrier with a large pore volume (up to 1.4 ml/g), which is sufficiently robust, so that it can be impregnated under ‘standard conditions’ of a wet impregnation process without enduring a structural collapse as is often found for silica carriers.

The only limitation of this particular technology is that the minimum diameter is limited to approximately 3.5 mm, which excludes some target applications that have a need for still significantly smaller diameters.

It also needs to be said that the manufacturing costs of this process are comparable to what customers are typically used to from tableted shapes or extruded specialty supports. Therefore, though it is competitive for many specialty applications, it should not be considered as a simple ‘drop-in’ solution in order to replace existing low cost ‘snowballed’ spheres of alumina, which are produced as a massive bulk commodity with a certain standard quality for the catalyst and adsorption market. An application of the ‘EXAct spheres’ should be rather envisaged, if a customer can draw clear benefits from the superior characteristics of this carrier type (e.g., reduced pressure drop, less metal losses, higher selectivity, …) – in such a case the move to an advanced carrier will quickly pay off also in economic terms,

The ‘EXAct spheres’ are currently still in an early phase, where we produce them at a size of multiple kgs/run in pilot units, which are already fully scalable to any larger tonnage. A first small commercial production line, which shall be capable of producing around 5-10 tons per month is currently under construction and shall start its operation within 2023. After gathering more experience,  Exacer will be ready to scale this process further up to the next level, so that any potential large customer demand can be matched starting from 2024 – there are already projects requests in the pipeline, that could generate such a market demand of a few hundred tons per year.

Check out more details and some examples on our technical leaflet (EXAct spheres leaflet) and contact us for your specific requests!

Please check also out our tableted spheres (tableted products)! They are the right choice, if a customer is looking for perfectly uniform bodies and a material with extreme strong mechanics.