Evaluation of SDR Spinning Disk Reactor Technology for the Manufacture of Pharmaceuticals

Evaluation of Spinning Disk Reactor Technology for the Manufacture of Pharmaceuticals



Evaluation of Spinning Disk Reactor Technology for the Manufacture of Pharmaceuticals


1) This article describes a set of experiments that were performed to investigate the viability of implementing a Spinning Disk Reactor (SDR) to speed the production of pharmaceutical constituents.

2) It has been suggested that the SDR offers distinct advantages over the traditional Stirred Tank method of processing technology which is quote – simply scaled-up versions of the beaker in which the process was originally devised – unquote.

3) One downside of the Stirred Tank methodology is that the surface-to-volume ratio decreases as the system is scaled up. This induces inefficiencies that are not present in the beaker-scale process these systems are designed around. The largescale vessels may inhibit the naturally fast reaction times inherent in the composition.

4) For SDR viable reactions, quote – fluid residence times…are in the range of 1-5s compared with a few hours in a stirred vessel – unquote, offering the potential for significant process time reduction.

5) The greater mixing intensity offered by the SDR also has the potential to improve reactant concentration profiles as well as yield better product particle size selectivity.

6) An SDR in its basic sense is a horizontal rotating disk. The reactants in a desired chemical reaction are poured into a small well in the center of the top side of the disk. Forces created by the spinning nature of the disk move the reactants outwards in a thin film towards the perimeter of the disk, inducing significant shear forces along the way. These shear forces are what is primarily responsible for the great mixing intensity offered by the SDR.

7) SDR architecture also allows for precise temperature control. The housing walls can be heated or cooled along with the disk. The disk has fluid channels machined in which direct heat transfer fluid from the periphery of the disk towards the center and back out the shaft.

8) This heat transfer fluid path creates a counter current flow with regard to the thin film of reactants offering highly efficient and selectable temperature environment.

9) The trial investigated 6 types of reactions: (1) phase-transfer Darzen’s process (2) crystallization study (3) Knoevenagel reaction (4) condensation process (5) elimination reaction (6) exothermic condensation.

10) Due to the short residence times of 1-5 seconds, reaction types (3)-(5) were found to be not viable using the SDR. These reaction types, quote – displayed low conversions in the range of 0 percent to 10 percent – unquote, due to their low intrinsic reaction speed.

11) Reaction type (6) was found to be non-viable due to product selectivity which was, quote – significantly lower than that in the batch process – unquote.

12) Reaction types (1) and (2) were used to further investigate the impact of disk rotational speed, disk texture, and process temperatures on overall process efficiency.

13) While attempting to test different process temperatures it was necessary to use a heat transfer fluid other than water to achieve sub zero C cooling. In this case, Therminol 59 and Dowcal 10 were tested as possible options.

14) Heat transfer fluid testing indicated that not only the fluid, but also the disk material itself (316 SS or Naval Brass) had a significant impact on the heat transfer capability of the system.

15) This article concludes that SDR technology is viable and advantageous for certain chemical reaction processes.

16) Reactions quote – with species half-lives up to 5s, can be performed much more effectively in an SDR than in a stirred vessel – unquote, with up to a 99.9% reduction in process time.

17) It was also observed that higher rotational speeds generated better mixing and shorter residence times.

18) The authors calculate that the 15cm SDR, bench-top scale, that was constructed and used for their trails had the throughput capacity to generate quote – 8 ton of product per year – unquote.

19) While not a universal fit, this trial strongly supports the further development of SDR processes in the production of pharmaceuticals and chemical in manufacturing.

Publication: Paul Oxley, Clemens Brechtelsbauer, Francois Ricard, Norman Lewis, and Colin Ramshaw,“Evaluation of Spinning Disk Reactor Technology for the Manufacture of Pharmaceuticals.” Ind. Eng. Chem. Res. 2000, 39, 2175-2182

Review by: SP

Spinning Disc Reactor – A novel processing machine for the food and chemical industry

Spinning Disc Reactor – A novel processing machine for the food and chemical industry



Spinning Disc Reactor – A novel processing machine for the food and chemical industry

1) An SDR is, quote – basically, a rotating disc, that can be heated or cooled, and is fed with one or more liquids at its center- unquote. What makes it attractive to food processing is its ability to efficiently mix materials, transfer heat, and transfer mass.

2) According to the presenter, SDR’s have the ability to, quote – very rapidly heat and cool fluids – unquote.

3) They are also able to perform pasteurization, fine crystal formation, and are easy to clean.

4) Additionally, their, quote – unique combination of shear and draw gives opportunities for structure manipulation – unquote.

5) The technology is also scalable, allows for catalyst introduction, and residence times are controllable.

6) Water was successfully removed from oil by heating the disc, cooling the walls, and allowing gas flow through the chamber.

7) The oil and water mixture had 1,000 ppm water to start and only 25 ppm water after SDR processing.

8) Leeds University tested four following food processes using the SDR: Mayonnaise production, Emulsification, Ice Cream production, and Fruit Juice pasteurization.

9) Mixing the ingredients for mayonnaise then passing them through an SDR at temperatures up to 58C produces a, quote – smooth and homogeneous mayonnaise – unquote, devoid of salmonella.

10) Further analysis indicated that the, quote – SDR mayonnaise was more consistent, smoother and softer than Hellmann’s real mayonnaise – unquote.

11) The SDR was also used to produce a water-in-oil-in-water multiple emulsion.

12) In the production of ice cream, an SDR can be used to homogenize and pasteurize the ingredient

mixture. Additionally, much of the ageing time required in standard production can be avoided.

13) As a test, E. coli K-12 was introduced to a sample of ice cream base which was then processed using an SDR at 90C. Results, quote – indicated that sufficient heat was applied to achieve a reduction in microbial loading associated with a safe product – unquote.

14) The SDR produced ice cream was then analyzed qualitatively by a panel of taste testers. In the categories of smoothness, stickiness, meltability, and coldness, the SDR ice cream performed as well or better in most areas.

15) Processing fruit juice with an SDR at 90C showed effective pasteurization.

16) SDR pasteurized fruit juice was then qualitatively judged by a panel of tasters who deemed it, quote – preferable to the commercial sample – unquote.

17) This presentation concludes that the use of an SDR as a food processer has the ability to improve the efficiency of may current processes as well as offer the ability to introduce new products.

Publication: “Spinning Disc Reactors: A novel processing machine for the food and chemical industry.” PDF. 2010.

Review by: SP