FLOW CHEMISTRY
Figure 3- Examples of hydrogenation reactions run in the TWR
optimising catalyst bed structure for enhanced mass transfer and activity. This improves catalyst utilisation and process robustness.
The design also accommodates a wide range of catalyst forms, including particulate catalysts, broadening its applicability across multiple reaction types.
Perhaps the most significant advantage for industry is the reactor’ s straightforward scalability. Traditionally, scaling from lab to commercial scale involves moving from packed beds with fine powders to trickle beds with pellets, which alters catalyst performance and requires extensive re-optimisation and validation, which are both costly and time-consuming.
In contrast, the TWR allows direct linear scale-up by maintaining the same reactor stack configuration and reaction conditions developed at the lab scale. Scaling is achieved by increasing the reactor’ s crosssectional area; for example, a tenfold increase in area( and catalyst mass) enables a tenfold increase in throughput. Fluid velocity, residence time, flow regime and pressure drop remain consistent across scales, eliminating the need for process reoptimisation. This helps to facilitate rapid, low-risk transition from lab to manufacturing scale.
Chemistry & scalability
The performance of the TWR has been validated across a range of hydrogenation reactions, including nitro and alkene reductions, and debenzylations( Figure 3). All consistently achieved high yields with residence times of < 1 minute through the catalyst bed, without requiring elevated temperatures or pressures.
This demonstrates the reactor’ s ability to drive rapid, selective hydrogenations under mild operating conditions. In addition, the TWR can be used in other heterogeneously catalysed gas-liquid-solid reactions,
including oxidations using oxygen or ozone, sulfonations and fluorinations.
To validate scalability, the nitrobenzene reduction to aniline was conducted at both lab and pilot scales. The pilot reactor featured a ten times larger area( catalyst mass) so it was operated at ten times higher flow rates.
Due to the TWR’ s internal geometry and design, this leads to the same bed characteristic as the lab scale reactor. Therefore, by maintaining process conditions and everything else constant, what is achievable at a certain flow rate at the lab scale can also be achieved at ten times the flow rate in the pilot scale( Figure 4).
This direct scalability is a hallmark of this technology, offering a predictable and low-risk pathway from development to commercial manufacturing. By eliminating the need for costly re-optimisation during scale-up, it significantly accelerates time-to-market.
Zaiput is currently developing scaled versions of the TWR capable of handling liquid flow rates of 1 and 10 L / min, supporting a broad range of process development and commercial production needs. ●
J j
Andrea Adamo
CEO
ZAIPUT aadamo @ zaiput. com www. zaiput. com
Figure 4- Comparison of lab- & pilot-scale performance
52 SPECIALITY CHEMICALS MAGAZINE ESTABLISHED 1981