Scale-up

Coflore reactors are significantly simpler and quicker to scale up than conventional batch reactors and most types of flow reactor.

Coflore reactors maintain good mixing and plug flow in large diameter tubes at very low velocities through the reactor, due to the use of multiple stages and dynamic mixing. This contributes to compact size, low pressure drop and low build/operating cost. Other than heat transfer capacity, the performance characteristics of Coflore reactors remain substantially unchanged with scale up. This greatly simplifies scale up calculations and saves development time. With the right data, the Coflore reactor can be scaled up quickly and with a high certainty of success:

To scale up a Coflore reactor, the reaction characteristics (yield/time and heat/time) need to be determined using a small stirred vessel (ideally less than 100 millilitres). This data is converted to yield/volume and heat/volume for the required throughput (reactor volume = design flow x time). This information is used to size the individual reaction stages and overall reactor capacity.

The aim when scaling up is to break the reaction up into substantially equal conversion stages.

Zero order reaction – Reaction stages are equal sized

N^th order reaction – Reaction stages are smaller where the reaction rate is faster

N^th order reaction with high initial rate – A micro reactor is used to handle 50% of the reaction but only represents 3% of the reactor volume in this example. In some applications it will not be possible to use a micro reactor for reasons of mass transfer, blockage and mixing. In these cases, the need for a microreactor can be eliminated by increasing the throughput which effectively reduces the slope of the yield volume curve.

Heat load – the final stage of the scale up process is to evaluate the heat load on the first Coflore stage. A heat balance is carried out in the first stage to determine temperature rise. Where the rise exceeds acceptable limits, a smaller reaction tube can be used for this phase. Alternatively, in the above example, the size of the micro reactor can be increased.

This procedure also applies to the design process when transferring a reaction from batch to continuous at the lab scale.