Industrial microreactor process scale

Microreactor Laboratory-scale Process Developments for Future Industrial Use... 

Microreactor Laboratory-scale Process Developmentsfor Future Industrial Use I 111... 

With MRT the synthesis of increased amounts of a compound is reduced to a simple question of the rate of throughput. Once a synthesis has been optimized in a microreactor, small-scale production will be only a matter of numbering up the microreactor systems or a problem of scaling out the microreactor [22]. Not surprisingly, chemists in process development departments, particularly in the pharmaceutical industry, recognized MRT as a versatile tool for their daily work as it enabled fast and low-cost kilogram-scale synthesis, e.g. for early clinical studies, in an... 

In this chapter, the microstructured devices are introduced underlying their potential benefits for the process industries. The reduced scale facilitates the temperature control giving an opportunity to maintain the temperature within any window required. Enhanced (heat/mass) transfer rates allow control of highly exothermic and hazardous reactions. It also increases production rates and thus reduces the total processing volume. In addition, microreactors can be simply numbered up for large-scale production, avoiding the problem of scale-up of conventional reactors. 

Currently, after each step in the synthesis process, a sample is analyzed to approve or reject the operation. Not only is this inefficient for the industry in general, this is also a stumbling block for a rapid scale-up. Controls and measurements of the process need to be accomplished in situ, which is again an issue that requires the chemists and chemical engineers to work together toward a solution. It may, in fact, involve lab-on-a-chip technologies and microreactors that were presented by other speakers in this workshop. 

Miniaturized near-infrared sensors were developed and implemented for online analysis and automated process control to also meet the safety requirements for handling of ozone and halogenating agents [49,50]. A target is to reduce the time from process idea to production (time-to-market) as well as development costs and costs for installation of the production unit. As pharmaceutical industry relies on the manufacture of many different products on smaller scale, and intermediates in quantities ranging from some kilograms to tons per year a modular approach toward a multipurpose microreactor plant is demanded. 

Based on these kinetic and microscopic observations, olefin polymerization by supported catalysts can be described by a shell by shell fragmentation, which progresses concentrically from the outside to the centre of the support particles, each of which can thus be considered as a discrete microreactor. A comprehensive mathematical model for this complex polymerization process, which includes rate constants for all relevant activation, propagation, transfer and termination steps, serves as the basis for an adequate control of large-scale industrial polymerizations with Si02-supported metallocene catalysts [A. Alex-iadis, C. Andes, D. Ferrari, F. Korber, K. Hauschild, M. Bochmann, G. Fink, Macromol. Mater. Eng. 2004, 289, 457]. 

Most industrial processes using the interaction of fluids to obtain chemical changes can be classified into one, or sometimes more of the preceding five liquid reactor types. Variations on these themes are used for gas-gas, gas-liquid, or gas-solid reactions, but these variations parallel many of the processing ideas used for liquid-liquid reactors [20]. A new continuous, spinning disk reactor concept has recently attracted interest for some intrinsically fast organic reactions and for possible application in crystallizations [21]. Modular microreactors have also become of interest to fine chemicals producers and pharmaceutical companies for their faster reactions, ease of scale-up, and low cost [22]. 

In Chapter 9, we mentioned that the use of microreactors leads to a significant improvement in the control of the molecular-weight distribution in free radical polymerization by virtue of superior heat-transfer efficiency.Free-radical polymerization reactions are usually highly exothermic, so precise temperature control is essential to carry out these reactions in a highly controlled manner. Thus, from an industrial viewpoint, a major concern with free-radical polymerization is the controllability of the reaction temperature. Temperature control often arises as a serious problem during the scale-up of a bench process to industrial production. In this section, we will discuss the numbering-up of microreactors to increase production volumes in radical polymerization in industry. 

---