(115a) A New Generation of Efficiency - Novel Milli and Micro Structured Heat Exchangers and Reactors

Microreactors open new pathways for the development of economical, innovative and intensified processes. Ehrfeld Mikrotechnik BTS GmbH has focused on a modular (or toolbox) approach to Microtechnology. The individual modules ? which may be micro-mixers, micro-heat-exchangers, microreactors, sensors, actuators can be assembled in minutes for a unique chemical-plant. Moreover, each of the modules can be completely disassembled, cleaned and even modified to suit a certain application. This modular approach has translated to unprecedented flexibility for its users, quicker customization, expeditious scale-up of processes and fast time-to-market. With the Ehrfeld modular microreactor system one can develop processes in the lab and easily and quickly scale-up to pilot and production scale.

However, for time and cost efficient scale-up and for production-scale applications modular micro and milli structured devices are needed. We will present the newly designed exchangers and reactors with Miprowa® channels, which can considerably reduce problems met with common heat exchangers, such as product deterioration, product deposits on the exchange surfaces and bad heat transport. Furthermore, they can also increase the productivity and economy of a plant.

Miprowa® channels are rectangular in shape with inserts which are free-edged, and easily removable. The inserts boost (pseudo) turbulence and heat transfer. The inserts are two or three layered, placed on top of each other and put in position form a spatial grid over the whole of the channel length through which the fluid can flow. Such inserted grids decrease the specific product volume with an approximately unchanged heat transfer area and affect a forced cross-flow with good mixing over the whole of the flow cross-sectional area. A fluid that flows through the grid is intensively mixed; the product is kept moving at the tempered wall without interruption so that temperature peaks can be rapidly compensated and both contact and residence times at the tempering surface can be reduced.

Miprowa® channels offer a number of advantageous features in heat exchangers, in evaporators and as tubular reactors. For example: ? High heat exchange performance even with laminar flow, ? Large specific area/volume ratio, ? Intensive cross-flow in the product-guiding channel, ? Flow subject to little back-mixing, ? Rapid temperature equalization and so short residence time, ? Various grid structures for process-optimized heat exchangers, evaporators or continually operated coaxial reactors, ? Removable free-edged grids allow quick and effective cleaning, and ? Compact device construction.

The features of the heat exchangers offer users definite process advantages. They can not only be used for standard applications but also for difficult temperature-controlling tasks in the chemical and food-processing industries. The benefits of these channels are in particular apparent when; ? rapid heating or cooling is needed, even at low flow rates, ? a temperature sensitive fluid must be gently tempered, ? a highly viscous fluid is forced to flow laminarly, ? a two-phase or multi-substance system is to be intensively mixed during heating, or ? a continuous coaxial reactor is used for endothermic or exothermic reactions.

The presentation will show the latest development of this technology and applications.