Reaction Calorimetry for Exothermic Reactions in Plate‐Type Microreactors Using Seebeck Elements

Abstract

Dedicated to Professor Rüdiger Lange on the occasion of his 65th birthdayA flexible reactor and measurement setup to safely obtain thermokinetic data for exothermic chemical reactions in plate-type microreactors is presented. Precise heat flux measurement is realized by means of Seebeck elements and allows for direct as well as space-and time-resolved heat flux determination across the reactor. The microreactor used in this work is manufactured from poly(vinylidene fluoride) foils and consists of 11 SZ-shaped mixing channel elements. The Seebeck elements are calibrated by the Joule effect, while its performance is demonstrated in heat transfer and neutralization reaction experiments. Furthermore, the local resolution enables an estimation of mixing time scale for rapid reactions. A comparison of obtained results indicates good accordance with literature data and is the base of further investigations using the calorimeter.

Smart Equipment – A Perspective Paper

“…Our group developed a setup which allows for thermokinetic measurement and simultaneous optical observation of processes within the microreactor, such as particle or bubble formation or color change of the reaction systems . The Seebeck element‐based calorimeter concept includes a sealing block, a temperature‐controlled base plate, and heat flux sensors in the form of Seebeck elements.…”

“…a) Reaction calorimeter setup developed by Fraunhofer‐ICT , b) reaction calorimeter setup developed by the Laboratory of Equipment Design .…”

“…This isoperibolic concept has been used to record space‐ and time‐resolved heat flux profiles of highly exothermic reactions (Fig. ), such as neutralization and the oxidation of sodium thiosulfate using hydrogen peroxide . Mixing time scales can be derived from recorded heat flux profiles for rapid reactions .…”

Equipment and Separation Units for Flow Chemistry Applications and Process Development

“…A reaction calorimeter for plate reactors was designed, which uses an array of Seebeck elements as heat flow sensors on the underside of the reactor , (see Fig. ).…”

Mixing Time Scale Determination in Microchannels Using Reaction Calorimetry

“…A locally resolved heat flux profile is recorded for the microreactor in steady state and the peak position gives the location of main reaction progress. The reaction calorimeter and its measurement technique have been introduced in previous works , . The calibration of heat flux sensors has been shown and reaction enthalpies were determined for acid‐base reactions.…”