A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Enhancement of energy efficiency in stirred tank reactors by use of computational fluid dynamics
The research subject of this work is the fluid and heat flow in a stirred tank reactor with immersing internals like heating elements and baffles. On the basis of an industrial esterification process, the investigation is focused on the efficiency improvement of the reactors unit operations and the interaction between stirrer and static elements. Since flow field measurements are not possible on the industrial precedent, the investigation is approached by computational fluid dynamics (CFD) simulation. Additionally, appropriate downscale models are constructed for flow pattern measurements via particle image velocimetry and serve as an essential validation instrument for the simulation results. The analysis of the flow conditions of the industrial reactor reveals considerable dead zone formations within the reactor. Those zones included substantial parts of the heater and therefore facilitated heat accumulation and product overheating. Moreover, the phase boundary shows very insufficient movement that delays particle suspension. Those issues are approached in a simulation study by varying the stirrer configuration. As a result, an optimized modification of the stirrer is implemented in the industrial reactor and shows significant improvement on operating utility consumption, heating characteristics, product quality and process control. The production capacity is augmented by up to 12 % higher batch sizes at 6.5 % shorter runtime. In order to maximize the heat transfer and to homogenize the temperature distribution in the reactor, a novel approach to heater design development is introduced where the kinetic energy that is generated by the stirrer is maximally exploited for incident flow towards the heat exchange surface. An iterative algorithm for adaptive design of the heater is formulated and successfully applied to systems with a radial pumping impeller. The result is a heater element, that achieves the same heat transfer as conventional helical heater coils – however with substantially lower exchange area and ...
Enhancement of energy efficiency in stirred tank reactors by use of computational fluid dynamics
The research subject of this work is the fluid and heat flow in a stirred tank reactor with immersing internals like heating elements and baffles. On the basis of an industrial esterification process, the investigation is focused on the efficiency improvement of the reactors unit operations and the interaction between stirrer and static elements. Since flow field measurements are not possible on the industrial precedent, the investigation is approached by computational fluid dynamics (CFD) simulation. Additionally, appropriate downscale models are constructed for flow pattern measurements via particle image velocimetry and serve as an essential validation instrument for the simulation results. The analysis of the flow conditions of the industrial reactor reveals considerable dead zone formations within the reactor. Those zones included substantial parts of the heater and therefore facilitated heat accumulation and product overheating. Moreover, the phase boundary shows very insufficient movement that delays particle suspension. Those issues are approached in a simulation study by varying the stirrer configuration. As a result, an optimized modification of the stirrer is implemented in the industrial reactor and shows significant improvement on operating utility consumption, heating characteristics, product quality and process control. The production capacity is augmented by up to 12 % higher batch sizes at 6.5 % shorter runtime. In order to maximize the heat transfer and to homogenize the temperature distribution in the reactor, a novel approach to heater design development is introduced where the kinetic energy that is generated by the stirrer is maximally exploited for incident flow towards the heat exchange surface. An iterative algorithm for adaptive design of the heater is formulated and successfully applied to systems with a radial pumping impeller. The result is a heater element, that achieves the same heat transfer as conventional helical heater coils – however with substantially lower exchange area and ...
Enhancement of energy efficiency in stirred tank reactors by use of computational fluid dynamics
Stefan, Alexander (author) / Ulbricht, Mathias
2019-02-08
Theses
Electronic Resource
English
Stirring and Stirred‐Tank Reactors
| Wiley | 2014
| British Library Conference Proceedings | 1992