Dynamic Optimization of an Evaporator by a Nonlinear Model Predictive Controller for Operation at Modular Micro Rectification

Knauss, Ralf; Wiesegger, Lukas; Marr, Rolf; Brandner, Juergen J.

doi:10.1115/icnmm2009-82100

“…With these devices, not only straight rectangular micro channels but also semielliptic micro channels in convoluted or sinusoidal arrangements have been tested for evaporation. It could be shown that, depending on the applied mass flow, either a single microstructure device or a two-stagearrangement, which means two devices in a row, can be used for complete evaporation and superheating of water and other liquids [9]. Substantial data on the droplet content contained in the vapour flow could be obtained by a simple photometer setup.…”

Section: Metallic Multi-micro Channel Devicesmentioning

confidence: 99%

Microstructure devices for water evaporation

Anurjew¹,

Hansjosten²,

Maikowske³

et al. 2011

Applied Thermal Engineering

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Evaporation of liquids is of major interest for many topics in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of superheated steam is mandatory for numerous processes. Generally, this is performed by use of classical pool boiling and evaporation process equipment, providing relatively limited performance, or by other systems like fallingfilm evaporators. Due to the advantages of microstructure devices especially in chemical process engineering the interest in microstructure evaporators and steam generators have been increased through the last decade. In this publication different microstructure devices used for evaporation and generation of steam will be described. Starting with simple liquid-heated devices, different types of electrically powered devices containing micro channels as well as non-channel microstructures will be shown. While evaporation of liquids in crossflow and counterflow or co-current flow micro channel devices is possible, it is, in many cases, not possible to obtain superheated steam due to certain boundary conditions. Thus, a new design was proposed to obtain complete evaporation and superheating of the generated steam.

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“…It could be shown that, depending on the applied mass flow, either a single microstructure device or a two-stage-arrangement, which means two devices in a row, can be used for complete evaporation and superheating of water and other liquids [14,15]. Substantial data on the droplet content contained in the vapour flow could be obtained by a simple photometer setup, which gives at least a qualitative result on the steam quality.…”

Section: Metallic Multi Micro Channel Devicesmentioning

confidence: 99%

A New Microstructure Device for Efficient Evaporation of Liquids

Brandner

¹

,

Maikowske

²

,

Vittoriosi

³

2012

JTST

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Evaporation of liquids is of major interest for many topics in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of superheated steam is mandatory for numerous processes. Generally, this is performed by use of classical pool boiling and evaporation process equipment. Another possibility is creating mixtures of gases and liquids, combined with a heating of this haze. Both methods provide relatively limited performance. Due to the advantages of microstructure devices especially in chemical process engineering [1] the interest in microstructure evaporators and steam generators have been increased through the last decade. In this publication several microstructure devices used for evaporation and generation of steam as well as superheating will be described. Here, normally electrically powered devices containing micro channels as well as non-channel microstructures are used due to better controllability of the temperature level. Micro channel heat exchangers have been designed, manufactured and tested at the Institute for Micro Process Engineering of the Karlsruhe Institute of Technology for more than 15 years. Starting with the famous Karlsruhe Cube, a cross-flow micro channel heat exchanger of various dimensions, not only conventional heat transfer between liquids or gases have been theoretically and experimentally examined but also phase transition from liquids to gases (evaporation) and condensation of liquids. However, the results obtained with sealed microstructure devices have often been unsatisfying. Thus, to learn more onto the evaporation process itself, an electrically powered device for optical inspection of the microstructures and the processes inside has been designed and manufactured [2]. This was further optimized and improved for better controllability and reliable experiments [3]. Exchangeable metallic micro channel array foils as well as an optical inspection of the evaporation process by high-speed videography have been integrated into the experimental setup. Fundamental research onto the influences of the geometry and dimensions of the integrated micro channels, the inlet flow distribution system geometry as well as the surface quality and surface coatings of the micro channels have been performed. While evaporation of liquids in crossflow and counterflow or co-current flow micro channel devices is possible, it is, in many cases, not possible to obtain superheated steam due to certain boundary conditions [4]. In most cases, the residence time is not sufficiently long, or the evaporation process itself cannot be stabilized and controlled precisely enough. Thus, a new design was proposed to obtain complete evaporation and steam superheating. This microstructure evaporator consists of a concentric arrangement of semi-circular walls or semi-elliptic walls providing at least two nozzles to release the generated steam.*Received 15 Dec., 2011 (No. 11-0773) [DOI: 10.1299 Copyright © 2012 by JSME Vol. 7, No. 3, 2012 Journal of Ther...

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Microstructure Devices for Water Evaporation

Brandner

¹

,

Anurjew

²

,

Hansjosten

³

et al. 2010

ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels: Parts a and B

5

0

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Evaporation of liquids is of major interest for many topics in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of superheated steam is mandatory for numerous processes. Generally, this is performed by use of classical pool boiling and evaporation process equipment, providing relatively limited performance, or by other systems like fallingfilm evaporators. Due to the advantages of microstructure devices especially in chemical process engineering the interest in microstructure evaporators and steam generators have been increased through the last decade. In this publication different microstructure devices used for evaporation and generation of steam will be described. Starting with simple liquid-heated devices, different types of electrically powered devices containing micro channels as well as non-channel microstructures will be shown. While evaporation of liquids in crossflow and counterflow or co-current flow micro channel devices is possible, it is, in many cases, not possible to obtain superheated steam due to certain boundary conditions. Thus, a new design was proposed to obtain complete evaporation and superheating of the generated steam.

show abstract

Dynamic Optimization of an Evaporator by a Nonlinear Model Predictive Controller for Operation at Modular Micro Rectification

Cited by 3 publications

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Microstructure devices for water evaporation

Microstructure devices for water evaporation

A New Microstructure Device for Efficient Evaporation of Liquids

Microstructure Devices for Water Evaporation

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