Work package 2.2 - Ceramic functional structures for tailored chemical reactors
Principal investigators: Prof. Dr.-Ing. habil. R. Lange (TUD), Dr. rer. nat. U. Petasch (IKTS)
PhD students: Dipl.-Ing. Franziska Mayer (TUD), Dipl.-Ing. Christine Meitzner (TUD), MSc. Dawit T. Semu (TUD, IKTS)
Main scientific Goals:
Work package 2.2 deals with the development and test of new catalytic structures for the hydrogenation of nitrobenzene to aniline.
TU Dresden, Chair of Chemical Reaction Engineering and Environmental Technology (CVT) and Chair of Inorganic Non-Metallic Materials (IfWW), and Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) are working on this work package to create an energy saving concept by using structured catalysts for large-scale processes like aniline production.
The work package at the IfWW of TU Dresden and Fraunhofer IKTS aims on developing structure and property optimized catalysts using ceramic foam substrates (Figure 1) for heterogeneous multiphase chemical reactions.
|Figure 1a: Cordierite and SiC foam structures (Fraunhofer IKTS).
|Figure 1b: SiSiC ceramic foam of ppi 20.
Ceramic foams have a significant potential to be applied as structured catalyst substrate for multiphase chemical reactions since they enable turbulent flow and radial mixing which enhance mass and heat transfer.
The work focuses particularly on improvement of the heat and mass transport properties of the catalyst system by optimizing ceramic substrates in both structure functionalization and improvement of the catalyst wash-coat stability. SiSiC ceramic foams are particularly of interest due to their high thermal conductivity and good mechanical stability. So far, homogeneous and more adherent catalyst layers on ceramic SiSiC foams were developed using various approaches such as inorganic binders, surface pretreatment of substrates and the application of improved coating technology. SiSiC foams with various porosities were already functionalized using a Pd/γ-Al2O3 catalyst wash-coat system (Figure 2).
Figure 2: Image of catalyst coated SiSiC foams.
The microstructure and coating thickness of the catalyst layers were investigated using SEM (Figure 3).
|Figure 3: SEM image of Pd/γ-Al2O3 layer thickness.
Pressure drop measurements on the foams were additionally performed at lab scale to investigate the effect of catalytic coating (Figure 4).
|Figure 4: Pressure drop behavior of coated and uncoated SiSiC foams.
The catalytic activities of the prepared catalyst systems are already tested and demonstrated using heterogeneous gas phase reaction of CO and propane oxidation. Further optimization and application of the structured catalysts in heterogeneous multiphase chemical reactions will be done in cooperation with CVT (TUD) and FAU (Erlangen).
The Chair of Chemical Reaction Engineering and Process Plants at TU Dresden has a long time expertise in the field of process intensification by using structured catalysts. In work package 2.2 this experience is used to characterize the catalysts produced by Fraunhofer IKTS. This work included pretests and reaction tests.
Before using the catalyst structures in the reaction several tests are realized to guarantee an optimized chemical and flow stability. At the same time a differential loop reactor system is built to investigate catalysts structures under real reaction conditions.
Furthermore several studies are performed to fill in the gaps of benchmark data for other work packages. One of these studies deals with hydrogen absorption in various reaction mixtures of aniline/nitrobenzene, which will be provided in WP 4.1 for process simulations. Additionally, chemical sensor tests are performed for the developed phase and temperature detection sensors in WP 5.1 (Figure 5).
|Figure 5: Chemical stability tests of miniaturized phase and temperature detection sensors.
WP 2.3 – FAU (Erlangen)
WP 2.4 – KIT (Karlsruhe)
WP 3.3 – TUHH (Hamburg)
WP 4.1 – FAU (Erlangen)
WP 4.2 – KIT (Karlsruhe)
WP 5.1 – TUD (Dresden)
WP 5.3 – HZDR (Dresden)
Ch. Meitzner, F. Mayer, T. Kwast, R. Lange, 2014. Hydrogen Solubility in the Large-Scale Hydrogenation Process of Nitrobenzene to Aniline. AIChE Annual meeting 2014. 16. – 21.11.2014. Atlanta, GA, USA.