Laboratory of Chemical Reaction Engineering
Bi-Functional Catalysts for Fischer-Tropsch-Synthesis
Fischer-Tropsch (FT) synthesis is an interesting process to convert renewable ressources into fuels and chemicals, as it allows to convert CO derived from biomass and waste gasification with H2 from water electrolysis towards hydrocarbons. Even though the process is implemented on industrial scale already, it suffers from a broad product distribution, which requires elaborate processing to meet the desired product specifications. Bi-funtional catalysts, combining a FT-active with a hydroprocessing component, offer the possibility to tailor the product distribution. This project aims at devoloping such catalyst materials at the nanoscale. In particular, Co@zeolite core-shell materials are synthesized and the effect of their structural architecture on the product distribution is evaluated.
Funding: Deutsche Forschungsgemeinschaft
The catalytic conversion of CO2 to methane and other hydrocarbons is suspected to benefit substantially from irradiation with light. Current reports do not cover the relevant interplay between photon absorption, mass transport and heat management. A microchannel reactor is used to maintain a controlled temperature, even under intense irradiation, and to quantify the performances of various catalysts.
Contact: Dr.-Ing. Henning Becker
Funding: Vector Stiftung
Bio-Based Chemicals from Industrial Side Streams
The utilization of side streams from industries processing biomass, such as paper and pulp, provides an opportunity to create value by production of chemicals. The main challenge is the broad distribution of compounds with a wide variation of chemical and physical characteristics, such as function groups and solvability in various solvents. The chemical conversion process is thus characterized by several subsequent steps, including solvent solvent changes. In addition to that elaborate separation of compounds following chemical conversion has to be considered. The project aims at developing an integrated process for production of furfural from xylose by combination of modeling and simulation with experimental investigations.
Contact: Dr.-Ing. Farzad Lali
Collaborators: Prof. Dr. Heike Frühwirth
Dynamic Behavior of Methanation Reactors
The operation of chemical reactors under unsteady-state conditions is getting more and more important, due to the implementation of renewable ressources into the chemical value chain. This induces dynamics at different length scales inside of the reactor, such as at the active surface, inside the catalyst pellet and at reactor scale, which are coupled with each other. The interplay of the respective kinetic processes determine the dynamic reactor response upon transient changes of inlet and operations conditions, which is challenging to be predicted for realistic reactions. This project aims at decoupling the dynamics of the involved kinetic processes by experimental methods for methanation of CO/CO2-mixtures as an example.
Contact: Dominik Meyer
Collaborators: Prof. Dr.-Ing. Thomas Turek
Dynamic Behavior of a Catalyst Pellet for Methanation
The need for dynamic operation of the methanation reactor in power-to-gas applications leads to a transient character of heat and mass transfer superimposed to chemical reaction. While the developing temperature and concentrations profiles can be measured on reactor scale, modeling and simulation is required to understand the system at the scale of a catalyst pellet. For methanation, however, the volume contraction associated with the extent of reaction and the counterdiffusion require suitable transport models to adequately describe the transient profiles.
Collaborators: Prof. Dr.-Ing. Thomas Turek
Iron-Based Core-Shell Model Catalysts for Methanation
Iron-based materials are environmently benign catalysts for syngas conversion into methane, which offer tolerance towards the feed gas mixture, due to their activity in both the CO/CO2 hydrogenation as well as the water-gas-shift reaction. Thus, catalysts based on abundantly available iron are highly interesting for utilizing industrial exhaust gases, consisting of mixtures of CO and CO2 in many cases associated with dynamic availability, for methanation. One of the major challenges for implementation of those materials are the complex transformations the iron-species undergo during reaction. Therefore, nanostructured Fe@SiO2 model catalysts uniquely offer to study those transformations and to develop a relation between material structure and catalytic perfomance, which is the basis for rational catalyst design.
Collaborators: Prof. Dr. Sven Kureti
Continuous Oxidation of Organics in a Gas-Liquid-Reactor
Gas-liquid reactions, such as hydrogenations or oxygenations of organic compounds, are a very important class of reactions in the chemical value chain. One of the major challenges is the mass transfer between gas and liquid phase in order to maximize the space-time-yield for the desired product. For continuous production in microstructured equipment segmented flow is preferable in many cases, as it achieves high mass transfer rates at moderate energy input. The project aims at continuous selective oxidation of an organic model compound with molecular polyoxometallate catalysts, with emphasis on derivation of the reaction kinetics and minimization of mass transfer issues ar the same time.
Contact: Dr.-Ing. Jens Friedland
Collaborators: Prof. Dr. Carsten Streb