Marcel Kai Loewert
Karlsruhe Institute of Technology, Germany
Title: Determining the limits of intensified, decentralized and dynamic fischer-tropsch synthesis
Biography
Biography: Marcel Kai Loewert
Abstract
The Fischer-Tropsch (FT) reaction is usually operated stationary to convert syngas from fossil carbon sources to produce high-grade synthetic fuels. Nowadays, huge efforts are made to close the anthropogenic carbon cycle based on renewable resources. In the context of Power-to-X, an excess of renewable electrical energy could be used to transform water and CO2 into syngas, which is the essential feedstock to the Fischer-Tropsch reaction. The problem of renewable electricity is its decentralized and fluctuating nature which is often misaligned with the actual demand. To avoid large, expensive storage tanks for hydrogen, dynamic operation of the synthesis step is considered for effective storage processes. A large internal surface area strongly improves heat and mass transfer within microstructured reactors developed at IMVT. Due to their compactness compared to industrial reactors, they operate in much smaller applications, while showing a distinctly higher overall process performance. Consequently to the lower holdup, changes in process parameters such gas velocity, concentration or temperature can occur faster. Additionally, innovative evaporation cooling could help change reactor temperatures in shorter time. In this study, highly dynamic changes in temperature and gas composition were applied. The laboratory scale reactor system has the capability to produce up to 7 L of product per day. To determine the limits of this system, periodic changes of different time scales were applied and finally lead to a real-time scenario for highly fluctuating gas concentrations discretized from a solar panel energy output profile to be translated into a simulated, standalone electrolysis unit. Additionally, synchrotron experiments were conducted to analyze the catalyst state during and after drastic parameter changes to measure e.g. the degree of catalyst oxidation during potential deactivation. These experiments were conducted using a special measurement cell compatible with the liquid products that form during reaction and rapid process changes.